Academic literature on the topic 'Stentai'
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Journal articles on the topic "Stentai"
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Krasauskas, Arnoldas, Renatas Aškinis, Saulius Cicėnas, Tamara Tyrina, Ramūnas Ambrozaitis, and Eugenijus Stratilatovas. "Pooperacinio stemplės ir skrandžio ar stemplės ir plonosios žarnos jungties nesandarumo gydymas išsiplečiančiais stentais." Lietuvos chirurgija 8, no. 3 (2010): 0. http://dx.doi.org/10.15388/lietchirur.2010.3.2113.
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Arnoldas Krasauskas1, Renatas Aškinis1, Saulius Cicėnas1,2, Tamara Tyrina1, Ramūnas Ambrozaitis1, Eugenijus Stratilatovas11Vilniaus universiteto Onkologijos institutas, Santariškių g. 1, LT-08660 VilniusEl paštas: torakalinis@gmail.com 2Vilniaus universiteto Medicinos fakulteto Reabilitacijos, sporto medicinos ir slaugos institutas Įvadas: Po rezekcinių operacijų stemplės ir skrandžio ar stemplės ir žarnos jungties nesandarumas yra grėsmingiausia komplikacija, pasireiškianti iki 27 % operuotų ligonių. Ji gali būti mirtina iki 9 % tokių ligonių dėl infekcijos ir negalėjimo valgyti. Nuo 2005 m. fistulei panaikinti pradėjome į jungties spindį implantuoti išsiplečiančius silikonu dengtus stentus. Darbo tikslas – įvertinti, ar šis būdas tinka pooperacinių fistulių sukeltoms komplikacijoms gydyti. Ligoniai ir metodai: Vilniaus universiteto Onkologijos institute nuo 2005 iki 2009 metų buvo atlikta 417 stemplės ir skrandžio rezekcinių operacijų dėl onkologinių ligų. Po skrandžio pašalinimo operacijų atsirado 2,87 % fistulių, po stemplės operacijų – 21,65 % fistulių. Per šį laikotarpį 15 ligonių buvo implantuota 21 stentas dėl pooperacinių jungties fistulių: 4 (26,67 %) ligoniams – po Akyama operacijų, 7 (46,67 %) – po Lewis operacijų ir 4 (26,7 %) – po gastrektomijos. Spindis buvo protezuojamas maždaug po 17 dienų nustačius fistulę (nuo 3 iki 60 dienų). Buvo naudojami išsiplečiantys silikonu dengti plastikinio ar nitinolinio karkaso stentai. Dviem (13,3 %) ligoniams stentai keisti po 1 kartą ir dviem (13,3 %) – po 2 kartus. Rezultatai: Mirčių po šių procedūrų nebuvo. Tiriant rentgenu 6 (40 %) ligoniams po stento implantavimo kontrastinio skysčio tekėjimo pro fistulę nematyta, 4 (26,67 %) – gautas dalinis efektas, o 1 (6,67 %) – tik sumažėjęs geriamojo kontrastinio skysčio kiekio pratekėjimas fistule. Vidutiniškai po 5 dienų (3–14 dienų) 3 (20 %) ligoniams stentai pašalinti dėl nestabilios jų padėties ir 1 (6,7 %) ligonei – dėl nestabilios stento padėties sukelto kraujavimo iš jungties kraštų. Dviem (13,3 %) ligoniams stentai pasišalino savaime, 1 (6,7 %) ligonei stentas pašalintas laparotomijos būdu, nes buvo įstrigęs terminalinėje klubinės žarnos srityje. Vienas (6,67 %) ligonis atvyko tik po vienerių metų dėl sutrikusio (IV°) rijimo, sukelto randinio susiaurėjimo. Jam stentas pašalintas laparotomijos būdu, suformuota nauja stemplės ir plonosios žarnos jungtis. Šešiems (40 %) ligoniams stentai pašalinti nelikus jungties nesandarumo vidutiniškai po 47 parų (29–127 dienų) endoskopinės procedūros metu. Išvados: Stemplės ir skrandžio ar stemplės ir žarnos jungties protezavimas implantuojant į spindį išsiplečiančius silikonu dengtus stentus yra saugus ir efektyvus būdas fistulių okliuzijai bei jų sukeltoms komplikacijoms gydyti. Vienuolikai (73,3 %) iš 15 ligonių būklė pagerėjo dėl greičiau išnykusios infekcijos. Šeši (54,5 %) iš 11 ligonių galėjo valgyti jau kitą dieną po procedūros. Dviem (13,3 %) ligoniams įdėjus stentą įvyko komplikacijų. Po 6 mėn. ir vėliau 4 (26,67 %) geros būklės ligoniams reikėjo chirurginės intervencijos galutinei fistulių sukeltų komplikacijų korekcijai. Pagrindiniai žodžiai: pooperacinė fistulė, stentavimas, savaime išsiplečiantis stentas. Treatment of postoperative esophagogastrostomy/esophagoenterostomy leaks by using self-expanding stents Arnoldas Krasauskas1, Renatas Aškinis1, Saulius Cicėnas1,2, Tamara Tyrina1, Ramūnas Ambrozaitis1, Eugenijus Stratilatovas11Institute of Oncology, Vilnius University, Santariškių str., 1, LT-08660 Vilnius, LithuaniaE-mail: torakalinis@gmail.com 2Vilnius University, Faculty of Medicine, Institute of Rehabilitation, Sport Medicine and Nursing Background: Esophagogastrostomy/esophagoenterostomy leak is a major complication after esophagectomy or gastrectomy and could causes an up to 9 % postopertive mortality. Since 2005, we use self-expanding stents for the occlusion of anastomotic leaks. The objective is to analyse the usefulness of this method for the treatment of anastomotic fistulas. Patients and methods: From 2005 to 2009, 417 esophageal resections and gastrectomies for oncology patiens were made. After gastectomies, there were 2.87% and after oesophageal resection 21.65 % of anastomotic leaks. Twenty-one silicon-covered self-expanding stents were placed for 15 patients: for 4 patients (26.67 %) after Akyama type operations, 7 (46.67 %) after Lewis type operations and 4 (26.67 %) after gastrectomies. For 4 (26.67 %) patients, leaks were complicated with neck fistulas, 2 (13.3 %) with peritonitis, 8 (53.3%) with empyema and tracheoesophageal fistula. The median interval between detecting the fistula and stenting were 17 days (range, 3–60 days). We used silicon-covered plastic or nitinol armed self-expanding stents. For 2 (13.3 %) patients we replaced stents once and for 2 (13.3 %) twice. Results: Postinterventional esophagogram demonstrated full coverage of the leak in 6 (40 %) patients, and 1 (6.67 %) showed only a lower volume flow of the swallowed contrast. In 4 (26.67 %) patients, in the horizontal posistion we observed retrogradic contrast effusion. In 4 (26.67 %) patients, stents were removed on average after 5 days (range 3–14 days) of instability and for 1 (6.7 %) after a volatile situation caused by bleeding from the edges of the fistula. Two (13.3 %) stents moved down to gut, 1 (6.7 %) need laparotomy because it was stuck in the ileum terminale. One (6.67 %) patient came after 1 year with IV° dysphagia. We performed laparotomy to remove the stent and a new anastomosis to treat stenosis. Six (40 %) stents were removed during endoscopic procedures without residual leaks on average after 47 days (range 29–127 days). Conclusions: Silicon-covered self-expanding stent is an effective method of occluding postoperative esophagogastrostomy/esophagoenterostomy leaks. In 11 (73.3 %) of 15 patients, the condition improved because of accelerated healing of infectious complications. 6 (54.5 %) of 11 patients could begin eating next day after the procedure. There were only 2 (13.3 %) stent implantation-related complications. After 6 months and later in good condition 4 (26.67 %) patients had a surgical intervention for the final correction of fistulas-caused complications. Key words: esophagogastrostomy leaks, esophagoenterostomy leaks, self-expanding stents.
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Pranculis, Andrius, Artūras Vaičius, Mantas Kievišas, Lina Kievišienė, Rytis Stasys Kaupas, and Žilvinas Dambrauskas. "PERKUTANINIO TRANSHEPATINIO TULŽIES LATAKŲ PIKTYBINIŲ STRIKTŪRŲ STENTAVIMO NEDENGTAIS NITINOLIO SAVAIME IŠSISKLEIDŽIANČIAIS STENTAIS ARTIMIEJI IR ATOKIEJI REZULTATAI." Medicinos teorija ir praktika 22, no. 1 (2016): 14–22. http://dx.doi.org/10.15591/mtp.2016.002.
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Reikšminiai žodžiai: piktybinė tulžies latakų obstrukcija, tulžies latakų stentavimas, perkutaninis transhepatinis stentavimas (PTS), nedengti nitinolio savaime išsiskleidžiantys stentai. Perkutaninis transhepatinis tulžies latakų stentavimas (PTS) – tai paliatyvi minimaliai invazyvi procedūra, galinti pašalinti vėžinių ligų sukeltą tulžies latakų obstrukciją. Ši procedūra dažniausiai pasirenkama, kai radikalus chirurginis gydamas dėl naviko išplitimo ar gretutinių ligų negalimas, o endoskopinis stentavimas nesėkmingas arba techniškai neįmanomas. Tikslas. Įvertinti perkutaninio transhepatinio tulžies latakų piktybinių striktūrų stentavimo, atlikto naudojant metalinius (nitinolio) nedengtus savaime išsiskleidžiančius stentus, artimuosius ir atokiuosius rezultatus. Tyrimo medžiaga ir metodai. Nuo 2007 m. iki 2015 m. gegužės mėn. prospektyviai buvo kaupiami ir analizuojami duomenys apie atliekamas PTS procedūras LSMUL KK Chirurgijos ir Gastroenterologijos klinikose. Į tyrimą įtraukta 215 pacientų, kuriems atliktas PTS panaudojant metalinius (nitinolio) nedengtus savaime išsiskleidžiančius stentus. Vertinta, kokios ligos sukėlė tulžies takų obstrukciją, PTS trukmė ir sėkmė, komplikacijos po procedūros, pakartotinių stentavimų dažnis ir priežastys, stento funkcionavimo laikas, išgyvenamumas, bendro bilirubino koncentracijos kraujo serume pokyčiai lyginant koncentraciją prieš procedūrą ir per 2–5 dienas po jos. Proksimalinių latakų striktūros tipas buvo vertinamas pagal Bismutho- Corlette klasifikaciją. Išgyvenamumas analizuotas Kaplano-Meierio metodu. Rezultatai. Techniškai sėkmingos buvo 95,8 proc. visų intervencijų, geras gydomasis efektas pasiektas 82,8 proc. atvejų. Daugiausia striktūrų buvo bendrojo tulžies latako srityje (34,4 proc.). Iš proksimalinių latakų striktūrų dažniausias buvo I striktūros tipas (bendrojo kepenų latako srityje), rečiausias – IV, todėl didžiajai daliai pacientų (73 proc.) užteko vieno stento. Pakartotinis stentavimas atliktas 23 pacientams (10,7 proc.). Dažniausios restentavimo priežastys buvo stento užsikimšimas arba dislokacija, kurios pasireiškė 7 proc. pacientų. Dažniausios komplikacijos – kraujavimas be hemotransfuzijos poreikio, sepsis ir cholangitas. Bendras komplikacijų dažnis siekė 14,4 proc. Bendro bilirubino koncentracija serume 2–5 d. po PTS sumažėjo statistiškai reikšmingai (vidutiniškai per 111,4 μmol/l, p < 0,001). Vidutinė išgyvenamumo trukmė nuo PTS procedūros atlikimo datos buvo 137,4 ± 19,6 d. 30 dienų mirštamumas siekė 14,9 proc., su procedūra susijusių mirčių nebuvo. Išvados. PTS metaliniais nedengtais savaime išsiskleidžiančiais stentais yra efektyvus ir saugus metodas paliatyviai gydant pacientus su intrahepatinių ar ekstrahepatinių tulžies latakų obstrukcija, sukelta lokaliai išplitusių pirminių ar metastatinių navikų.
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Žegunis, Vidmantas. "ARTROEREZĖS OPERACIJA STABILIZUOJANT PAŠOKIKAULINĮ PĖDOS SĄNARĮ. KLAIPĖDOS UNIVERSITETINĖS LIGONINĖS PATIRTIS." Visuomenės sveikata 27, no. 5 (2017): 16–21. http://dx.doi.org/10.5200/sm-hs.2017.070.
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Autorius retrospektyvoje analizuoja rezultatus 250 pašokikaulinio sąnario artroerezės operacijų, atliktų 178 pacientams Klaipėdos universitetinėje ligoninėje nuo 2009.12.04 iki 2015.02.28 dienos. Beveik visas operacijas atliko pats straipsnio autorius, naudodamas tą pačią metodiką ir tokį pat stentą (HyProCure, Gramedica, USA). Skirtingai nei kitose šia tema publikuotose studijose, operuoti pacientai priklausė įvairioms amžiaus grupėms nuo 5 iki 77 metų amžiaus. Indikacija operacijai buvo pašokikaulinio sąnario nestabilumo sąlygota plokščiapėdystė, pasireiškusi kulno hiperpronacija ir buvusi kitų lydinčių skundų ir pėdos deformacijų priežastimi. Per apžvelgtą 5 metų periodą 21 stentą, kas sudarė 8,1%, teko pašalinti dėl įvairių priežasčių. Pusė jų buvo pašalinti dėl subjektyvių pacientų skundų skausmu, nepatogumu, o pusė dėl nustatytos neteisingos padėties po panirimo ar galimos malpozicijos operacijos metu. Nei pagal lytį, nei pagal amžių padidintos rizikos grupės pacientų patikimai nustatyti nepavyko. Pacientai, kuriems studijos laikotarpiu stentai likę implantuoti, rezultatu buvo patenkinti ir galėtų šią procedūrą rekomenduoti savo artimiesiems. Šios palyginti naujos mūsų šalyje operacijos rezultatai, autoriaus nuomone, teikia vilčių gydant pėdos patologiją ankstyvose ligos stadijose ir įvairiose amžiaus grupėse.
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Gumbienė, Lina, Sigitas Čibiras, Alicija Dranenkienė, Živilė Katliorienė, Giedrė Nogienė, and Eugenijus Kosinskas. "Aortos rekoarktacijos gydymas angioplastika ir stentais." Lietuvos chirurgija 5, no. 3 (2007): 0. http://dx.doi.org/10.15388/lietchirur.2007.3.2225.
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Lina Gumbienė, Sigitas Čibiras, Alicija Dranenkienė, Živilė Katliorienė, Giedrė Nogienė, Eugenijus KosinskasVilniaus universiteto Širdies chirurgijos centras, Santariškių g. 2, LT-08661 VilniusEl paštas: Lina.Gumbiene@santa.lt Įvadas / tikslas Aprašomas naujo metodo – balioninės angioplastikos ir kraujagyslinių stentų – pritaikymas gydant aortos rekoarktaciją, atsiradusią po chirurginės ydos korekcijos. Ligoniai ir metodai Atlikta retrospektyvi duomenų analizė dešimties ligonių, kuriems Vilniaus universiteto Širdies chirurgijos centre 1994–2006 metais aortos rekoarktacija buvo gydyta balionine angioplastika ar stentavimu. Aprašoma centre taikyta aortos angioplastikos ir stentų implantavimo metodika. Rezultatai Aortos rekoarktacijos angioplastika atlikta keturiems ligoniams. Intraaortinis gradientas aortos koarktacijos vietoje po procedūros sumažėjo vidutiniškai 82,15%. Vėlyvuoju stebėjimo periodu (vid. 6,14 ± 5,2 metai) rekoarktacija buvo trims ligoniams. Aortos rekoarktacijos stentavimas atliktas septyniems ligoniams, vienam iš jų dėl atsinaujinusios rekoarktacijos po angioplastikos. Dviem ligoniams procedūra nepavyko. Kitiems penkiems ligoniams intraaortinis gradientas reAoCo vietoje vidutiniškai sumažėjo nuo 29,6 ± 11,6 mm Hg iki 2,6 ± 3,7 mm Hg. Stebėjimo laikotarpiu 0,58–3,75 metų po procedūros rekoarktacija nustatyta tik vienam ligoniui. Jam atliktas stento plėtimas. Išvada Perkateterinė balioninė angioplastika ir balionais išplečiami kraujagysliniai stentai veiksmingi ir saugūs aortos rekoarktacijų gydymo metodai. Pagrindiniai žodžiai: aortos koarktacija, rekoarktacija, perkateterinis gydymas Treatment of recurrent coarctation of the aorta employing balloon angioplasty and endovascular stents Lina Gumbienė, Sigitas Čibiras, Alicija Dranenkienė, Živilė Katliorienė, Giedrė Nogienė, Eugenijus KosinskasVilnius University, Centre of Heart Surgery, Santariškių g. 2, LT-08661 Vilnius, LithuaniaE-mail: Lina.Gumbiene@santa.lt Background / objective We present a new method of treatment – balloon angioplasty and endovascular stent – for patients with aortic re-coarctation following surgical correction. Patients and methods Ten patients with re-coarctation of the aorta after surgery underwent balloon angioplasty or stent implantation at Vilnius University Heart Surgery Centre in 1994–2006. Results Balloon angioplasty was performed in 4 patients. The intraaortic gradient in the site of coarctation decreased on average by 82.15% after the procedure. Re-coarctation developed in 3 patients in the late follow-up period (mean 6.14 ± 5.2 years). Stents were implanted in 7 patients (one developed re-coarctation after angioplasty). The procedure failed in two. The intraaortic gradient at the site of re-coarctation decreased on average from 29.6 ± 11.6 mm Hg to 2.6 ± 3.7 mm Hg. Re-coarctation was diagnosed only in one patient during the follow-up (0.58–3.75 years), and stent dilatation was performed in this case. Conclusions Balloon angioplasty and endovascular stents are effective and safe methods for the treatment of re-coarctation of the aorta. Key words: coarctation of the aorta, recurrent coarctation, transcatheter treatment
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Adamonis, Kęstutis, Dainius Pavalkis, Žilvinas Saladžinskas, and Algimantas Tamelis. "Endoskopinis ūminės storosios žarnos obstrukcijos gydymas." Lietuvos chirurgija 1, no. 1 (2003): 0. http://dx.doi.org/10.15388/lietchirur.2003.1.2450.
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Kęstutis Adamonis, Dainius Pavalkis, Žilvinas Saladžinskas, Algimantas TamelisKMU Gastroenterologijos klinika, KMU Chirurgijos klinika Šiuolaikis virškinimo trakto piktybinės obstrukcijos gydymas vis labiau tampa minimaliai invazinis. Ligoniai, sergantys storosios žarnos vėžiu, komplikuotu obstrukcija, į gydymo įstaigas patenka skubos tvarka, neretai sunkios būklės, ir nėra idealūs kandidatai chirurginei operacijai. Šiuolaikinėje medicinos literatūroje gausėja mokslinių straipsnių apie sėkmingą ir saugų endoskopiniu būdu įkišamų savaime išsiplečiančių metalinių stentų naudojimą proktologijoje. Nors stentai ir yra brangūs, tačiau proktologinis stentavimas yra rentabili procedūra, leidžianti ligoniams, sergantiems storosios žarnos vėžiu, komplikuotu ūminė storosios žarnos obstrukcija, išvengti neatidėliotinos operacijos, o esant nerezektabiliam vėžiui, – kolostomos. Straipsnyje aprašomas KMU Chirurgijos klinikoje atliktas pirmasis Lietuvoje sėkmingas endoskopinis ūminės žarnų obstrukcijos gydymas stentuojant žarnyną. Prasminiai žodžiai: žarnyno obstrukcija, kolorektinis vėžys, endoskopija, stentavimas. Acute colonic obstruction: endoscopical management Kęstutis Adamonis, Dainius Pavalkis, Žilvinas Saladžinskas, Algimantas Tamelis Management of malignant gastrointestinal obstruction presents a significant challenge. Most patients are in a profoundly decompensated state due to underlying malignancy and are not ideal candidates for invasive surgical procedures. In recent years, self-expandable metal stents have emerged as an effective and safe, less invasive alternative for the treatment of malignant intestinal obstruction. Although stents are expensive, the procedure appears to be cost-effective, since emergency surgery can be avoided in patients with acute bowel obstruction, and in those with advanced disease no resection of the colon is necessary. Here we report a retrospective analysis of a first self-expandable metal stent placed for colorectal obstruction at Kaunas Medical University Hospital, as well as review the literature published on self-expandable metal stent placement. Our first data confirm self-expandable metal stent efficacy in palliation of malignant intestinal obstruction. Keywords: intestinal obstruction, colorectal cancer, endoscopy, endoluminal stenting.
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Agid, R., M. Schaaf, and Ri Farb. "CE-MRA for Follow-up of Aneurysms Post Stent-Assisted Coiling." Interventional Neuroradiology 18, no. 3 (2012): 275–83. http://dx.doi.org/10.1177/159101991201800305.
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This study compared the accuracy of contrast-enhanced MR angiography (CE-MRA) to intraarterial cerebral angiography (IA-DSA) for assessment of intracranial aneurysms after stent-assisted coiling and to check if the presence of a stent in the parent artery diminishes the accuracy of CE-MRA. Consecutive patients with cerebral aneurysms treated by stent-assisted coiling were evaluated retrospectively. Matching follow-up CE-MRA and IA-DSA were evaluated separately. Evaluation included the presence of aneurysmal remnant, patency and stenosis of parent artery. Twenty-seven patients with 28 aneurysms and 33 matched CE-MRA and IA-DSA studies were evaluated. Nineteen aneurysmal remnants were seen on CE-MRA and 16 on IA-DSA. CE-MRA diagnosed three aneurysmal remnants not appreciated on IA-DSA. Five other remnants were larger on CE-MRA than IA-DSA. None of the remnants were missed on CE-MRA. Parent arteries were patent on both modalities. CE-MRA showed false stenosis of the stented artery in six cases and exaggerated stenosis in two. In 18 cases, CE-MRA showed a short focal “pseudo-stenosis” where the stent's marker bands were located. This was noted whenever the stent's marker bands were located in an artery with luminal diameter ≤2 mm and was called “marker band effect”. CE-MRA is an accurate technique for follow-up of aneurysms post stent-assisted coiling with excellent depiction of remnants in spite of the presence of a stent. Apparent stenosis of the stented parent artery on CE-MRA is often false or exaggerated. “Marker band effect” should be recognized as an artifact that appears when stent's marker bands are in a small artery.
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Gruslys, Vygantas, Ričardas Janilionis, and Arūnas Žilinskas. "Stemplės stentavimas esant pooperacinei ezofagopleurinei fistulei: dviejų klinikinių atvejų analizė." Lietuvos chirurgija 5, no. 3 (2007): 0. http://dx.doi.org/10.15388/lietchirur.2007.3.2217.
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Vygantas Gruslys, Ričardas Janilionis, Arūnas ŽilinskasVilniaus universiteto ligoninės Santariškių klinikų Centro filialas, Krūtinės chirurgijos centras,VšĮ VUL SK Centro filialas, Žygimantų g. 3, VilniusEl paštas: azilinskas@rygveda.lt Tikslas – pasitelkiant du panašius klinikinius atvejus pagrįsti mintį, kad gydant pooperacinę ezofagopleurinę fistulę, greitai ir radikaliai jos pašalinti dažniausiai negalima; būtina nuosekliai siekti rezultato, o gydymo taktika kiekvienu konkrečiu atveju turi būti individuali.Stemplės stentavimo ištakos – XIX amžiaus pabaiga. Per praėjusį šimtmetį stemplės stentai buvo gerokai ištobulinti. Tačiau vis dar tebesama eksperimentinės stadijos. Esant neoperabiliai navikinės kilmės stemplės stenozei ar stemplės ir kvėpavimo takų jungčiai, stemplės arba mišrus – stemplės ir trachėjos (broncho) – stentavimas tapo pirmojo pasirinkimo gydymo būdu. Santūraus optimizmo teikia ir pirmieji silikoninių solidinių (ne savaime išsiskleidžiančių) stentų naudojimo, esant randinės kilmės striktūrai, rezultatai. Tačiau stemplės stentavimo sergant kitomis stemplės ligomis – achalazija, savaiminiu stemplės plyšimu ar pooperaciniu nesandarumu – rezultatai yra prieštaringi. Itin diskusinis tikslingumas atlikti stemplės stentavimą, kai yra pooperacinė ezofagopleurinė fistulė, kurios komplikacija – piopneumotoraksas. Pasitelkiant du panašius klinikinius atvejus, kai vienam ligoniui stemplės stentavimas paskatino atsirasti ezofagoaortinę jungtį, sukėlusią mirtiną kraujavimą, o kitam neabejotinai padėjo išvengti erozinio kraujavimo, grindžiama mintis, kad pooperacinę ezofagopleurinę fistulę būtina kantriai gydyti ir nuosekliai siekti rezultato, o gydymo taktika kiekvienu konkrečiu atveju turi būti individuali. Pagrindiniai žodžiai: ezofagopleurinė fistulė, stentavimas Role of esophageal stenting in the management of patients with nonmalignant esophagopleural fistula: Experience of two cases Vygantas Gruslys, Ričardas Janilionis, Arūnas ŽilinskasVilnius University Hospital, Department of General Thoracic Surgery,Žygimantų str. 3, Vilnius, LithuaniaE-mail: azilinskas@rygveda.lt We present two cases of patients with non-malignant postoperative esophageal fistulas following pulmonary surgery. Both patients were treated with esophageal stenting. However, one of them died due to intrapleural haemorrhage, while the other survived and has been doing well.Esophageal endoprostheses over the last 100 years have undergone a remarkable technological evolution from the hollowed whalebone and the rigid plastic tube to the present-day self-expanding plastic and metal stents, as well as biodegradable ones. The use of esophageal stents may be a reasonable option in patients with benign esophageal fistula, especially in patients who have failed other conventional treatments or are not good candidates for conventional therapy.Hitherto, there are still no strong worldwide recommendations how to treat patients with non-malignant esophageal fistula. We would like to emphasize that the method of management and design of esophageal endoprosthesis in each case must be planned on the individual basis. Keywords: esophagopleural fistula, stenting
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Overbeck, Peter. "Stenten, um nicht zu stenten?" MMW - Fortschritte der Medizin 154, no. 11 (2012): 17. http://dx.doi.org/10.1007/s15006-012-0720-0.
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De Grazia, Antonio, Gareth LuTheryn, Alireza Meghdadi, et al. "A Microfluidic-Based Investigation of Bacterial Attachment in Ureteral Stents." Micromachines 11, no. 4 (2020): 408. http://dx.doi.org/10.3390/mi11040408.
Full textAbstract:
Obstructions of the ureter lumen can originate from intrinsic or extrinsic factors, such as kidney stones, tumours, or strictures. These can affect the physiological flow of urine from the kidneys to the bladder, potentially causing infection, pain, and kidney failure. To overcome these complications, ureteral stents are often deployed clinically in order to temporarily re-establish urinary flow. Despite their clinical benefits, stents are prone to encrustation and biofilm formation that lead to reduced quality of life for patients; however, the mechanisms underlying the formation of crystalline biofilms in stents are not yet fully understood. In this study, we developed microfluidic-based devices replicating the urodynamic field within different configurations of an occluded and stented ureter. We employed computational fluid dynamic simulations to characterise the flow dynamic field within these models and investigated bacterial attachment (Pseudomonas fluorescens) by means of crystal violet staining and fluorescence microscopy. We identified the presence of hydrodynamic cavities in the vicinity of a ureteric occlusion, which were characterised by low levels of wall shear stress (WSS < 40 mPa), and observed that initiation of bacterial attachment occurred in these specific regions of the stented ureter. Notably, the bacterial coverage area was directly proportional to the number of cavities present in the model. Fluorescence microscopy confirmed that the number density of bacteria was greater within cavities (3 bacteria·mm−2) when compared to side-holes of the stent (1 bacterium·mm−2) or its luminal surface (0.12 bacteria·mm−2). These findings informed the design of a novel technological solution against bacterial attachment, which reduces the extent of cavity flow and increases wall shear stress over the stent’s surface.
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Seth, Ashok. "“Stentman” returns." Catheterization and Cardiovascular Interventions 75, no. 6 (2010): 971. http://dx.doi.org/10.1002/ccd.22576.
Full textDissertations / Theses on the topic "Stentai"
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Brikas, Marijus. "Silicio ir metalų mikroapdirbimas didelio impulsų pasikartojimo dažnio pikosekundiniais lazeriais." Doctoral thesis, Lithuanian Academic Libraries Network (LABT), 2011. http://vddb.laba.lt/obj/LT-eLABa-0001:E.02~2011~D_20110324_161301-79480.
Full textAbstract:
Disertacijos tikslas yra ištirti didelio impulsų pasikartojimo dažnio pikosekundinių lazerių pritaikomumą medžiagų mikroapdirbimui, bei išaiškinti tokių lazerių spinduliuotės sąveikos su metalais ir siliciu ypatybes. Eksperimentiškai buvo ištirta abliacijos slenksčio ir akumuliacijos koeficiento priklausomybė nuo lazerio impulso trukmės siliciui ir metalams. Sukurtas ir eksperimentiškai patvirtintas modelis optimalioms fokusavimo sąlygoms surasti, siekiant maksimalios abliacijos spartos. Didelei impulso energijai, medžiagos nugarinimo efektyvumas mažėja dėl ekranuojančio plazmos poveikio. Įvairių impulso trukmių lazeriai buvo panaudoti silicio gręžimui bei pjovimui. Paviršiaus spektroskopijos metodais, nustatyta, kad pjovimo metu silicis yra legiruojamas anglimi iki 5 µm gylio iš atmosferoje esančio anglies dvideginio, o susidariusi silicio karbido fazė įtakoja lazerinio pjovimo kokybę silicio bandinio gylyje. Taikant didelio impulsų pasikartojimo dažnio pikosekundinius lazerius sudėtingos formos detalių gamybai, rasti sąryšiai tarp paviršiaus šiurkštumo bei proceso parametrų. Pjaunant lazeriu stentus iš Nitinolio, šilumos nukreipimas nuo ruošinio riboja galimą panaudoti lazerio vidutinę galią ir tuo pačiu pasiekiamą efektyvųjį pjovimo greitį; Vykdant sidabro ir aukso abliaciją pikosekundiniu lazeriu skystyje, generuojamos siauro dydžių skirstinio nanodalelės, kurios sudaro stabilius koloidinius tirpalus.<br>The objective of the thesis is to investigate applicability of high pulse repetition rate picosecond lasers for microfabrication and to clarify high repetition rate pulse interaction with metals and silicon.
The ablation threshold and accumulation rate dependence on the laser pulse duration for silicon and metals has been experimentally studied. The model of optimal focus conditions for the maximum ablation rate was developed and experimentally confirmed. The material evaporation rate decreases duo to plasma screening for high pulse energies.
Various pulse length lasers have been used for cutting and drilling of silicon.
In this work key properties of laser radiation, radiation absorption, ablation and plasma formation are discussed. Surface spectroscopy methods have shown that laser cutting of silicon in the air leads to the cut surface doping with carbon atoms up to 5 µm depth from carbon dioxide in the atmosphere, and the resulting silicon carbide influences the laser cut quality.
Testing of applicability of high pulse repetition rate picosecond lasers for the production of complex shapes, relationships between surface roughness and process parameters were determined. Heat abstraction from the workpiece, during laser cutting of stents from nitinol, limits the potential use of the average laser power and the effective cutting speed
The silver and gold picosecond laser ablation in the liquid medium generates a narrow size distribution of nanoparticles, which form a stable... [to full text]
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Brikas, Marijus. "Microprocessing of silicon and metals with high pulse repetition rate picosecond lasers." Doctoral thesis, Lithuanian Academic Libraries Network (LABT), 2011. http://vddb.laba.lt/obj/LT-eLABa-0001:E.02~2011~D_20110324_161348-78636.
Full textAbstract:
The objective of the thesis is to investigate applicability of high pulse repetition rate picosecond lasers for microfabrication and to clarify high repetition rate pulse interaction with metals and silicon.
The ablation threshold and accumulation rate dependence on the laser pulse duration for silicon and metals has been experimentally studied. The model of optimal focus conditions for the maximum ablation rate was developed and experimentally confirmed. The material evaporation rate decreases duo to plasma screening for high pulse energies.
Various pulse length lasers have been used for cutting and drilling of silicon.
In this work key properties of laser radiation, radiation absorption, ablation and plasma formation are discussed. Surface spectroscopy methods have shown that laser cutting of silicon in the air leads to the cut surface doping with carbon atoms up to 5 µm depth from carbon dioxide in the atmosphere, and the resulting silicon carbide influences the laser cut quality.
Testing of applicability of high pulse repetition rate picosecond lasers for the production of complex shapes, relationships between surface roughness and process parameters were determined. Heat abstraction from the workpiece, during laser cutting of stents from nitinol, limits the potential use of the average laser power and the effective cutting speed
The silver and gold picosecond laser ablation in the liquid medium generates a narrow size distribution of nanoparticles, which form a stable... [to full text]<br>Disertacijos tikslas yra ištirti didelio impulsų pasikartojimo dažnio pikosekundinių lazerių pritaikomumą medžiagų mikroapdirbimui, bei išaiškinti tokių lazerių spinduliuotės sąveikos su metalais ir siliciu ypatybes. Eksperimentiškai buvo ištirta abliacijos slenksčio ir akumuliacijos koeficiento priklausomybė nuo lazerio impulso trukmės siliciui ir metalams. Sukurtas ir eksperimentiškai patvirtintas modelis optimalioms fokusavimo sąlygoms surasti, siekiant maksimalios abliacijos spartos. Didelei impulso energijai, medžiagos nugarinimo efektyvumas mažėja dėl ekranuojančio plazmos poveikio. Įvairių impulso trukmių lazeriai buvo panaudoti silicio gręžimui bei pjovimui. Paviršiaus spektroskopijos metodais, nustatyta, kad pjovimo metu silicis yra legiruojamas anglimi iki 5 µm gylio iš atmosferoje esančio anglies dvideginio, o susidariusi silicio karbido fazė įtakoja lazerinio pjovimo kokybę silicio bandinio gylyje. Taikant didelio impulsų pasikartojimo dažnio pikosekundinius lazerius sudėtingos formos detalių gamybai, rasti sąryšiai tarp paviršiaus šiurkštumo bei proceso parametrų. Pjaunant lazeriu stentus iš Nitinolio, šilumos nukreipimas nuo ruošinio riboja galimą panaudoti lazerio vidutinę galią ir tuo pačiu pasiekiamą efektyvųjį pjovimo greitį; Vykdant sidabro ir aukso abliaciją pikosekundiniu lazeriu skystyje, generuojamos siauro dydžių skirstinio nanodalelės, kurios sudaro stabilius koloidinius tirpalus.
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Čibiras, Sigitas Vladas. "Methods of interventional pediatric cardiology in treatment of congenital heart diseases: immediate and long-term results." Doctoral thesis, Lithuanian Academic Libraries Network (LABT), 2010. http://vddb.laba.lt/obj/LT-eLABa-0001:E.02~2010~D_20100204_100248-32962.
Full textAbstract:
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]<br>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.
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Hettl, Johanna [Verfasser]. "Vergleich eines Paclitaxel-freisetzenden Stents mit einem Everolimus-freisetzenden Stent / Johanna Hettl." Ulm : Universität Ulm. Medizinische Fakultät, 2012. http://d-nb.info/1029295808/34.
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Dailida, Robertas. "Stabdžių bandymo stendo modernizavimas." Bachelor's thesis, Lithuanian Academic Libraries Network (LABT), 2014. http://vddb.library.lt/obj/LT-eLABa-0001:E.02~2014~D_20140716_105956-24937.
Full textAbstract:
Dviračių stabdžių bandymo stendas yra skirtas, nustatyti įtvirtinto dviračio stabdžių
efektyvumui. Jų veikimą esant skirtingomis oro sąlygomis (lietus, purvas ir t.t.). Dviračio
slydimo atstumui ir stabdant stabdančiūjų dalių susidevėjimui. Šis stendą modernizuojame
pritaikant greičio matuoklį, kuris nustato besisukančio (bandomojo dviračio) rato greitį.
Įrenginys gaminamas iš paprastų medžiagų, kurias būtų galima nusipirkti metalu
prekiaujančiose įmonėse. Standartinius gaminius (tokius kaip guoiai, holo davikliai ir t.t.)
taipogi galima įsigyti specializuotuose parduotuvėse. Būtent gaminamoms detalėms
naudojamos medžiagos – plienas C45, konstrukcinis plienas S235, kaprolonas. Įrenginio
gamybai nereikia didelio kiekio medžiagų, taigi medžiagos bus naudojamos iš likučių
esančių gamyklos sandelyje.
Reikės suprojektuoti ir pagaminti, stabdžių bandymo stendui, besisukančio rato
greičio matuokį, kuris bandymu metu leis nustatyti bandomojo dviračio besisukančio rato
greitį. Ratukas yra pristumiamas, prie bandomojo rato, 400N jėga. Pagal gautus
skaičiavimus skersinė jėga ašelę veikia – 128 N jėga, o lenkimo momentas tik 4 N/m, tai
nesukels konstrukcijoje jokių žymių deformacijų. Dviračių stabdžių stendo modernizacija
reikalinga – dėl to, kad bandymų stendas naudojamas, bandymų centre, kuriame tikrinama
naujų gaminių kokybė. Šie bandymai turi atitikti standartus, o standartai reikalauja... [toliau žr. visą tekstą]<br>The theme of this bachelor project of Mechanical Engineering is contemporary, i.e. about the latest technology in modern industry, where everything is fully computerized and systematized. In this bachelor project we analyze the modernization of bicycle brake stand. The main purpose of this technical modernization is to create and adapt a device which measures the speed of spinning wheel of trial bike. As the brake stand is used for investigational purposes, during the tests, we have to follow standards (LST 14766) which we use to create design of the device. The device is designed to be an open, easily accessible place. Freely access was necessary in order to connect the device to a computer, which treated the information and performed calculations. In this project, we will examine several different options for analysis. After selecting the optimal one, we will try to perform technical calculations. Economical analysis showed that manufacturing, i.e. from designing to final product, will take long approximately about seven days. Total manufacturing costs to produce two speed meter devices would be 3386, 92 Lt. Cost of single device – 1693, 46 Lt. The product price can change depending on product standards and designing time.
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Frahnow, Andreas [Verfasser]. "Lebensqualitätsentwicklung nach Implantation von drug eluting stents im Vergleich zu bare metal stents : eine Analyse des Deutschen Drug Eluting Stent-Registers (DES.DE) / Andreas Frahnow." Berlin : Medizinische Fakultät Charité - Universitätsmedizin Berlin, 2019. http://d-nb.info/1202042147/34.
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Johnsen, Ludger [Verfasser], and Wolfgang [Akademischer Betreuer] Reith. "Das Stent-gestützte Coiling unter Verwendung des Acandis Acclino 1.9F Stents / Ludger Johnsen ; Betreuer: Wolfgang Reith." Saarbrücken : Saarländische Universitäts- und Landesbibliothek, 2019. http://d-nb.info/1213294630/34.
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Costa, Ricardo Alves da. "Achados ultrassonográficos em lesões de bifurcação coronária tratadas com stent único versus estratégia com dois stents." Universidade de São Paulo, 2011. http://www.teses.usp.br/teses/disponiveis/98/98131/tde-19092011-075117/.
Full textAbstract:
Estudos comparativos prévios com inclusão de lesões de bifurcação selecionadas sugerem ausência de benefício de implante eletivo de dois versus stent único. No entanto, a aplicabilidade do técnica provisional parece ser dependente da complexidade da lesão de bifurcação. A área luminar da lesão após tratamento percutâneo, conforme medida pelo ultrassom intracoronário, tem demonstrado valor preditivo significante na evolução tardia dos pacientes submetidos a ICP. Os objetivos desta análise foram avaliar as dimensões luminares de lesões de bifurcação coronária complexas tratadas por ICP, conforme a análise pelo ultrassom, e correlacionar os achados com os resultados imediatos e tardios. Também objetivou-se identificar preditores angiográficos e ultrassonográficos de falência do ramo lateral nos diferentes passos do tratamento e seguimento. Entre maio de 2008 e agosto de 2009, 59 pacientes portadores de lesão de bifurcação complexa, com comprometimento significativo (estenose > 50%) dos dois ramos e lesão no ramo lateral extendendo-se além do óstio, foram abordados inicialmente com pré-dilatação do ramo lateral, a qual foi realizada com sucesso (estenose < 50%, fluxo TIMI 3, sem dissecção) em 54 pacientes (91,5%). Esse pacientes foram então randomizados para tratamento com stent único (estratégia provisional) (n = 27) versus stent duplo (n = 27). Durante o procedimento, 6 pacientes alocados no grupo stent único apresentaram falência do tratamento no ramo lateral (estenose residual >50%, fluxo TIMI < 3 ou dissecção), sendo que, 5 pacientes receberam stent adicional no ramo lateral para otimizar o resultado angiográfico. Ao final do procedimento, os valores médios e desvios padrão (DP) da área mínima do lúmen no óstio do ramo lateral (desfecho primário) foram 3,37 (1,62) mm2 no grupo stent único versus 5,50 (1,41) mm2 no grupo stent duplo (p < 0,001), conforme a alocação randômica. No seguimento angiográfico de 9 meses, as taxas de reestenose no ramo lateral foram 21,7% no grupo stent único versus 4% no grupo stent duplo (p = 0,06), sendo que, todas as recorrências envolveram a localização ostial. Considerando-se o tratamento recebido, a taxa de reestenose no ramo lateral foi significantemente maior nos pacientes tratados com stent único versus stent duplo (27,8% versus 3,3%, p = 0,01). Os preditores de falência da estratégia provisional foram: excêntricidade da lesão (p = 0,02), área mínima do lúmen (p = 0,08) e diâmetro mínimo do lúmen no óstio do ramo lateral (p = 0,06), extensão da lesão (p = 0,09) e percentual de estenose (p = 0,07) do ramo lateral. Com relação a reestenose angiográfica no ramo lateral, os preditores foram: área mínima do lúmen no óstio do ramo lateral ao final do procedimento (p = 0,03), tratamento com stent duplo (p = 0,02), diâmetro mínimo do lúmen (p = 0,03) e percentual de estenose (p = 0,02) no óstio do ramo lateral ao final do procedimento, ganho imediato no óstio do ramo lateral (p = 0,09) e diâmetro de referência do ramo lateral (p = 0,03). Estes resultados sugerem que lesões de bifurcação coronária complexas beneficiam-se de tratamento percutâneo com abordagem inicial com estratégia de dois stents, sendo que, tal benefício esteve relacionado a obtenção de maior área luminar no óstio do ramo lateral.<br>Previous comparative studies including selected bifurcation lesions have shown no advantage of elective double stenting implantation versus single stenting. However, the applicability of the provisional technique appears to be dependent on the bifurcation lesion complexity. The lesion luminal area after percutaneous treatment, as assessed by intravascular ultrasound, has demonstrated significant predictive value in the late follow-up of patients undergoing PCI. The objectives of this analysis were to evaluate the lesion luminal dimensions of complex coronary bifurcation lesions, as assessed by intravascular ultrasound, and to correlate such findings with acute and late outcomes. Also, it was aimed to identify angiographic and intravascular ultrasound predictors of side branch failure throughout the procedural steps and follow-up. Between may 2008 and august 2009, 59 patients with complex bifurcation lesions, including significant involvement (> 50% stenosis) of both branches and side branch lesion length extending from its ostium, were approached initially with side branch predilatation, which was successful (< 50% stenosis, TIMI 3 flow, no dissection) in 54 patients (91.5%). These patients were then randomized for treatment with single stenting (provisional strategy) (n = 27) versus double stenting (n = 27). During procedure, 6 patients allocated in the single stenting arm presented side branch failure (> 50% residual stenosis, TIMI flow < 3 or dissection), given that 5 patients received an additional stent in the side branch in order to optimize the angiographic result. At final procedure, the mean value and standard deviation (SD) for minimum lumen area at the side branch ostium (primary endpoint) were 3.37 (1.62) mm2 in single stenting versus 5.50 (1.41) mm2 in double stenting (p < 0.001), according to the randomized allocation. In the angiographic follow-up at 9 months, the restenosis rates in the side branch were 21.7% in single stenting versus 4% in double stenting (p = 0.06), given that all recurrences involved the ostial location. Considering the treatment received, the side branch restenosis rate was significantly increase among patients treated with single stenting versus double stenting (27.8% versus 3.3%, p = 0.01). The predictors of provisional strategy failure were: lesion eccentricity (p = 0.02), minimum lumen area (p = 0.08) and minimum lumen diameter in the side branch ostium (p = 0.06), lesion length (p = 0.09) and percent diameter stenosis (p = 0.07) of the side branch. Regarding angiographic restenosis in the side branch, predictors were: minimum lumen area in the side branch ostium at final procedure (p = 0.03), treatment with double stenting (p = 0.02), minimum lumen diameter (p = 0.03) and percent diameter stenosis (p = 0.02) in the side branch ostium at final procedure, acute gain at the side branch ostium (p = 0.09) and side branch reference diameter (p = 0.03). These results suggest that complex coronary bifurcation lesions may benefit from a primary percutaneous approach with double stenting strategy, given that most such benefit was associated with a larger lumen area obtained at the side branch ostium.
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Botadra, Dharam. "Stent Tester: Design and Application." OpenSIUC, 2012. https://opensiuc.lib.siu.edu/theses/863.
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Cardiovascular diseases which include high blood pressure, coronary heart diseases, heart failure, stroke and peripheral arterial diseases (PAD) affect one out of three American adults or 105 million people. By 2030, the prevalence of cardiovascular disease is estimated to rise 10 percent to more than 40 percent of American adults, or 116 million people. Approximately 8 million people in the United States have PAD, including 12-20% of individuals older than age 60. The main reason of PAD is obstruction of blood flow through lower extremities causing Atherosclerosis. The major artery affected in the lower extremities due to PAD is superficial femoral artery (SFA). Huge numbers of clinical procedures like superficial femoral artery stenting, balloon angioplasty, and percutaneous transluminal intervention are done to treat the disease. Thorough in vitro (biological phenomena made to occur outside the human body) testing of this kind should reduce the risk of in vivo (biological phenomena occurring inside the human body) stent failure and thus lead to increased survivability for patients suffering with cardiovascular diseases and PAD. It has been recognized that a metal subjected to a repetitive or fluctuating stress will fail at a stress much lower than that required to cause failure on a single application of load. As per literature review, typically SFA stents survive no more than 12-18 months until the first fracture is detected in MRI. There was a need of a customized designed device such that it would simulate realistic blood pressure conditions and test the capacity the SFA stents. Commercially, the stents are tested under accelerated cyclic loading conditions at different frequencies for longer cycle periods. In order to demonstrate how stents perform once deployed into an artery, a testing device was required which will simulate arterial blood pressure variations and compressive loads over artery as close as possible to human body. The stent tester documented in this report is capable of subjecting a stent to appropriate physiological loading by deploying it in a simulated vessel and subjecting it to external compression. Loading of this kind was performed at frequencies at 60 Hz and, as such, simulating one million heartbeats of artery pulsation. The primary purpose of this thesis was to successfully design stent tester which cycles artificial fluid simulating blood pressure in arteries and superimposing cyclic compression of stent deployed in an artificial artery. The goal was to obtain a test machine that allows for a cost effective testing of cardiovascular and peripheral stents. Another goal was to externally compress the arterial wall subjected to compressive load with the help of an air controlled mechanical piston attached with load cell assembly. The load cell measures the amount of load applied over the silicone tubing. The design of the device contains two peristaltic pumps which alternate pressure every second by pumping distilled water via plastic tubing. The stent was crimped with the guide wire catheter and deployed in the silicone artery (diameter 11mm O.D) from Dynatek labs. Wall and bridge stents (Medtronic, Schneider Inc.) 10 x 39 mm were used for testing with and without external load. Industrial pressure transducer S-10 (Wika Instruments Corporation) ranging from 0-5 PSI (0-259mmHg) is used to monitor the pressure in the artificial artery. The pressure transducer is connected to the data logger (Omega om320) which serially communicates with computer. The silicon mock test artery was 20cm long so that stents used in various arterial interventions can be tested. The silicon artery has primary advantages over rubber latex artery which are clarity and close resemblance to human artery and durable (ideal for long term durability tests). Preliminary results from literature review show that stent materials, based on its mechanical properties survive for more than one million heartbeats. To demonstrate the capacity of current design a nitinol stent was tested under physiological conditions at 60Hz frequency. A load of 980 grams for 2001 - 5000 heartbeats, 1.98 kg for 5001 - 10000 heartbeats, 4.25 kg for 10001 - 25000 heartbeats and 6.54 kg for 25001 - 50000 heartbeats was applied over the artificial artery. The mechanical piston with load cell assembly was allowed to externally compress the artificial artery. Partial functionality of device was demonstrated by running it for one million heartbeats and 48000 compressive cycles. The device was successfully designed and has the capacity to cycle artificial fluid simulating blood pressure changes in arteries and have demonstrated the ability to test any type of stents. The device was designed efficient which was simulated in an acceptable pressure range as compared to human blood pressure and allow for compression of stent in a cyclic testing pattern. The system was maintained to as close as between diastolic value of 76mmHg to diastolic 122mmHg pressure range. The device was run for about one million heartbeats and it was observed that the NiTi stent successfully survived. The stent was observed visually with a magnifying glass for any cracks or failure at intervals of 500, 1000, 2000, 5000, 10000, 25000, 50000 and one million heartbeats respectively. After running the device for one week at a frequency of 60Hz, no fractures on the stent were visually observed. However, the stent was deformed from the center. Data analysis showed that the mean diastolic and systolic pressure measurements for intervals with no load were found to be statistically significant i.e. in acceptable range. However, the device design lacks stability due to various reasons like device operates in an open looped system, has bubbles in the artificial artery which might be producing varying pressure values and variation in applying load. The device was partly unable to simulate arterial blood pressure changes under no loading conditions. Efforts are being made to improve the design of the device to make it realistic simulation of variation in arterial blood pressure for long term durable testing of the stents.
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Martinez, Adam W. "Design and development of an elastin mimetic stent with therapeutic delivery potential." Diss., Georgia Institute of Technology, 2011. http://hdl.handle.net/1853/45926.
Full textAbstract:
Stenting remains a common treatment option for atherosclerotic arteries. The main drawback of early stent platforms was restenosis, which has been combated by drug eluting stents; however, these stents have suffered from a higher incidence of late stage thrombosis. To address current stenting limitations, the major research focuses have been the development of the next generation of drug eluting stents and first generation bioabsorbable stents. The main objective of this dissertation was the design and development of a new class of bioabsorbable stent composed of elastin mimetic protein polymers. The first phase explored different stent design schemes and fabrication strategies. Successfully fabricated stents were then mechanically tested to ensure they possessed sufficient mechanical strength. Additionally, described herein is the potential to modulate the properties of the elastin mimetics through different crosslinking strategies. We have demonstrated that chemical crosslinking allows for the tailoring of the physical, mechanical, drug delivery, and endothelialization properties of these materials. The potential for drug delivery from this elastin mimetic stent was benchmarked as was the potential to endothelialize these stents. Furthermore, we developed the necessary delivery systems to allow for deployment in the rat aorta model.
Books on the topic "Stentai"
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1963-, Protz Andreas, and Krause-Kleint Wilhelmine 1943-, eds. Stendal. Nicolai, 1992.
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Sigwart, Ulrich, and George I. Frank, eds. Coronary Stents. Springer Berlin Heidelberg, 1992. http://dx.doi.org/10.1007/978-3-642-76924-5.
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Krasnogorskai͡a, I. Tam, za stenami sedymi--. Moskovskiĭ rabochiĭ, [Ri͡azanskoe otd-nie], 1987.
Find full textBook chapters on the topic "Stentai"
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Grenon, S. Marlene. "Angioplasty Balloon, Stents, and Stent Grafts." In Handbook of Endovascular Peripheral Interventions. Springer US, 2011. http://dx.doi.org/10.1007/978-1-4614-0839-0_4.
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De Vroey, Frederic, John A. Ormiston, and Mark Webster. "Dedicated Bifurcation Stents: The Petal Stent." In Bifurcation Stenting. John Wiley & Sons, Ltd, 2012. http://dx.doi.org/10.1002/9781444347005.ch16.
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Pazienza, John D., and Willard Hennemann. "Large-Caliber NiTi SMA Stents and Stent Grafts." In Shape Memory Implants. Springer Berlin Heidelberg, 2000. http://dx.doi.org/10.1007/978-3-642-59768-8_21.
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Schulsinger, David A. "Ureteral Stents: To Stent or Not to Stent, That Is a Great Question!" In Kidney Stone Disease. Springer International Publishing, 2014. http://dx.doi.org/10.1007/978-3-319-12105-5_22.
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Gooch, Jan W. "Stenter." In Encyclopedic Dictionary of Polymers. Springer New York, 2011. http://dx.doi.org/10.1007/978-1-4419-6247-8_11199.
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Moreno, M. R., J. Bedoya, C. Meyer, and J. E. Moore. "Computational Modeling of Stented Arteries: Considerations for Evolving Stent Designs." In Mechanics of Biological Tissue. Springer Berlin Heidelberg, 2006. http://dx.doi.org/10.1007/3-540-31184-x_17.
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Larena-Avellaneda, A., T. Kölbel, and C. Heintz. "Stents." In Operative und interventionelle Gefäßmedizin. Springer Berlin Heidelberg, 2012. http://dx.doi.org/10.1007/978-3-642-01709-4_13.
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Ambani, Ravi N., and Jae S. Cho. "Stents." In Endovascular Tools & Techniques Made Easy. CRC Press, 2020. http://dx.doi.org/10.1201/9780429299056-11.
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Goreczny, Sebastian, and Eric Rosenthal. "Stents." In Atlas of Cardiac Catheterization for Congenital Heart Disease. Springer International Publishing, 2019. http://dx.doi.org/10.1007/978-3-319-72443-0_4.
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Rosenthal, Eric, and Sebastian Goreczny. "Stents." In Cardiac Catheterization for Congenital Heart Disease. Springer Milan, 2014. http://dx.doi.org/10.1007/978-88-470-5681-7_8.
Full textConference papers on the topic "Stentai"
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Miller, Ross, and Francine Battaglia. "A Novel Computational Approach for Modeling Stent Reconstructing of an Aortic Bifurcation." In ASME 2006 2nd Joint U.S.-European Fluids Engineering Summer Meeting Collocated With the 14th International Conference on Nuclear Engineering. ASMEDC, 2006. http://dx.doi.org/10.1115/fedsm2006-98169.
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Stent reconstruction of the aorta-iliac bifurcation was studied using computational fluid dynamics. Stents were modeled using a novel method, whereby the stents were represented as porous media. Three-dimensional numerical simulations using FLUENT were performed to determine how stent orientation affects the fluid dynamics. Three cases were studied and compared for both iliacs unstented, one iliac stented, and both iliacs stented. The stents lowered wall shear stress along the stented artery walls as compared to the unstented aorta-iliac model. However, the stent presence elevated vorticity, both in magnitude and size of the region. Additional studies were conducted to determine the effects for stent mis-alignment, where one stent protruded more into the aorta. It was found that when the stents were misaligned, wall shear stress increased near the stent inlet for the stent further inserted into the iliac. The resulting flow phenomena were consistent with other numerical models and medical investigations of stent reconstruction.
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Wang, Longzhen, Junfei Tong, Pengfei Dong, David L. Wilson, Hiram G. Bezerra, and Linxia Gu. "Mechanical Performance of PLLA Stent." In 2018 Design of Medical Devices Conference. American Society of Mechanical Engineers, 2018. http://dx.doi.org/10.1115/dmd2018-6957.
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Stent implantation is widely used to treat blocked lumen. Stents were meshed structure made of polymers and metal alloys, including stainless steel, cobalt chrome and nitinol [1]. Clinical studies had demonstrated that stents helped to scaffold the diseased lesion up to one year when tissue adapted to the stented environment [2]. However, the permanently implanted stents inside artery were associated with complications such as stent fracture, tissue inflammation, in-stent restenosis and thrombosis [3]. Currently, biodegradable stents are attracting more attention due to its potential long-term efficacy in treating blocked lumens. The detailed characterizations of biodegradable stents are essential for the desired clinical outcomes.
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Yazdani, Saami K., and Joel L. Berry. "Investigation of Strut Thickness in Coronary Stents via Finite Element Analysis." In ASME 2004 International Mechanical Engineering Congress and Exposition. ASMEDC, 2004. http://dx.doi.org/10.1115/imece2004-61873.
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Strut thickness in coronary stents has been shown to affect their clinical performance. The purpose of this investigation was to understand how stent strut thickness influenced stress in the vessel wall. Finite element modeling was used to compare stress distribution between a thick and thin strut stent in a curved coronary artery model. Specifically, we modeled two 8 mm long Guidant MULTI-LINK VISION stents, one with strut thickness of 81 μm and the other with strut thickness of 112 μm. Results showed larger values of stress, both in the radial direction and in the circumferential direction, for the thicker stent model. As expected, these higher stress values occurred beneath the stent struts and at the edges of the stent. Stented vessel compliance measurements of both models revealed that the thick strut VISION stent is less compliant than the thin strut VISION stent. These results support the hypothesis that compliance mismatch between the stent and the host vessel contributes to excessive stress in the walls of stented vessels.
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Timmins, Lucas H., Clark A. Meyer, Michael R. Moreno, and James E. Moore. "Stented Artery Biomechanics in the Presence of Stenoses and Tapering." In ASME 2007 Summer Bioengineering Conference. American Society of Mechanical Engineers, 2007. http://dx.doi.org/10.1115/sbc2007-176143.
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The implantation of a balloon expandable stent induces chronic stent-induced stresses on the artery wall. These highly non-physiologic stresses can provoke inflammation and smooth muscle cell proliferation. Ultimately, this cascade of events leads to restenosis, or the development of a new blockage in the stented artery. Since the initial human implantation of balloon expandable stents, technological advances in stent design, material properties, and deliverability have expanded the application and success rate of the procedure. More recently, anti-restenotic strategies such as drug-eluting stents have aimed to counteract the restenosis process. While clinical trials have demonstrated the success of drug eluting stents in coronary arteries [1], risk of late thrombosis [2] and failure to prevent restenosis in peripheral arteries [3] has limited this technology. A further investigation into the artery wall stresses induced by stent implantation, and the pursuit of strategies to minimize them could reduce the restenosis rates for both bare metal and drug-eluting stents.
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Karri, Satyaprakash, Stephen Peter, and Pavlos P. Vlachos. "Effect of Stent Design Parameters on Coronary Artery Flow." In ASME 2009 Summer Bioengineering Conference. American Society of Mechanical Engineers, 2009. http://dx.doi.org/10.1115/sbc2009-206569.
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The most widely accepted modality for treating diseased arteries is the implantation of endovascular stents. Stents are metallic wireframe devices used to reopen clogged arteries. Despite their widespread use, problems persist post-implantation of these devices beginning with sub-acute thrombus formation followed by inflammation, proliferation and remodeling [1]. The specific stent design and its design parameters profoundly impact the hemodynamic environment of the stent [2], in turn affecting thrombus accumulation between struts and thus restenosis [3]. Prior research examining the hemodynamic effects of stents has been performed in simplified geometries [4] however the effects of stent design parameters such as strut thickness and crown radius of curvature or analysis in realistic geometries is generally lacking. A more thorough understanding of the effect of a stent’s geometric parameters on the arterial flow will provide insight into their long-term performance and will lead to better design.
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Yang, Hongcheon, and Kwang-Sun Kim. "Numerical Hemodynamics Analysis of Stented Cerebral Artery." In ASME 2011 International Mechanical Engineering Congress and Exposition. ASMEDC, 2011. http://dx.doi.org/10.1115/imece2011-63608.
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Stroke is one of the most dangerous causes of a sudden death. It is generally caused by the blood clotting in the stenotic region of artery. Cerebrovascular and cardiovascular systems are blocked by plaques so that it can lead to occlusion of the artery. Stenosis in the cerebral artery can be cause of ischemic stroke, or even death if it doesn’t get treatment earlier. Ballooning and stent implementation are main methods to treat stenosis in the artery vascular. Stent implantation has widely been used for cardio-artery diseases and as nano-technology has been developed recently, stents can be produced at sufficiently small sizes, with sufficient delicacy for use in cerebral artery. The blood flow in the stented cerebral artery depends on biomechanical factors such as blood viscosity, blood velocity, vascular density, or body temperature. In this research, we investigated the effects of stent in different types of stented cerebral artery model. The result can be adapted for particular part of the blood vessel or new types of safer stent model. For numerical analysis, we used Solidworks 2010[1] and Star-CCM+[2] softwares for modeling and simulation. Then we compared the result to look into the differences of hemodynamic characteristics between the stenotic blood vessels and stented blood vessels.
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Holton, Andrea D., Brigitta C. Brott, Edward G. Walsh, et al. "Comparative Computational Fluid Dynamics and Experimental Phase-Contrast MRI: Evaluations of In-Stent Restenosis." In ASME 2004 International Mechanical Engineering Congress and Exposition. ASMEDC, 2004. http://dx.doi.org/10.1115/imece2004-59355.
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While angiography and other translesional catheter-based assessments of stented peripheral vasculature are currently used in clinical applications, a quantitative non-invasive imaging modality would improve the treatment of intermediate levels of in-stent restenosis (ISR). The use of magnetic resonance imaging (MRI), in metal stents has been limited due to magnetic susceptibility artifacts and radiofrequency shielding effects. However, MRI compatible materials such as nickel-titanium alloys used in stents have shown superior lumen visibility. In this study, we used phase contrast MRI in a flow phantom of three different geometries of stenosis: a) 90% axisymmetric, b) 75% axisymmetric and c) 50% asymmetric. The velocity distribution was obtained at 3 different locations inside the stent. This was compared with an equivalent computational fluid dynamics (CFD) model of the same stenotic geometries.
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Leung, Solomon W., Arya Ebrahimpour, Marco P. Schoen, and James C. K. Lai. "Self-Cleansing Flexible Stent for Prevention of Clogging of Blood Vessels." In ASME 2007 International Mechanical Engineering Congress and Exposition. ASMEDC, 2007. http://dx.doi.org/10.1115/imece2007-42118.
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Different types of stents are available to be implanted into blood-vessels (e.g., cardiovascular stent) or organs to maintain unobstructed blood flow or flow of tissue fluid through ducts (e.g., biliary and uretic stents and others). On the one hand, it is imperative to use smart material such that its mechanical and elastic properties meet those of the ideal stent. A smart stent can change the orientation of the material(s) either by sensing control, temperature, or blood pressure, thus alter the overall shape of the stent (wiggling). These wiggling motions can prevent or reduce the deposit of cholesterol inside the stent’s lumen. On the other hand, there is a need for a better physiological model of how the tensile and shear stresses of a blood vessel are altered as the blood pressure changes along a defined length of that vessel and how the shape changes of the blood vessel could prevent the deposits of lipid material on the vessel wall thereby possibly decrease the likelihood of stenosis. However, the design of an ideal stent is complicated by the lack of proper materials and modeling studies, and difficulties to have an optimized design because of complexities of environmental factors. In this literature review, we therefore propose that an optimal stents design should incorporate the use of highly biocompatible material(s) of well characterized properties and with an adequately modeled mechanical design. We have discussed the importance and relevance of these issues for future stent design and fabrication.
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Zarandi, Marjan Molavi, Rosaire Mongrain, Olivier F. Bertrand, and Ali Bonakdar. "Non-Newtonian Effects on Blood Flow Dynamics in Stented Coronary Artery Bifurcations." In ASME 2010 3rd Joint US-European Fluids Engineering Summer Meeting collocated with 8th International Conference on Nanochannels, Microchannels, and Minichannels. ASMEDC, 2010. http://dx.doi.org/10.1115/fedsm-icnmm2010-31187.
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From clinical practice, it is known that coronary artery bifurcations are regions where the flow is strongly perturbed, and is prone to the development of atherosclerotic lesions. Bifurcation lesions have always represented a major challenge for placement of stents for treatment of stenosis. Conventional bare metal stents are mostly used in clinical practice of bifurcation lesion treatments since there is no specific commercially available stent dedicated for treating bifurcations. Stent design is strongly influenced by the specific hemodynamic conditions in a given vessel. Therefore, in principal, what was previously assessed for standard stent design, should be re-assessed for stenting bifurcations. In this paper a blood flow model for stented coronary artery bifurcation is presented. The non-Newtonian approach incorporating blood rheology under low shear rates is presented by employing Carreau model. Computational fluid dynamics modeling is used to adapt the model and characterize the non-Newtonian flow patterns and identify the hemodynamic factors that may influence the stent design. The results shows that the flow conditions and particularly shear stress distribution in the vicinity of stent struts and near arterial wall are significantly different compared to the usually assumed Newtonian flow conditions.
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Qiao, Aike, and Zhanzhu Zhang. "Solid and Fluid Simulations of Vertebral Artery Stenosis Treated With Stents With Different Shapes of Link." In ASME 2013 Summer Bioengineering Conference. American Society of Mechanical Engineers, 2013. http://dx.doi.org/10.1115/sbc2013-14062.
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Stenting technology has emerged as an effective alternative for treating arterial stenosis, which recovers blood fluency through mechanical scaffold using struts. Different kinds of endovascular stents cause varying degrees of injury on the artery wall, inducing different ratios of post-operative in-stent restenosis (ISR). Therefore, the design of stent structure has a significant influence on the therapeutic effect of stent intervention. From the viewpoint of solid mechanics, the artery is subjected to long-term press by stent strut after intervention, leading to external mechanical force acting on artery. Straightening, mechanical stress, and stress concentration occurred, causing in-stent intimal hyperplasia extremely, which consequently induce ISR. From the viewpoint of hemodynamics, hemodynamic environment is changed to some extent after stenting. As a result, local blood flow is changed greatly. Vortex and low WSS occur, promoting thrombosis and intimal hyperplasia, which induce ISR more easily. To investigate the effect of stents with different links on treating stenotic vertebral artery and the relation between the shape of link and ISR, as well as provide scientific guidelines for designing stent structure and selecting stent in clinical procedure, numerical simulations of solid mechanics and hemodynamics were performed in this paper, which coupled the boundaries of stent, plaque and blood in the stented vertebral arteries using three kinds of stent with different links.
Reports on the topic "Stentai"
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Krastev, Plamen, Diana Trendafilova, Filip Abedinov, Iliyan Petrov, Peyo Simeonov, and Hristo Angelov. Drugeluting Stent versus Bare-metal Stent in Saphenous Grafts Angioplasty. "Prof. Marin Drinov" Publishing House of Bulgarian Academy of Sciences, 2019. http://dx.doi.org/10.7546/crabs.2019.06.16.
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Cordis. TRYTON Side Branch Stent. Touch Surgery Simulations, 2017. http://dx.doi.org/10.18556/touchsurgery/2017.s0096.
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Pal, Nikhil, Jehangir Din, and Peter O'Kane. Contemporary Management of Stent Failure. Radcliffe Cardiology, 2019. http://dx.doi.org/10.15420/rc.2019.m028.
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Bruce Thomadsen, Robert J. Nickles, Larry DeWerd, et al. Engineering Radioactive Stents for the Prevention of Restenosis. Office of Scientific and Technical Information (OSTI), 2004. http://dx.doi.org/10.2172/831121.
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Jin, Ginger Zhe, Hsienming Lien, and Xuezhen Tao. Top-up Design and Health Care Expenditure: Evidence from Cardiac Stents. National Bureau of Economic Research, 2020. http://dx.doi.org/10.3386/w28107.
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Patricio, Lino, Renato Fernandes, Angelo Bento, and David Neves. Percutaneous Coronary Intervention of an In-stent Restenosis, Utilising the Accuforce® Non-compliant PTCA Balloon Catheter for Optimisation of Stent Placement. Radcliffe Cardiology, 2018. http://dx.doi.org/10.15420/rc.2018.m027.
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Robertson, Scott W. On the Mechanical Properties and Microstructure of Nitinol forBiomedical Stent Applications. Office of Scientific and Technical Information (OSTI), 2006. http://dx.doi.org/10.2172/901533.
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Petrov, Iliyan, Valentin Govedarski, Petya Kashukeeva, Filip Abedinov, Ralitza Marinova, and Plamen Krastev. Shortterm Results for Revascularization of the Femoropopliteal Segment using Interwoven One-wire Stent. "Prof. Marin Drinov" Publishing House of Bulgarian Academy of Sciences, 2020. http://dx.doi.org/10.7546/crabs.2020.02.16.
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Zhao, Chun-Lei, Bing Gu, Xiao-Bing Huo, and Feng-Fei Xia. I-125 seeds-loaded versus normal stent insertion for obstructive esophageal cancer: a meta-analysis. INPLASY - International Platform of Registered Systematic Review and Meta-analysis Protocols, 2020. http://dx.doi.org/10.37766/inplasy2020.12.0138.
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Liu, Xin-Qiang, Sha-Sha Cui, Yu-Ling Kan, Lu-Lu Yang, and Jia-Fen Wang. Stent insertion for hilar cholangiocarcinoma: a meta-analysis of comparison between unilateral and bilateral stenting. INPLASY - International Platform of Registered Systematic Review and Meta-analysis Protocols, 2021. http://dx.doi.org/10.37766/inplasy2021.1.0051.
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