Dissertations / Theses on the topic 'Interventional cardiology'

This thesis details the measurement and simulation of patient skin doses arising from X-ray exposure during interventional cardiology procedures. Interventional cardiology procedures can be long and complex resulting in high skin doses, to the extent that radiation burns may be produced. Twenty patients were used in the study consisting of 10 coronary angiogram and 10 coronary angioplasty procedures. Radiochromic films were used to measure skin dose directly. The Gafchromic® XR-RV2 film was chosen for its suitability for this project. The key characteristics of this film were experimentally determined including: dose response, energy dependence, polarisation and post-exposure growth. The dose range was found to be ideally suited for the doses encountered in this study. Energy dependence was found to be ~14% between 60 and 125 kVp at 1 Gy and introduced an unavoidable uncertainty into dose calculations from unknown beam energies. Document scanner characteristics were also been investigated and a scanning protocol is determined. A mathematical model was created to use the geometry and exposure information encoded into acquisition files to reconstruct dose and dose distributions. The model requires a set of study files encoded according to the DICOM format, as well as user input for fluoroscopic estimations. The output is a dose map and dose summary. Simulation parameters were varied and results compared with film measurements to provide the most accurate model. From the data collected the relation between dose area product, maximum skin dose and fluoroscopic time were also investigated. The results demonstrated that a model based on acquisition information can accurately predict maximum skin dose and provide useful geometrical information. The model is currently being developed into a standalone program for use by the Medical Physics and Bioengineering department.

The International Commission of Radiological Protection (ICRP) advises that in principle Diagnostic Reference Levels (DRL) could be used in fluoroscopically guided interventional procedures to avoid unnecessary stochastic radiation risk. The increase in complexity of interventional procedures, combined with a lack of specialist training on radiation techniques, poses a significant risk to patients. These risks have not gone unnoticed by government authorities worldwide and in 2015 the South African Department of Health: Directorate Radiation Control issued requirements to license holders of interventional fluoroscopy units, requiring that a medical physicist optimize their radiation usage using DRLs. The Dose Area Product (DAP) quantity measured for each patient represents a dosimetry index, the value of which for the purpose of improvement should be optimized against the DRL. In this dissertation, I aim to establish if DRLs in the South African private healthcare interventional theatres are high compared to international levels and whether DRLs will optimize the doses used.

"March 2003" Includes bibliographical references (leaves 61-68). Appendices: Publications arising from the research portfolio. 1. Conducting a systematic review -- 2. The effectiveness of mechanical compression devices in attaining hemostasis after removal of a femoral sheath following femoral artery cannulation for cardiac interventional procedures : a systematic review -- 3. Effectiveness of mechanical compression devices in attaining hemostasis after femoral sheath removal Contains three separate research projects, presented as separate reports, but all related to one area of interest - interventional cardiology. Seeks to identify effective femoral sheath removal practices after interventional cardiac procedures and determine patient's perceptions of the education prior to and after interventional procedures.

Thesis advisor: Barabara Hazard
This randomized controlled trial (RCT) examined a discharge nursing intervention (DNI) aimed at promoting self-regulation of care for early discharge interventional cardiology patients. The purpose of this study was to compare medication adherence, patient satisfaction, use of urgent care, and illness perception in patients with cardiovascular disease (CVD) undergoing interventional revascularization procedures who receive usual care and those who receive a DNI. The Common Sense Model (CSM) of illness representation provided the theoretical foundation for this study. The CSM is a cognitive parallel processing model that draws relationships between illness representation, coping methods, and illness outcomes to help explain the process by which people make sense of their illness. Intervention research aimed at life style changes to reduce secondary events after treatment for CVD is needed to guide evidence based care. Treatment for CVD has shifted from surgical repair with prolonged hospitalizations to interventional procedures requiring shorter hospital stays. This trend reduces nursing time to monitor complications and provide education about medication management and lifestyle changes. Patients recover in short stay areas and return home within hours or one to two days of the procedure. Cardiac disease is then managed as a chronic, but often stable condition. With this change in the delivery of care, several trends have emerged that have implications for quality nursing care and patient outcomes: a) the burden of care shifts from the hospital setting to home, b) patients are discharged without extensive education about complications and disease management, c) the occurrence of secondary events and disease progression remain a valid threat, and d) nurses with expert practice are in a unique position to assist patients and families with CVD management. This study addressed the following questions. 1. Do patients receiving the nursing intervention differ significantly from those receiving usual care on medication adherence? 2. Do patients receiving the nursing intervention differ significantly from those receiving usual care on patient satisfaction? 3. Is there a significant difference in the utilization of urgent care between those patients receiving the nursing intervention when compared to those patients receiving usual care? 4. Does a difference exist between the patients receiving the nursing intervention and those patients receiving usual care on illness perception, as measured by seven components of the IPQ-R: time line (acute and chronic), consequence, personal control, treatment (cure) control, illness coherence, timeline (cyclical), and emotional representations? Purposive sampling was used to select a sample of patients admitted for interventional procedures at an academic teaching hospital. One hundred and fifty four patients were and randomized into control and experimental groups. Final analyses included data from 129 patients. Sixty-four participants in the experimental group received the DNI which included: 1) additional written information about taking medications, 2) a medication pocket card, 3) a list of 3 cardiac internet sites,and 4) a phone call, 24 hours post procedure, from an expert cardiac nurse to review discharge instructions. Sixty-five participants in the control group received usual care. Analyses on four outcome measures, medication adherence, use of urgent care, patient satisfaction, and illness perception, revealed one statistically significant result. Participants in the experimental group, receiving the DNI, scored significantly higher than the control group on one measure, the timeline (acute/chronic) component of illness perception (p = .006) indicating a greater appreciation of the chronicity of their disease. Otherwise, there were no significant group differences found. This study provides support for nursing intervention research guided by self-regulation theory that examines the patient's perception of illness. Patients with cardiac disease who received the DNI were statistically more likely to acknowledge that their illness would last a long time. This awareness, may improve adherence to a prescribed regimen of medication and lifestyle modification. Nursing interventions guided by an understanding of patients' belief that their cardiovascular disease is chronic will add to the body of knowledge that informs providers about decisions patients make concerning medication adherence and lifestyle modifications. However, the results underscore the limitations of adding additional discharge care to this population of patients to improve medication adherence, use of urgent care, and patient satisfaction. Future research should include a longitudinal study to examine how patients who perceive their disease to be chronic in nature managed their medications and care decisions at home
Thesis (PhD) — Boston College, 2009
Submitted to: Boston College. Connell School of Nursing
Discipline: Nursing

Objective - to assess possibilities and specific characteristics of pediatric cardiology in treatment of congenital heart diseases (CHD), to evaluate efficacy of curative per-catheter procedures by means of analysis of immediate and long-term results. Retrospective study. The data of 422 patients who underwent 467 CHD palliative-curative procedures during the period since 1971 till 2007 were analyzed. It was postulated that balloon atrial septostomy resulted in statistically significant increase of atrial septal defect, increase of arterial blood oxygen saturation and decrease of interatrial preasure gradient (PG). Balloon pulmonary valvulotomy (BPV) is one of the most common curative procedures; this procedure has an effect of marked decrease of pressure gradient between the right ventricle and right atrium; development of pulmonary artery valve insufficiency is the most common complication of this procedure. The long - term results of BPV are less positive when higher PG prior the procedure is present and residual PG after the procedure is 36mmHg and higher. It was postulated, that closure of small (less than 3 mm) persistent ductus arteriosus using Cook coils may compete with surgical treatment successfully. It was stated, that the efficacy of balloon angioplasties of aorta, caval veins and pulmonary artery branches is transient; treatment using stents is more effective. It was postulated, that closure of congenital and postsurgical anomalies connections using coils is... [to full text]
Disertacijos objektas yra nustatyti intervencinės pediatrinės kardiologijos galimybes ir ypatumus, gydant įgimtas širdies ydas (ĮŠY), įvertinti gydomųjų perkateterinių procedūrų efektingumą, remiantis ankstyvųjų ir vėlyvųjų rezultatų analize. Tai retrospektyvus tyrimas. Analizuoti 422 ligonių duomenys, kuriems 1971 - 2007 m. buvo atliekamos 467 įgimtų širdies ydų paliatyvinės - gydomosios procedūros. Nustatyta, kad po balioninės tarpprieširdinės pertvaros septostomijos, statistiškai reikšmingai padidėja prieširdžių pertvaros defektas, didėja arterinio kraujo įsotinimas deguonimi ir mažėja spaudimų skirtumas (SS) tarp prieširdžių. Balioninė plaučių arterijos valvuloplastika (BPV) yra viena iš dažniausiai taikomų gydomųjų procedūrų, jos efektas – ryškus SS tarp dešiniojo skilvelio ir plaučių arterijos (PA) sumažėjimas, o pagrindinė komplikacija – PA vožtuvo nesandarumo vystymasis. BPV vėlyvieji rezultatai blogesni, kai yra didelis SS prieš procedūrą, o po procedūros liekamasis SS ≥ 36mmHg. Nustatyta, kad mažų iki 3mm AAL kimšimas Cook spiralėmis gali sėkmingai konkuruoti su operaciniu gydymu. Rasta, kad aortos, tuščiųjų venų ir plaučių arterijos šakų balioninės plastikos efektas trumpalaikis, o gydymas stentais daug sėkmingesnis. Nustatyta, kad anomalinių įgimtų ir pooperacinių kraujagyslinių jungčių užkimšimas spiralėmis yra saugus ir efektyvus gydymo metodas.

Thesis (S.M.)--Harvard-MIT Division of Health Sciences and Technology, 2006.
Vita.
Includes bibliographical references (p. 52-56).
Post-marketing surveillance of medical pharmaceuticals and devices has received a great deal of media, legislative, and academic attention in the last decade. Among medical devices, these have largely been due to a small number of highly publicized adverse events, some of them in the domain of cardiac surgery and interventional cardiology. Phase three clinical trials for these devices are generally underpowered to detect rare adverse event rates, are performed in near-optimal environments, and regulators face significant pressure to deliver important medical devices to the public in a timely fashion. All of these factors emphasize the importance of systematic monitoring of these devices after being released to the public, and the FDA and other regulatory agencies continue to struggle to perform this duty using a variety of voluntary and mandatory adverse event rate reporting policies. Data quality and comprehensiveness have generally suffered in this environment, and delayed awareness of potential problems. However, a number of mandatory reporting policies combined with improved standardization of data collection and definitions in the field of interventional cardiology and other clinical domains have provided recent opportunities for nearly "real-time" safety monitoring of medical device data.
(cont.) Existing safety monitoring methodologies are non-medical in nature, and not well adapted to the relatively heterogeneous and noisy data common in medical applications. A web-based database-driven computer application was designed, and a number of experimental statistical methodologies were adapted from non-medical monitoring techniques as a proof of concept for the utility of an automated safety monitoring application. This application was successfully evaluated by comparing a local institution's drug-eluting stent in-hospital mortality rates to University of Michigan's bare-metal stent event rates. Sensitivity analyses of the experimental methodologies were performed, and a number of notable performance parameters were discovered. In addition, an evaluation of a number of well-validated external logistic regression models, and found that while population level estimation was well-preserved, individual estimation was compromised by application to external data. Subsequently, exploration of an alternative modeling technique, support vector machines, was performed in an effort to find a method with superior calibration performance for use in the safety monitoring application.
by Michael E. Matheny.
S.M.

The core problem, leading to this study, is that inventory in general is pushed onto downstream supply chain links, based on forecasts. The effect is that downstream links are often overstocked and slow to react to end-user pull. This study delved into the triggers for inventory flow of medical devices used on a consignment basis at hospitals within the interventional cardiology medical device industry. There has been very little research conducted on the topic of consignment stock management and the inventory flow of these devices. The study aimed to look for answers around the questions of flow and types of waste possibly present within this industry. A qualitative research strategy was followed, where interviews were conducted with key role players within the industry. Eight case studies were designed, using interview data collected from leading supply companies and hospital staff members. In order to validate the results, a dynamic buffer management simulation was conducted, using primary data collected in the industry. The simulation followed theory of constraints thinking processes and served as a tool to strengthen the credibility of the results through a process called triangulation. It was concluded that overwhelming evidence exists, demonstrating that end-user consumption is used as the trigger for flow of interventional cardiology medical devices placed on consignment at hospitals. Replenishment of inventory on consignment was performed to daily pull. However, the core problem is that goods still flow as a result of a forecast. Considerable potential exists to improve flow through the use of a dynamic buffer management approach. Significant forms of waste were found to be present within this industry.
Mini Dissertation (MBA)--University of Pretoria, 2015.
vn2016
Gordon Institute of Business Science (GIBS)
MBA
Unrestricted

Mitte des Jahres 2009 wurden an 30 Tagen am neu installierten Herzkatheterarbeitsplatz der Abteilung für Kardiologie und Angiologie, der Klinik für Innere Medizin Messungen durchgeführt um die Exposition von Untersucher und assistierender Pflegekraft während koronarangiographischer und –interventioneller Prozeduren an einer der modernsten Herzkatheterarbeitsplätze zu erfassen. Dazu wurden an 8 Körperteilen des Untersuchers und Assistenzpersonals (jeweils Auge, Schulter, Handrücken und Unterschenkel beidseits) Thermolumeszenzdosimeter angebracht und diese dann nach einem Untersuchungstag ausgewertet. Bei den Ergebnissen stellte sich heraus, dass die empfohlenen jährlichen Expositionswerte unter den vorherrschenden Bedingungen nicht erreicht werden und die Arbeit an einem modernen Herzkatheterarbeitsplatz als sicher gilt. Jedoch ist das Strahlenfeld als solches sehr inhomogen und weist auch starke Schwankungen je nach Art der Untersuchung, der Erfahrung des Untersuchers und auch der Komplexität des Falles auf. Desweiteren muss beachtet werden, dass die technischen Neuerungen der letzten Jahre erheblich zur Verminderung der Exposition geführt haben und somit an älteren Anlage eine Überschreitung der jährliche empfohlenen Teilkörperdosis als wahrscheinlich gilt.

This thesis explored the development of statistical methods to support the monitoring and improvement in quality of treatment delivered to patients undergoing coronary angioplasty procedures. To achieve this goal, a suite of outcome measures was identified to characterise performance of the service, statistical tools were developed to monitor the various indicators and measures to strengthen governance processes were implemented and validated. Although this work focused on pursuit of these aims in the context of a an angioplasty service located at a single clinical site, development of the tools and techniques was undertaken mindful of the potential application to other clinical specialties and a wider, potentially national, scope.

Background: Glucagon-like Peptide 1 (GLP-1) is a human incretin hormone that has been demonstrated to protect against non-lethal ischaemia reperfusion injury in the left ventricle in humans. It has been suggested from some animal research that this protection may be mediated through the pathway of ischaemic conditioning, of which the opening of the mKATP channel is a key step. Furthermore, it is uncertain whether the protection applies to the right ventricle. Finally, there is limited human evidence of a protective effect against lethal ischaemia reperfusion injury. Methods: Two studies use non-lethal ischaemia to test whether GLP-1 protection is maintained despite blockade of the mKATP channel with the sulfonylurea, glibenclamide. A demand ischaemia study uses dobutamine stress echo to compare LV function. The other uses transient coronary balloon occlusion to generate supply ischaemia during GLP-1 infusion, assessed by conductance catheter. A further transient balloon occlusion is also used to assess the effect of supply ischaemia on RV function. Finally, the GOLD PCI study assesses whether GLP-1 protects against periprocedural myocardial infarction when administered during elective PCI in a randomised, placebo controlled double blind trial. Results: Glibenclamide did not affect GLP-1 cardioprotection in either supply of demand ischaemia suggesting that GLP-1 protection is not mediated through the mKATP channel. The RV experienced stunning with RCA balloon occlusion but there was little evidence of cumulative ischaemic dysfunction with further occlusions. GOLD PCI is continuing to recruit patients. The nature of the study means results cannot be assessed until recruitment is complete. Conclusions: GLP-1 is an agent with potential for clinical use as a cardioprotective therapy. It’s mechanism of action in the heart remains uncertain.

La bifurcation coronaire est un site privilégié d’athérosclérose. Jusqu’alors aucune des techniques de stenting provisionnel percutanées avec juxtaposition de ballons n’a démontré de bénéfice clinique. Ces échecs peuvent être expliqués par le non-respect de la géométrie fractale des bifurcations qui pourtant doit toujours guider la revascularisation (correction de la malapposition et optimisation de l’ostium de la branche collatérale). Fort de ce constat, nous avons imaginé une nouvelle technique séquentielle et simple, en 3 temps, le rePOT, associant Proximal Optimizing Technique (POT) initial, ouverture de la branche collatérale et POT final. Son évaluations s’est voulue progressive en 4 étapes : 1) concept, 2) preuve expérimentale de concept, 3) confirmation des bénéfices mécaniques in vivo, et 4) validation clinique. Dans ce travail nous avons donc d’abord expérimentalement démontré la supériorité du résultat mécanique final du rePOT par rapport aux techniques non séquentielles de provisional stenting (manuscrit # 1). Ainsi, le rePOT effondre la malapposition globale du stent, conserve la circularité proximale physiologique et optimise l’obstruction ostiale résiduelle de la branche accessoire. Ces excellents résultats sont confirmés indépendamment du design ou de la composition des stents (manuscrits # 2, 4). Nous avons par ailleurs démontré l’importance de chacune des 3 étapes du rePOT: POT initial (manuscrit # 1), ouverture de SB et POT final (manuscrit # 3). Enfin, fort de ces démonstrations expérimentales, nous avons confirmé in vivo avec mesures OCT itératives à la fois les excellents résultats expérimentaux et la bonne évolution clinique à moyen terme (manuscrit # 5). Ce travail démontre donc étape par étape, de l’expérimentale à la clinique, l’ensemble des bénéfices de cette nouvelle technique séquentielle de stenting provisionnel "rePOT", devenue une référence en Europe dans la revascularisation percutanée des bifurcations coronaires
Coronary bifurcations are a preferential location for atherosclerosis development. Until now, no technic with balloons juxtaposition demonstrated a clinical benefit in percutaneous coronary bifurcation revascularization by provisional stenting (with 1 stent). Successive failures could be explained by the absence of respect of the bifurcations fractal geometry, which need to be systematically followed during all revascularization (correction of the malapposition and optimization of the side branch ostium). Thus, we imagined a new technique, simple and sequential, in 3 steps, named rePOT. It is combining initial Proximal Optimizing Technique (POT), side-branch opening and final POT. We proposed a demonstration in 4 steps : 1) concept, 2) experimental proofs of concept, 3) confirmation of the clinical benefits in vivo, and 4) clinical validation. In this work, we experimentally demonstrated the superiority of the final mechanical results of the rePOT compared to all non-sequential provisional stenting (manuscript # 1). Thus, rePOT decreased stent global malapposition, maintained the initial proximal circularity and optimized the final ostial side branch obstruction. These excellent results were confirmed independently of stent design or material (manuscripts # 2, 4). Moreover, we demonstrated the specific benefits of each steps of the rePOT : initial POT (manuscript # 1), SB opening, and final POT (manuscript # 3). Finally, we confirmed in vivo, with serial OCT analysis, these excellent mechanical results and the good clinical outcome at mid-term. (manuscript # 5). Thank to this step by step demonstration, from experimental to clinic, we confirmed all benefits of this new provisional stenting sequential technique "rePOT". Thereby, before the last step of the demonstration, rePOT became a reference in Europe for the percutaneous revascularization of coronary bifurcations

During catheterized x-ray interventions the patient and medical staff is exposed to scatter radiation, as a consequence of tissue interactions. Ionizing radiation for medical purpose is potentially dangerous and can cause malignancy, skin damage and more. Studies have suggested an increase in the prevalence of eye lens cataract, thyroid cancer and left sided brain tumors in doctors. Therefore, it is mandatory to reduce the radiation dose in medicine, a principle known as ALARA (as low as Reasonably Achievable). Lead aprons, collars and shieldings are safety precautions to protect the team in the operating room. The x-ray equipment and surgical techniques are constantly evolving and the interventions become more complex which may increase the x-ray dose. Although x-ray imaging is required in interventional procedures endeavors of reducing radiation exposure to staff is of high interest. There is a need to increase the awareness about scatter radiation and radiation protection efforts are gaining momentum. Initiative to train a dose reducing behavior by education and awareness are key documents within the European Union’s guidelines on Radiation protection. The aims of this thesis were to create a 3D model for representation of real-time exposure and accumulated scatter radiation to staff performing interventional x-ray procedures and identify parameters that affect the scatter radiation. Extensive measurements were made with real time dosimeters while irradiating an anthropomorphic phantom. For five lateral C-arm projections, 68 - 80 data points each were used to measure scatter dose distribution around the patient. In the typical operator position, the effect of craniocaudal projection angle, patient size, field size, image detector height and pulse rate on scatter radiation dose was also investigated. It was possible to create a 3D model from interpolated measurement data that can generate dose rate with promising results. Six out of eight modelled doses deviated +/- 26.6 % from the validation cases. A model that delivers relative dose is an intuitive approach in education for interventional x-ray radiation safety. The staff position in relation to the x-ray source and the patient size have a significant correlation to the dose rate. Additional measurements are needed to ensure the reliability of the model. This work completes the effect of scatter radiation distribution around the patient table, which is not yet evaluated as thoroughly by other authors.

Dietary fat quality influences the risk of type 2 diabetes and cardiovascular disease. A low-grade inflammation is suggested to contribute to the disease development, often accompanied by obesity. Whereas n-3 polyunsaturated fatty acids (PUFA) have been considered anti-inflammatory, n-6 PUFA have been proposed to act pro-inflammatory. Saturated fatty acids (SFA) act pro-inflammatory in vitro. This thesis aimed to investigate effects of different fatty acids on low-grade inflammation in observational and interventional studies. In Paper I and II, fatty acid composition in serum cholesterol esters was used as objective marker of dietary fat quality and related to serum C-reactive protein (CRP) and other circulating inflammatory markers in two population-based cohorts, conducted in middle-aged men and elderly men and women, respectively. In Paper III and IV, the impact of diets differing in fat quality on inflammation and oxidative stress was investigated in randomised controlled studies, in subjects with metabolic syndrome and abdominal obesity. In Paper I and II, a low proportion of linoleic acid (18:2 n-6) in serum was associated with higher CRP concentrations, indicating that a low intake of vegetable fats may be related to low-grade inflammation. High CRP concentrations were also associated with high proportions of palmitoleic (16:1) and oleic (18:1) acids and high stearoyl coenzymeA desaturase index, possibly reflecting altered fat metabolism and/or high SFA intake in this population. When comparing two high-fat diets rich in either saturated or monounsaturated fat, and two low-fat diets with or without long-chain n-3 PUFA supplementation during 12 weeks (Paper III), no differences in inflammation or oxidative stress markers were observed. Moreover, a 10-week intervention (Paper IV) with high linoleic acid intake showed no adverse effects on inflammation or oxidative stress. Instead, interleukin-1 receptor antagonist and tumor necrosis factor receptor-2 decreased after linoleic acid intake compared with a diet high in SFA. The results in this thesis indicate that dietary n-6 PUFA found in vegetable fats is associated with lower inflammation marker levels, and to some extent reduces systemic inflammation when compared with SFA. Supplementation of n-3 PUFA did not exert any systemic anti-inflammatory effects, maybe due to a relatively low dose.

Le vieillissement vasculaire est un phénomène inéluctable. Il s'accompagne de modifications structurelles et fonctionnelles du système cardio-vasculaire constituant la rigidité vasculaire. Ce processus dégénératif affecte essentiellement la matrice extra cellulaire des artères élastiques. La perte de l'élasticité du système vasculaire va impacter la fonction ventriculaire gauche et la perfusion cardiaque, rénale et cérébrale par des mécanismes différents. La rigidité vasculaire est un puissant marqueur de risque cardio-vasculaire. Cette notion est peu répandue dans le domaine de la cardiologie interventionnelle alors qu'elle pourrait avoir des implications pronostiques et thérapeutiques importantes. Nous nous sommes intéressés à deux domaines de la cardiologie interventionnelle, pour lesquels la rigidité vasculaire pourrait ouvrir de nouvelles voies de recherche, la maladie coronaire et le traitement interventionnel du rétrécissement aortique. Concernant la maladie coronaire il existe un besoin de mieux comprendre la physiopathologie de la microcirculation et de l'ischémie myocardique. La survenue des accidents coronaires aigus reste également incomplètement comprise. Nous avons abordé la problématique par une approche épidémiologique en étudiant l'impact pronostique de la rigidité vasculaire sur la mortalité liée aux coronaropathies dans une cohorte de 1034 patients hypertendus avec 30 années de suivi. La rigidité vasculaire a été appréciée par la pression pulsée et un score d'athérosclérose de l'aorte abdominale. Un lien très fort a été mis en évidence entre la rigidité vasculaire et la survenue d'infarctus du myocarde. Nous avons ensuite développé un moyen d'étudier la rigidité vasculaire localement au niveau des artères coronaires. Nous avons mis au point une technique de mesure de la vitesse de l'onde de pouls coronaire. Cette technique repose sur l'utilisation d'un guide de pression ntra-coronaire et un algorithme breveté du traitement de signal. Nous sommes parvenus à mesurer une vitesse de l'onde de pouls sur 71 artères coronaires chez 49 patients. Nous avons observé une vitesse de l'onde de pouls plus lente témoignant d'artères plus compliantes chez les patients présentant un infarctus du myocarde en comparaison aux patients présentant un angor stable. Nous avons également constaté une augmentation de la vitesse de l'onde de pouls après implantation d'un stent endocoronaire témoignant d'une rigidification attendue de l'artère coronaire. Ces travaux pourraient ouvrir une nouvelle voie de recherche dans la compréhension de l'ischémie myocardique et de la survenue de l'accident coronaire aigu à savoir l'interaction rigidité vasculaire globale et rigidité locale coronaire. Concernant le traitement interventionnel du rétrécissement aortique, de nouveaux facteurs prédictifs du bénéfice de l'intervention sont nécessaires chez des patients souvent âgés et fragiles. Nous nous sommes intéressés à l'étude du volume de calcifications de l'aorte, reflet de la rigidité vasculaire. Ce paramètre a été mesuré par scanner chez des patients traités par remplacement valvulaire aortique par voie percutanée appelé TAVI pour transcatheter aortic valve implantation. Nous avons d'abord montré que le volume de calcifications de l'aorte ascendante était un puissant marqueur de risque indépendant de mortalité cardiaque et d'insuffisance cardiaque sur une série de 127 patients consécutifs traités par TAVI, avec un suivi médian de 907 jours. Ce travail a ensuite été complété en étudiant le volume de calcifications de l'aorte totale sur une série de 164 patients. Le volume de calcifications de l'aorte complète était prédicteur de mortalité totale et cardiaque. De plus, chaque segment d'aorte pris séparément (aorte ascendante, descendante et abdominale) prédisait la mortalité cardiaque. Enfin, seul le volume de calcifications du segment ascendant était prédicteur d'insuffisance cardiaque [etc…]
Vascular aging is an inevitable phenomenon. It is accompanied by structural and functional modifications of the cardiovascular system mainly referred to as vascular stiffening. This degenerative process essentially affects the extracellular matrix of the elastic arteries. The loss of elasticity of the vascular tree affects left ventricular function as well as cardiac, renal and cerebral perfusions involving different mechanisms. Vascular stiffness is a powerful risk marker of cardiovascular disease. However, most interventional cardiologists are not familiar with this concept while it may have both important prognostic and therapeutic implications. We tackled two areas of interventional cardiology, where vascular stiffness may open new fields of research; coronary artery disease and interventional treatment of aortic stenosis namely, transcatheter aortic valve implantation (TAVI). With regards to coronary artery disease there is a need to better understand the pathophysiology of microcirculation and myocardial ischemia. Moreover, the occurrence of acute coronary events is also incompletely understood. Our first approach was epidemiological. We studied the prognostic impact of vascular stiffness on coronary artery disease mortality in a cohort of 1034 hypertensive patients after 30 years of follow-up. Vascular stiffness was assessed both by pulse pressure and by a score related to atherosclerosis of the abdominal aorta. A strong link was found between vascular stiffness and the occurrence of myocardial infarction and coronary artery disease related deaths. We then developed a way to study the local vascular stiffness at coronary artery level by measuring coronary pulse wave velocity. This technique relies on the use of an intracoronary pressure wire and a patented signal processing algorithm. We measured a coronary pulse wave velocity on 71 coronary arteries in 49 patients. Interestingly, patients with acute coronary syndromes had a lower coronary pulse wave velocity (which means more compliant arteries) when compared to patients with stable coronary artery disease. After an endocoronary stent implantation we noticed an increase of coronary pulse wave velocity in line with an expected stiffening. This work opens a new avenue of research regarding coronary perfusion physiology and plaque complications by studying the interaction of regional vascular stiffness and local coronary stiffness. Regarding TAVI, a procedure that often concerns elderly and frail patients, new factors predicting the benefit of the intervention are needed. We studied aortic calcifications as a surrogate of vascular stiffness. This parameter was measured by CT scan before TAVI. We first showed in 127 consecutive patients with a median follow-up of 907 days that ascending aorta calcifications were a powerful risk marker of cardiac mortality and heart failure after TAVI. This study was then completed by studying the volume of the whole aorta in 164 patients. The volume of calcifications of the whole aorta was a predictor of both all-cause and cardiac mortality. In addition, each segment of aorta taken separately (ascending, descending and abdominal aorta) predicted cardiac mortality. Finally, only ascending aorta calcifications predicted heart failure. These results support the hypothesis that ascending aorta calcifications are a marker of vascular stiffness and contribute to the left ventricular afterload. Moreover the volume of the whole aorta could mirror the global atherosclerosis burden of the patient. This easily measurable parameter could thus represent a new risk stratification tool in patients treated with TAVI. This work on vascular stiffness opens a new field of research in several areas of interventional cardiology. Regarding coronary artery disease, coronary pulse wave velocity could represent a way to better understand coronary perfusion, microcirculation, ischemia and the occurrence of coronary plaque rupture [etc...]

Thesis (MScEng (Mechanical and Mechatronic Engineering))--University of Stellenbosch, 2009.
Elderly patients suffering from aortic valvular dysfunction are often denied aortic valve replacement due to the fact that they are classified as too old and fragile to handle the physical stress of open-heart surgery and cardio-pulmonary bypass. There exists a need for an alternative solution which places less physical stress on the body. The development of a percutaneous aortic heart valve (PAHV), which may be implanted through a minimally invasive procedure, will provide a solution to old and fragile patients who otherwise have a very limited life expectancy. The development of such a device entails a costly and time-consuming process which involves a number of phases, including a prototype development phase, an in-vitro testing phase, an animal trial phase and a human trial phase. This thesis focuses on the design and analysis of the stent component for a PAHV, suitable for implantation in sheep (animal trial phase). The process of developing a first prototype, involved an analysis of the stent design requirements. This analysis was followed by a concept generation phase as well as comprehensive finite element (FE) analyses of the most promising concepts. The objective of the FE analyses was to determine the effects of a variation in strut width on the performance characteristics of the concepts. Based on the results of the FE analyses, final geometries were selected for each of the two most promising concepts. Subsequent to the selection of the final geometries, a number of prototypes were manufactured. The prototypes were subjected to an electro-polishing process. An experimental analysis was also conducted on the prototypes to evaluate the accuracy of the (FE) simulations as well as the actual performance of the stent prototypes. The results of the FE analyses and experimental analyses indicated that strut width had a substantial influence on the parameters that were defined to characterise stent performance. The results of the analyses also highlighted the advantages and disadvantages of each concept and aided in identifying the concept that would be most suitable for the required application. Limitations of the study were identified and recommendations were made to assist the continued research and development of the device.

In der vorliegenden Arbeit werden die Ergebnisse von Stent Implantationen bei Kindern mit angeborenen Herzfehlern an der Humboldt Universität zu Berlin, Charité vorgestellt. Zwischen 1994 und 2001 wurden bei 103 Patienten 146/149 Stents erfolgreich in 115 Gefäßstenosen oder Ductus arteriosus implantiert. Das Alter der Patienten bei der Implantation lag zwischen einem Tag und 34 Jahren (ein erwachsener Patient), im Mittel 4 Jahre, Median 1,1 Jahre; das Körpergewicht lag zwischen 1,75 kg und 75 kg, im Mittel 14,4 kg bei einem Median von 7,5 kg. Von den 149 Stents wurden 39,5% in periphere Pulmonalarterienstenosen, 17,5% in Aortenisthmusstenosen, 28,5% in den Ductus arteriosus, 8,5% in Systemvenenstenosen und 6% in Pulmonalvenenstenosen. 40% der 146 erfolgreich implantierten Stents wurden palliativ, 60% kurativ implantiert. Während eines Nachbeobachtungszeitraumes von einem Monat bis 7,5 Jahren, im Mittel 2,14 Jahren, wurden 60 der implantierten Stents insgesamt 79 mal redilatiert. 15 dieser Stents zweimal und 4 dreimal. Der häufigste Grund für eine Redilatation war das Körperwachstum der Patienten (58%). In-Stent Restenosen aufgrund von Intima-Proliferation führten in 25,5% zu einer Redilatation, die übrigen 16,5% Restenosen wurden durch Kompression von außen verursacht. Bei der vorliegenden Studie zeigte sich, dass die Stent-Implantation nicht nur eine effektive Methode zur Behandlung von Gefäßstenosen bei Patienten mit angeborenen Herzfehlern ist. Vielmehr gilt sie bei dem vorgestellten Patientengut als: 1. Vorbereitung, Erleichterung oder Ermöglichung von korrigierenden Operationen bei Neugeborenen durch palliativen Stent Einsatz in den Ductus arteriosus, Aortenisthmusstenosen oder in interventionell eröffnete rechtsventrikuläre Ausflußtrakte; 2. Vermeidung komplexer chirurgischer Eingriffe durch Stent Implantationen in native Aortenisthmusstenosen oder in den Ductus arteriosus bei Patienten mit kritischer Pulmonalstenose oder- atresie mit intaktem Ventrikelseptum; 3. Verbesserung post-operativer Ergebnisse und damit Verbesserung der langfristigen Prognose durch Beseitigung post-operativer Restenosen, zum Beispiel peripherer Pulmonalstenosen nach operativer Korrektur einer Fallotschen Tetralogie. Darüber hinaus lassen sich mit Hilfe von Stents komplexe chirurgisch/interventionelle Therapiestrategien, zum Beispiel dem Etablieren einer Fontanzirkulation, verwirklichen. Da in den meisten Fällen ein lebenslanger Verbleib der Stents geplant war wurden ausschließlich ballonexpandierbare Stents implantiert. Diese können, dem Alter und dem Körperwachstum der Patienten entsprechend durch Redilatation angepaßt werden. Diese limitierten Langzeit-Ergebnisse erscheinen diesbezüglich vielversprechend. Dagegen sind die Ursachen der In-Stent Restenosen aufgrund von Intima-Proliferation, die bei einigen Kindern gefunden wurden, noch nicht verstanden und bedürfen weiterer Untersuchungen. Eine Limitation der vorgestellten Methode besteht in der Stent-Technologie. Derzeit stehen keine Stents zur Verfügung, die im Neugeborenenalter implantiert werden können und bis zum Abschluß des Größenwachstums der Patienten eine gefäßstützende Funktion gewährleisten. Neue Stent-Technologien sind daher für den kurativen Einsatz bei Neugeborenen und kleinen Säuglingen erforderlich und werden in dieser Arbeit im Tiermodel vorgestellt. Zwei unterschiedliche neu Stents, die von zwei unabhängigen Herstellern entwickelt wurden, können durch eine Miniaturisierung der Einführungssysteme im Neugeborenenalter eingesetzt werden und ermöglichen eine Erweiterung der gestenteten Gefäßdurchmesser von minimal 4 Millimeter auf über 20 Millimeter. Weitere chronische Untersuchungen im Tiermodel sind notwendig bevor diese neuen Stent-Technologien in die klinische Erprobung bei Neugeborenen mit angeborenen Herzfehlern eingeführt werden können.
This study reports on stent implantation in paediatric patients with congenital heart disease at the department of paediatric cardiology, Humboldt university of Berlin, Charité. Between 1994 and 2001 146/149 stents were successfully implanted in 115 lesions or arterial ducts of 103 patients. The age of the patients ranged between 1 day and 34 years (one adult patient), mean 4 years, median 1.1 years; the bodyweight was measured between 1.75 kg and 75 kg, mean 14.4 kg, median 7.5 kg. The stent were implanted into different lesions: 39.5% in peripheral pulmonary artery stenoses, 17.5% in coarctation, 28.5% in the arterial duct, 8.5% in systemic vein stenoses and 6% in pulmonary vein stenoses. The implantations were performed for palliativ reasons in 40% or as a definite treatment in 60%. During a follow up period between 1 months and 7.5 years, mean 2.14 years 79 repeat dilations were performed on 60 stents, 15 stents twice and 4 stents three times. The most common reason for repeat intervention were dilation according to patients growth (58%). In-stent restenoses due to intimal hyperplasia were noted in 25.5% and 16.5% restenoses occurred due to compression from surrounding structures. The results of this study demonstrated stent-implantation not only as an effective method for treatment of vessel stenosis in young patients with congenital heart diseases. In addition 1. palliative stenting of the arterial duct, critical coarctation or right ventricular outflow tract obstruction in neonates improves surgical outcome or increases operability. 2. stent implantation can be an attractive alternative to complex surgery i.e. the establishment of Fontan circulation as part of a combined surgical/interventional concept 3. postoperative stenting of restenosis improves surgical results and reduces mortality and morbidity by reduction of the individual number of surgical procedures. Balloon expandable stents were used exclusively as the vast majority were considered to treat vessel stenosis for a lifelong period. The limited experiences on long-term follow-up are encouraging concerning the possibility of repeat dilation according to patients growth. However, the mechanisms of in-stent restenosis are not fully understand. For long-term treatment of vessel stenosis in neonates and small infants the conventional stent technology was found as a major limitation. New stent-designs are necessary. The report encloses two different new stent-technologies in animal studies. Miniaturised stents and delivery systems developed by two different companies are demonstrated. An additional advantage of the new stent designs is the broad variability of the stent diameters. After the initial implantation with a minimum diameter of 4 millimetres those stents can be dilated to a maximum diameter of more than 20 millimetres. Further investigations are necessary to demonstrate the efficacy of the new stent designs in different lesions of human neonates.

L'intervention coronarienne percutanée (ICP) est réalisée en utilisant l'imagerie radiographique en temps réel dans une suite interventionnelle. La modélisation de ces procédures ICP pour aider le praticien implique la compréhension des différentes phases de la procédure ICP, par la machine d’intervention, qui peut être utilisées pour optimiser la dose de rayons X et l'agent de contraste. Pour atteindre cet objectif, l’une des tâches importantes consiste à segmenter différents outils d’intervention dans les flux d’images fluoroscopiques et à en déduire des informations sémantiques. L’arbre des composants, un puissant outil morphologique mathématique, constitue la base des méthodes de segmentation proposées. Nous présentons ce travail en deux parties: 1) la segmentation du cathéter vide à faible contraste, et 2) la segmentation de la pointe du guide et le suivi de la détection du vaisseau d’intervention. Nous présentons une nouvelle méthode de segmentation basée sur l’espace à plusieurs échelles pour détecter des objets faiblement contrastés comme un cathéter vide. Pour la dernière partie, nous présentons la segmentation de la pointe du guide avec le filtrage basé sur l’arbre de composants et proposons un algorithme pour suivre sémantiquement la pointe segmentée pour déterminer le vaisseau d’intervention
Percutaneous coronary intervention (PCI) is performed using real-time radiographic imaging in an interventional suite. Modeling these ICP procedures to help the practitioner involves understanding the different phases of the ICP procedure, by the interventional machine, which can be used to optimize the X-ray dose and the contrast agent. One of the important tasks in achieving this goal is to segment different interventional tools into the flow of fluoroscopic images and to derive semantic information from them. The component tree, a powerful mathematical morphological tool, forms the basis of the proposed segmentation methods. We present this work in two parts: 1) the segmentation of the low-contrast empty catheter, and 2) the segmentation of the tip of the guide and the monitoring of the detection of the intervention vessel. We present a new multi-scale space-based segmentation method for detecting low-contrast objects such as an empty catheter. For the last part, we present the segmentation of the tip of the guide with filtering based on the component tree and propose an algorithm to semantically follow the segmented tip to determine the intervention vessel

Background. Primary and secondary prevention trials have shown that implantable cardioverter-defibrillators (ICD) reduce the risk of cardiac death, but concerns have been raised regarding the psychological well-being of ICD patients. Anxiety can affect a significant proportion of these patients, but there is limited information about prevalence and determinants of anxiety after the implementation of the more recent guidelines for ICD implantation. Several behavioral interventions have been effective in improving anxiety in these patients, however the efficacy of mindfulness-based interventions (MBI) has not been investigated in ICD patients, and there is limited information regarding the characteristics of pre-intervention, “dispositional” mindfulness in patients with cardiovascular disease never exposed to mindfulness training. The aims of this dissertation project were: 1) To determine the feasibility of a randomized clinical trial of a phone-administered, mindfulness-based training program, as measured by recruitment and retention rates, treatment adherence and fidelity; 2) To evaluate the current baseline prevalence and determinants of anxiety in the study population and 3) To describe the correlates of dispositional mindfulness in the study population. Methods. The study was conducted at the Electrophysiology Service at the UMass Memorial Medical Center. All consecutive patients who recently underwent an ICD procedure or received ICD shocks were screened for eligibility to participate in a pilot randomized controlled trial in which an eight session, phone-delivered, weekly MBI was compared to a usual care condition. Assessments were performed at baseline and post-intervention. A cross-sectional design was used for aims 2 and 3. Anxiety was assessed using the Hospital Anxiety and Depression Scale; a shortened version of the Five Facets of Mindfulness questionnaire was used to evaluate mindfulness. Results. Thirty patients (21 M, 9 F; mean age 63.1 ±10.3 years) were enrolled in the study. The methods ultimately adopted to screen, recruit, and retain study participants were feasible to conduct and satisfactory to ICD outpatients, and the study intervention was safe. Phone delivery resulted in excellent retention rates and limited costs. Assessments of treatment fidelity showed that the content of the intervention was delivered as intended in almost 100% of cases. The study findings do not show a decrease in the overall prevalence of anxiety in ICD patients compared with earlier cohorts; anxiety was associated with young age, low socio-economic status and previous psychological morbidity, but not with ICD-related factors including prior shock delivery. Finally, baseline mindfulness was most strongly associated with previous psychological morbidity (in particular, depression), and current anxiety symptoms. Conclusion. Psychological morbidity appears to be the major determinant of anxiety in the patients currently enrolled in the study. Dispositional mindfulness is inversely associated with current anxiety and depression and with prior psychological morbidity, supporting the hypothesis of a modulating role of mindfulness on the processing of negative emotions. A phone-delivered, individual MBI is feasible, acceptable to patients and can be adequately delivered by trained instructors. The findings from this dissertation work support the need for larger clinical trials of MBI in ICD patients.

Background: Cardiovascular disease (CVD) is an important health concern in prison populations as they have an increased risk of the disease compared to the general population. However, there is a lack of interventions to reduce prisoners’ cardiovascular risk, and little is known about the knowledge and risk perceptions of the disease in prison. This study aims to explore the knowledge and risk perceptions of CVD from the perspectives of prisoners and staff to guide the development of a cardiovascular risk reduction intervention for prisoners. Methods: This was a qualitative, exploratory study. Semi-structured interviews were conducted with 16 prisoners and 11 staff, who were purposively recruited from a private prison in Scotland. Framework analysis was used to analyse the data. Findings: The prisoners and staff had limited, non-expert knowledge of CVD. Common behavioural risk factors and cardiovascular events were identified, but gaps in knowledge were evidenced. There were similarities and differences in perceptions of prisoners’ risk of the disease; risk was primarily assessed by judgements about the prisoners’ current health status rather than their risk factor status. Prisoners’ risk of CVD was attributed to negative health behaviours such as smoking and physical inactivity, and these were influenced by multiple factors that interacted across three levels of influence. Individual factors included self-efficacy and mental health problems, social factors included the prison culture and social interactions, and institutional factors included the prison regime and healthcare barriers. An ecological framework was designed to guide a cardiovascular risk reduction intervention that focuses on the multi-level influences of prisoners’ cardiovascular risk. Conclusion: Prisoners have limited knowledge and misconceptions of CVD, and engage in several risky behaviours. There are multi-level influences on prisoners’ CVD risk and cardiovascular health. An ecological approach is recommended to address these influences to reduce the prisoners’ risk of CVD.

L'imagerie par tomographie en cohérence optique (OCT) est prometteuse comme support de la prise de décision au cours des procédures d'interventions coronariennes percutanées (PCI), pou évaluer les lésions athéromateuses, juger de la bonne implantation du stent, et dépister les lésions vasculaires dues au stent. L'OCT représente donc bien une aide potentielle pour le cardiologue interventionnel tout au long de la procédure de stenting, avec un impact certain sur la stratégie interventionnelle initialement programmée. De plus, l'OCT se révèle comme un nouvel outil pour prédire la dissection des bords de stent chez les patient avec ACS sans élévation du segment ST, rendant possible une stratification des patients quant à ce risque. Des essais cliniques randomisés sont maintenant nécessaires pour savoir si l'assistance par l'OCT pendant la procédure améliore le pronostic à long terme des patients après PCI
Optical Coherence Tomography (OCT) imaging is promising in decision making during Percutaneus Coronary Interventions {PCI) procedures, including evaluating controversial plaque lesions, assessing stent implantation, and surveying stent-related vascular injury. Thus, OCT has potential to guide interventional cardiologists throughout the stent implantation procedure, impacting on planned interventional strategy. In addition, OCT is the most novel image technology to predict stent edge dissection for patients with non-ST-segment elevation ACS, enabling risk stratification of patients who are at a higher risk of this complication. Large-scale randomized trials are now warranted to assess whether OCT results and guidance during de procedure improve long-term clinical outcomes of PCis

Background. Primary and secondary prevention trials have shown that implantable cardioverter-defibrillators (ICD) reduce the risk of cardiac death, but concerns have been raised regarding the psychological well-being of ICD patients. Anxiety can affect a significant proportion of these patients, but there is limited information about prevalence and determinants of anxiety after the implementation of the more recent guidelines for ICD implantation. Several behavioral interventions have been effective in improving anxiety in these patients, however the efficacy of mindfulness-based interventions (MBI) has not been investigated in ICD patients, and there is limited information regarding the characteristics of pre-intervention, “dispositional” mindfulness in patients with cardiovascular disease never exposed to mindfulness training. The aims of this dissertation project were: 1) To determine the feasibility of a randomized clinical trial of a phone-administered, mindfulness-based training program, as measured by recruitment and retention rates, treatment adherence and fidelity; 2) To evaluate the current baseline prevalence and determinants of anxiety in the study population and 3) To describe the correlates of dispositional mindfulness in the study population. Methods. The study was conducted at the Electrophysiology Service at the UMass Memorial Medical Center. All consecutive patients who recently underwent an ICD procedure or received ICD shocks were screened for eligibility to participate in a pilot randomized controlled trial in which an eight session, phone-delivered, weekly MBI was compared to a usual care condition. Assessments were performed at baseline and post-intervention. A cross-sectional design was used for aims 2 and 3. Anxiety was assessed using the Hospital Anxiety and Depression Scale; a shortened version of the Five Facets of Mindfulness questionnaire was used to evaluate mindfulness. Results. Thirty patients (21 M, 9 F; mean age 63.1 ±10.3 years) were enrolled in the study. The methods ultimately adopted to screen, recruit, and retain study participants were feasible to conduct and satisfactory to ICD outpatients, and the study intervention was safe. Phone delivery resulted in excellent retention rates and limited costs. Assessments of treatment fidelity showed that the content of the intervention was delivered as intended in almost 100% of cases. The study findings do not show a decrease in the overall prevalence of anxiety in ICD patients compared with earlier cohorts; anxiety was associated with young age, low socio-economic status and previous psychological morbidity, but not with ICD-related factors including prior shock delivery. Finally, baseline mindfulness was most strongly associated with previous psychological morbidity (in particular, depression), and current anxiety symptoms. Conclusion. Psychological morbidity appears to be the major determinant of anxiety in the patients currently enrolled in the study. Dispositional mindfulness is inversely associated with current anxiety and depression and with prior psychological morbidity, supporting the hypothesis of a modulating role of mindfulness on the processing of negative emotions. A phone-delivered, individual MBI is feasible, acceptable to patients and can be adequately delivered by trained instructors. The findings from this dissertation work support the need for larger clinical trials of MBI in ICD patients.

Trabalho de projecto de mestrado, Bioestatística, Universidade de Lisboa, Faculdade de Ciências, 2016
Invasive techniques are essential in investigation and management of cardiac and vascular diseases, particularly obstructive coronary artery disease. These invasive techniques can be performed for diagnostic or interventional purposes, and the access to the target arteries can be done through the femoral or the radial artery. The transradial approach may be clinically preferable, namely because its use has been associated with fewer peri-procedural complications, like bleeding. Despite the advantages over transfemoral approach, concerns have risen on the potential for transradial approach to increase the incidence of peri-procedural neurological complications, like Stroke or Transient Ischemic Attack (TIA) (Jurga et al., 2011). The aim of this work is to access the association between the risk of peri-procedural Stroke/TIA and the transradial or the transfemoral approaches. A propensity score analysis was performed in a sample of 16 710 patients included in a single prospective registry between January of 2006 and November of 2012. Various PS methods like matching, genetic matching, stratification and inverse probability of treatment weighting were used to estimate the Average Treatment Effect for the Treated (ATT) and the Average Treatment Effect (ATE). To find the best possible matching, PS estimates were fitted from a GAMs and from logistic regressions. A logistic regression (LR) was performed too in order to identify all the factors associated to the occurrence of peri-procedural Stroke/TIA and estimate the Odds Ratios. To handle the low number of events and the subsequent separation problem, a Firth’s logistic regression correction was run. Both Propensity Score analysis and regression methods reached the same conclusions. The use of Transradial or Transfemoral Approach does not impact the occurrence of peri-procedural Stroke/TIA. So the clinically preferential use of Transradial can be performed without concerns relative to this technique. Regarding the methodology, GAM PS estimates provide better matchings when there are variables non-linear related with the treatment assignment logit, but genetic matching can overcome these differences by matching individually on these variables through the Generalized Mahalanobis Distance.
A doença coronária é uma das principais causas de morbilidade e mortalidade à escala global quer nos no mundo moderno quer nos países em desenvolvimento devido ao estilo de vida das populações e ao progressivo envelhecimento da população. Os principais fatores de risco são a hipertensão arterial, a dislipidémia, a diabetes, o tabagismo e o sedentarismo (Sacco et al., 1997; Donnan et al., 2008). As manifestações clínicas dependem largamente do território vascular afectado. Uma variedade de técnicas invasivas é utilizada em cardiologia, nomeadamente para o diagnóstico e tratamento e da doença coronária obstrutiva. Por norma, estes procedimentos usam um catéter (essencialmente um ”tubo” inserido através de um ponto de acesso e guiado ao local de diagnóstico/intervenção, de modo a executar o procedimento). O ponto de acesso pelo qual o catéter é inserido é em geral a artéria femoral ou a artéria radial. Uma das complicações mais temidas da manipulação endovascular associada a este tipo de procedimentos é o Acidente Vascular Cerebral (AVC). A obstrução das artérias intra-craneanas devido a fenómenos trombo-embólicos provoca isquémia cerebral e em última análise, morte celular com perda temporária e definitiva de função neutológica (por exemplo, dificuldade na fala, dificuldade em compreender outras pessoas, perda de visão e falta de capacidade em sentir e mover certas partes do corpo) (Donnan et al., 2008). Durante grande parte do século XX, o acesso transfemoral foi o mais utilzado pela maior parte dos cardiologistas de intervenção. Recentemente, tem sido demonstrado que o acesso transradial se associa a menos complicações peri-procedimento, como por exemplo a hemorragia, menos morbilidade e mortalidade, e tem menos custos que o acesso femoral. Todas estas vantagens contribuíram para a grande expansão do uso da artéria radial como ponto de acesso (Nathan and Rao, 2012; Burzotta et al., 2013). No entanto, surgiram preocupações relativamente ao acesso transradial e ao risco de complicações neurológicas, sobretudo devido à maior manipulação do arco aórtico e das artérias subclávias (Jurga et al., 2011). O grande objetivo deste trabalho é estudar a associação entre a ocorrência de complicações neurológicas e o tipo de acesso usado durante o procedimento. Os dados usados neste estudo observacional foram recolhidos a partir de cateterismos diagnósticos e de intervenção realizadas no Hospital de Santa Cruz, Carnaxide, entre Janeiro de 2006 e Novembro de 2012, sendo que os indivíduos incluídos no estudo têm 18 anos de idade, ou mais, tendo sido sujeitos a manipulação da artéria aorta ascendente ou do arco aórtico. A população final do estudo compreende 16710 indivíduos. A primeira abordagem executada para estudar esta associação foi a regressão logística pois é a abordagem mais usada e considerada ”standard”. Para uma correta aplicação desta metodologia é conveniente ter 10 eventos por cada variável registada, para que assim os resultados sejam fiáveis (Peduzzi et al., 1996). No entanto, neste estudo apenas temos 27 eventos para 25 variáveis, o que põe em causa a utilização da regressão logística. Este número baixo de eventos origina o problema da Separação, no qual não é possível calcular a real contribuição das variáveis ”Transplante Renal” e ”Histórico de AVC/AIT” na ocorrência do desfecho. Para contornar este problema, optou-se que pela aplicac¸ ˜ao da regressão logística de Firth, em que a estimação de máxima verosimilhança tem por base uma verosimilhança penalizada (Firth, 1993). O baixo número de eventos e o grande número de variáveis a controlar (como é o caso) foi a principal motivação para a utilização da metodologia assente em Propensity Scores, além de outras vantagens referidas neste trabalho. O Propensity Score (PS) de cada individuo é, neste caso, a sua probabilidade de ter sido intervencionado pelo acesso transradial, sabendo determinado conjunto de variáveis. Tradicionalmente, os PS são calculados usando uma regressão logística. O cálculo destes pela regressão logística pressupõe que existe uma relação linear entre o logit da variável dependente (Acesso Transradial) e as covariáveis, pelo que, se este pressuposto não for verdadeiro, as estimativas dos PS estão erradas. Neste estudo, os PS também vão ser calculados via modelos aditivos generalizados (GAMs), pois este tipo de modelos são mais flexíveis e, portanto, conseguem descrever mais eficazmente a real relação entre uma covariável e a variável dependente, originando estimativas dos PS mais fiáveis (Woo et al., 2008). A primeira metodologia de Propensity Scores usada ´e o ”Matching”, a qual consiste em emparelhar indivíduos que foram intervencionados pelo acesso transradial com outros intervencionados pelo acesso transfemoral. O ”Matching” emparelha indivíduos com PS semelhantes. Isto porque, está provado que dois indivíduos são assintoticamente comparáveis (mesma distribuição de variáveis) se tiverem PS estimados semelhantes (Rubin and Rosenbaum, 1983). Vários emparelhamentos foram executados, diferindo na forma de serem estimados os PS (usando a regressão logística ou modelos aditivos generalizados), ou diferindo nos conjuntos de vari´aveis usados como covariáveis nos modelos. Além do ”Matching” simples, também foi executado o ”Matching” genético, que utiliza a distância de Mahalanobis (distância multivariada) como medida de emparelhamento. Esta distância é calculada a partir das variáveis observadas durante o estudo e dos PS estimados. No ”Matching” genético também foram experimentados vários conjuntos de variáveis, e os dois métodos de regressão para estimar PS. No final, o melhor ”Matching” conseguido (de entre os ”Matchings” simples e genéticos) foi um emparelhamento genético o qual incluiu todas as variáveis observadas e PS estimados a partir de um GAM. A qualidade do emparelhamento é medida através do quão homogéneas são as distribuições das variáveis nos dois grupos a comparar. O emparelhamento escolhido possibilitou a criação de dois grupos de tratamento homogéneos relativamente às distribuições das variáveis, e assim foi possível calcular o ”Average Treatment Effect for the Treated (ATT)”. Também se provou que os PS ajustados a partir de GAMs originam melhores emparelhamentos, em termos gerais, como sugere a literatura (Woo et al., 2008). Outra metodologia baseada em Propensity Scores usada foi a Estratificação. Aqui, tomando partido dos Propensity Scores ajustados a partir de GAMs com todas as variáveis registadas como dependentes, agrupou-se os indivíduos em 5 estratos. Dentro de cada estrato, os indivíduos são semelhantes relativamente ao PS e, consequentemente, semelhantes em relação à distribuição das variáveis, pelo que assim é possível calcular o ”Average Treatment Effect (ATE)” (Rosenbaum and Rubin, 1984). Outro modo usado para calcular o ATE, foi pela metodologia de ”Inverse Probability of Treatment Assignment (IPTW)”. O IPTW consiste em atribuir um peso a cada indivíduo, sendo cada peso calculado com base no PS de cada indivíduo. A soma dos pesos em cada grupo de tratamento é igual. Este procedimento cria duas amostras sintéticas com a mesma dimensão, que são diretamente comparáveis, não levantando quaisquer problemas relativos a um possível confundimento (Austin, 2011a). Ambos os métodos de regressão e as metodologias usando PS, retornaram as mesmas conclusões. O uso do acesso transradial ou transfemoral não influencia a ocorrência de complicações neurológicas peri-procedimento. Assim, o uso clinicamente preferencial do acesso transradial pode continuar a ser aplicado sem preocupações de maior. Estas conclusões reforçam a literatura (Raposo et al., 2015).

Dissertação de Mestrado Integrado em Engenharia Mecânica apresentada à Faculdade de Ciências e Tecnologia
A simulção médica é um campo em crescimento, incentivando a medicina pesonalizada e um melhor tratamento dos pacientes. Com o aumento do uso de técnicas de prototipagem rápida como a impressão 3D, aparecem novas oportunidades de uso das mesmas aplicadas a esta área. O facto de que o erro médico é a terceira maior causa de morte nos Estados Unidos e que a American Food and Drug Administration considera que deve existir treino de simulação para a utilização de novos dispositivos reitera esta necessidade.Até agora, as soluções oferecidas pelo mercado no que toca a simulação de intervenção coronária percutânica, limitavam-se a produtos baseados em software e teste em cadáveres. No entanto, este tipo de técnica apresenta diversas limitações, como sendo a dficuldade de simular casos específicos e o realismo da intervenção.O propósito desta tese é a execução de um simulador físico de cardiologia de intervenção para auxiliar o tratamento de doença coronária. Para isso, recorreu-se a métodos de impressão 3D de estruturas anatómicas específicas, com o desenvolvimento e manufatura de todo o equipamento necessário para acomodoar estes modelos. Métodos incluem a utilização de pós processamento de impressões 3D com revestimentos elastoméricos e moldes destrutivos com revestimentos de silicone.Vários testes reais foram concretizados, indicando um comportamento de simulação muito similar à intervenção real. O feedback dos cardiologistas de intervenção foi muito positivo, apontando que pelo facto de terem aprendido e previsto possíveis complicações, o sucesso das operações foi claramente superior.
Simulation in healthcare is a growing field, leading to personalized medicine and better patient treatment. With an increasing use of rapid prototyping techniques such as 3D printing, new opportunities arise for enhancing this medical practice. The fact that medical error accounts for the third most common cause of death in the United States, and that American Food and Drug administration considers that simulation training should be part of new procedure device training, just emphasizes this need.Until now, both software and corpse-based simulation were available options when considering percutaneous coronary intervention simulation. However, these methods have big limitations in patient specific anatomies as well as overall realism.The purpose of this thesis is to produce a physical interventional cardiology simulator to aid the treatment of coronary artery disease. For this, 3D printing of patient specific anatomical structures was broadly used, alongside with designing and manufacturing a real like setup to accommodate these models. Methods include post processing stereolithography 3D printings with elastomeric coatings and destructive molds with silicone coatings.Real tests were done in cath lab environment and final results indicated a very similar behavior between real and simulated procedures. Interventional cardiologists’ feedback was very positive, indicating that by having learned and predicted possible complications beforehand, the intervention outcome was much better.

碩士
國立清華大學
生醫工程與環境科學系
105
The International Commission on Radiological Protection (ICRP) recommended that the equivalent dose limit for the lens of the eye be decreased from 150 mSv/y (ICRP, 2007) to 20 mSv/y averaged over five years (ICRP, 2011). How to accurately measure the eye-lens dose has, therefore, been an issue of interest recently. Interventional radiologists are at a higher risk of radiation-induced eye injury, such as cataracts, than all other occupational radiation workers. The main objective of this study is to investigate the relationship between the doses to the eye lenses of interventional radiologists measured by different commercial eye-lens dosimeters. This study measured a reference eye-lens dose, which involved placing thermoluminescent dosimeter (TLD) chips at the surface of the eye of the Rando Phantom, and the TLD chips were covered by a 3-mm-thick tissue-equivalent bolus. Commercial eye-lens dosimeters, such as a headband dosimeter and standard personnel dose badges, were placed at the positions recommended by the manufacturers. The results show that the personnel dose badge is not an appropriate dosimeter for evaluating eye-lens dose when it is worn on the chest inside a lead apron. Dose deviations for different dosimeters are discussed and presented in this study. Besides, the eye-lens dose measured by the headband dosimeter may estimate a higher dose to the eye lens than the dose measured by TLD-100H chips due to difference of physical TLD geometry and difference response in a low-energy photon filed. Therefore, the correction factor of energy dependence for TLD is important. Additionally, the issue of eye-lens dose accepted by interventional radiologists in Taiwan should be studied in the near future as their doses are already over the new dose limit.

This thesis presents the first work, to our knowledge, to evaluate the potential of Optical Coherence Tomography (OCT) as an intravascular imaging modality to characterize and guide interventions on chronic total occlusions (CTOs) in arteries. An ex vivo imaging study using OCT is presented that characterizes various pathologies associated with peripheral CTOs and illustrates the ability to differentiate between the vessel wall and the occluded lumen. We also found that, while OCT could image approximately 1mm through tissue, it was effective for imaging deeper through clarified microchannels seen within the occluded lumen. While others had reported observing such microchannels within the lumen before, little was known about the global architecture of these channels. This motivated a study of the global morphology of microchannels in occlusions using micro computed tomography (microCT). In this microCT study, we found that microchannels within the occluded lumen of the artery appeared to be continuous over several millimeters. However, these channels also exited the artery frequently, suggesting the need for some form of imaging guidance. As a potential intravascular imaging set-up, a forward-viewing OCT catheter was built. This catheter uses a novel scanning mechanism that combines high voltage and a dissipative polymer to achieve fast compact actuation. Doppler OCT results are presented using this catheter to image flow in the forward direction. Doppler OCT imaging of microchannels in vivo is also shown in a surgically exposed occluded artery in situ.

Mitte des Jahres 2009 wurden an 30 Tagen am neu installierten Herzkatheterarbeitsplatz der Abteilung für Kardiologie und Angiologie, der Klinik für Innere Medizin Messungen durchgeführt um die Exposition von Untersucher und assistierender Pflegekraft während koronarangiographischer und –interventioneller Prozeduren an einer der modernsten Herzkatheterarbeitsplätze zu erfassen. Dazu wurden an 8 Körperteilen des Untersuchers und Assistenzpersonals (jeweils Auge, Schulter, Handrücken und Unterschenkel beidseits) Thermolumeszenzdosimeter angebracht und diese dann nach einem Untersuchungstag ausgewertet. Bei den Ergebnissen stellte sich heraus, dass die empfohlenen jährlichen Expositionswerte unter den vorherrschenden Bedingungen nicht erreicht werden und die Arbeit an einem modernen Herzkatheterarbeitsplatz als sicher gilt. Jedoch ist das Strahlenfeld als solches sehr inhomogen und weist auch starke Schwankungen je nach Art der Untersuchung, der Erfahrung des Untersuchers und auch der Komplexität des Falles auf. Desweiteren muss beachtet werden, dass die technischen Neuerungen der letzten Jahre erheblich zur Verminderung der Exposition geführt haben und somit an älteren Anlage eine Überschreitung der jährliche empfohlenen Teilkörperdosis als wahrscheinlich gilt.

Aortic stenosis is the most common acquired heart valve condition. Open-heart surgical aortic valve replacement is an effective treatment for patients who receive it. However, approximately one-third of patients who require this treatment do not receive it due to the risks associated with the surgery. Percutaneous aortic valve replacement (PAVR) is a minimally invasive technique that can replace the aortic valve of patients contraindicated for open-heart surgery. Although PAVR is now entering clinical practice, a closed bore hybrid x-ray/MRI (CBXMR) imaging system is under development to improve the safety and efficacy of PAVR. This system will harness the complementary strengths of x-ray imaging (surgical tool/vascular imaging) and MRI (cardiac soft tissue contrast) to deploy a bioprosthesis in the aortic annulus. An x-ray C-arm will be placed about 1 m from the entrance of the MRI scanner to facilitate smooth intermodality patient transfer during the procedure. The performance of a rotating-anode x-ray tube in the magnetic fringe field of a 1.5 T MRI scanner was investigated. A rotating-anode x-ray tube provides the fluoroscopy and angiography needed for PAVR. The magnetic fringe field can affect the ability of the x-ray tube to dissipate heat. It was shown that the fringe field perpendicular to the anode rotation axis can reduce anode rotation frequency. These effects can limit the maximum permissible power that can be safely dissipated on the anode track during a single exposure. In the fringe field strengths at the C-arm position (4-5 mT), anode rotation frequency only decreased by about 1%, which will have negligible impact on tube heat loadability. The fringe field can cause a field of view shift. The field of view shifted by approximately 3 mm, which can be corrected by active magnetic shielding and further collimation. An active magnetic shielding system was constructed that can correct focal spot deflection. These results are facilitating the construction of a prototype CBXMR system, the goal of which is to improve success rates for PAVR procedures.

Trabalho Final do Mestrado Integrado em Medicina apresentado à Faculdade de Medicina
The number and complexity of transcatheter interventions in the treatment of structural heart diseases has been increasing in clinical practice and has been associated with the development of new imaging technologies, to make these interventions even more accurate and secure. Complementary imaging modalities are commonly used in clinical practice, but it requires an additional mental reconstruction effort by the interventional team. The concept of fusion imaging, where two different imaging modalities are fused in real time and on a single monitor, aims to solve these limitations. The EchoNavigator® software, through the real-time fusion of classical fluoroscopy and the image of transesophageal echocardiography, is an important tool to guide and monitoring percutaneous interventions, enabling a good visualization of catheters, guidewires and devices employed, with enhanced spatial resolution and anatomical definition. It also allows the marking of anatomical reference points of interest for the procedure. Some studies show decreased procedural time and total radiation dose with fusion imaging; however, there is still a need to obtain data with more robust scientific methodology to assess the impact of this technology in clinical practice. The aim of this review is to describe the concept and basic principles of fusion imaging, its main clinical applications currently described in the literature and some considerations about the promising future of this imaging technology.
O número e a complexidade das intervenções percutâneas no tratamento de doenças cardíacas estruturais tem vindo a aumentar largamente na prática clínica, estando associado ao desenvolvimento de novas tecnologias de imagem para intervenções cada vez mais precisas e seguras. A utilização de modalidades de imagem complementares é comummente utilizada na prática clínica, contudo exige um esforço de reconstrução mental por parte da equipa de intervenção. O conceito de imagem de fusão, onde duas modalidades de imagem são fundidas em tempo real e num só monitor, vem colmatar essas limitações. O software EchoNavigator®, através da fusão em tempo real da fluoroscopia clássica com a imagem da ecocardiografia transesofágica, revela-se uma ferramenta importante para a monitorização das intervenções percutâneas, associando uma correta visualização dos cateteres, fios-guia e dispositivos utilizados a uma melhor resolução espacial e definição anatómica. Permite também a marcação de pontos de referência com interesse anatómico para o procedimento. Alguns estudos revelam a diminuição da duração de procedimento e da dose total de radiação; contudo, persiste a necessidade de obtenção de dados com metodologia científica mais robusta para aferir o impacto desta tecnologia na prática clínica. Esta revisão pretende abordar o conceito e os princípios básicos da imagem de fusão, as suas principais aplicações clínicas, bem como algumas considerações acerca do futuro promissor desta tecnologia de imagem.

Yes
Heart failure affects 26 million people globally, and the optimal management of medicines is crucial for patients, particularly when their care is transferred between hospital and the community. Optimising clinical outcomes requires well-calibrated cross-organisational processes with staff and patients responding and adapting to medicines changes. The aim of this study was to assess the feasibility of implementing a complex intervention (the Medicines at Transitions Intervention; MaTI) co-designed by patients and healthcare staff. The purpose of the intervention was to optimise medicines management across the gaps between secondary and primary care when hospitals handover care. The study objectives were to (1) assess feasibility through meeting specified progression criteria to proceed to the trial, (2) assess if the intervention was acceptable to staff and patients, and (3) determine whether amendment or refinement would be needed to enhance the MaTI. The feasibility of the MaTI was tested in three healthcare areas in the North of England between July and October 2017. Feasibility was measured and assessed through four agreed progression to trial criteria: (1) patient recruitment, (2) patient receipt of a medicines toolkit, (3) transfer of discharge information to community pharmacy, and (4) offer of a community pharmacy medicines review/discussion or medicines reconciliation. From the cardiology wards at each of the three NHS Acute Trusts (sites), 10 patients (aged ≥ 18 years) were recruited and introduced to the 'My Medicines Toolkit' (MMT). Patients were asked to identify their usual community pharmacy or nominate a pharmacy. Discharge information was transferred to the community pharmacy; pharmacists were asked to reconcile medicines and invited patients for a medicines use review (MUR) or discussion. At 1 month following discharge, all patients were sent three questionnaire sets: quality-of-life, healthcare utilisation, and a patient experience survey. In a purposive sample, 20 patients were invited to participate in a semi-structured interview about their experiences of the MaTI. Staff from hospital and primary care settings involved in patients' care were invited to participate in a semi-structured interview. Patient and staff interviews were analysed using Framework Analysis. Questionnaire completion rates were recorded and data were descriptively analysed. Thirty-one patients were recruited across three sites. Eighteen staff and 18 patients took part in interviews, and 19 patients returned questionnaire sets. All four progression to trial criteria were met. We identified barriers to patient engagement with the intervention in hospital, which were compounded by patients' focus on returning home. Some patients described not engaging in discussions with staff about medicines and lacking motivation to do so because they were preoccupied with returning home. Some patients were unable or unwilling to attend a community pharmacy in person for a medicines review. Roles and responsibilities for delivering the MaTI were different in the three sites, and staff reported variations in time spent on MaTI activities. Staff reported some work pressures and staff absences that limited the time they could spend talking to patients about their medicines. Clinical teams reported that recording a target dose for heart failure medicines in patient-held documentation was difficult as they did not always know the ideal or tolerable dose. The majority of patients reported receiving the patient-held documentation. More than two-thirds reported being offered a MUR by their community pharmacists. Delivery of the Medicines at Transitions Intervention (MaTI) was feasible at all three sites, and progression to trial criteria were met. Refinements were found to be necessary to overcome identified barriers and strengthen delivery of all steps of the intervention. Necessary changes to the MaTI were identified along with amendments to the implementation plan for the subsequent trial. Future implementation needs to take into account the complexity of medicines management and adaptation to local context.
This study is funded by the National Institute for Health Research (NIHR) (Programme Grants for Applied Research (Grant Reference Number RP-PG-0514-20009)). The study is also supported by the NIHR Yorkshire and Humber Patient Safety Translational Research Centre.

Les maladies valvulaires constituent une cause importante de morbidité et de mortalité. Dans les pays industrialisés, l’insuffisance mitrale et la sténose aortique sont les pathologies valvulaires les plus fréquentes et leur prévalence augmentent avec l’âge. Étant donné l’augmentation de l’espérance de vie dans ces pays, la prévalence des valvulopathies dégénératives deviendra plus importante et aura un impact non négligeable sur la santé publique. Les avancées en chirurgie cardiaque ainsi que les nouvelles percées en cardiologie interventionnelle ont modifié considérablement la prise en charge des patients avec des valvulopathies en offrant des approches minimalement invasives, surtout pour les patients à haut risque chirurgical. Dans le cadre de ce mémoire, deux études rétrospectives de cohorte ont été réalisées. La première consiste à comparer les résultats postopératoires et sur trois ans de la chirurgie conventionnelle par rapport à la procédure transcathéter MitraClip chez 259 patients avec une insuffisance mitrale ischémique sévère. La deuxième étude compare les résultats postopératoires de trois approches de remplacement de la valve aortique, soit la sternotomie, la ministernotomie et la minithoracotomie. La première étude permet de conclure que la procédure MitraClip a un taux de mortalité postopératoire et sur 3 ans inférieur à celui de la chirurgie mais qu’elle est associée à un plus haut taux de récurrence de l’insuffisance mitrale après 3 ans. La deuxième étude démontre que les deux approches minimalement invasives, la ministernotomie et la mini-thoracotomie, ont un taux équivalent de mortalité intra-hospitalier à la sternotomie. La mini-thoracotomie est associée à moins de saignement périopératoire et moins de douleur au repos que la sternotomie. En conclusion, les approches minimalement invasives offrent une excellente alternative à la chirurgie conventionnelle dans le traitement de la maladie valvulaire. Les bénéfices cliniques sont d’autant plus évidents lorsque les patients sont adéquatement sélectionnés; d’où l’importance d’une ‘Heart Team’ qui collabore pour une meilleure prise en charge des patients.
Valvular heart disease is an important cause of morbidity and mortality. In western countries, mitral regurgitation and aortic stenosis are the most frequent valvular pathologies and their prevalence increases with age. With the increase in life expectancy in these countries, the prevalence of degenerative valve disease will increase with a significant burden on healthcare systems. Advances in cardiac surgery as well as new breakthroughs in interventional cardiology have considerably modified the management of patients with valvular disease, by offering minimally invasive approaches, especially for patients at high surgical risk. In this thesis, two retrospective cohort studies were carried out. The first compares the postoperative and 3 years outcomes of mitral valve surgery vs MitraClip, a transcatheter procedure, in 259 patients with severe ischemic mitral regurgitation. The second study compares the postoperative results of two minimally invasive techniques (ministernotomy and minithoracotomy) for aortic valve replacement to conventional sternotomy. In the first study, MitraClip procedure had lower postoperative and 3-year mortality rate than surgery, but it was associated with higher recurrence rate of mitral regurgitation after 3 years. The second study showed that the two minimally invasive approaches had similar intrahospital mortality rate to sternotomy. Minithoracotomy was associated with less perioperative bleeding and less pain at rest than sternotomy. In conclusion, minimally invasive approaches offer an excellent alternative to conventional surgery in the treatment of valvular disease. The clinical benefits are more highlighted when patients are properly selected; hence the importance of a "Heart Team" that collaborates for better patient care.

Trabalho Final do Curso de Mestrado Integrado em Medicina, Faculdade de Medicina, Universidade de Lisboa, 2020
Introdução: Em todo o mundo, os acidentes vasculares cerebrais são a segunda principal causa de morte e a terceira principal causa de incapacidade. O Acidente Vascular Cerebral é a morte súbita de algumas células cerebrais devido à falta de oxigénio quando o fluxo sanguíneo para o cérebro é perdido pelo bloqueio ou rutura de uma artéria. Causa danos sensoriais, motores, cognitivos e visuais e restringe o desempenho das atividades da vida diária. As sequelas motoras são observadas em 80% dos doentes com Acidente Vascular Cerebral e podem incluir perda de equilíbrio e da marcha. Esses problemas são importantes alvos da reabilitação, porque reduzem a capacidade dos indivíduos de realizar atividades da vida diária, prejudicando também as atividades comunitárias e sociais. Nos últimos anos, houve um interesse crescente no uso de novas tecnologias, como a Realidade Virtual na reabilitação do Acidente Vascular Cerebral. Os resultados clínicos indicam que o uso de tecnologias de Realidade Virtual melhora o funcionamento motor. A Realidade Virtual é definida pelo uso de simulações interativas criadas com hardware e software de computador para fornecer aos utilizadores ambientes que se parecem com eventos e objetos do mundo real. A Realidade Virtual é uma opção de tratamento emergente, que pode ter a capacidade de fornecer uma elevada dose de treino repetitivo de tarefas específicas. Além de fornecerem uma elevada dose terapêutica, as intervenções com Realidade Virtual também parecem ser adequadas para a reabilitação do Acidente Vascular Cerebral, pois fornecem feedback simultâneo, podem ser adaptadas para corresponder à capacidade da pessoa e podem envolver e motivá-la a alcançar os seus objetivos. O treino em Realidade Virtual visa melhorar a neuroplasticidade, através do fornecimento de um ambiente seguro e enriquecido para a realização de atividades funcionais específicas, com mais repetições, mais intensidade e mais motivação para o cumprimento da intervenção. A natureza virtual do ambiente permite que até movimentos muito limitados no mundo físico tenham resultados de sucesso no mundo virtual, oferecendo assim uma sensação de realização e motivação para tentativas sucessivas. Apesar do crescente interesse em estudar o uso da Realidade Virtual na reabilitação do Acidente Vascular Cerebral, atualmente não existem critérios definidos e validados para essa abordagem, tanto em relação à população-alvo, fase de reabilitação ou protocolo a ser utilizado. Este artigo teve como objetivo principal identificar os critérios de uso específicos para a aplicação da Reabilitação baseada em Realidade Virtual em doentes com Acidente Vascular Cerebral, observando os estudos experimentais que foram realizados nesta área como uma forma de validar as abordagens propostas. Além disso, procurou também definir ou adaptar os critérios para aplicação deste tipo de abordagem, a fim de garantir sua qualidade no auxílio da reabilitação
Introduction: Virtual Reality has been shown to be an effective resource in Stroke patients Rehabilitation. This paper’s main objective was to determine the specific criteria for the application of Virtual Reality based Rehabilitation in Stroke patients, it also intended to define or adapt test criteria for this type of approach. Methods: PubMed database was used to collect studies using the search terms “Virtual Reality”, “Virtual Reality Exposure Therapy”, “Rehabilitation”, “Physical and Rehabilitation Medicine”, “Rehabilitation Research”, “Exercise Therapy”, “Recovery of Function”, “Video games”, “Games”, “Recreational”, “Stroke” and “Stroke Rehabilitation”, a total of 14 studies were included in this review. Results: The quality of the included studies was assessed using the Delphi List, the quality score was 3.5 (SD=1.7). The concept influence graph showed that rehabilitation with the use of virtual reality has a strong association with the training program. Discussion: This paper shows that there is a limited number of studies addressing the use of Virtual Reality applied to stroke rehabilitation. The stroke survivors of the included studies were mainly older chronic hemiparetic subjects. Of the 14 studies included studies 5 used the Xbox Kinect and 3 used the Nintendo Wii. Intervention time varied from 1 day to 8 weeks, the number of sessions per week varied from 1 to 7, and session times varied from 30 minutes to 180 minutes. Conclusions: Virtual Reality is an effective resource for the treatment of motor impairments and cognitive sequelae of stroke, even though it presents variations in duration and frequency. The variability in the evaluation and intervention protocols of the included studies makes it impossible to generalize the results to other populations. It is necessary to conduct studies with greater methodological rigor to ensure greater reliability and applicability of this resource in a rehabilitation program.

Esta investigação consiste num estudo teórico e empírico em torno da problemática dos acordos de cooperação em saúde entre Portugal e os Países Africanos de Língua Oficial Portuguesa e as suas implicações no acesso a cuidados de saúde especializados em cardiologia. O objectivo principal visa compreender o papel dos acordos de cooperação em saúde, bem como, as estratégias utilizadas entre os actores sociais e instituições para responder às necessidades daquelas pessoas. Este trabalho foi desenvolvido no Centro Hospitalar e Universitário de Coimbra, através da realização de um estudo qualitativo do tipo exploratório, sendo utilizado como instrumento de recolha de dados a entrevista semi-directiva. Os participantes do estudo foram informadores privilegiados, envolvidos na cooperação em saúde. Os resultados do estudo realçaram a relevância dos acordos de cooperação em saúde; a forma de acesso aos cuidados de saúde; as estratégias adoptadas entre as instituições e actores sociais; o impacto das respostas institucionais nos doentes que necessitam de cuidados de saúde especializados; os tipos de intervenção em doentes com patologia cardíaca; o impacto nos sistemas de saúde dos países africanos e as perspectivas dos actores sociais. A importância dos acordos de cooperação em saúde entre Portugal e os referidos países, e a relevância dos problemas de saúde do foro cardíaco nestes doentes, incentivam a que sejam definidas estratégias ao nível da cooperação em saúde, com o objectivo de melhorar as estruturas de saúde dos países africanos, autonomizando-as, no sentido de auxiliarem estes doentes, proporcionando-lhes formas de acesso aos cuidados de saúde especializados.
This investigation consists of a theoretical and empirical study about the issue of agreements on cooperation in health between Portugal and the African Countries of Portuguese Official Language and its implications on access to skilled care in cardiology. The main objective is to understand the role of agreements on cooperation in health, as well as the strategies used between social actors and institutions to meet the needs of those people. This work was developed at the Hospital Center and University of Coimbra, through the realization a qualitative study is an exploratory, being used as an instrument of data collection a semi-directive. Study participants were key informants involved in health cooperation. The study results highlighted the importance of agreements on cooperation in health; the form of access to health care; strategies adopted between institutions and social actors; the impact of institutional responses in patients who require specialized health care; types of intervention in patients with cardiac disease; the impact on health systems of african countries and perspectives of social actors. The importance of agreements on cooperation in health between Portugal and these countries, and relevance of cardiac disease in these patients, encourage strategies are defined at the level of health cooperation, in order to improve the health structures of african countries, empowering them, in order to assist these patients, by providing them with means of access to health care specialized.