Dissertations / Theses: 'Transcatheter aortic valve implantation (TAVI)'

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Leung, Wing-ki Vikki, and 梁頴琪. "The implications of transcatheter aortic valve implantation (TAVI) adoption." Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 2012. http://hub.hku.hk/bib/B48424031.

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Aortic stenosis is a life-threatening valvular heart disease. At the onset of symptoms, a patient’s prognosis becomes poor and the risk of death rapidly increases. Aortic valve replacement surgery remains the gold standard in treatment for aortic stenosis. However, in the total population of patients with severe aortic stenosis, about one third are deemed inoperable due to their high surgical risk. In recent years, the development of transcatheter aortic valve implantation (TAVI), a non-invasive heart valve replacement procedure brought hope for the elderly, high-risk and inoperable aortic stenosis patient population pool. A literature review was performed to examine the safety, efficacy and effectiveness evidence for transcatheter aortic valve treatment option. The results showed that TAVI is a safe treatment option, however the effectiveness for the whole patient population is unknown. The adoption of this alternative treatment option is certainly coupled with multiple dimension of impact from a public health perspective. It remains inconclusive whether TAVI is an effective treatment option to be adopted.
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Public Health
Master
Master of Public Health

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Kemp, Iain Henry. "Development,testing and fluid interaction simulation of a bioprosthetic valve for transcatheter aortic valve implantation." Thesis, Stellenbosch : Stellenbosch University, 2012. http://hdl.handle.net/10019.1/71710.

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Thesis (MScEng)--Stellenbosch University, 2012.
ENGLISH ABSTRACT: Bioprosthetic heart valves (BHVs) for transcatheter aortic valve implantation (TAVI) have been rapidly developing over the last decade since the first valve replacement using the TAVI technique. TAVI is a minimally invasive valve replacement procedure offering lifesaving treatment to patients who are denied open heart surgery. The biomedical engineering research group at Stellenbosch University designed a 19 mm balloon expandable BHV for TAVI in 2007/8 for testing in animal trials. In the current study the valve was enlarged to 23 mm and 26 mm diameters. A finite element analysis was performed to aid in the design of the stents. New stencils were designed and manufactured for the leaflets using Thubrikar‟s equations as a guide. The 23 mm valve was manufactured and successfully implanted into two sheep. Fluid structure interaction (FSI) simulations constitute a large portion of this thesis and are being recognized as an important tool in the design of BHVs. Furthermore, they provide insight into the interaction of the blood with the valve, the leaflet dynamics and valve hemodynamic performance. The complex material properties, pulsating flow, large deformations and coupling of the fluid and the physical structure make this one of the most complicated and difficult research areas within the body. The FSI simulations, of the current valve design, were performed using a commercial programme called MSC.Dytran. A validation study was performed using data collected from a cardiac pulse duplicator. The FSI model was validated using leaflet dynamics visualisation and transvalvular pressure gradient comparison. Further comparison studies were performed to determine the material model to be used and the effect of leaflet free edge length and valve diameter on valve performance. The results from the validation study correlated well, considering the limitations that were experienced. However, further research is required to achieve a thorough validation. The comparative studies indicated that the linear isotropic material model was the most stable material model which could be used to simulate the leaflet behaviour. The free edge length of the leaflet affects the leaflet dynamics but does not greatly hinder its performance. The hemodynamic performance of the valve improves with an increase in diameter and the leaflet dynamics perform well considering the increased surface area and length. Many limitations in the software prevented more accurate material models and flow initiation to be implemented. These limitations significantly restricted the research and confidence in the results. Further investigation regarding the implementation of FSI simulations of a heart valve using the commercial software is recommended.
AFRIKAANSE OPSOMMING: Bio-prostetiese hartkleppe (Bioprosthetic Heart Valves - BHVs) wat gebruik word vir transkateter aortaklep-inplantings (Transcatheter Aortic Valve Implantation - TAVI) het geweldig vinnige ontwikkeling getoon in die afgelope tien jaar sedert die eerste klepvervanging wat van die TAVI prosedure gebruik gemaak het. TAVI is ŉ minimaal indringende klepvervangingsprosedure wat lewensreddende behandeling bied aan pasiënte wat ope-hart sjirurgie geweier word. Die Biomediese Ingenieurswese Navorsingsgroep (BERG) by Stellenbosch Universiteit het in 2007/8 ŉ 19 mm ballon-uitsetbare BHV vir TAVI ontwerp vir eksperimente met diere, en hierdie tesis volg op die vorige projekte. In die huidige studie is die klep vergroot na 23 mm en 26 mm in deursnee. ŉ Eindige element analise is gedoen om by te dra tot die ontwerp van die rekspalke vir die klep. Nuwe stensils is ontwerp en vervaardig vir die klepsuile, deur gebruik te maak van Thubrikar se vergelykings. Die 23 mm klep is vervaardig en suksesvol in twee skape ingeplant. Vloeistruktuur interaksie (Fluid Structure Interaction (FSI)) simulasies vorm ‟n groot deel van die tesis en word gesien as ŉ noodsaaklike hulpmiddel in die ontwerp van BHVs. Die simulasies verskaf ook insig in die interaksie van die bloed met die klep, die klepsuil-dinamika en die klep se hemodinamiese werkverrigting. Die komplekse materiaal eienskappe, polsende vloei, grootskaalse vervorming, die verbinding van die vloeistof en die fisiese struktuur maak van hierdie een van die mees gekompliseerde voorwerpe om te simuleer. Die FSI simulasies van die huidige ontwerp, is uitgevoer deur van kommersiële sagteware, MSC.Dytran, gebruik te maak. ŉ Geldigheidstudie wat data gebruik het vanaf die hartklop-nabootser, is uitgevoer. Die FSI model word geverifieer deur klepsuil dinamika visualisering en ŉ vergelyking van die drukgradiënt gebruik te maak. Verdere vergelykende studies is uitgevoer om te bepaal watter materiaal model om te gebruik, asook die uitwerking van die klepsuil-vrye rand en klepdeursnee op die klep se werkverrigting. Die resultate van die studie korreleer goed, in ag genome die beperkings wat ervaar is. Verdere navorsing is egter nodig vir ŉ volledige geldigheidstudie. Vergelykende studies het getoon dat die liniêre isotropiese materiaalmodel die meer stabiele materiaalmodel is wat kan gebruik word om klepsuilgedrag te simuleer. Die vrye-rand lengte van die klepsuil affekteer die dinamika van die klepsuil, maar belemmer nie die werkverrigting grootliks nie. Die hemodinamiese werkverrigting van die klep verbeter met die toename in deursnee en die klepsuil-dinamika vertoon goed in ag genome die verhoogde oppervlak area en lengte. Die vele beperkings in die sagteware het die implementering van meer akkurate materiaalmodelle verhoed. Hierdie beperkings het ŉ verminderde vertroue in die resultate tot gevolg gehad. Verdere ondersoek rakende die implementering van die FSI simulasies van ŉ hartklep deur kommersieel beskikbare sagteware te gebruik, word aanbevel.

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Shirzadi, Mohammad Mehdi. "Development of a patient-specific finite element model of the transcatheter aortic valve implantation (TAVI) procedure." Master's thesis, University of Cape Town, 2016. http://hdl.handle.net/11427/22893.

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Transcatheter Aortic Valve Implantation (TAVI) is a procedure developed for replacing the defective aortic valve of a patient as an alternative to open heart Surgical Aortic Valve Replacement (SAVR). In the TAVI procedure a prosthetic valve, which is assembled on to a stent, is crimped and delivered to the patient's aortic root site through several available percutaneous means. The percutaneous nature of TAVI, which is its core advantage in comparison to other SAVR procedures, can however also be its main disadvantage. This is due to lack of direct access to the calcified leaflets, and hence reliance on the host tissue for the proper positioning and anchorage of the deployed prosthetic valve. Therefore, it is desired to have a preoperative quantitative understanding of patient-specific biomechanical interaction of the stent and the native valve to be able to maximise the chance of success of the procedure. The aim of this study was to develop a patient-specific Finite Element (FE) model of the Transcatheter Aortic Valve Implantation (TAVI) procedure for two patients, using a model of the 23 mm percutaneous prosthetic aortic valve developed by Strait Access Technologies (SAT), for the purpose of its post-operative performance. In this regard, the image processing software ScanIP was used to extract the 3D models of the patient-specific aortic roots and leaflets from the provided Multi-Slice Computer Tomography (MSCT) images of the patients. An anisotropic hyperelastic material model was implemented for the roots and leaflets, using two and one families of collagen fibres for their tissues respectively. The stent is made of a cobalt-chromium alloy and its mechanical response was modelled as an isotropic elastoplastic material, with a linear elastic initial response, followed by plastic behaviour with isotropic hardening. The prosthetic leaflets are made of polymer and were modelled as an isotropic hyperelastic material, using the provided experimental test data. The results for the first patient showed that the stent maintained its structural integrity after deployment, and successfully pushed the native leaflets back to keep the aortic root clear of all impediments. No obstruction of the coronary ostia was observed, and prosthetic leaflets were seen to function normally. The stent radial recoil was calculated to be between 2 to 4.28 % after deployments. Its foreshortening was calculated to be approximately 20%. The stent was observed to move back and forth by approximately 3 mm in the last simulation step in which cardiac cycle pressure were applied to the aortic root and prosthetic leaflets. Also, two openings were observed between the stent and aortic root wall during this simulation step, which indicates the possibility of paravalvular leakage. From the second patient simulation, it was observed that the 23 mm stent was not a good choice for this patient, and will cause severe damage or tissue tearing. The maximum principal stress in the aortic root and valve tissues were observed to follow approximately the defined collagen fibre directions.

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Schneider, Stephan [Verfasser], and Christian [Akademischer Betreuer] Thilo. "Transcatheter Aortic Valve Implantation (TAVI) - Durchführung des minimalistischen Ansatzes ("The minimalist approach") / Stephan Schneider ; Betreuer: Christian Thilo." München : Universitätsbibliothek der Ludwig-Maximilians-Universität, 2021. http://d-nb.info/1229350306/34.

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Abdulghafor, Marwan [Verfasser], and Daniel [Akademischer Betreuer] Wendt. "Long- term clinical outcomes after Transcatheter Aortic Valve Implantation (TAVI) in Patients with chronic renal failure / Marwan Abdulghafor ; Betreuer: Daniel Wendt." Duisburg, 2019. http://d-nb.info/1191691896/34.

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Hartmann, Lisa [Verfasser]. "Evaluation der Aortenklappe in der CT und Korrelation mit paravalvulären Insuffizienzen in Patienten nach Transcatheter Aortic Valve Implantation (TAVI) / Lisa Hartmann." Berlin : Medizinische Fakultät Charité - Universitätsmedizin Berlin, 2015. http://d-nb.info/1076038743/34.

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Grünwald, Felix. "Einfluss des Crimping auf Haltbarkeit und Gewebeintegrität bei kathetertechnischen Aortenklappenprothesen: eine experimentelle Analyse." Doctoral thesis, Universitätsbibliothek Leipzig, 2015. http://nbn-resolving.de/urn:nbn:de:bsz:15-qucosa-175443.

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Eine Verengung der Aortenklappe, die während der Systole zu einem Druckunterschied zwischen dem linkem Auswurftrakt und der Aorta führt, wird als Aortenstenose bezeichnet. Sie stellt nach der KHK die häufigste Indikation für eine herzchirurgische Intervention dar. Die Entstehung der Aortenstenose ist bisher nicht völlig aufgeklärt. Die Verengung ist meist durch Verkalkung der Klappensegel bedingt. Der derzeitige Stand der Forschung gibt Grund zur Annahme, dass dieser Entstehungsprozess der Ätiologie der Arteriosklerose sehr ähnlich ist. Die Aortenstenose kann anhand der Aortenklappen-Öffnungsfläche in leicht-, mittel- und hochgradig eingeteilt werden. Zurzeit ist die Echokardiographie die wichtigste Methode zur Evaluation der Aortenstenose, weil damit die Öffnungsfläche und die Druckgradienten bestimmt werden können. Für die Entscheidung zur Operation ist insbesondere auch das Einsetzen der Symptomatik mitbestimmend. Der konventionelle Aortenklappenersatz mit einer biologischen oder mechanischen Aortenklappenprothese ist der Goldstandard in der heutigen Therapie der Aortenstenose. Patienten höheren Alters erhalten heutzutage eine biologische Aortenklappenprothese, da keine dauerhafte Antikoagulation notwendig ist. Bei älteren Patienten (über 70 Jahre) steigt die postoperative Mortalität auf 5-15% an. In Deutschland waren 2010 über 50% der herzchirurgischen Patienten älter als 70 Jahre und 12,4% sogar über 80 Jahre. Laut einer Studie werden 33% der über 75-Jährigen nicht zur Operation zugelassen, da diese als zu risikoreich eingestuft wird. Um dieses Patientenkollektiv besser zu versorgen, wurde ein Verfahren zur kathetergestützten Implantation einer Aortenklappenprothese entwickelt. Die neue Prothese wird auf einen Ballonkatheter gepresst und anschließend in Aortenposition dilatiert. Die Implantation kann durch die Herzspitze antegrad, also transapikal, oder über die femoralen Gefäße retrograd, also transfemoral, erfolgen. Eine Sternotomie oder die Verwendung einer Herz-Lungenmaschine mit künstlichem Herzstillstand sind dazu nicht notwendig. Die in dieser Arbeit verwendete Sapien-Prothese besteht aus vorbehandeltem Rinderperikard und ist in einem Kobalt-Chrom-Stent aufgehängt. Bereits 2010 wurden in Deutschland schon fast ein Viertel aller isolierten Aortenklappenersätze mittels der kathetertechnischen Aortenklappenprothesen durchgeführt, 2011 ist der Anteil auf über 30% gestiegen. Der Einsatz ist im Moment auf Hochrisikopatienten über 75 Jahre beschränkt, da es noch keine Ergebnisse über die Langzeithaltbarkeit der Katheter-Herzklappen gibt. Außerdem scheint die Häufigkeit von periinterventionellen Komplikationen bei diesem Verfahren noch sehr hoch. Ganz im Gegensatz zur schonenden Behandlung der Prothese beim konventionellen Eingriff wird die Sapien-Herzklappenprothese durch einen Crimper auf den Ballonkatheter gepresst. Der Durchmesser wird dabei von 23 bzw. 26mm auf unter 8,7mm verringert. Nur so kann die Prothese über das zum Studienzeitpunkt 26 French große Applikationssystem in Position gebracht werden. Mittlerweile beträgt der Diameter für den transfemoralen Zugang nur noch 18 French. Bisher gibt es keine Studien darüber, ob die Krafteinwirkung des Crimping einen Einfluss auf die Langzeithaltbarkeit der Transkatheter-Herzklappen hat. Dabei ist gerade eine lange Haltbarkeit enorm wichtig, um das neue minimalinvasive System einem größeren Patientenkollektiv zugänglich zu machen. Ziel der hier vorgelegten Studie war es deshalb, den Einfluss von Crimping auf die Haltbarkeit und Gewebeintegrität der Edwards Sapien-Prothese in Abhängigkeit von der Crimping-Dauer zu untersuchen. Dazu kam ein subkutanes Rattenmodell zur Anwendung, das zum Vergleich verschiedener Herzklappenprothesen häufig herangezogen wird. Hierbei wird vor allem das Verkalkungspotential der Prothesen untersucht, da die Verkalkung der Klappen die Funktionalität derselben limitiert. Hierfür wurden in dieser Arbeit 21 Tage alten Sprague-Dawley-Ratten (n=15) jeweils fünf Gewebeproben in separate subkutane Taschen implantiert. Nach einem Implantationszeitraum von zwölf Wochen gingen wir von der maximal möglichen Verkalkung aus. Im Menschen entspricht das einem Zeitraum von etwa zehn Jahren. Drei Gruppen á fünf Sapien-Prothesen wurden unterschiedlich lange gecrimpt: für einen Monat, einen Tag und eine Stunde. Eine vierte Gruppe wurde nicht gecrimpt. Die fünfte Gruppe bestand aus der operativ häufig verwendeten Standardklappe Perimount Magna und wurde als Kontrolle eingesetzt. Die Klappensegel wurden nach Crimping und Dilatation exzidiert (je Gruppe n=15) und unter inhalativer Anästhesie wurde jeder Ratte ein Präparat aller fünf Gruppen in subkutane separate Taschen faltenfrei implantiert. Die Taschen wurden dorsal paravertebral durch stumpfe Präparation angelegt. Die Implantation erfolgte bei allen 15 Tieren komplikationslos. Nach zwölf Wochen erfolgte die Explantation. Ein Präparat der für einen Tag gecrimpten Prothesen und eines der Kontrollgruppe Magna konnten nicht aufgefunden werden. Ansonsten ergaben sich bei der Explantation keine Schwierigkeiten. Zur Bestimmung des Kalziumlevels im Serum wurde den Ratten eine Blutprobe abgenommen. Die explantierten Präparate wurden dann zur Analyse in drei Teile geschnitten. Ein Teil wurde der Kalziumbestimmung durch optische Emissionsspektroskopie mit induktiv gekoppeltem Plasma (ICP-OES) zugeführt. Das Ergebnis wird in mg/g Trockengewicht angegeben. Der zweite Teil wurde für die histologische Untersuchung in Paraffin eingebettet. Es wurden Standardschnitte angefertigt und drei Färbungen pro Präparat durchgeführt. Dies waren die Hämatoxylin-Eosin-Färbung (Orientierung), die Van Kossa-Färbung (Verkalkung) und die mod. Pikrosiriusrot-Färbung (kollagene Fasern). Der Kalziumgehalt der Präparate wurde zusätzlich zur chemischen Bestimmung histologisch durch ein interaktives Bildanalyseverfahren in mm2 gemessen. Die Fragmentierung und Irregularität der Kollagenfasern wurde histologisch in vier Grade eingestuft: ohne pathologischen Befund, gering-, mittel- oder hochgradig fragmentiert bzw. irregulär. Ein weiterer Teil der Präparate wurde für die exemplarische Darstellung im Elektronenmikroskop in Epon 100 eingebettet und mit Uranylacetat und Tannin kontrastiert. Die Kalziummessungen ergaben, dass die ungecrimpten Klappen Sapien und Perimount Magna tendenziell stärker verkalkten als die anderen Gruppen. Die Unterschiede zwischen den Gruppen waren jedoch nicht signifikant, sowohl bei der histologischen als auch bei der chemischen Quantifizierung. Die Streuung der Messwerte war sowohl intra- als auch interindividuell sehr hoch. Die Bedeutung für die Langzeithaltbarkeit bezüglich der Kalzifizierung ist unklar. Jedoch kann festgestellt werden, dass es in dieser Studie keinen signifikant messbaren Unterschied in der Verkalkung zwischen gecrimpten und ungecrimpten Prothesen gab. In der histologischen Strukturanalyse waren die Kollagenfasern der gecrimpten Klappen signifikant stärker fragmentiert bzw. die Struktur irregulärer als die der ungecrimpten Klappen. Erstaunlich war hier auch die Tatsache, dass selbst die ungecrimpte Sapien-Prothese signifikant stärker fragmentiert war als die Perimount Magna. Dieses Ergebnis überrascht, da die Sapien-Klappe der Perimount Magna im Produktionsprozess sehr ähnlich ist. Beide bestehen aus Rinderperikard und sind mit dem Antimineralisationsverfahren ThermaFix vorbehandelt. Sie unterscheiden sich lediglich im Stent. Dieser muss für das kathetergestützte Verfahren komprimierbar und wieder dilatierbar sein. Der Produktionsprozess sollte auf Grund dieses Ergebnisses reevaluiert werden. Wie bereits erwähnt, waren die gecrimpten Klappen signifikant stärker fragmentiert. Mit zunehmender Crimping-Dauer nahm dieser Effekt tendenziell sogar zu. Dass Crimping einen schädlichen Einfluss auf die strukturelle Integrität des Klappengewebes hat, war bis dato nicht bewiesen. Diese Tatsache allein lässt allerdings noch keine genaue Aussage über die Auswirkung von Crimping auf die Haltbarkeit im Blutstrom zu. Es ist jedoch hervorzuheben, dass die Fragmentierung der Kollagenfasern, also der Haltefasern der Aortenklappenprothese, die Erwartung einer guten Langzeitfunktionalität drastisch mindert. Dazu gibt es Hinweise aus aktuellen multizentrischen Studien wie dem Partner-Trial, in dem bereits nach 30 Tagen 1,3% und nach einem Jahr 4,2% der Patienten eine mittel- bis schwergradige transvalvuläre Aorteninsuffizienz aufwiesen. Diese Tatsache verbunden mit dem Wissen, dass Crimping die Kollagenfasern frakturiert, stellt die Langzeithaltbarkeit der Prothese in Frage. Zu beachten ist, dass der Diameter des Systems in diesem Versuchsaufbau keine Rolle spielte. Seit Beginn der Studie hat sich der Diameter des Applikationssystems aber von 26 auf 22 French (transfemoral sogar nur 18 French) verringert. Es ist anzunehmen, dass die Krafteinwirkung beim Crimping auf 22 bzw. 18 French noch deutlich größer und damit die Fragmentierung der Fasern noch ausgeprägter wäre. Als Limitationen des hier angewandten subkutanen Rattenmodells sind der fehlende Kontakt mit dem Blut sowie die fehlende Wirkung hämodynamischer Kräfte zu nennen. Es handelt sich hierbei um einen Tierversuch, der nicht direkt auf den Menschen übertragbar ist. Für histologische und chemische Analyse mussten jeweils unterschiedliche Teile der Präparate verwendet werden. Die histologische Beurteilung ist untersucherabhängig. In diesem Versuchsaufbau wurde lediglich ein Prothesen-Typ untersucht, so dass nicht klar ist, ob die beschriebenen Phänomene auch bei anderen kathetertechnischen Herzklappenprothesen auftreten. Die Ergebnisse liefern neue Gesichtspunkte im Hinblick auf die Haltbarkeit der Sapien-Klappenprothese. Daraus lassen sich einige Empfehlungen ableiten. Crimping verursacht einen irreparablen Schaden an den Kollagenfasern der Herzklappenprothesen, der tendenziell mit der Dauer des Crimpings zunimmt. Der Vorgang des Crimping sollte daher so kurz wie möglich gehalten werden. Die kathetergestützte Aortenklappenprothese sollte erst kurz vor der Implantation auf den Ballonkatheter gecrimpt werden. Crimping auf sehr kleine Diameter sollte vorerst vermieden werden. Künftig sollte außerdem eine genauere Analyse der Auswirkungen der strukturellen Schäden auf die Haltbarkeit der Transkatheter-Herzklappen durchgeführt werden. Vor der Ausweitung der Behandlung auf ein Patientenkollektiv mit höherer Lebenserwartung müssen noch viele Fragen hinsichtlich der Langzeithaltbarkeit dieser Herzklappen-Prothesen in weiteren Studien geklärt werden.

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Auffret, Vincent. "Aide à la décision pour le remplacement valvulaire aortique percutané." Thesis, Rennes 1, 2019. http://www.theses.fr/2019REN1B035.

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La sténose aortique serrée est la valvulopathie acquise de l’adulte la plus fréquente affectant jusqu’à 10% des octogénaires. Sa prise en charge percutanée est en plein essor et confronte les cliniciens à des problèmes nouveaux constituant un champ de recherche important. Notre travail s’inscrit dans le cadre des gestes médico-chirurgicaux assistés par ordinateur et vise à proposer des solutions d’aide à la décision basées sur l’assistance informatique. Cette Thèse est ainsi composée de 4 parties. Une première partie porte sur la problématique médicale dans laquelle s’inscrit le remplacement valvulaire aortique percutané (TAVI) ainsi que le contexte du TAVI en France et présente un article évaluant l’évolution des caractéristiques des patients et des procédures à l’échelle nationale entre 2010 et 2015 dans les registres nationaux FRANCE 2 et FRANCE TAVI. Ce premier chapitre identifie des problématiques médicales auxquelles les opérateurs sont confrontés au quotidien notamment la sélection optimale des candidats et la minimisation des complications de la procédure dans le contexte d’une réduction du profil de risque des patients traités. La seconde partie s’intéresse à l’étude de populations, par des méthodes statistiques classiques, pour établir des facteurs prédictifs de résultats du TAVI ou de survenue d’une complication donnée afin d’aider le clinicien dans sa planification de la procédure. Cette partie est articulée autour de 3 articles portant sur les facteurs prédictifs d’accidents vasculaires cérébraux, les troubles conductifs et les facteurs prédictifs de « mauvais résultats » après TAVI. Nous démontrons l’intérêt de ce type d’analyse qui resteront nécessaires à l’avenir mais abordons également leurs limites qui expliquent pourquoi d’autres pistes doivent être explorées pour stocker, trier, restituer les informations pertinentes à l’opérateur voire les augmenter pour faciliter ses décisions notamment en préopératoire.L’objet de la 3ème partie est d’aborder un système d’aide à la décision par ordinateur de type « case-based reasoning » (CBR) qui pourrait tirer bénéfice de l’identification de ces facteurs pronostiques et à terme les intégrer dans une interface globale et ergonomique d’aide à la décision. Nous avons travaillé dans le cadre du projet européen H2020 EurValve sur l’élaboration d’un CBR dont la problématique se concentre pour l’instant sur le choix optimal de la voie d’abord, du type et de la taille de prothèse. Notre travail s’est concentré sur une étape analytique de la conception de ce type de système portant sur l’étude et l’amélioration de la mesure de similarité utilisée pour rapprocher le cas à traiter (problème) de ses plus proches voisins (cas déjà traités et leur « solution » thérapeutique). Enfin, une dernière partie porte sur l’augmentation des informations disponibles pour l’aide à la décision en préopératoire par la simulation numérique spécifique patient. Après un état de l’art des méthodes utilisées dans le domaine du TAVI, nous avons travaillé à l’élaboration et au paramétrage d’un modèle de simulation de l’insertion du guide rigide dans le ventricule gauche (une étape de la procédure qui peut conditionner le positionnement de la prothèse et donc le résultat final). Afin de réaliser une première validation de cette simulation exploitant l’imagerie tomodensitométrique 3D préopératoire, l’approche proposée repose sur l’extraction de la région d’intérêt dans le volume 3D (segmentation) et sa mise en correspondance avec l’imagerie fluoroscopique 2D peropératoire par le biais d’un recalage 3D/2D. Nos travaux sur ces méthodes de traitement de l’image nécessaires à la mise en œuvre et la validation de notre stratégie de simulation sont discutés dans cette partie. Enfin nous présentons une application clinique potentielle du modèle de simulation portant sur l’influence de la forme du guide et de ses conditions d’insertion sur sa stabilité et les forces de pression s’exerçant sur le ventricule gauche
Aortic stenosis represents the most frequent acquired valvular heart disease, affecting up to 10% of octogenarians. Transcatheter aortic valve implantation (TAVI) is booming and confronts clinicians with new issues that constitute a major field of research. Our work falls within the framework of computer-assisted medico-surgical interventions, and aims at proposing computer-assisted decision support systems. The present Thesis is composed of four parts. The first part focuses on the medical problematic surrounding TAVI, as well as the current French TAVI field on the basis of an article describing temporal trends in patients’ and procedural’s characteristics from 2010 to 2015 in the FRANCE 2 and FRANCE TAVI nationwide registries. This first part identifies medical issues that operators currently face, especially the optimal selection of TAVI candidates, and the reduction of procedural complications within the current trends towards treatment of patients with lower baseline surgical-risk profile. The second part deal with population-based studies, through standard statistical methods, to identify predictors of TAVI outcomes or selected procedural complications in order to facilitate procedural planning. Three articles compose this part. The first focuses on predictors of short-term cerebrovascular events post-TAVI, the second deals with conduction disturbances post-TAVI while the third aims at identifying predictors of global poor outcomes. We demonstrate the benefits of these analyses, which will remain necessary in the future, but also address their limitations, which support the use of new methods to store, sort, retrieve, and even augment relevant information to facilitate operators’ decision, especially at the pre-procedural step.The purpose of Part 3 is to address a case-based reasoning (CBR) decision-support system that could benefit from the identification of these prognostic factors and ultimately integrate them into a global and ergonomic interface for decision support. We have worked in the framework of the European project H2020 EurValve on the development of a CBR whose problematic is,for the time being, limited to the optimal choice of the approach, type and size of prosthesis. Our work focused on an analytical step in the design of this type of system dealing with the study and improvement of the similarity measure used to identify nearest neighbours (previously treated cases and their therapeutic "solution") of the current problem (case which clinicians are planning to treat). Finally, the last part focuses on increasing the information available for preoperative decision support through patient-specific numerical simulation. After a state of the art of the methods used in the field of TAVI, we worked on the elaboration and parameterization of a simulation model of the insertion of the stiff guidewire in the left ventricle (one of the first steps of the procedure that can condition the positioning of the prosthesis and thus the final result). In order to perform a first validation of this patient-specific simulation using preoperative 3D CT imaging, the proposed approach is based on the extraction of the region of interest in the 3D volume (segmentation) and its mapping to intraoperative 2D fluoroscopy through 3D / 2D registration. Our work on these image processing methods needed to implement and validate our simulation strategy is also discussed in this section. Finally, we present a potential clinical application of the simulation model regarding the influence of the shape of the guide and its insertion conditions on its stability and the pressure forces exerted on the left ventricle

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Zenses, Anne-Sophie. "Performance hémodynamique de prothèses valvulaires aortiques percutanées et stratégies d'implantation lors de procédures "valve-in-valve" : études in vitro et in vivo." Thesis, Aix-Marseille, 2018. http://www.theses.fr/2018AIXM0417/document.

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L’implantation valvulaire aortique percutanée (TAVI) a émergé comme une alternative à la chirurgie pour les patients avec sténose sévère et haut risque chirurgical. Cette technique s’étend à une population plus large (e.g. anatomie plus complexe, risque chirurgical plus bas), ainsi qu'au traitement Valve-in-Valve (ViV) des bioprothèses (BPs) chirurgicales défaillantes. Cependant, deux complications majeures en limitent la généralisation. En TAVI « classique », la présence de fuites péripothétiques a été associée à une mortalité augmentée. Les effets du surdimensionnement de la prothèse percutanée pour assurer son étanchéité, ou de la forme de l’anneau souvent non circulaire, sur la performance hémodynamique, sont mal connus. En ViV, la présence de hauts gradients est fréquente et associée à une mortalité augmentée. Les BPs de taille nominale ≤ 21 mm et le mode de dégénérescence par sténose, facteurs mis en cause dans la sténose résiduelle et associés à une mortalité augmentée, ne sont pas assez spécifiques et il n’existe actuellement aucune recommandation pour le traitement des petites BPs. Par ailleurs, le bénéfice hémodynamique réel du ViV par rapport aux statuts avant ViV n’a pas été étudié.L’objectif général de ce travail doctoral est de comprendre les interactions entre la prothèse percutanée et l’anneau aortique ou la BP à traiter, impliquées dans la performance hémodynamique, en particulier dans des conditions d’implantation complexes, afin d’étendre les indications du TAVI. En ViV, le défi est de préciser les facteurs associés à sa performance et son utilité hémodynamique et de proposer des stratégies d’implantation afin d’optimiser le succès de la procédure
Transcatheter aortic valve implantation (TAVI) has emerged as an alternative to surgery for patients with severe aortic stenosis and high surgical risk. This technique is extending to a wider population (e.g. with more complex anatomy or lower surgical risk), as well as to patients with degenerated surgical bioprostheses (BPs). However, two major concerns remain limiting. Regarding “classical TAVI”, periprosthetic leaks have been associated with increased mortality. Oversizing is used to secure the device within the aortic annulus which is often non circular. The effects of oversizing and annulus shape on the hemodynamic performance are unknown. Regarding ViV implantations, elevated post-procedural gradients are common and have been associated with increased mortality. The principal factors associated with this residual stenosis as well as with increased risk of mortality, have been BPs label size ≤ 21 mm and mode of failure by stenosis. These factors are not specific enough and there is currently no recommendation for the treatment of small BPs. Besides, the actual hemodynamic benefit associated with ViV has not been evaluated (vs. pre ViV status).The general objective of this work is to understand the interactions between the transcatheter prosthesis and the aortic annulus or the BP to be treated, which impact the hemodynamic performance, especially in complex conditions of implantation, in order to extend the indications of TAVI. In the context of ViV, the objective is to specify the factors associated with the hemodynamic performance and utility of the treatment. The final aim is to provide strategies of implantation in order to optimize the success of the procedure

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Abdul-Jawad, Altisent Omar. "Caracterización del daño neurológico asociado a la TAVI y estrategias terapéuticas para su prevención." Doctoral thesis, Universitat Autònoma de Barcelona, 2017. http://hdl.handle.net/10803/456574.

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Actualmente la implantación de prótesis aórtica transcatéter (TAVI) representa la principal opción terapéutica para pacientes con estenosis aórtica severa y alto riesgo quirúrgico. La ampliación de las indicaciones TAVI a una población de menor riesgo está limitada por la relativa alta incidencia de eventos cerebrovasculares. El daño neurológico relacionado con la TAVI se ha clasificado en distintos niveles: clínico (ictus y accidente cerebral transitorio); subclínico (infartos silentes detectados por resonancia magnética con ponderación de difusión [DWI]); y cognitivo. Estudios con DWI realizados en pacientes con un perfil de riesgo elevado han mostrado una alta incidencia de daño cerebral subclínico tras la TAVI. No obstante, la repercusión clínica en forma de variaciones del estado cognitivo ha mostrado resultados poco concluyentes. Tampoco conocemos el riesgo de daño subclínico ni las consecuencias cognitivas en una población TAVI con un perfil de riesgo menor. Existen dos principales estrategias para prevenir el daño neurológico asociado a la TAVI: farmacológica (agentes antitrombóticos) y mecánica (dispositivos de protección embólica). Las guías de práctica clínica recomiendan una terapia antiplaquetar (TAP) post-TAVI para reducir el riesgo de ictus. No obstante, no hay datos sobre la eficacia y seguridad de esta recomendación en pacientes que se encuentren en tratamiento concomitante con antagonistas de la vitamina K (AVK) por fibrilación auricular (FA). El primer objetivo (estudio 1) fue comparar el grado de daño neurológico subclínico (mediante DWI) y las variaciones del estado cognitivo entre la TAVI y el recambio valvular aórtico quirúrgico (RVA) en una población considerada de riesgo quirúrgico intermedio. El segundo objetivo fue examinar el riesgo de eventos isquémicos y hemorrágicos asociados a dos estrategias antitrombóticas distintas en pacientes con FA sometidos a TAVI. Los dos estudios presentados son observacionales. El estudio 1 se realizó en el Hospital Vall Hebron. Cuarenta y seis pacientes sometidos a TAVI (78,8±8.3 años, STS score 4,4±1.7) se compararon con 37 pacientes sometidos a RVA (78,9±6,2 años, STS score 4,7±1,7). La DWI se realizó durante los primeros 15 días tras la intervención y la valoración cognitiva a nivel basal y a los 3 meses tras la intervención. No se observaron diferencias en la incidencia de ictus (2,2% en TAVI vs. 5,4% en RVA, p=0.58), ni en la incidencia de lesiones cerebrales subclínicas detectadas por DWI (45% vs. 40,7%, OR-ajustada 0,95 [0,25-3,65], p=0,94). La edad fue un predictor de nuevas lesiones (p=0,01), y el tratamiento con antagonistas de la vitamina K (AVK) tuvo un efecto protector (p=0,037). No se observaron cambios significativos en las puntuaciones de los test cognitivos tras la intervención. El estudio 2 incluyó a 621 pacientes con FA sometidos a TAVI. Se compararon dos estrategias antitrombóticas utilizadas en mundo real: monoterapia (MT) con el uso único de AVK (n=101) vs. terapia multi-antitrombótica (MAT) con el uso de TAP más AVK (n=520). Durante un seguimiento medio de 13 meses no se observaron diferencias en la incidencia de ictus (p=0.67), eventos cardiovasculares mayores (combinado de ictus, infarto o muerte cardiaca, p=0.33), o muerte (p=0.76). No obstante sí se documentó un mayor riesgo de hemorragia mayor o amenazante en el grupo MAT (HR 1,85 [1,05-3,28], p=0,04). El estudio 1 mostró que en una población de riesgo intermedio el daño neurológico tras la TAVI fue similar que tras el RVA. Aunque la incidencia de daño subclínico era elevada (tras la TAVI o RVA) su impacto clínico no pareció relevante. En el estudio 2 se observó que añadir una TAP a pacientes que están en tratamiento con AVK por FA y son sometidos a TAVI no aportó ningún beneficio y en cambio sí aumentó el riesgo de hemorragia.
Transcatheter aortic valve implantation (TAVI) is now the principal therapeutic option in patients with severe aortic stenosis deemed at high surgical risk. Implementing TAVI in a lower risk profile population could be limited by relatively high incidence of neurological damage related with the procedure. Neurological damage has been classified at different levels: clinical (stroke or transient ischemic attack), subclinical (silent embolic infarcts after procedure demonstrated by Diffusion Weighted resonance Imaging [DWI]), and cognitive. DWI studies performed in high risk patients have demonstrated the ubiquitous presence of subclinical damage following TAVI. However its effects on cognition showed inconclusive results. To date, the risk of subclinical damage and cognitive fluctuations following TAVI in a population deemed at lower risk is unknown. There are currently two main strategies to prevent neurological damage related with TAVI: pharmacological (antithrombotic agents) and mechanical (embolic protection devices). Guidelines recommend antiplatelet therapy (APT) post-TAVR to reduce the risk of stroke. However, data on the efficacy and safety of this recommendation in the setting of a concomitant indication for oral anticoagulation (due to atrial fibrillation [AF]) are scare. The first objective (study 1) was to compare the degree of neurological damage using DWI and cognitive testing between TAVI and surgical aortic valve implantation (SAVR) in patients deemed at intermediate surgical risk. The second objective (study 2) was to examine the risk of ischemic events and bleeding episodes associated with differing antithrombotic strategies in patients undergoing TAVI with concomitant AF. The two studies presented were observational. Study #1 was conducted in Vall Hebron Hospital. Forty-six patients undergoing TAVI (78.8±8.3 years, STS score 4.4±1.7) and 37 patients undergoing SAVR (78.9±6.2 years, STS score 4.7±1.7) were compared. DWI was performed within the first 15 days post-procedure. A cognitive assessment was performed at baseline and at 3 months follow-up. TAVI and SAVR groups were comparable in terms of baseline characteristics. There were no differences in incidence of stroke (2.2% in TAVR vs. 5.4% in SAVR, p=0.58), neither in the rate of acute ischemic cerebral lesions detected by DWI (45% vs. 40.7%, adjusted OR 0.95 [0.25-3.65], p=0.94). An older age was a predictor of new lesions (p=0.01), and therapy with vitamin K antagonist (VKA) had a protective effect (p=0.037). Overall no significant changes were observed in global cognitive scores post-intervention. Study #2 was a real world multicenter evaluation comprising 621 patients with AF undergoing TAVI. Two groups were compared: mono-therapy (MT) group (with the use of VKA alone, n=101) vs. multi-antithrombotic (MAT) group (with the use of VKA plus APT, as recommended by guidelines, n=520). During a follow-up of 13 months there were no differences between groups in the rates of stroke (MT 5% vs. MAT 5.2%, HR 1.25 [0.45-3.48], p=0.67), major cardiovascular endpoint (combined of stroke, myocardial infarction or cardiovascular death, p=0.33) or death (p=0.76), however a higher risk of major or life-threatening bleeding was found in the MAT group (HR 1.85 [1.05-3.28], p=0.04). Study #1 found similar rate of cerebral damage following TAVI and SAVR in patients at intermediate risk. Although acute lesions occurred frequently in both strategies, their cognitive impact was not clinically relevant. Study #2 found that in TAVI recipients prescribed VKA therapy for AF, concomitant APT use appears not to reduce the incidence of stroke, major adverse cardiovascular events, or death, while increasing the risk of major or life-threatening bleeding. Though only observational, the important lessons to be drawn from this thesis are that under a neurological perspective implementing TAVI in an intermediate risk populations appears reasonable; and that the currently recommendation of prescribing APT for patients with AF who are already on long-term anticoagulation does not confer any benefit while potentially being harmful.

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Vincent, Flavien. "Facteur Willebrand et modifications hémodynamiques associées à l’utilisation de dispositifs cardiovasculaires : mécanisme et applications cliniques." Thesis, Lille 2, 2018. http://www.theses.fr/2018LIL2S039/document.

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Le facteur Willebrand (VWF) est une proteine multimerique qui a une sensibilite unique aux forces de cisaillement et aux variations hemodynamiques du flux sanguin comme celles rencontrees lors d’utilisation de dispositifs cardiovasculaires tels qu’un remplacement valvulaire aortique transcatheter (TAVI) ou un assistance circulatoire mecanique a flux continu (ACM-FC). Des travaux anterieurs nous ont permis de mettre en evidence une secretion endotheliale declenchee par les modifications du flux liees a l’utilisation de ces dispositifs.Dans la première partie de la these, nous avons choisi d’etudier le role de la pulsatilite arterielle dans la reponse endotheliale a l’aide de plusieurs modeles animaux porcins d’ACM-FC pour isoler le role de la pulsatilite dans un environnement a forces de cisaillement elevees et constantes. Nous avons observe dans un modele dose-reponse la relation entre le niveau de pulsatilite et la multimerisation du VWF et dans un modele en cross-over le caractere dynamique du relargage endothelial en reponse a des variations aigues de pulsatilite.Ces resultats nous ont permis de conceptualiser dans la deuxième partie l'utilisation du VWF dans l’evaluation de la severite des fuites paravalvulaires (FPV) post-procedure TAVI. Deux cohortes de 183 et 201 patients ont permis de demontrer l’excellente capacite diagnostique de l’analyse multimerique du VWF avec une sensibilite, une specificite et une valeur predictive negative de respectivement 92.3%, 94.9%, et 98.7%. Le test de diagnostic rapide TO-ADP (temps d’occlusion a l’ADP) donnait des resultats equivalents pour un seuil > 180 sec.Enfin dans la troisième partie de la these nous avons concu le design d’un essai clinique permettant d’evaluer la valeur ajoutee de l’utilisation de ce test de diagnostic rapide TO-ADP en salle de catheterisme pour l’amelioration des resultats proceduraux et cliniques des procedures TAVI
Willebrand factor (VWF) is a multimeric protein that has a unique sensitivity to shear forces and hemodynamic variations in blood flow such as those encountered when using cardiovascular devices such as transcatheter aortic valve replacement (TAVI) or continuous flow mechanical circulatory assistance (CF-CAM)

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Alassar, Aiman. "Incidence and mechanisms of cerebral ischaemia following transcatheter aortic valve implantation compared with surgical aortic valve replacement." Thesis, St George's, University of London, 2013. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.686423.

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Background The most likely mechanisms of neurological injury following transcatheter aortic valve implantation (TA VI) and aortic valve replacement (A VR) are cerebral embolisation and hypoperfusion. Primary aim was to compare the potential mechanisms of neurological injury following TA VI and A YR. Methods 127 consecutive high risk patients with severe aortic stenosis who underwent TA VI (n=85) or A VR (n=42) were studied. Transcranial Doppler (TCD), cerebral oximetry, diffusion-weighted MRI (DW -MRI) (before, 6 days and 3 months following procedure) and neurocognitive assessment before and at 3 months were perfonned. Results Neurological injury was not significantly different between TA VI and AVR at one (1.1 % vs. 2.2%, p=0.25) and three months (4.7% vs. 2.2%, p= 1). At 3 months, overall cognitive score was higher in A VR compared with TA VI when adjusted for baseline score; the estimated difference between groups was 0.63 (95% Cl 0.87 - 1.17; p=0.02). Cerebral embolic load was 212 (123-344) during A VR and 134 (76-244) during TAVI, (p=0.07). Cerebral oxygen de saturation during AVR (7.56 ± 2.16) was higher compared to TAVI (5.93 ± 2.47) (p<0.01). Ischemic lesions measured by DW-MRI occurred in 76% ofTAVI and 71% of AVR patients at 6 days (p=0.69) and 63% and 39% at 3 months (p= 0.11). No significant association was found between cerebral emboli, cerebral oxygen desaturation, brain ischemic lesions and general cognitive score. Copclusions At 3 months follow-up, overall cognitive score was higher in A VR compared to TA VI, adjusted for baseline score. However, there was no difference in cerebral embolic load, ischemic lesions and oxygen desaturation.

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Gonçalves, Alexandra Maria Gomes da Silva. "Life after Transcatheter Aortic Valve Implantation: a clinical and echocardiographic appraisal." Tese, Faculdade de Medicina da Universidade do Porto, 2011. http://hdl.handle.net/10216/63780.

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Olsson, Karin. "Hope and life-struggle : patients' experiences with Transcatheter Aortic Valve Implantation." Doctoral thesis, Umeå universitet, Institutionen för folkhälsa och klinisk medicin, 2016. http://urn.kb.se/resolve?urn=urn:nbn:se:umu:diva-127873.

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The overall aim of this thesis is to explore experiences and self-reported outcomes from Transcatheter Aortic Valve Implantation, TAVI, among people with severe aortic stenosis. The thesis includes four studies. Study I-II are based on interviews performed the day before TAVI and Qualitative Concept Analysis was used for analysis. Study III is based on interviews at six months’ follow-up and Grounded Theory was used for analysis. Study IV is quantitative and based on questionnaires at baseline and at six months’ follow-up. Nonparametric, descriptive statistics were used for the analysis. Study I described the vulnerable situation for patients with severe aortic stenosis before TAVI. They were facing death and at the same time struggling to cope with their symptoms and to maintain independent. TAVI offered hope but also caused uncertainty about the new method. Study II focused on the patients’ decision-making process. Three patterns were identified; ambivalent, obedient, and reconciled. The ambivalent patient is unsure of the value of treatment and aware of the risks; the obedient patient is unsure of the value of one's own decision and wants to leave the decision to others; the reconciled patient has reached a point where there is no choice anymore and is always sure that the decision to undergo TAVI is right. Study III offered a deeper understanding of the TAVI trajectory. A journey of balancing between hope and life-struggle was the core category of the analysis. Before TAVI patients felt threatened, but also experienced hope. The rehabilitation phase was described as demanding and depressing or surprisingly simple. At the six months’ followup patients described being pleased to return to life, however, many were still struggling with limitations. Study IV focused on quantifying the symptom burden, function and health related quality of life before and after TAVI. The results were reflected against that of patients treated with open surgery. Self-rated function and health related quality of life increased and symptoms were reduced at follow-up, but breathlessness and fatigue were still common. Conclusively, TAVI patients are struggling with limitations, both because of their comorbidities and because of their valve disease which also poses a threat to their lives. TAVI gives an opportunity to survive, to stay independent and to increase quality of life. To feel and preserve hope is essential for patients’ wellbeing, both before and during the recovery process.

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Gonçalves, Alexandra Maria Gomes da Silva. "Life after Transcatheter Aortic Valve Implantation: a clinical and echocardiographic appraisal." Doctoral thesis, Faculdade de Medicina da Universidade do Porto, 2011. http://hdl.handle.net/10216/63780.

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Bagur, Rodrigo Hernan. "Transcatheter aortic valve implantation for the treatment of patients with severe symptomatic aortic stenosis." Thesis, Université Laval, 2012. http://www.theses.ulaval.ca/2012/29420/29420.pdf.

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Pan, Hao. "Current Status of Transcatheter Aortic Valve Implantation: A Systematic Review of Non-orthodox Deployment Strategies." Thesis, The University of Arizona, 2012. http://hdl.handle.net/10150/221384.

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A Thesis submitted to The University of Arizona College of Medicine - Phoenix in partial fulfillment of the requirements for the Degree of Doctor of Medicine.
points included feasibility, safety, efficacy, and durability. Results: The current literature regarding TAVI is limited to observational studies. Overall procedural success rates ranged from 90% to 100%. The incidence of major adverse events included: 30-day mortality (0%-18%), major adverse cardiovascular and cerebral events ranged from 2% to 35% and the rate of postoperative multiple organ failure was 2% to 8%. There was statistically significant hemodynamic improvement demonstrated by postoperative echocardiography measurements with no significant deterioration up to 6 months postprocedure. Survival at 6 months ranged from 59% to 93%. Only 5 one study with long-term of transapical TAVI follow-up could reliably evaluate long-term survival of 58% at 3 years. Significance: TAVI has proven to be feasible and potentially an effective intervention for non-surgical patients with symptomatic aortic stenosis. Although short-term efficacy based on echocardiography has been promising, there is a paucity of data concerning long-term outcomes. The evolution of TAVI will be dependent on the development of a valid tool for estimating the surgical risk to define indications for surgical aortic valve replacement versus transcatheter aortic valve implantation.

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KARAR, Mohamed Esmail Abdel Razek Hassan. "Development of a Surgical Assistance System for Guiding Transcatheter Aortic Valve Implantation." Doctoral thesis, Universitätsbibliothek Leipzig, 2012. http://nbn-resolving.de/urn:nbn:de:bsz:15-qucosa-83426.

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Development of image-guided interventional systems is growing up rapidly in the recent years. These new systems become an essential part of the modern minimally invasive surgical procedures, especially for the cardiac surgery. Transcatheter aortic valve implantation (TAVI) is a recently developed surgical technique to treat severe aortic valve stenosis in elderly and high-risk patients. The placement of stented aortic valve prosthesis is crucial and typically performed under live 2D fluoroscopy guidance. To assist the placement of the prosthesis during the surgical procedure, a new fluoroscopy-based TAVI assistance system has been developed. The developed assistance system integrates a 3D geometrical aortic mesh model and anatomical valve landmarks with live 2D fluoroscopic images. The 3D aortic mesh model and landmarks are reconstructed from interventional angiographic and fluoroscopic C-arm CT system, and a target area of valve implantation is automatically estimated using these aortic mesh models. Based on template-based tracking approach, the overlay of visualized 3D aortic mesh model, landmarks and target area of implantation onto fluoroscopic images is updated by approximating the aortic root motion from a pigtail catheter motion without contrast agent. A rigid intensity-based registration method is also used to track continuously the aortic root motion in the presence of contrast agent. Moreover, the aortic valve prosthesis is tracked in fluoroscopic images to guide the surgeon to perform the appropriate placement of prosthesis into the estimated target area of implantation. An interactive graphical user interface for the surgeon is developed to initialize the system algorithms, control the visualization view of the guidance results, and correct manually overlay errors if needed. Retrospective experiments were carried out on several patient datasets from the clinical routine of the TAVI in a hybrid operating room. The maximum displacement errors were small for both the dynamic overlay of aortic mesh models and tracking the prosthesis, and within the clinically accepted ranges. High success rates of the developed assistance system were obtained for all tested patient datasets. The results show that the developed surgical assistance system provides a helpful tool for the surgeon by automatically defining the desired placement position of the prosthesis during the surgical procedure of the TAVI
Die Entwicklung bildgeführter interventioneller Systeme wächst rasant in den letzten Jahren. Diese neuen Systeme werden zunehmend ein wesentlicher Bestandteil der technischen Ausstattung bei modernen minimal-invasiven chirurgischen Eingriffen. Diese Entwicklung gilt besonders für die Herzchirurgie. Transkatheter Aortenklappen-Implantation (TAKI) ist eine neue entwickelte Operationstechnik zur Behandlung der schweren Aortenklappen-Stenose bei alten und Hochrisiko-Patienten. Die Platzierung der Aortenklappenprothese ist entscheidend und wird in der Regel unter live-2D-fluoroskopischen Bildgebung durchgeführt. Zur Unterstützung der Platzierung der Prothese während des chirurgischen Eingriffs wurde in dieser Arbeit ein neues Fluoroskopie-basiertes TAKI Assistenzsystem entwickelt. Das entwickelte Assistenzsystem überlagert eine 3D-Geometrie des Aorten-Netzmodells und anatomischen Landmarken auf live-2D-fluoroskopische Bilder. Das 3D-Aorten-Netzmodell und die Landmarken werden auf Basis der interventionellen Angiographie und Fluoroskopie mittels eines C-Arm-CT-Systems rekonstruiert. Unter Verwendung dieser Aorten-Netzmodelle wird das Zielgebiet der Klappen-Implantation automatisch geschätzt. Mit Hilfe eines auf Template Matching basierenden Tracking-Ansatzes wird die Überlagerung des visualisierten 3D-Aorten-Netzmodells, der berechneten Landmarken und der Zielbereich der Implantation auf fluoroskopischen Bildern korrekt überlagert. Eine kompensation der Aortenwurzelbewegung erfolgt durch Bewegungsverfolgung eines Pigtail-Katheters in Bildsequenzen ohne Kontrastmittel. Eine starrere Intensitätsbasierte Registrierungsmethode wurde verwendet, um kontinuierlich die Aortenwurzelbewegung in Bildsequenzen mit Kontrastmittelgabe zu detektieren. Die Aortenklappenprothese wird in die fluoroskopischen Bilder eingeblendet und dient dem Chirurg als Leitfaden für die richtige Platzierung der realen Prothese. Eine interaktive Benutzerschnittstelle für den Chirurg wurde zur Initialisierung der Systemsalgorithmen, zur Steuerung der Visualisierung und für manuelle Korrektur eventueller Überlagerungsfehler entwickelt. Retrospektive Experimente wurden an mehreren Patienten-Datensätze aus der klinischen Routine der TAKI in einem Hybrid-OP durchgeführt. Hohe Erfolgsraten des entwickelten Assistenzsystems wurden für alle getesteten Patienten-Datensätze erzielt. Die Ergebnisse zeigen, dass das entwickelte chirurgische Assistenzsystem ein hilfreiches Werkzeug für den Chirurg bei der Platzierung Position der Prothese während des chirurgischen Eingriffs der TAKI bietet

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Forman, Jacqueline Marie. "Exploring changes in functional status while waiting for transcatheter aortic valve implantation." Thesis, University of British Columbia, 2013. http://hdl.handle.net/2429/44803.

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As the body ages, there is a natural decline in physical and cognitive abilities. The presence of chronic disease can accelerate this process. Aortic stenosis (AS) is a structural heart disease primarily associated with aging. Untreated patients die within 2 to 5 years following the onset of symptoms. For individuals with multiple co-morbidities, surgical treatment is not an option because of high risk for surgical complications. An innovative and minimally invasive procedure called transcatheter aortic valve implantation (TAVI) has emerged as a safe and viable treatment option for higher risk patients. Because of the rapid disease progression of severe AS and the varying wait-times prior to procedure, it is important to understand changes in functional status while waiting for TAVI. The purpose of this study was to examine the changes in functional status between time of eligibility assessment and TAVI procedure date. Changes in functional status including 5-Metre Gait Speed, Canadian Study of Health and Aging Clinical Frailty Scale and Mini Mental State Examination were evaluated using an exploratory prospective cohort design. Thirty two patients participated in the study with median age 81 (range 64 to 93). Functional status declined between time of assessment and time of TAVI: Gait speed increased by 0.53 seconds (p = 0.01) and Clinical Frailty Scale increased by 0.31 (from 4.3 to 4.6, p = 0.01). Patients who waited longer than six weeks for TAVI (n = 19) had a larger decline in gait speed than patients who waited less than six weeks (n = 10) (0.8 sec vs 0.0 sec, p = 0.04). Patients who were living alone (n =11) had a larger increase in frailty scores compared to patients living with another adult (n = 21) (0.6 vs 0.1, p = 0.05). This study has shown that change in functional status may be an important assessment to monitor while patients are waiting for TAVI. Results may be used to facilitate individualized care and management strategies and inform health care policy to develop evidence based benchmarks for safe wait-times. Future research with larger samples could validate the exploratory findings of this study.

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Wang, Qian. "Patient-specific finite element modeling of biomechanical interaction in transcatheter aortic valve implantation." Diss., Georgia Institute of Technology, 2015. http://hdl.handle.net/1853/54849.

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Transcatheter aortic valve implantation (TAVI) is an effective alternative treatment option for patients with severe aortic stenosis, who are at a high risk for conventional surgical aortic valve replacement or considered inoperable. Despite the short- and mid-term survival benefits of TAVI, adverse clinical events, such as paravalvular leak, aortic rupture, and coronary occlusion, have been reported extensively. Many of these adverse events can be explained from the biomechanics perspective. Therefore, an in-depth understanding of biomechanical interaction between the device and native tissue is critical to the success of TAVI. The objective of this thesis was to investigate the biomechanics involved in the TAVI procedure using patient-specific finite element (FE) simulations. Patient-specific FE models of the aortic roots were reconstructed using pre-procedural multi-slice computed tomography images. The models incorporated aged human aortic material properties with material failure criteria obtained from mechanical tests, and realistic stent expansion methods. TAV deployment and tissue-device interaction were simulated; and the simulation results were compared to the clinical observations. Additionally, parametric studies were conducted to examine the influence of the model input on TAVI simulation results and subsequently the potential clinical complications such as paravalvular leak, annular rupture, and coronary artery occlusion. The methodology presented in this thesis could be potentially utilized to develop valuable pre-procedural planning tools to evaluate device performance for TAVI and eventually improve clinical outcomes.

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Bailey, Jonathon. "Implications for leaflet behaviour in heavily calcified patient-specific aortic roots : simulation of transcatheter aortic valve implantation." Thesis, University of Southampton, 2015. https://eprints.soton.ac.uk/397077/.

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As life expectancy increases, there are more and more cases of age-related disease presenting to medical attention. Aortic stenosis (AS) is a common age-related heart condition in which there is a thickening and distortion of the valve leaflets together with calcium deposition in the aortic root and valve. Surgical valve replacement (SVR) of the calcified valve is the current default treatment for AS. However, due to the invasive nature of the procedure, a large population of patients are deemed too high risk to undergo SVR. Transcatheter aortic valve implantation (TAVI) was developed as a percutaneous alternative to SVR. TAVI is a purely mechanical process beyond the initial positioning of the device, that is, there is no decision making. As a result it can be computationally modelled using finite element analysis (FEA). This thesis describes how FEA has been used to analyse the stresses within the prosthetic leaflets during and post-deployment. Further, the application of patient-specific deployment simulation for predicting adverse effects post TAVI was explored. FEA simulation of TAVI deployment is challenging as a realistic aortic root model must be developed. This was accomplished by extracting data from patient specific medical images. The TAVI device itself, in particular the leaflets, are subjected to elevated stresses and deformation during deployment. Creating an FEA model robust enough to withstand the deployment process was achieved by modelling the leaflets in a planar orientation, then using a preliminary simulation to manipulate the leaflets into a functional position while maintaining a highly regular mesh. The key findings in this thesis concern device orientation and how it influences the operating stress of the valve. Sub-optimal device orientation can result in an average stress increase of 25%, which could potentially reduce the lifespan of the device. Patient-specific deployment simulations were also shown to have application outside of device orientation assessment as regions of potential paravalvular aortic regurgitation were identifiable.

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Hagen-Peter, Gayle Ann. "Living with Aortic Stenosis: A Phenomenological Study of Patients' Experiences and Subsequent Health Choices." ScholarWorks @ UVM, 2015. http://scholarworks.uvm.edu/graddis/516.

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Symptomatic aortic stenosis (AS) is an increasing phenomenon as more adults live longer. The gold standard for treating AS is surgical aortic valve replacement (SAVR). Frequently, as older individuals with AS often have multiple comorbidities, a SAVR is determined to be too high risk. Therefore, a less invasive treatment option is available, namely a transcatheter aortic valve implantation (TAVI) or transcatheter aortic valve replacement (TAVR). Such biomedical procedures have encouraged life extension and the decision to intervene commonplace with the aging population. Without an intervention, significant debilitating symptoms affect a person's quality of life (QoL). Multiple quantitative studies evaluating QoL before and after a TAVI have been performed. However QoL has multiple attributes and is not a single construct. By limiting practice to these defined QoL measures, we exclude the human experience and what values individuals describe as important to them. The dilemma in the present medical model is influenced by two paradigms, evidence based medicine and patient centered medicine. Some people opt not to have a TAVI. This study aims to understand what it is like living with aortic stenosis as perceived by the participant and to gain a more meaningful understanding of why some individuals with AS choose not to have this procedure performed. Using a convenience sample of patients who declined a TAVI, a telephone interview with the person focused on their perceived QoL and the implications determining not to pursue a TAVI. In this qualitative phenomenological design, open-ended questions included: 1) What is it like to live with Aortic Stenosis. 2) Why did you choose not to have the TAVI? Interviews will explore emerging themes. Advanced practice nurses are in ideal positions for performing research to gain greater insight on the complexity of people's health choices. As the incidence of AS occurs more frequently in the increasing aged population, TAVI offers a treatment option for those patients who are symptomatic with AS and are not surgical candidates. However, health care providers should focus on the illness, not the disease, and explore the patients' biopsychosocial values with their medical needs. The information gathered in this study will help guide heath care providers with offering holistic health care incorporating both paradigms of evidence based practice and patient centered medicine options on treatment for people with symptomatic AS.

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Nguyen, Michelle. "An exploratory analysis of factors associated with length of stay following transcatheter aortic valve implantation." Thesis, University of British Columbia, 2016. http://hdl.handle.net/2429/57943.

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Background: Transcatheter aortic valve implantation (TAVI) is a minimally invasive treatment option for higher surgical risk patients with severe symptomatic aortic stenosis (AS) and significant co-existing conditions which may preclude them from surgical valve replacement. Patient characteristics and wait time have been shown to impact length of stay (LOS) in individuals with heart disease; however, these variables have not been extensively evaluated in the TAVI population. Objective: The purpose of this study was to explore factors associated with post-TAVI recovery, as measured by hospital LOS. Method: A retrospective chart review of consecutive patients who underwent TAVI in Vancouver, British Columbia between January 01, 2013 to December 31, 2014 was conducted. Study variables included patient characteristics and wait time. The outcome variable, LOS, was defined as time, in days, from procedure to hospital discharge. Univariate and bivariate analyses were used to select moderately correlated variables for multivariate regression analysis. Results: The study sample consisted of 257 patients, with a mean age of 81.4 years. The median wait time from acceptance to procedure was 36 days, while the median LOS was 3.0 days. Bivariate analysis showed age, living situation, symptom severity, prior surgical aortic valve replacement (SAVR), and prior balloon aortic valvuloplasty (BAV) to be statistically significantly associated with post-TAVI stay in-hospital. The multivariate model revealed that relative to having a LOS of 1 to 2 days, patients who had previously undergone a BAV were 10.7 times more likely to stay 5 days or more (CI [1.16, 98.1]) compared with patients who had not undergone a BAV. No other baseline factors were found to be statistically predictive of prolonged LOS, although odds ratios suggest patients with lower symptom severity and patients who underwent valve-in-valve TAVI were less likely to experience a longer LOS. The model also showed that patients 75 to 79 years of age, with NYHA class III or IV symptoms, and no prior history of an AVR were more likely to follow a standard course of recovery, staying 3 to 4 days, while patients who had a valve-in-valve procedure were more likely to stay 1 to 2 days.
Applied Science, Faculty of
Nursing, School of
Graduate

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Tse, Lurdes. "Delirium after transcatheter aortic valve implantation : a retrospective chart review of associated risk factors and outcomes." Thesis, University of British Columbia, 2011. http://hdl.handle.net/2429/33985.

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A retrospective chart review was performed to determine the incidence and risk factors of delirium after transfemoral and transapical transcatheter aortic valve implantation (TAVI), and open-heart aortic valve replacement (AVR) (n = 45 per group). A number of secondary outcomes were also compared between the surgeries, including 24-hour, 30-day, 1-year and 2-year mortality; time spent in intensive care; total length of hospitalization; need for emergency cardiopulmonary bypass during operation (for TAVI procedures only); and frequencies of postoperative complications. Delirium occurred significantly less frequently in transfemoral TAVI (16%) than in transapical TAVI (51%) or open-heart AVR (38%) (p < 0.01 for transfemoral vs. transapical; p < 0.05 for transfemoral vs. open-heart). There were no significant differences in the use of emergency cardiopulmonary bypass between the two TAVI procedures. Transapical TAVI patients required longer periods of intensive care compared to transfemoral or open-heart patients (84 ± 118.4 hours for transapical compared to 36 ± 36.9 hours for transfemoral and 41 ± 32.1 hours for open-heart; p = 0.014 for transapical vs. transfemoral; p = 0.025 for transapical vs. open-heart), and transfemoral patients had significantly shorter lengths of hospitalization (8 ± 6.0 days for transfemoral compared to 14 ± 9.5 days for transapical and 11 ± 7.2 days for open-heart; p = 0.001 for transfemoral vs. transapical; p = 0.047 for transfemoral vs. open-heart). The 2-year cumulative mortality rate was significantly lower for open-heart patients than for TAVI patients (2% of open-heart patients, compared to 20% of transapical patients and 18% of transfemoral patients; p = 0.007 for transapical vs. open-heart; p = 0.014 for transfemoral vs. open-heart). Transapical and open-heart patients suffered from more postoperative complications than transfemoral patients. A large number of risk factors for delirium were also identified within each surgical group. This study demonstrated that benefits are incurred with transfemoral TAVI compared to transapical TAVI and compared to open-heart AVR. The contribution of medications taken in the perioperative period on the outcome of postoperative delirium is discussed, and clinical considerations with regards to using TAVI for mitigating the incidence of delirium are mentioned.

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Silaschi, Miriam Christine [Verfasser], and Hermann [Akademischer Betreuer] Reichenspurner. "Transcatheter aortic valve implantation versus surgical aortic valve replacement : a propensity score analysis in patients at high surgical risk / Miriam Christine Silaschi. Betreuer: Hermann Reichenspurner." Hamburg : Staats- und Universitätsbibliothek Hamburg, 2014. http://d-nb.info/1048626458/34.

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26

Akram, Abawi. "Transcatheter aortic valve implantation for patients with aorticstenosis and concomitant ischemic heart disease: : A five-yearfollow-up." Thesis, Örebro universitet, Institutionen för medicinska vetenskaper, 2019. http://urn.kb.se/resolve?urn=urn:nbn:se:oru:diva-76214.

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Introduction: Transcatheter aortic valve implantation (TAVI) is an established procedure to treat severe aortic stenosis (AS). This study investigates the impact of ischemic heart disease (IHD) on survival in patients undergoing TAVI. Aim: Five-year all-cause mortality stratified according to the presence or absence of IHD. Methods: Retrospective register study including all patients that underwent a TAVI-procedure 2009 to 2018. Patients were stratified according to the presence or absence of IHD. Our primary end-point was five-year all-cause mortality. Survival was analyzed using Kaplan-Meier curve. Data were acquired through the SWENTRY registry and patient files. Results: A total of 264 patients were included in the study, with 139 (52.7 %) patients in the IHD group vs 125 (47.3 %) patients in the non-IHD group. Mean follow-up time was 40 ±30 months. At baseline, there was a higher proportion of males, patients with hypertension, peripheral arterial disease, left ventricular ejection fraction <50 % and, a higher EuroSCORE I in the IHD-group. Transfemoral approach was most common in both groups. No differences were noted in respect to peri- and postoperative complications. Five-year all-cause mortality was 17/38 (44.7 %) vs 18/30 (60.0 %), p = 0,232, in the IHD and non-IHD group respectively. Non-adjusted cumulative five-year survival was not significantly different between the groups (Log-Rank, p = 0,056). Conclusions: In patients with severe AS undergoing TAVI, the five-year all-cause mortality was not statistically different between patients with or without IHD.

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Zappe, Ann-Katrin Reglinde [Verfasser]. "Follow-Up bei Patienten nach perkutaner Valve-in-Valve Aortenklappenimplantation : Patients with transcatheter valve-in-valve implantation for failed surgical aortic valves / Ann-Katrin Reglinde Zappe." Berlin : Medizinische Fakultät Charité - Universitätsmedizin Berlin, 2020. http://d-nb.info/1223928322/34.

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Murphy, Aileen Margaret. "Economic evaluations for health technologies with an evolving evidence base : a case study of transcatheter aortic valve implantation." Thesis, University of Glasgow, 2013. http://theses.gla.ac.uk/4061/.

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The primary aim of this thesis is to investigate the challenges in conducting economic evaluations for medical devices with evolving evidence bases. While economic evaluations for capital projects and medicines are well established in theory and practice, the same cannot be said for novel medical devices. New medical devices are often expensive and rely on scarce evidence for efficacy and cost. This increases uncertainty surrounding their clinical and cost effectiveness. In addition, as fewer formal procedures exist for evaluating devices relative to medicines, evidence bases are weak and health technology assessment agencies are reluctant to make rapid decisions. To address these issues a continuous iterative framework developed and proposed for economic evaluations of medical devices. In this thesis, using Transcatheter Aortic Valve Implantation (TAVI) as a case study, an iterative economic evaluation, employing Bayesian techniques, is developed to investigate how the challenges associated with medical devices can be overcome to produce an efficient and informative economic evaluation. This study is the first to investigate these challenges and identify solutions while conducting an economic evaluation early in a device’s life cycle, using the proposed continuous iterative framework. The consideration of Access with Evidence Development schemes to overcome these challenges and balance access with evidence generation for expensive and novel medical devices, with evolving evidence, is another important contribution of the thesis. Transcatheter Aortic Valve Implantation (TAVI) is a novel treatment for severe Aortic Stenosis for operable and inoperable patients. The iterative economic evaluation concludes that TAVI can be considered cost effective for inoperable patients compared to medical management. There is little value in commissioning new research for continued data collection for this group. However, the continued collection of evidence via the UK TAVI registry as indicated in the National Institute of Clinical Excellence (NICE) guidelines will ensure up to date evidence is available to inform future decisions regarding TAVI in this patient group. For operable patients, the iterative model could not conclude that TAVI was cost effective compared to Aortic Valve Replacement (AVR). However, additional evidence of improved outcomes from TAVI should enhance its cost effectiveness for these patients. The Bayesian value of information analysis indicates that further information on short and long term probability, resource and quality of life parameters is most valuable and the optimal research design for collecting such information is a registry.

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Martin, Glen. "Methodological development to support clinical prediction modelling within local populations : applications in transcatheter aortic valve implantation and an analysis of the British Cardiovascular Interventional Society national registry." Thesis, University of Manchester, 2017. https://www.research.manchester.ac.uk/portal/en/theses/methodological-development-to-support-clinical-prediction-modelling-within-local-populations-applications-in-transcatheter-aortic-valve-implantation-and-an-analysis-of-the-british-cardiovascular-interventional-society-national-registry(22691de9-ebb8-4d2a-a942-b3e46dbe9577).html.

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There is growing interest in using large-scale observational data collected through national disease registries to develop clinical prediction models (CPMs) that use the experiences of past patients to make predictions about risks of outcome in future patients. CPMs are often developed in isolation across different populations, with repetitive de novo development a common modelling strategy. However, this fails to utilise all available information and does not respond to changes in health processes through time/space. Using the UK transcatheter aortic valve implantation (TAVI) registry as motivation, this thesis aimed to develop methods that improve the development of CPMs within local populations. Three research questions (RQs) were considered: (1) what are the challenges of mortality risk prediction in TAVI due to changes in procedure knowledge and the patient population? (2) Can we use a combination of baseline patient characteristics to predict the risk of mortality post TAVI? (3) How can we exploit multi-dimensional information about patients to inform clinical decision-making at a local-level? Chapter 2 demonstrates potential to simplify the procedure by removing pre-dilation of the aortic valve, thereby altering the underlying treatment pathway, and Chapter 3 shows that mortality rates from registries should be reported in the context of the underlying patient population. Despite Chapter 2 and 3 presenting potential challenges to TAVI risk prediction (RQ 1), CPMs are fundamental to support benchmarking/audit analyses. To this end, Chapter 4 found that the performance of existing TAVI CPMs was inadequate for use in UK patients. Through the discovery of new risk factors (e.g. frailty) in Chapter 5, the thesis derived a UK-TAVI CPM for audit analyses within the UK cohort (Chapter 6). While Chapters 4-6 present the classic framework of CPM development (RQ 2), this cannot overcome the challenges of mortality prediction in the TAVI setting (RQ 1) and is not suited to support local healthcare decision-making (RQ 3). Thus, Chapter 7 found that local model development could be supported through aggregating existing models rather than re-development. Existing methods of model aggregation were extended in Chapter 8 to allow prior research and new data to be utilised within the modelling strategy; application of the herein derived method to the UK TAVI registry indicated that it could facilitate the choice between model aggregation and de novo CPM derivation. Generally, this thesis has the potential to improve the implementation of CPMs within local populations by moving away from the iterative process of re-development. Practically, the thesis derived a UK-TAVI CPM for audit analyses, using classic and novel methodology.

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Ding, Wenhong. "Survival and functional recovery following valve replacement in patients with severe aortic stenosis." Doctoral thesis, Umeå universitet, Medicin, 2013. http://urn.kb.se/resolve?urn=urn:nbn:se:umu:diva-82644.

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Background: Aortic stenosis (AS) is the most common heart valve disease in Europe and North America. Age-related calcification of the valve is the commonest cause of acquired AS, especially in patients older than 70 years.Conventional surgical aortic valve replacement (SAVR) and the novel, minimally invasive transcatheter aortic valve implantation (TAVI), effectively preserve left ventricular (LV) function, relieve symptoms and improve survival in patients with severe symptomatic AS. However, patients with impaired LV function may carry significant operative risk, and long recovery time. In addition, such patients might have other comorbidities, and hence adding another challenge. Thus evaluation of ventricular function before and after AVR, as well as critical evaluation of TAVI patients should contribute to better clinical outcome. Methods: We studied LV function by conventional echocardiography before and after SAVR in the following groups; (I) 86 patients (aged 71±10 years) with severe AS and LV dysfunction; (II) 112 consecutive elderly AS patients (aged 77±2 years) and compared them with 72 younger patients (aged 60±1 years); (III)66 patients (age 70±2 years, 53 male) who underwent AVR for severe AS with concurrent LV dysfunction; (IV) 89 consecutive patients with symptomatic severeAS who underwent successful TAVI, 45 of whom received trans-apical TAVI (TA)(age 80.8±4.9 year, 26 male) and 44 trans-femoral TAVI (TF) (age 82.9±5.8 year,22 male).The conventional echocardiographic measurements were made according to the guidelines. Severe AS was identified by aortic valve mean pressure gradient >40mmHg or valve area <1.0 cm2. LV systolic dysfunction was identified as ejection fraction (EF) <50%. LV long-axis function was presented by mitral annular plane systolic excursion ( MAPSE ) at lateral wall and septal wall, which were measured from apical four-chamber view. Also from the same view, LV septal and lateral wall deformation using STE as well as global longitudinal systolic strain. The LV systolic twist as the net difference between apical rotation and basal rotation was measured from the parasternal apical and basal short-axis views in the TAVI patients. Results: Study I: In the low flow and high gradient group, operative (30-day) mortality was 10%, and peri-operative mortality was associated with lower mean LVEF, higher mitral E:A ratio, peak systolic pulmonary artery pressure (PSPAP), and higher serum creatinine (all p<0.001), NYHA class III–IV, concomitant coronary artery bypass graft (CABG), urgent surgery, and longer bypass-time (all p< 0.05). Mortality at 4 years was 17%. Univariate predictors of 4-year mortality were: lower EF (p<0.001), presence of restrictive LV filling (p<0.001), raised PSPAP (p<0.001) and CABG (p=0.037). However, only EF<40 % (p=0.03), the presence of restrictive LV filling (p=0.033) and raised PSPAP (p<0.01)independently predicted mortality in this group.Study II: Elderly patients had higher NYHA class, more frequent atrial fibrillation (AF), coronary artery disease (CAD), emergency operation and use of bioprosthetic valves. They also had shorter E-wave deceleration time (DT) and larger left atria (LA) (p<0.05 for all). 30-day mortality was 12% vs 4 % (Log Rank x2=3.02, p=0.08) and long term mortality was 18% vs 7% (Log Rank x2=4.38,p=0.04) in the two groups, respectively. Age was not related to mortality after adjustment for other variables. Among all variables, anemia (OR 4.20, CI:1.02–6.86, p=0.04), cardiopulmonary bypass (CPB) time (OR 1.02, CI 1.01–1.04,p<0.01), significant patient prosthesis mismatch (PPM) (OR 5.43, CI 1.04–18.40,p<0.05) were associated with 30-day mortality in elderly patients. Their long-term mortality was related to CBP time (OR 1.02, CI 1.00–1.05, p=0.04),PPM (OR 4.64, CI 1.33–16.11, p=0.02) and raised LA pressure: DT (OR 0.94, CI0.84–0.99, p=0.03) and pulmonary artery systolic pressure (PASP) (OR 1.12, CI1.03–1.19, p<0.001).STUDY III: Following SAVR peak aortic pressure gradient (AOPG) decreased and indexed valve area increased (64±3 to 19±1 mmHg and 0.30±0.01 to 0.89±0.03 cm2/m2, p<0.001 for both). LVEF increased (from 45±1 to 54±2%;p<0.001), LV end diastolic and end-systolic dimensions fell (LVEDD index: from 33±1 to 30±1 mm/m2; and LVESD index: from 27±1 to 20±1 mm/m2; (p<0.01 forboth). LV diastolic dysfunction improved as evidenced by the fall in E/A ratio (from 2.6±0.2 to 1.9±0.4) and prolongation of total filling time; (from 29.2±0.6 to31.4±0.5 s/min, p=0.01 for both). Among all echocardiographic variables, LV dimensions (LVEDD index, OR 0.70, CI 0.52–0.97, p<0.05; LVESD index, OR 0.57, CI 0.40–0.85, p=0.005) were the two independent predictors of post-operative LV functional recovery on multivariate analysis. A cut-off value ofpre-operative LVESD index<=27.5 mm/m2 was 85% sensitive and 72% specific inpredicting intermediate-term recovery of LV function after AVR (AUC, 0.72, p=0.002). STUDY IV: Before TAVI, there was no difference between the two patient groups in gender, age, body surface area (BSA) and baseline LV function. However, left ventricular mass index (LVMi), left atrial volume index (LAVi) and tricuspid regurgitation pressure drop (TRPdrop) were increased in the TA group (p<0.05).One week after TAVI, aortic pressure gradient (AOPG) markedly dropped in thetwo groups (both p<0.001), LVEDD index and LVESD index fell but EF andmyocardial strain remained unchanged. Overall cavity twist reduced (p<0.048).Significant LVESD index reduction was only seen in TF group (p=0.02) with a slight increase in LVEF (p=0.04). Lateral MAPSE increased only in the TF group(p=0.02). LV longitudinal systolic strain remained unchanged in TA patients while apical lateral strain increased in TF group. LV apical rotation fell in the two groups but basal rotation increased only in the TA patients (p=0.02). LAVi reduced in bothgroups and to a greater extent in TF TAVI (p=0.006), as did TRPdrop (p<0.001). Conclusion: SAVR and TAVI are two effective treatments for severe AS patients.The severity of pre-operative systolic and diastolic LV dysfunction is the major predictor of mortality following SAVR for low-flow and high gradient AS.Peri-operative AVR survival is encouraging in the elderly. Long term mortality in the elderly is related to PPM, LV diastolic dysfunction and secondary pulmonary hypertension. LV functional recovery was evident in most patients with LV dysfunction after SAVR. A lower prevalence of LV functional recovery in patients with large pre-operative LVESD index might signify the loss of contractile reserveand thus predict post-operative functional recovery. TAVI results in significant early improvement of segmental and overall ventricular function, particularly in patients receiving the trans-femoral approach. The delayed recovery of the trans-apical TAVI group, we studied, might reflect worse pre-procedural diastolic cavity function.

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Voigtländer, Lisa [Verfasser], and Ulrich [Akademischer Betreuer] Schäfer. "Impact of kidney function on mortality after transcatheter valve implantation in patients with severe aortic valvular stenosis / Lisa Voigtländer. Betreuer: Ulrich Schäfer." Hamburg : Staats- und Universitätsbibliothek Hamburg, 2016. http://d-nb.info/109341152X/34.

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Vy, Phuoc. "Simulation numérique personnalisée du positionnement des guides dans les procédures d'implantation de valve aortique percutanée." Thesis, Lyon, 2018. https://tel.archives-ouvertes.fr/tel-02921452.

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Cette thèse s’intéresse à l’implantation de prothèse de valve aortique par voie endovasculaire (TAVI). Cette technique mini-invasive bénéficie d’un intérêt croissant depuis son invention il y a environ deux décennies. Elle consiste à conduire une prothèse compressible dans les artères du patient par le biais d’un système de largage composé d’un guide rigide et d’un cathéter de pose. Le bon fonctionnement de la prothèse dépend entre autres de sa position et de son orientation correctes au sein de la racine aortique du patient. Ainsi, la prédiction de la configuration spatiale de la prothèse constitue une aide pertinente pour armer les médecins lors de leur planification pré-opératoire. Dans l’hypothèse que les interactions mécaniques entre le système de largage et les tissus biologiques déterminent la configuration spatiale de la prothèse, la thèse aborde la simulation numérique de la déformation du guide rigide à son insertion.Un modèle mécanique a été mis au point et traduit en modèle numérique résolu par la méthode des éléments finis. La configuration spatiale au niveau de la valve aortique du guide rigide simulé a ensuite été validée avec les données per-opératoires de deux patients. Une vérification globale du modèle a également été réalisée à l’aide d’un fantôme physique imprimé en 3D basé sur la géométrie d’un patient. Enfin, le modèle numérique est exploité pour éclairer le choix d’un guide rigide personnalisé à un cas de patient réel
This work revolves around transcatheter aortic valve implantation (TAVI), which delivers a collapsible prosthesis to the native aortic valve through a delivery system (stiff guidewire and prosthesis sheath) inserted in an artery. This procedure became very popular ever since its introduction two decades ago. However, the performance of the treatment is correlated with the positioning of the prosthesis within the aortic root of the patient. Therefore, prediction of the spatial configuration of the prosthesis appears relevant data to assist pre-operative planning. It is assumed that the mechanical interactions between the delivery system and biological tissues determine the spatial configuration of the prosthesis. The thesis explores numerical simulation as a predictive tool. More specifically, the thesis attempts to numerically reproduce the deformations of the inserted stiff guidewire.A mechanical model was developed and translated into a Finite-Element model. The numerical prediction of the guidewire positioning within the aortic valve was validated with intra-operative data from two patient cases. The numerical model was also verified through an experiment using a 3D-printed patient-specific phantom. It was then exploited to choose a guidewire specifically suited for a patient

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Hernández, Enríquez Marco. "Transcatheter Aortic Valve Implantation: Moving Forward to Minimize Vascular and Bleeding Complications = Implante Transcatéter de Válvula Aórtica: Avanzando hacia la Reducción de Complicaciones Vasculares y Hemorrágicas." Doctoral thesis, Universitat de Barcelona, 2020. http://hdl.handle.net/10803/669896.

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INTRODUCTION: TAVI has settled as the standard of care of AS for inoperable, high-risk, and selected intermediate-risk patients undergoing aortic valve replacement. Vascular and bleeding complications are related to worst outcomes. HYPOTHESES: a. The reduction and early recognition of vascular and bleeding complications might improve clinical outcomes in patients treated with TAVI. b. A full percutaneous transfemoral approach for TAVI is related to a lower rate of major bleedings in comparison to the surgical cut-down approach. c. The development of post-TAVI thrombocytopenia has a prognosis value in short-term clinical outcomes. d. The kinetics of drop platelet count (DPC) after TAVI are different according to the type of valve implanted. MATERIALS AND METHODS: Sub-project 1: “Comparison of complications between percutaneous puncture or surgical cut-down for transfemoral access in TAVI” Data from the Spanish TAVI Registry were analyzed. Patients undergoing transfemoral TAVI in 41 Spanish centers from January 2010 to July 2015 were included. Subjects were divided into percutaneous puncture (PG) and cut-down group (CG). A propensity-matched comparison was performed to avoid selection bias. Vascular and bleeding complications were evaluated at 30-days and mid-term follow-up. Sub-project 2: “Study of Thrombocytopenia after TAVI” a. Patients from 2 Spanish centers between 2012 to 2016 were included. Subjects with severe baseline thrombocytopenia (<100x109/L) and peri-procedural death were excluded. Laboratory analyses were performed. Two groups were created according the DPC: ≤30% or >30%. Clinical, procedural characteristics and outcomes were collected retrospectively. b. Patients treated with transfemoral TAVI in a French high-volume center from 2008 to 2016 were included. Exclusion criteria were non-transfemoral approach, severe baseline thrombocytopenia and peri-procedural death. The study protocol was like the previous study. RESULTS: Sub-project 1 A total of 2,465 transfemoral TAVI patients were included. The PG had 1,833 patients (74,3%) and the CG had 632 patients (25,6%). Propensity matching score resulted in 615 pairs. Vascular complications at 30-days were significantly higher in the PG (RR 2,66; IC95% [1,85-3,64], p = <0,001) mainly driven to minor vascular complications. In contrast, the bleeding complications were higher in the CG (RR 0,45; IC95% [0,26-0,78], p = 0,003). At a mean follow-up of 323 days, the rates remained similar. Higher rates of vascular complications in the PG: 15% vs. 5,1% (HR 2,23; IC95% [1,6-3,11]; p = <0,001) and higher rates of major bleedings in the CG: 3,4% vs. 1,6% (HR 0,57; IC95% [0,35-0,95], p = 0,03). Sub-project 2 a) The analyzed population included 195 patients: 100 (52,2%) treated with self-expanding valves (SEV) and 95 (48,8%) with balloon-expandable valves (BEV). The mean percentage of DPC was 31,9±15,3%. The DPC was significantly higher in the BEV population in comparison to SEV (36,3±15,1% vs 27,7±14,4, p<0,001). After multivariate analysis, the use of BEV was independently associated to a DPC>30% (67,4% vs. 36,0%; OR 3,4; 95% CI, 1,42-8,16). AT 30-days, the DPC>30% was associated to a higher rate of major and life-threatening bleedings, vascular complications, sepsis, and death. At 1-year there were no differences in mortality. (6,35% vs. 10,0%; HR 1,54; 95% CI, 0,56-4,25). b) A total of 609 were included. The mean DPC was 32,5±13,9%. The DPC was higher in the BEV group (33.9±14.2 vs 30.7±13.4%, p=0.006), and the nadir was reached significantly later in comparison with the SEV group. (3,0±1,3 vs 2,5±1,1 days, p<0,001). After the multivariate analysis, the factors related to a DPC>30% were the use of BEV, known coronary disease and preserved left ventricle ejection fraction. At 30-days the DPC>30% was associated to a higher rate of major and life-threatening bleedings (6,8 vs 2,1%, p=0.009) and death (3,5 vs 0,8%, p=0.036). At 1-year there were no differences in mortality CONCLUSIONS: 1. The reduction and early recognition of vascular and bleeding complications is associated to an improvement in clinical outcomes in patients treated with TAVI. 2. The completely percutaneous approach of transfemoral TAVI yielded lower rate of major bleedings and higher rate of minor vascular complications in comparison to the surgical cut-down and closure. 3. A post-procedural DPC>30% is related with worse clinical outcomes at 30-days after TAVI. 4. The use of balloon-expandable valves seems to be associated with a higher risk of drop on platelet counts after TAVI.
El Implante Transcatéter de Válvula Aórtica (TAVI) se ha consolidado como el tratamiento de elección en pacientes inoperables, de alto y seleccionados con intermedio riesgo quirúrgico. Las complicaciones vasculares y hemorrágicas están asociadas a peores resultados clínicos y a mayor estancia intrahospitalaria. Subproyecto 1: “Comparación entre las complicaciones de la punción percutánea y disección quirúrgica en el Implante Transfemoral de Válvula Aórtica” Análisis retrospectivo del Registro Nacional TAVI. Se incluyeron pacientes tratados con TAVI transfemoral en 41 centros españoles desde enero 2010 hasta julio 2015. Se evaluaron la complicaciones vasculares y hemorrágicas a los 30 días y a medio término. Asimismo, se evaluó la frecuencia de ictus, daño renal agudo, infarto del miocardio y muerte. Para reducir el sesgo de selección se realizó un “score de propensión”. Subproyecto 2: “Estudio de la Trombocitopenia después del Implante Transcatéter de Válvula Aórtica” a) Se incluyeron pacientes tratados con TAVI en 2 centros españoles entre enero 2012 y diciembre 2016. Se excluyeron pacientes con plaquetopenia severa basal (<100x109/L) y con muerte peri-procedimiento. Se realizaron analíticas seriadas durante el ingreso. El seguimiento clínico se realizó a los 30 días, 3 meses y 1 año posterior al procedimiento. Se recogieron las características basales, del procedimiento y los eventos clínicos en una base de datos. Se crearon 2 grupos de acuerdo con el porcentaje de caída de plaquetas: ≤30% y >30%. b) Se incluyeron pacientes tratados con TAVI transfemoral en un centro francés de alto volumen de TAVI, entre enero 2008 y diciembre 2016. Se excluyeron los pacientes con acceso no transfemoral, con plaquetopenia severa pre-procedimiento y con muerte peri-procedimiento. El protocolo del estudio fue similar al del estudio previo. La disminución y el reconocimiento temprano de complicaciones vasculares y hemorrágicas permite mejores resultados clínicos en pacientes tratados con TAVI. El abordaje completamente percutáneo de la TAVI se asoció a una tasa menor de sangrados mayores y a una mayor tasa de complicaciones vasculares menores en comparación con el abordaje quirúrgico. La caída en el porcentaje de plaquetas >30% se relaciona con peores resultados clínicos a los 30 días post-TAVI. El uso de las prótesis balón-expandibles parece asociarse a un mayor riesgo de disminución de plaquetas.

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KARAR, Mohamed Esmail Abdel Razek Hassan [Verfasser], Oliver [Akademischer Betreuer] Burgert, Thomas [Gutachter] Deserno, and Gerik [Gutachter] Scheuermann. "Development of a Surgical Assistance System for Guiding Transcatheter Aortic Valve Implantation / Mohamed Esmail Abdel Razek Hassan KARAR ; Gutachter: Thomas Deserno, Gerik Scheuermann ; Betreuer: Oliver Burgert." Leipzig : Universitätsbibliothek Leipzig, 2012. http://d-nb.info/1238020909/34.

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Figulla, Laura [Verfasser], Till [Akademischer Betreuer] Neumann, Heinz [Akademischer Betreuer] Jakob, and Rüdiger [Akademischer Betreuer] Autschbach. "Evidence on safety and efficacy transcatheter aortic valve implantation or medical therapy in symptomatic severe aortic stenosis : a systematic review of current literature / Laura Figulla. Gutachter: Till Neumann ; Heinz Jakob ; Rüdiger Autschbach." Duisburg, 2012. http://d-nb.info/1019930101/34.

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Schiefer, Conrad. "Transfemorale Aortenklappenimplantation bei älteren Hochrisikopatienten mit symptomatischer, hochgradiger Aortenklappenstenose – prospektiver Vergleich der Edwards SAPIEN™/SAPIEN XT™ Transcatheter Heart Valves mit dem Medtronic CoreValve ReValving™ System." Doctoral thesis, Universitätsbibliothek Leipzig, 2012. http://nbn-resolving.de/urn:nbn:de:bsz:15-qucosa-97519.

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Die transfemorale Aortenklappenimplantation stellt für ältere Patienten mit einer symptomatischen, hochgradigen Aortenklappenstenose und einem erhöhten perioperativen Letalitätsrisiko eine Alternative zum konventionell-chirurgischen Aortenklappenersatz dar. In der vorliegenden Arbeit wurden die beiden aktuell in Europa zugelassenen transfemoralen Systeme in Bezug auf deren prozedurale Sicherheit, den klinischen Nutzen, die 1-Jahres-Letalitätsrate und die langfristige Klappenfunktionalität unter Anwendung der Kriterien zur standardisierten Komplikationsanalyse des Valve Academic Research Consortiums (VARC) verglichen. Jeweils 100 konsekutive Patienten, bei denen eine transfemorale Aortenklappenimplantation mit den Edwards SAPIEN™/SAPIEN XT™ Transcatheter Heart Valves bzw. dem Medtronic CoreValve ReValving™ System durchgeführt wurde, wurden in die Analyse eingeschlossen. Dies stellt das größte bisher publizierte Patientenkollektiv für den Vergleich der beiden Aortenklappenimplantationssysteme in einem Zentrum über den femoralen Zugangsweg dar. Es wurden mit beiden Systemen ähnlich gute postinterventionelle hämodynamische und klinische Ergebnisse erreicht. Ein signifikanter Unterschied bezüglich der prozeduralen Sicherheit und der 1-Jahres-Letalitätsrate zwischen den beiden Systemen konnte trotz signifikanter Unterschiede in Bezug auf bestimmte periinterventionelle Risiken nicht nachgewiesen werden. Die langfristige Klappenfunktion beider Systeme war exzellent.

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Matos, Mariana Lopes. "Transcatheter Aortic Valve Implantation (TAVI): certainties, controversies and future perspectives." Dissertação, 2018. https://hdl.handle.net/10216/112285.

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Matos, Mariana Lopes. "Transcatheter Aortic Valve Implantation (TAVI): certainties, controversies and future perspectives." Master's thesis, 2018. https://hdl.handle.net/10216/112285.

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HSU, CHING-I., and 徐靜儀. "Transcatheter Aortic Valve Implantation (TAVI) for Aortic Stenosis in Sarcopenia Patients: Investigating Nutritional Status and Family Support." Thesis, 2018. http://ndltd.ncl.edu.tw/handle/vfh864.

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碩士
國立臺北護理健康大學
護理研究所
106
Background: Sarcopenia in older adult is an issue that has attracted international attention in recent years. Sarcopenia is often caused by insufficient nutrition to support bodily functions. Patients who undergo transcatheter aortic valve implantation (TAVI) are mostly elderly patients. Malnutrition in these patients will result in multiple complications. However, only a few studies have examined the nutritional status, family support, and correlation between nutrition status and family support in TAVI patients with or without sarcopenia. Aim: The purpose of this study was to explore the correlation between nutritional status and family support in patients who had undergone TAVI with and without sarcopenia. Methods: This was a case-control study. Eighty one patients were recruited from the cardiology outpatient and wards of hospital in Taiwan. Instruments included Mini-Nutritional Assessment-Short Form (MNA-SF), Numerical Rating Scale and a demographic questionnaire surveys. The SPSS 20 software was used for coding and statistical analysis. Results: The results showed that the TAVI patients with the sarcopenia were older and had shorter height, lower weight, higher creatine levels, lower albumin levels, and lower simplified Mini-Nutritional Assessment scores, which may indicate malnutrition. Conclusion: We found significant differences in nutritional status between the TAVI patients with and those without sarcopenia (p = 0.047). The risk of malnutrition in TAVI patients with sarcopenia was 5.5 times higher than that in TAVI patients without sarcopenia.

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Freixo, Sara Dias. "Aortic valve stenosis in octogenerians: what is the role of conventional aortic valve replacement?" Master's thesis, 2019. http://hdl.handle.net/10316/89637.

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Trabalho Final do Mestrado Integrado em Medicina apresentado à Faculdade de Medicina
Objetivos: A implantação percutânea da válvula aórtica (TAVI) tem levantado cada vez mais questões quanto ao uso da cirurgia convencional de substituição da válvula aórtica (AVR) em doentes com risco cirúrgico intermédio a elevado, particularmente em octogenários. No entanto, a AVR tornou-se menos invasiva e os resultados cirúrgicos melhoraram nos últimos anos. Neste estudo avaliamos os resultados peri-operatórios, a sobrevida e o estado funcional dos doentes octogenários, submetidos a AVR isolada.Métodos: De janeiro de 2006 a dezembro de 2016, 2947 doentes foram submetidos a AVR isolada, dos quais 385 (13.1%) eram octogenários e constituem a população deste estudo. A média de idades foi de 82.1 ± 2,0 anos, 57.7% eram mulheres e 47.3% estavam em classe NYHA III-IV. A mediana do EuroSCORE-II foi de 3.6 ± 3.9. O alargamento da raiz da aorta foi realizado em 105 casos (27.1%).Resultados: Houve apenas um caso de mortalidade intra-hospitalar e a mortalidade total nos primeiros 30 dias foi de 0,8% (2 doentes). Verificou-se a implantação definitiva de pacemaker em 3.5% dos casos, 0.8% tiveram como complicação acidente vascular cerebral e 0,8% enfarte agudo do miocárdio. Não se verificaram casos de regurgitação peri-protésica grave ou moderada e apenas 18 doentes tiveram regurgitação mínima ou ligeira. A média de permanência hospitalar foi de 8,0 ± 3,2 dias. A mediana de tempo de seguimento foi de 4.4±2.64 anos. A sobrevida aos 1, 5 e 10 anos foi de 95.1±1.1%, 76.3±2.5% e 41.7±5.3%, respetivamente, significativamente melhor do que a sobrevivência da população em geral com idade e género correspondentes. A presença de fibrilação auricular (HR:2.428; CI:1.552-3.798, p=0.008), insuficiência renal (HR:1.404; CI:1.037-1.902, p=0.028) e classes de NYHA mais altas (HR:1.464; CI:1.106-1.939, p=0.007) foram fatores de risco independentes de mortalidade tardia. A maioria dos doentes (97%) demonstrou alto grau de satisfação com a cirurgia e 82,9% estavam na classe I-II de NYHA.Conclusões: A AVR isolada convencional em octogenários tem mortalidade e morbidade muito baixas. Na nossa série de doentes, os scores de risco sobrevalorizaram a mortalidade. Estes resultados devem ser vistos como referência e devem ser comparados com os procedimentos percutâneos.
Background: Transcatheter aortic valve implantation (TAVI) increasingly questions the use of conventional aortic valve replacement (AVR) in high-intermediate risk patients, particularly in octogenarians. Nevertheless, AVR has become less-invasive and surgical outcomes have improved in the last years. In this study, we evaluate the perioperative outcomes, survival and functional status after AVR in octogenarian patients.Methods: From Jan-2006 to Dec-2016, 2947 patients were submitted to AVR, of whom 385 (13.1%) were octogenarians and constitute the subject of this study. Mean age was 82.1±2.0 years, 57.7% female, and 47.3% were in New York Heart Association (NYHA) class III-IV. Median EuroSCORE-II: 3.6 ± 3.9. Aortic root enlargement was performed in 105 cases (27.1%).Results: Only one patient died during hospitalization (0.3%) and thirty-day mortality was 0.8% (3 patients). Permanent pacemaker implantation occurred in 3.5%, stroke in 0.8% and acute myocardial infarction in 0.8%. Only 18 patients had peri-prosthetic leak (minimal or mild), no moderate or severe leakage was observed. Mean hospital stay was 8.0±3.2 days. Median follow-up time was 4.4±2.64 years (range: 1-12 years). Survival at 1, 5 and 10 years was 95.1±1.1%, 76.3±2.5% and 41.7±5.3%, respectively, significantly better than the expected survival of the general population (age and gender-matched). Atrial fibrillation (HR:2.428; CI:1.552-3.798, p=0.008), renal failure (HR:1.404; CI:1.037-1.902, p=0.028) and higher NYHA classes (HR:1.464; CI:1.106-1.939, p=0.007) were independent risk factors of late mortality. The majority of subjects (97%) showed a high degree of satisfaction with the surgery and 82.9% were in NYHA class I-II. Colocar o resultado da comparação com a população geral Conclusions: Contemporary isolated AVR in octogenarians carries very low mortality and morbidity. In our series, the risk-score calculators overvalued mortality. These results should be viewed as benchmark to which transcatheter procedures should be compared.

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Simões, Fernando Jorge Rocha. "General anesthesia vs. sedation in transcatheter aortic valve implantation (TAVI): retrospective study of the incidence of acute kidney injury." Dissertação, 2020. https://hdl.handle.net/10216/128682.

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Objetivos: O objetivo deste estudo foi avaliar a existência de associação entre a abordagem anestésica (anestesia geral versus sedação) em pacientes submetidos a implantação de válvula aórtica transcateter (TAVI) e a incidência de lesão renal aguda (LRA) no pós-operatório. Como outcome secundário, também foi avaliada a associação entre o tipo de anestesia e a mortalidade. Desenho: Estudo retrospetivo, de centro único, observacional. Local: Centro Hospitalar Universitário de São João, um centro de referência português. Participantes: Foram incluídos todos os pacientes submetidos a TAVI na instituição dos autores de janeiro de 2015 a junho de 2018. Intervenções: Anestesia geral (AG) ou sedação para procedimentos TAVI. Medições e Principais Resultados: O outcome primário foi a incidência de LRA e o outcome secundário incluiu mortalidade intra-hospitalar e aos 30 e 90 dias. No período estudado, 107 pacientes foram submetidos a TAVI (AG: n=24; sedação: n=83) e a incidência de LRA foi de 14,02%. Encontramos uma maior incidência de hipotensão intraoperatória no grupo AG (83,3% vs 33,7%, p <0,001). Em relação aos resultados pós-operatórios, não houve diferenças significativas na incidência de LRA (20,8% vs 12,0%, p = 0,319) e mortalidade. A principal descoberta de interesse foi a associação significativa entre a incidência de LRA pós-operatória e doença renal crónica (DRC) pré-existente, classe funcional de insuficiência cardíaca pré-operatória, hipotensão intraoperatória, maior período de permanência na unidade de nível II e de internamento hospitalar, e agravamento do estádio prévio da DRC. Conclusões: Não foi possível estabelecer associação entre a abordagem anestésica para procedimentos TAVI e incidência de LRA pós-operatória e mortalidade. O nosso estudo reforça a importância de prevenir a incidência de LRA, considerando o seu impacto no agravamento da DRC basal e no aumento do período de internamento, levando a custos mais elevados de hospitalização.
Objective(s): The aim of this study was to assess the existence of association between anesthetic approach (general anesthesia versus sedation) for patients undergoing transcatheter aortic valve implantation (TAVI) and the postoperative acute kidney injury (AKI) incidence. As secondary outcome we also assess the association between anesthesia type and mortality. Design: Retrospective, single-center, observational study. Setting: Centro Hospitalar Universitário de São João, a Portuguese reference center. Participants: All patients undergoing TAVI from January 2015 to June 2018. Interventions: General anesthesia (GA) or sedation for TAVI procedures. Measurements and Main Results: The primary outcome was AKI incidence, and secondary outcome included in-hospital, 30-day and 90-day mortality. In the period studied, 107 patients underwent TAVI (GA: n=24; sedation: n=83) and the overall incidence of AKI was 14.02%. We found a higher incidence of intraoperative hypotension in the GA group (83.3% vs 33.7%, p<0.001). Regarding postoperative outcomes, there were no significant differences in AKI incidence (20.8% vs 12.0%, p=0.319) and mortality. The major finding of interest was the significant association between postoperative AKI and preexisting chronic kidney disease (CKD), preoperative heart failure functional class, intraoperative hypotension, longer length of stay in level II unit and longer hospital stay, and worsening of previous CKD stage. Conclusions: It was not possible to established association between the anesthetic approach for TAVI procedures and postoperative AKI and mortality. Our study reinforces the importance of preventing AKI incidence, considering its impact on the worsening of baseline CKD and on the length of stay, leading to higher hospitalization costs.

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Simões, Fernando Jorge Rocha. "General anesthesia vs. sedation in transcatheter aortic valve implantation (TAVI): retrospective study of the incidence of acute kidney injury." Master's thesis, 2020. https://hdl.handle.net/10216/128682.

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Objetivos: O objetivo deste estudo foi avaliar a existência de associação entre a abordagem anestésica (anestesia geral versus sedação) em pacientes submetidos a implantação de válvula aórtica transcateter (TAVI) e a incidência de lesão renal aguda (LRA) no pós-operatório. Como outcome secundário, também foi avaliada a associação entre o tipo de anestesia e a mortalidade. Desenho: Estudo retrospetivo, de centro único, observacional. Local: Centro Hospitalar Universitário de São João, um centro de referência português. Participantes: Foram incluídos todos os pacientes submetidos a TAVI na instituição dos autores de janeiro de 2015 a junho de 2018. Intervenções: Anestesia geral (AG) ou sedação para procedimentos TAVI. Medições e Principais Resultados: O outcome primário foi a incidência de LRA e o outcome secundário incluiu mortalidade intra-hospitalar e aos 30 e 90 dias. No período estudado, 107 pacientes foram submetidos a TAVI (AG: n=24; sedação: n=83) e a incidência de LRA foi de 14,02%. Encontramos uma maior incidência de hipotensão intraoperatória no grupo AG (83,3% vs 33,7%, p <0,001). Em relação aos resultados pós-operatórios, não houve diferenças significativas na incidência de LRA (20,8% vs 12,0%, p = 0,319) e mortalidade. A principal descoberta de interesse foi a associação significativa entre a incidência de LRA pós-operatória e doença renal crónica (DRC) pré-existente, classe funcional de insuficiência cardíaca pré-operatória, hipotensão intraoperatória, maior período de permanência na unidade de nível II e de internamento hospitalar, e agravamento do estádio prévio da DRC. Conclusões: Não foi possível estabelecer associação entre a abordagem anestésica para procedimentos TAVI e incidência de LRA pós-operatória e mortalidade. O nosso estudo reforça a importância de prevenir a incidência de LRA, considerando o seu impacto no agravamento da DRC basal e no aumento do período de internamento, levando a custos mais elevados de hospitalização.
Objective(s): The aim of this study was to assess the existence of association between anesthetic approach (general anesthesia versus sedation) for patients undergoing transcatheter aortic valve implantation (TAVI) and the postoperative acute kidney injury (AKI) incidence. As secondary outcome we also assess the association between anesthesia type and mortality. Design: Retrospective, single-center, observational study. Setting: Centro Hospitalar Universitário de São João, a Portuguese reference center. Participants: All patients undergoing TAVI from January 2015 to June 2018. Interventions: General anesthesia (GA) or sedation for TAVI procedures. Measurements and Main Results: The primary outcome was AKI incidence, and secondary outcome included in-hospital, 30-day and 90-day mortality. In the period studied, 107 patients underwent TAVI (GA: n=24; sedation: n=83) and the overall incidence of AKI was 14.02%. We found a higher incidence of intraoperative hypotension in the GA group (83.3% vs 33.7%, p<0.001). Regarding postoperative outcomes, there were no significant differences in AKI incidence (20.8% vs 12.0%, p=0.319) and mortality. The major finding of interest was the significant association between postoperative AKI and preexisting chronic kidney disease (CKD), preoperative heart failure functional class, intraoperative hypotension, longer length of stay in level II unit and longer hospital stay, and worsening of previous CKD stage. Conclusions: It was not possible to established association between the anesthetic approach for TAVI procedures and postoperative AKI and mortality. Our study reinforces the importance of preventing AKI incidence, considering its impact on the worsening of baseline CKD and on the length of stay, leading to higher hospitalization costs.

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Mucha, Corinne. "Prädiktoren für das Auftreten von Schlaganfällen nach interventionellem Aortenklappenersatz (TAVI) in Abhängigkeit von der gerinnungshemmenden Medikation." Doctoral thesis, 2017. http://hdl.handle.net/11858/00-1735-0000-0023-3E51-A.

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Peixoto, Daniela Filipe. "A evolução da Implantação Percutânea da Válvula Aórtica (TAVI) e o seu papel na Estenose Aórtica de baixo fluxo e baixo gradiente (EA LFLG)." Master's thesis, 2021. http://hdl.handle.net/10316/98345.

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Trabalho Final do Mestrado Integrado em Medicina apresentado à Faculdade de Medicina
Percutaneous aortic valve implantation (TAVI) has been showing similar results to surgical aortic valve replacement (SAVR), but its benefit in patients with low flow and low gradient aortic stenosis (LFLG AS) is not yet fully understood. The purpose of this thesis was to review the literature on TAVI and its evolution in the treatment of AS, namely LFLG AS – its advantages, disadvantages, which prognostic markers can guide the Heart Team's decision and what outcomes can be expected from the percutaneous intervention. For this, a total of 86 articles were reviewed, from a careful search in the PubMed / MEDLINE and EMBASE databases and the addition of some extra articles.The LFLG AS is divided into classic and paradoxical, both with myocardial dysfunction; the second, with a more controversial pathophysiology and, consequently, a harder evaluation of the stenosis severity – indication for intervention. TAVI has been seen as an alternative to SAVR, but in the articles reviewed in the present thesis, both had similar outcomes, with TAVI showing better early results: lower morbidity and mortality, faster functional recovery and shorter hospital stay. Classical LFLG AS is the one (of all types of aortic stenosis) with the worst prognosis, with higher mortality rates, however, with improvements in quality of life comparable to the others; TAVI has a clear benefit over the conservative approach.In patients with EA LFLG, with basis cardiac dysfunction, the percutaneous, a minimally invasive approach, is a valid option and, looking at the early outcomes, preferable. Publications of new studies with prostheses of more recent generations are awaited to see if the outcomes improve to the point that, both in patients with high or low surgical risk, with greater or lesser reserve of cardiac functionality, TAVI is preferable to SAVR.
A implantação percutânea da válvula aórtica (TAVI) tem vindo a mostrar resultados comparáveis à substituição cirúrgica da válvula aórtica (SAVR), porém o seu benefício em doentes com Estenose Aórtica de baixo gradiente e baixo fluxo (EA LFLG) ainda não se encontra totalmente esclarecido. A presente tese teve como propósito rever a literatura acerca da TAVI e da sua evolução no tratamento da EA, nomeadamente da EA LFLG – as suas vantagens, desvantagens, que marcadores de prognóstico podem orientar a decisão da Heart Team e que outcomes podemos esperar da intervenção percutânea. Para isso foram revistos um total de 86 artigos, resultantes de uma pesquisa criteriosa nas bases de dados PubMed/MEDLINE e EMBASE e da adição de alguns artigos extra. A EA LFLG divide-se em clássica e paradoxal, ambas com disfunção miocárdica de base, sendo que a fisiopatologia da segunda, e, consequentemente, a avaliação da severidade da estenose – indicação para intervenção valvular aórtica – é mais controversa. A TAVI tem sido vista como alternativa à SAVR, mas nos artigos analisados na presente tese ambas apresentaram outcomes semelhantes, com a TAVI a demonstrar melhores resultados precocemente: menor taxa de morbimortalidade, recuperação funcional mais rápida e menor tempo de hospitalização. A EA LFLG clássica (de todos os tipos de estenose aórtica) é a que apresenta pior prognóstico, com maiores taxas de mortalidade, porém, com melhorias na qualidade de vida comparáveis aos restantes; sendo que a TAVI apresenta um benefício claro em relação à abordagem conservadora. Em doentes com EA LFLG, com disfunção cardíaca de base, a abordagem percutânea, minimamente invasiva é uma opção válida e, a olhar para os resultados precoces, preferível. Aguardam-se publicações de novos estudos com próteses de gerações mais recentes, para perceber se os outcomes melhoram ao ponto de, quer nos doentes de alto risco cirúrgico quer nos com baixo, com maior ou menor reserva de funcionalidade cardíaca, a TAVI seja preferível à SAVR.

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Sobisiak, Bettina. "Einfluss der Gebrechlichkeit auf Morbidität und Mortalität nach kathetergestützter Aortenklappenimplantation (TAVI)." Doctoral thesis, 2017. http://hdl.handle.net/11858/00-1735-0000-0023-3E7A-0.

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Grünwald, Felix. "Einfluss des Crimping auf Haltbarkeit und Gewebeintegrität bei kathetertechnischen Aortenklappenprothesen: eine experimentelle Analyse: Einfluss des Crimping auf Haltbarkeit und Gewebeintegrität bei kathetertechnischen Aortenklappenprothesen: eine experimentelle Analyse." Doctoral thesis, 2014. https://ul.qucosa.de/id/qucosa%3A13412.

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Eine Verengung der Aortenklappe, die während der Systole zu einem Druckunterschied zwischen dem linkem Auswurftrakt und der Aorta führt, wird als Aortenstenose bezeichnet. Sie stellt nach der KHK die häufigste Indikation für eine herzchirurgische Intervention dar. Die Entstehung der Aortenstenose ist bisher nicht völlig aufgeklärt. Die Verengung ist meist durch Verkalkung der Klappensegel bedingt. Der derzeitige Stand der Forschung gibt Grund zur Annahme, dass dieser Entstehungsprozess der Ätiologie der Arteriosklerose sehr ähnlich ist. Die Aortenstenose kann anhand der Aortenklappen-Öffnungsfläche in leicht-, mittel- und hochgradig eingeteilt werden. Zurzeit ist die Echokardiographie die wichtigste Methode zur Evaluation der Aortenstenose, weil damit die Öffnungsfläche und die Druckgradienten bestimmt werden können. Für die Entscheidung zur Operation ist insbesondere auch das Einsetzen der Symptomatik mitbestimmend. Der konventionelle Aortenklappenersatz mit einer biologischen oder mechanischen Aortenklappenprothese ist der Goldstandard in der heutigen Therapie der Aortenstenose. Patienten höheren Alters erhalten heutzutage eine biologische Aortenklappenprothese, da keine dauerhafte Antikoagulation notwendig ist. Bei älteren Patienten (über 70 Jahre) steigt die postoperative Mortalität auf 5-15% an. In Deutschland waren 2010 über 50% der herzchirurgischen Patienten älter als 70 Jahre und 12,4% sogar über 80 Jahre. Laut einer Studie werden 33% der über 75-Jährigen nicht zur Operation zugelassen, da diese als zu risikoreich eingestuft wird. Um dieses Patientenkollektiv besser zu versorgen, wurde ein Verfahren zur kathetergestützten Implantation einer Aortenklappenprothese entwickelt. Die neue Prothese wird auf einen Ballonkatheter gepresst und anschließend in Aortenposition dilatiert. Die Implantation kann durch die Herzspitze antegrad, also transapikal, oder über die femoralen Gefäße retrograd, also transfemoral, erfolgen. Eine Sternotomie oder die Verwendung einer Herz-Lungenmaschine mit künstlichem Herzstillstand sind dazu nicht notwendig. Die in dieser Arbeit verwendete Sapien-Prothese besteht aus vorbehandeltem Rinderperikard und ist in einem Kobalt-Chrom-Stent aufgehängt. Bereits 2010 wurden in Deutschland schon fast ein Viertel aller isolierten Aortenklappenersätze mittels der kathetertechnischen Aortenklappenprothesen durchgeführt, 2011 ist der Anteil auf über 30% gestiegen. Der Einsatz ist im Moment auf Hochrisikopatienten über 75 Jahre beschränkt, da es noch keine Ergebnisse über die Langzeithaltbarkeit der Katheter-Herzklappen gibt. Außerdem scheint die Häufigkeit von periinterventionellen Komplikationen bei diesem Verfahren noch sehr hoch. Ganz im Gegensatz zur schonenden Behandlung der Prothese beim konventionellen Eingriff wird die Sapien-Herzklappenprothese durch einen Crimper auf den Ballonkatheter gepresst. Der Durchmesser wird dabei von 23 bzw. 26mm auf unter 8,7mm verringert. Nur so kann die Prothese über das zum Studienzeitpunkt 26 French große Applikationssystem in Position gebracht werden. Mittlerweile beträgt der Diameter für den transfemoralen Zugang nur noch 18 French. Bisher gibt es keine Studien darüber, ob die Krafteinwirkung des Crimping einen Einfluss auf die Langzeithaltbarkeit der Transkatheter-Herzklappen hat. Dabei ist gerade eine lange Haltbarkeit enorm wichtig, um das neue minimalinvasive System einem größeren Patientenkollektiv zugänglich zu machen. Ziel der hier vorgelegten Studie war es deshalb, den Einfluss von Crimping auf die Haltbarkeit und Gewebeintegrität der Edwards Sapien-Prothese in Abhängigkeit von der Crimping-Dauer zu untersuchen. Dazu kam ein subkutanes Rattenmodell zur Anwendung, das zum Vergleich verschiedener Herzklappenprothesen häufig herangezogen wird. Hierbei wird vor allem das Verkalkungspotential der Prothesen untersucht, da die Verkalkung der Klappen die Funktionalität derselben limitiert. Hierfür wurden in dieser Arbeit 21 Tage alten Sprague-Dawley-Ratten (n=15) jeweils fünf Gewebeproben in separate subkutane Taschen implantiert. Nach einem Implantationszeitraum von zwölf Wochen gingen wir von der maximal möglichen Verkalkung aus. Im Menschen entspricht das einem Zeitraum von etwa zehn Jahren. Drei Gruppen á fünf Sapien-Prothesen wurden unterschiedlich lange gecrimpt: für einen Monat, einen Tag und eine Stunde. Eine vierte Gruppe wurde nicht gecrimpt. Die fünfte Gruppe bestand aus der operativ häufig verwendeten Standardklappe Perimount Magna und wurde als Kontrolle eingesetzt. Die Klappensegel wurden nach Crimping und Dilatation exzidiert (je Gruppe n=15) und unter inhalativer Anästhesie wurde jeder Ratte ein Präparat aller fünf Gruppen in subkutane separate Taschen faltenfrei implantiert. Die Taschen wurden dorsal paravertebral durch stumpfe Präparation angelegt. Die Implantation erfolgte bei allen 15 Tieren komplikationslos. Nach zwölf Wochen erfolgte die Explantation. Ein Präparat der für einen Tag gecrimpten Prothesen und eines der Kontrollgruppe Magna konnten nicht aufgefunden werden. Ansonsten ergaben sich bei der Explantation keine Schwierigkeiten. Zur Bestimmung des Kalziumlevels im Serum wurde den Ratten eine Blutprobe abgenommen. Die explantierten Präparate wurden dann zur Analyse in drei Teile geschnitten. Ein Teil wurde der Kalziumbestimmung durch optische Emissionsspektroskopie mit induktiv gekoppeltem Plasma (ICP-OES) zugeführt. Das Ergebnis wird in mg/g Trockengewicht angegeben. Der zweite Teil wurde für die histologische Untersuchung in Paraffin eingebettet. Es wurden Standardschnitte angefertigt und drei Färbungen pro Präparat durchgeführt. Dies waren die Hämatoxylin-Eosin-Färbung (Orientierung), die Van Kossa-Färbung (Verkalkung) und die mod. Pikrosiriusrot-Färbung (kollagene Fasern). Der Kalziumgehalt der Präparate wurde zusätzlich zur chemischen Bestimmung histologisch durch ein interaktives Bildanalyseverfahren in mm2 gemessen. Die Fragmentierung und Irregularität der Kollagenfasern wurde histologisch in vier Grade eingestuft: ohne pathologischen Befund, gering-, mittel- oder hochgradig fragmentiert bzw. irregulär. Ein weiterer Teil der Präparate wurde für die exemplarische Darstellung im Elektronenmikroskop in Epon 100 eingebettet und mit Uranylacetat und Tannin kontrastiert. Die Kalziummessungen ergaben, dass die ungecrimpten Klappen Sapien und Perimount Magna tendenziell stärker verkalkten als die anderen Gruppen. Die Unterschiede zwischen den Gruppen waren jedoch nicht signifikant, sowohl bei der histologischen als auch bei der chemischen Quantifizierung. Die Streuung der Messwerte war sowohl intra- als auch interindividuell sehr hoch. Die Bedeutung für die Langzeithaltbarkeit bezüglich der Kalzifizierung ist unklar. Jedoch kann festgestellt werden, dass es in dieser Studie keinen signifikant messbaren Unterschied in der Verkalkung zwischen gecrimpten und ungecrimpten Prothesen gab. In der histologischen Strukturanalyse waren die Kollagenfasern der gecrimpten Klappen signifikant stärker fragmentiert bzw. die Struktur irregulärer als die der ungecrimpten Klappen. Erstaunlich war hier auch die Tatsache, dass selbst die ungecrimpte Sapien-Prothese signifikant stärker fragmentiert war als die Perimount Magna. Dieses Ergebnis überrascht, da die Sapien-Klappe der Perimount Magna im Produktionsprozess sehr ähnlich ist. Beide bestehen aus Rinderperikard und sind mit dem Antimineralisationsverfahren ThermaFix vorbehandelt. Sie unterscheiden sich lediglich im Stent. Dieser muss für das kathetergestützte Verfahren komprimierbar und wieder dilatierbar sein. Der Produktionsprozess sollte auf Grund dieses Ergebnisses reevaluiert werden. Wie bereits erwähnt, waren die gecrimpten Klappen signifikant stärker fragmentiert. Mit zunehmender Crimping-Dauer nahm dieser Effekt tendenziell sogar zu. Dass Crimping einen schädlichen Einfluss auf die strukturelle Integrität des Klappengewebes hat, war bis dato nicht bewiesen. Diese Tatsache allein lässt allerdings noch keine genaue Aussage über die Auswirkung von Crimping auf die Haltbarkeit im Blutstrom zu. Es ist jedoch hervorzuheben, dass die Fragmentierung der Kollagenfasern, also der Haltefasern der Aortenklappenprothese, die Erwartung einer guten Langzeitfunktionalität drastisch mindert. Dazu gibt es Hinweise aus aktuellen multizentrischen Studien wie dem Partner-Trial, in dem bereits nach 30 Tagen 1,3% und nach einem Jahr 4,2% der Patienten eine mittel- bis schwergradige transvalvuläre Aorteninsuffizienz aufwiesen. Diese Tatsache verbunden mit dem Wissen, dass Crimping die Kollagenfasern frakturiert, stellt die Langzeithaltbarkeit der Prothese in Frage. Zu beachten ist, dass der Diameter des Systems in diesem Versuchsaufbau keine Rolle spielte. Seit Beginn der Studie hat sich der Diameter des Applikationssystems aber von 26 auf 22 French (transfemoral sogar nur 18 French) verringert. Es ist anzunehmen, dass die Krafteinwirkung beim Crimping auf 22 bzw. 18 French noch deutlich größer und damit die Fragmentierung der Fasern noch ausgeprägter wäre. Als Limitationen des hier angewandten subkutanen Rattenmodells sind der fehlende Kontakt mit dem Blut sowie die fehlende Wirkung hämodynamischer Kräfte zu nennen. Es handelt sich hierbei um einen Tierversuch, der nicht direkt auf den Menschen übertragbar ist. Für histologische und chemische Analyse mussten jeweils unterschiedliche Teile der Präparate verwendet werden. Die histologische Beurteilung ist untersucherabhängig. In diesem Versuchsaufbau wurde lediglich ein Prothesen-Typ untersucht, so dass nicht klar ist, ob die beschriebenen Phänomene auch bei anderen kathetertechnischen Herzklappenprothesen auftreten. Die Ergebnisse liefern neue Gesichtspunkte im Hinblick auf die Haltbarkeit der Sapien-Klappenprothese. Daraus lassen sich einige Empfehlungen ableiten. Crimping verursacht einen irreparablen Schaden an den Kollagenfasern der Herzklappenprothesen, der tendenziell mit der Dauer des Crimpings zunimmt. Der Vorgang des Crimping sollte daher so kurz wie möglich gehalten werden. Die kathetergestützte Aortenklappenprothese sollte erst kurz vor der Implantation auf den Ballonkatheter gecrimpt werden. Crimping auf sehr kleine Diameter sollte vorerst vermieden werden. Künftig sollte außerdem eine genauere Analyse der Auswirkungen der strukturellen Schäden auf die Haltbarkeit der Transkatheter-Herzklappen durchgeführt werden. Vor der Ausweitung der Behandlung auf ein Patientenkollektiv mit höherer Lebenserwartung müssen noch viele Fragen hinsichtlich der Langzeithaltbarkeit dieser Herzklappen-Prothesen in weiteren Studien geklärt werden.

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Spaziano, Marco. "L'implantation valvulaire aortique par cathéter : évolution des résultats cliniques suite aux avancées technologiques et techniques." Thèse, 2017. http://hdl.handle.net/1866/19441.

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Contexte: L'implantation valvulaire aortique par cathéter (TAVI) est une procédure relativement jeune dont l'objectif est de traiter les patients atteints de sténose aortique sévère pour qui la chirurgie cardiaque conventionnelle est considérée à haut risque ou contre-indiquée. Cette procédure a subi, au fil du temps, des améliorations sur le plan technologique (succession de différentes générations de prothèses valvulaires) ainsi que sur le plan technique (simplification des différentes étapes de la procédure). Objectif: L'objectif de ce travail est de décrire l'impact clinique d'une avancée technologique, soit le passage de la deuxième vers la troisième génération de la prothèse Edwards, et d'une avancée technique, soit l'implantation de la prothèse sans pré-dilatation de la valve native. Méthodes: Nous présentons d'abord, par le biais d'une revue et méta-analyse, les résultats cliniques du TAVI au début de son utilisation à plus grande échelle, en 2012. Ensuite, une étude monocentrique rétrospective dans un centre à haut volume décrit les résultats du passage de la deuxième vers la troisième génération de la valve Edwards chez 507 patients. Enfin, une étude rétrospective avec appariement a testé différentes stratégies de pré-dilatation durant la procédure: une pré-dilatation systématique, une pré-dilatation sélective chez des patients présentant des caractéristiques cliniques précises, et l'absence de pré-dilatation. Résultats: Dans l'article présentant les résultats cliniques au début de l'expérience TAVI, le taux de mortalité à 30 jours variait entre 5 et 18%. Le taux de décès à 1 an était estimé à 23% (méta-analyse, random effects model). Le taux d'AVC à 30 jours était entre 0 et 6.7% et le taux de complication vasculaire majeure entre 2 et 16%. L'étude sur le passage de la SAPIEN XT vers la SAPIEN 3 a montré une diminution non significative de la mortalité à 30 jours (de 8.7 à 3.5%; p=0.21) et des AVC à 30 jours (de 2.8 à 1.4%; p=0.6), ainsi qu'une diminution significative des complications vasculaires majeures à 30 jours (de 9.9 à 2.8%; p<0.0001). Cependant, il y a eu une augmentation significative du taux de pacemaker (de 9.8 à 17.3%; p=0.03). L'étude sur la pré-dilatation versus le direct TAVI a montré une absence d'effet adverse du direct TAVI en termes de décès ou complications vasculaires à 30 jours. Nous avons trouvé une tendance à la réduction des AVC avec le direct TAVI (3 vs. 1%; p=0.11), en particulier chez les patients avec une valve aortique peu ou modérément calcifiée. Cependant, chez les patients avec calcification extensive de la valve, le risque de malposition de la prothèse était numériquement plus élevé. Au cours des 3 études présentées, la mortalité à 1 an a peu évolué (entre 20 et 25%). Conclusions: Les événements adverses à court terme ont diminué après le changement de génération de valve Edwards. Le direct TAVI permet de simplifier la procédure sans augmenter les taux d'effets adverses. Cependant, les deux avancées présentent des limites qui incitent à la prudence.
Context: Transcatheter aortic valve implantation (TAVI) is a relatively young procedure intended to treat patients with severe aortic stenosis who are at high risk for conventional surgery, or inoperable. This procedure underwent multiple technological improvements (successive generations of devices) and multiple technical improvements (simplification of various steps in the procedure). Objective: We intend to describe the clinical impact of a technological improvement (the transition from the second to the third generation of the Edwards device in a high-volume center) and that of a technical improvement (TAVI without pre-dilatation, known as direct TAVI). Methods: We first describe, through a meta-analysis, the state of TAVI at the beginning of its widespread use, in 2012. Next, we describe, through a single-center retrospective study, the clinical impact of the transition from the second to the third generation of the Edwards device in 507 patients. Finally, in a retrospective study with matching, we tested three pre-dilatation strategies: systematic pre-dilatation, selective pre-dilatation, and direct TAVI. Results: In the article describing the initial TAVI experience, the 30-day mortality rate was between 5 and 18%. One-year mortality was estimated at 23% by meta-analysis (random effects model). Stroke rate at 30 days was between 0 and 6.7% and major vascular complication rate was between 2 and 16%. The transition from SAPIEN XT to SAPIEN 3 resulted in a non-significant reduction in 30-day mortality (from 8.7 to 3.5%; p=0.21) and 30-day stroke rate (from 2.8 to 1.4%; p=0.6), and a significant reduction in major vascular complications (from 9.9 to 2.8%; p<0.0001). However, there was a significant increase in permanent pacemaker rate (from 9.8 to 17.3%; p=0.03). Next, we found no adverse effect of performing direct TAVI in terms of mortality or vascular complications at 30 days. We found a trend towards a reduction in stroke rate with direct TAVI (3 vs. 1%; p=0.11), particularly in patients with mildly or moderately calcified valves. However, in those with extensive valvular calcification, the risk of device malposition was numerically higher. In all three studies presented, there was little variation in 1-year mortality (20 to 25%). Conclusions: Short-term adverse events were reduced by the transition towards the third-generation Edwards device. Direct TAVI is feasible and safe. However, both of these improvements have limitations and should be considered carefully.

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Gonçalves, Alexandra Maria Gomes da Silva. "Life after Transcatheter Aortic Valve Implantation: a clinical and echocardiographic appraisal." Tese, 2012. https://repositorio-aberto.up.pt/handle/10216/65965.

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Gonçalves, Alexandra Maria Gomes da Silva. "Life after Transcatheter Aortic Valve Implantation: a clinical and echocardiographic appraisal." Doctoral thesis, 2012. https://repositorio-aberto.up.pt/handle/10216/65965.

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KARAR, Mohamed Esmail Abdel Razek Hassan. "Development of a Surgical Assistance System for Guiding Transcatheter Aortic Valve Implantation." Doctoral thesis, 2011. https://ul.qucosa.de/id/qucosa%3A11348.

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Abstract:

Development of image-guided interventional systems is growing up rapidly in the recent years. These new systems become an essential part of the modern minimally invasive surgical procedures, especially for the cardiac surgery. Transcatheter aortic valve implantation (TAVI) is a recently developed surgical technique to treat severe aortic valve stenosis in elderly and high-risk patients. The placement of stented aortic valve prosthesis is crucial and typically performed under live 2D fluoroscopy guidance. To assist the placement of the prosthesis during the surgical procedure, a new fluoroscopy-based TAVI assistance system has been developed. The developed assistance system integrates a 3D geometrical aortic mesh model and anatomical valve landmarks with live 2D fluoroscopic images. The 3D aortic mesh model and landmarks are reconstructed from interventional angiographic and fluoroscopic C-arm CT system, and a target area of valve implantation is automatically estimated using these aortic mesh models. Based on template-based tracking approach, the overlay of visualized 3D aortic mesh model, landmarks and target area of implantation onto fluoroscopic images is updated by approximating the aortic root motion from a pigtail catheter motion without contrast agent. A rigid intensity-based registration method is also used to track continuously the aortic root motion in the presence of contrast agent. Moreover, the aortic valve prosthesis is tracked in fluoroscopic images to guide the surgeon to perform the appropriate placement of prosthesis into the estimated target area of implantation. An interactive graphical user interface for the surgeon is developed to initialize the system algorithms, control the visualization view of the guidance results, and correct manually overlay errors if needed. Retrospective experiments were carried out on several patient datasets from the clinical routine of the TAVI in a hybrid operating room. The maximum displacement errors were small for both the dynamic overlay of aortic mesh models and tracking the prosthesis, and within the clinically accepted ranges. High success rates of the developed assistance system were obtained for all tested patient datasets. The results show that the developed surgical assistance system provides a helpful tool for the surgeon by automatically defining the desired placement position of the prosthesis during the surgical procedure of the TAVI.
Die Entwicklung bildgeführter interventioneller Systeme wächst rasant in den letzten Jahren. Diese neuen Systeme werden zunehmend ein wesentlicher Bestandteil der technischen Ausstattung bei modernen minimal-invasiven chirurgischen Eingriffen. Diese Entwicklung gilt besonders für die Herzchirurgie. Transkatheter Aortenklappen-Implantation (TAKI) ist eine neue entwickelte Operationstechnik zur Behandlung der schweren Aortenklappen-Stenose bei alten und Hochrisiko-Patienten. Die Platzierung der Aortenklappenprothese ist entscheidend und wird in der Regel unter live-2D-fluoroskopischen Bildgebung durchgeführt. Zur Unterstützung der Platzierung der Prothese während des chirurgischen Eingriffs wurde in dieser Arbeit ein neues Fluoroskopie-basiertes TAKI Assistenzsystem entwickelt. Das entwickelte Assistenzsystem überlagert eine 3D-Geometrie des Aorten-Netzmodells und anatomischen Landmarken auf live-2D-fluoroskopische Bilder. Das 3D-Aorten-Netzmodell und die Landmarken werden auf Basis der interventionellen Angiographie und Fluoroskopie mittels eines C-Arm-CT-Systems rekonstruiert. Unter Verwendung dieser Aorten-Netzmodelle wird das Zielgebiet der Klappen-Implantation automatisch geschätzt. Mit Hilfe eines auf Template Matching basierenden Tracking-Ansatzes wird die Überlagerung des visualisierten 3D-Aorten-Netzmodells, der berechneten Landmarken und der Zielbereich der Implantation auf fluoroskopischen Bildern korrekt überlagert. Eine kompensation der Aortenwurzelbewegung erfolgt durch Bewegungsverfolgung eines Pigtail-Katheters in Bildsequenzen ohne Kontrastmittel. Eine starrere Intensitätsbasierte Registrierungsmethode wurde verwendet, um kontinuierlich die Aortenwurzelbewegung in Bildsequenzen mit Kontrastmittelgabe zu detektieren. Die Aortenklappenprothese wird in die fluoroskopischen Bilder eingeblendet und dient dem Chirurg als Leitfaden für die richtige Platzierung der realen Prothese. Eine interaktive Benutzerschnittstelle für den Chirurg wurde zur Initialisierung der Systemsalgorithmen, zur Steuerung der Visualisierung und für manuelle Korrektur eventueller Überlagerungsfehler entwickelt. Retrospektive Experimente wurden an mehreren Patienten-Datensätze aus der klinischen Routine der TAKI in einem Hybrid-OP durchgeführt. Hohe Erfolgsraten des entwickelten Assistenzsystems wurden für alle getesteten Patienten-Datensätze erzielt. Die Ergebnisse zeigen, dass das entwickelte chirurgische Assistenzsystem ein hilfreiches Werkzeug für den Chirurg bei der Platzierung Position der Prothese während des chirurgischen Eingriffs der TAKI bietet.

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Dissertations / Theses on the topic 'Transcatheter aortic valve implantation (TAVI)'

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