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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
51

The assessment of two year clinical outcomes after stent implantation for the treatment of coronary artery disease

Harrypaul, Ashika 18 January 2013 (has links)
Submitted in fulfilment of the Master’s Degree in Clinical Technology, Durban University of Technology, 2012. / The sirolimus-eluting stent (Cypher) was the first approved drug- eluting stent by the Food and Drug Administration in April 2003. This is a stent that is based on a bare-metal stent and is coated with a layer of polymer incorporating sirolimus and releasing it by diffusion. Drug-eluting stents reduced risk of restenosis and repeat revascularization as compared with bare-metal stents. Clinical data has raised concerns that drug-eluting stents are associated with late untoward events. Objectives: The objective of this study was to test the hypothesis that stenting is safe and effective treatment for coronary artery disease. Methods and Results: Sirolimus-eluting stenting was performed in 30 patients with 34 coronary lesions. Detailed clinical follow-up data was collected by personal interview or telephone contact at 1, 6, 12 and 24 months. Patients were followed for 2 years for the occurrence of angina and cardiovascular events namely death, myocardial infarction, stent thrombosis and target lesion revascularization. The mean age of the cohort was 62.33±10.99 years; 83 percent were male, 6 percent were diabetic, 53 percent had hypertension. In spite of the overall patient and lesion complexity there were no incidences of major adverse cardiac events and all patients remained angina free out to two years. Dual antiplatelet therapy with aspirin and plavix varied from at least four weeks to one year. One patient had a bleeding event. Conclusions: Treatment of lesions with sirolimus-eluting stents is associated with a sustained clinical benefit two years after device implantation.
52

Elevação dos níveis séricos de endotelina-1 após implante de stend coronariano em humanos : um marcador de disfunção endotelial não associado à reestenose

Gonçalves, Sandro Cadaval January 2003 (has links)
Introdução: A reestenose intra-stent ocorre basicamente por uma resposta proliferativa da parede vascular à lesão. Além de ser um marcador de disfunção endotelial, a endotelina-1 (ET-1) exerce atividade proliferativa sobre as células musculares lisas. Evidências experimentais sugerem que a ET-1 possa contribuir para fisiopatogenia da reestenose. Porém, a relação entre os níveis de ET-1 com o implante de stent coronariano e a reestenose intrastent em humanos não está definida. Objetivo: Avaliar o comportamento dos níveis plasmáticos da ET-1 em pacientes submetidos a implante de stent coronariano e determinar se há associação desses com a ocorrência de reestenose. Métodos: Foram incluídos 41 pacientes (44 stents), encaminhados para revascularização coronariana eletiva com implante de stent, por indicação da equipe assistente. Os níveis séricos de ET-1 foram dosados pelo método de ELISA antes do procedimento, logo após e seis meses após o procedimento, quando se realizou nova angiografia quantitativa para avaliar a presença de reestenose. Os níveis de ET-1 foram comparados nos grupos com e sem reestenose e correlacionados com a perda luminal tardia. Resultados: A incidência de reestenose angiográfica foi de 41%. Ocorreu um aumento significativo da ET-1 logo após o procedimento em ambos os grupos (P<0,001), retornando a valores semelhantes aos basais no sexto mês. Não houve diferença significativa entre os grupos com e sem reestenose quanto aos valores de ET-1 em nenhum dos momentos analisados. Não houve correlação entre os níveis de ET-1 e a perda luminal tardia. Conclusões: Ocorre um aumento significativo dos níveis de ET-1 após o implante de stent, possivelmente por ser a ET-1 um marcador da disfunção endotelial provocada pela lesão. Entretanto, não houve uma associação entre os níveis de ET-1 e a ocorrência de reestenose pós-stent em humanos. / Background: Experimental evidence suggests that endothelin-1 (ET-1) levels may play a role in the occurrence of restenosis following percutaneous revascularization procedures. However, the relationship between serum ET-1 with coronary stent implantation and restenosis in humans is not well defined yet. The objective of this study was to evaluate the serum levels of ET-1 in patients submitted to coronary stenting and to determine if there is an association between ET-1 levels and the occurrence of in-stent restenosis. Methods: 41 patients (44 stents) submitted to elective coronary stent implantation were included in the study. Serum ET-1 levels were measured right before and after the procedure and after 6 months. ET-1 levels were compared in patients with and without restenosis and correlated with late luminal loss. Results: The incidence of restenosis was 41%. A significant increase in ET-1 levels right after the procedure was observed in both groups (P < 0.001), with return to basal values after 6 months. No difference was observed between the groups, with and without restenosis, in ET-1 levels pre-procedure, post-procedure or at 6-months. No correlation was observed between late luminal loss and ET-1 levels. Conclusions: There is a significant increase in ET-1 levels right after coronary stenting, probably as a marker of endothelial dysfunction associated arterial lesion. However, there was no association between ET-1 levels and in-stent restenosis in humans.
53

Elevação dos níveis séricos de endotelina-1 após implante de stend coronariano em humanos : um marcador de disfunção endotelial não associado à reestenose

Gonçalves, Sandro Cadaval January 2003 (has links)
Introdução: A reestenose intra-stent ocorre basicamente por uma resposta proliferativa da parede vascular à lesão. Além de ser um marcador de disfunção endotelial, a endotelina-1 (ET-1) exerce atividade proliferativa sobre as células musculares lisas. Evidências experimentais sugerem que a ET-1 possa contribuir para fisiopatogenia da reestenose. Porém, a relação entre os níveis de ET-1 com o implante de stent coronariano e a reestenose intrastent em humanos não está definida. Objetivo: Avaliar o comportamento dos níveis plasmáticos da ET-1 em pacientes submetidos a implante de stent coronariano e determinar se há associação desses com a ocorrência de reestenose. Métodos: Foram incluídos 41 pacientes (44 stents), encaminhados para revascularização coronariana eletiva com implante de stent, por indicação da equipe assistente. Os níveis séricos de ET-1 foram dosados pelo método de ELISA antes do procedimento, logo após e seis meses após o procedimento, quando se realizou nova angiografia quantitativa para avaliar a presença de reestenose. Os níveis de ET-1 foram comparados nos grupos com e sem reestenose e correlacionados com a perda luminal tardia. Resultados: A incidência de reestenose angiográfica foi de 41%. Ocorreu um aumento significativo da ET-1 logo após o procedimento em ambos os grupos (P<0,001), retornando a valores semelhantes aos basais no sexto mês. Não houve diferença significativa entre os grupos com e sem reestenose quanto aos valores de ET-1 em nenhum dos momentos analisados. Não houve correlação entre os níveis de ET-1 e a perda luminal tardia. Conclusões: Ocorre um aumento significativo dos níveis de ET-1 após o implante de stent, possivelmente por ser a ET-1 um marcador da disfunção endotelial provocada pela lesão. Entretanto, não houve uma associação entre os níveis de ET-1 e a ocorrência de reestenose pós-stent em humanos. / Background: Experimental evidence suggests that endothelin-1 (ET-1) levels may play a role in the occurrence of restenosis following percutaneous revascularization procedures. However, the relationship between serum ET-1 with coronary stent implantation and restenosis in humans is not well defined yet. The objective of this study was to evaluate the serum levels of ET-1 in patients submitted to coronary stenting and to determine if there is an association between ET-1 levels and the occurrence of in-stent restenosis. Methods: 41 patients (44 stents) submitted to elective coronary stent implantation were included in the study. Serum ET-1 levels were measured right before and after the procedure and after 6 months. ET-1 levels were compared in patients with and without restenosis and correlated with late luminal loss. Results: The incidence of restenosis was 41%. A significant increase in ET-1 levels right after the procedure was observed in both groups (P < 0.001), with return to basal values after 6 months. No difference was observed between the groups, with and without restenosis, in ET-1 levels pre-procedure, post-procedure or at 6-months. No correlation was observed between late luminal loss and ET-1 levels. Conclusions: There is a significant increase in ET-1 levels right after coronary stenting, probably as a marker of endothelial dysfunction associated arterial lesion. However, there was no association between ET-1 levels and in-stent restenosis in humans.
54

Elevação dos níveis séricos de endotelina-1 após implante de stend coronariano em humanos : um marcador de disfunção endotelial não associado à reestenose

Gonçalves, Sandro Cadaval January 2003 (has links)
Introdução: A reestenose intra-stent ocorre basicamente por uma resposta proliferativa da parede vascular à lesão. Além de ser um marcador de disfunção endotelial, a endotelina-1 (ET-1) exerce atividade proliferativa sobre as células musculares lisas. Evidências experimentais sugerem que a ET-1 possa contribuir para fisiopatogenia da reestenose. Porém, a relação entre os níveis de ET-1 com o implante de stent coronariano e a reestenose intrastent em humanos não está definida. Objetivo: Avaliar o comportamento dos níveis plasmáticos da ET-1 em pacientes submetidos a implante de stent coronariano e determinar se há associação desses com a ocorrência de reestenose. Métodos: Foram incluídos 41 pacientes (44 stents), encaminhados para revascularização coronariana eletiva com implante de stent, por indicação da equipe assistente. Os níveis séricos de ET-1 foram dosados pelo método de ELISA antes do procedimento, logo após e seis meses após o procedimento, quando se realizou nova angiografia quantitativa para avaliar a presença de reestenose. Os níveis de ET-1 foram comparados nos grupos com e sem reestenose e correlacionados com a perda luminal tardia. Resultados: A incidência de reestenose angiográfica foi de 41%. Ocorreu um aumento significativo da ET-1 logo após o procedimento em ambos os grupos (P<0,001), retornando a valores semelhantes aos basais no sexto mês. Não houve diferença significativa entre os grupos com e sem reestenose quanto aos valores de ET-1 em nenhum dos momentos analisados. Não houve correlação entre os níveis de ET-1 e a perda luminal tardia. Conclusões: Ocorre um aumento significativo dos níveis de ET-1 após o implante de stent, possivelmente por ser a ET-1 um marcador da disfunção endotelial provocada pela lesão. Entretanto, não houve uma associação entre os níveis de ET-1 e a ocorrência de reestenose pós-stent em humanos. / Background: Experimental evidence suggests that endothelin-1 (ET-1) levels may play a role in the occurrence of restenosis following percutaneous revascularization procedures. However, the relationship between serum ET-1 with coronary stent implantation and restenosis in humans is not well defined yet. The objective of this study was to evaluate the serum levels of ET-1 in patients submitted to coronary stenting and to determine if there is an association between ET-1 levels and the occurrence of in-stent restenosis. Methods: 41 patients (44 stents) submitted to elective coronary stent implantation were included in the study. Serum ET-1 levels were measured right before and after the procedure and after 6 months. ET-1 levels were compared in patients with and without restenosis and correlated with late luminal loss. Results: The incidence of restenosis was 41%. A significant increase in ET-1 levels right after the procedure was observed in both groups (P < 0.001), with return to basal values after 6 months. No difference was observed between the groups, with and without restenosis, in ET-1 levels pre-procedure, post-procedure or at 6-months. No correlation was observed between late luminal loss and ET-1 levels. Conclusions: There is a significant increase in ET-1 levels right after coronary stenting, probably as a marker of endothelial dysfunction associated arterial lesion. However, there was no association between ET-1 levels and in-stent restenosis in humans.
55

Investigation of the Hemodynamics of Coronary Arteries - Effect of Stenting

Coimbatore Selvarasu, Naresh Kumar 23 April 2013 (has links)
Cardiovascular diseases (CVD) are the leading cause of death in the world. According to the World Health Organization (WHO) 17.3 million people died from cardiovascular disease in 2008, representing 30% of all global deaths. The most common modality of treatment of occluded arteries is the use of stents. Despite the widespread use of stents, the incidence of post-stent restenosis is still high. The study of stents in conditions that are similar to in-vivo conditions is limited. This work tries to address the behavior of stents in conditions similar to in-vivo conditions in a generalized framework, thus providing insights for stent design and deployment. Three dimensional, time accurate computational fluid dynamics (CFD) simulations in a pulsatile flow with fluid-structure interaction (FSI) were carried out in realistic coronary arteries, with physiologically relevant flow parameters and dynamics due to induced motion of the heart. In addition, the geometric effects of the stent on the artery were studied to point towards possible beneficial stent deployment strategies. The results suggest that discontinuities in compliance and dynamic geometry cause critical changes in local hemodynamics, namely altering the local pressure and velocity gradients. Increasing the stent length, reducing the transition length and increasing the overexpansion caused adverse flow conditions. From this work, detailed flow characteristics and hemodynamic characteristics due to the compliance mismatch and applied motion were obtained that gave insights towards better stent design and deployment. / Ph. D.
56

Epidemiology and resistance patterns of bacterial and fungal colonization of biliary plastic stents

Lübbert, Christoph, Wendt, Karolin, Feisthammel, Jürgen, Moter, Annette, Lippmann, Norman, Busch, Thilo, Mössner, Joachim, Hoffmeister, Albrecht, Rodloff, Arne C. 27 June 2016 (has links) (PDF)
Background: Plastic stents used for the treatment of biliary obstruction will become occluded over time due to microbial colonization and formation of biofilms. Treatment of stent-associated cholangitis is often not effective because of inappropriate use of antimicrobial agents or antimicrobial resistance. We aimed to assess the current bacterial and fungal etiology of stentassociated biofilms, with particular emphasis on antimicrobial resistance. Methods: Patients with biliary strictures requiring endoscopic stent placement were prospectively enrolled. After the retrieval of stents, biofilms were disrupted by sonication, microorganisms were cultured, and isolates were identified by matrix-associated laser desorption/ionization time-of-flight (MALDI-TOF) mass spectrometry and/or biochemical typing. Finally, minimum inhibitory concentrations (MICs) were determined for various antimicrobial agents. Selected stents were further analyzed by fluorescence in situ hybridization (FISH). Results: Among 120 patients (62.5% males, median age 64 years) with biliary strictures (35% malignant, 65% benign), 113 double pigtail polyurethane and 100 straight polyethylene stents were analyzed after a median indwelling time of 63 days (range, 1–1274 days). The stent occlusion rate was 11.5%and 13%, respectively, being associated with a significantly increased risk of cholangitis (38.5% vs. 9.1%, P<0.001). Ninety-five different bacterial and 13 fungal species were detected; polymicrobial colonization predominated (95.8% vs. 4.2%, P<0.001). Enterococci (79.3%), Enterobacteriaceae (73.7%), and Candida spp. (55.9%) were the leading pathogens. Candida species were more frequent in patients previously receiving prolonged antibiotic therapy (63% vs. 46.7%, P = 0.023). Vancomycinresistant enterococci accounted for 13.7%, extended-spectrum beta-lactamase (ESBL)-producing Enterobacteriaceae with co-resistance to ciprofloxacin accounted for 13.9%, and azole-resistant Candida spp. accounted for 32.9% of the respective isolates. Conclusions: Enterococci and Candida species play an important role in the microbial colonization of biliary stents. Therefore, empirical antimicrobial treatment of stent-associated cholangitis should be guided toward enterococci, Enterobacteriaceae, streptococci, anaerobes, and Candida. To determine causative pathogens, an accurate microbiological analysis of the extracted stent(s) may be helpful.
57

Estudo do perfil inflamatório de pacientes submetidos à angioplastia transluminal percutânea periférica com stents de nitinol revestidos de politetrafluoretileno através das citocinas séricas IL-1b IL-6, IL-8, IL-10, TNF-a e TGF-b / Study of the inflammatory profile of patients undergoing peripheral percutaneous transluminal angioplasty with polytetrafluoroethylene-coated nitinol stents through the serum cytokines IL-1b IL-6, IL-8, IL-10, TNF-a e TGF-b

Guimarães, Thiago Adriano Silva 25 April 2017 (has links)
Introdução: A angioplastia transluminal periférica com o uso de stents revestidos tem se tornado uma opção viável para o tratamento da doença arterial obstrutiva em casos específicos, principalmente na região fêmuro-poplítea, apesar da incidência significativa de reestenose com papel importante do processo inflamatório. As citocinas são proteínas secretadas pelas células da imunidade natural e adquirida e participam de forma fundamental no processo inflamatório local e sistêmico. Objetivo: Avaliar as concentrações séricas de IL-1?, IL-6, IL-8, IL-10, TNF-?, TGF-?1e PCR, além do colesterol total e leucometria antes e após o implante de stents revestidos e a possível associação com a reestenose precoce em pacientes com doença arterial periférica fêmoropoplítea. População e método: Foram recrutados 38 pacientes consecutivos do ambulatório de Cirurgia Vascular e Endovascular do HCFMRP-USP com indicação de angioplastia transluminal periférica nos quais foram utilizados stents revestidos no segmento fêmoro- poplíteo para tratamento de doença arterial obstrutiva periférica aterosclerótica. Todos os pacientes foram acompanhados com exames clínicos e de ultrassom Doppler durante até seis meses após o procedimento com dosagens séricas de citocinas, além da proteína C reativa, colesterol total e hemograma. Foi considerado reestenose estreitamentos maiores que 50% do lúmen do vaso, mensurados, inicialmente, pelo ultrassom e confirmado através da arteriografia. Resultados: Dentre os 27 pacientes que foram incluídos no estudo, 23 não apresentaram reestenose (85,2%) e quatro casos evoluíram com reestenose precoce (14,8%). Nenhuma das citocinas estudadas - IL-1?, IL-6, IL-8, IL-10, TNF-? e TGF-? - mostrou correlação com a reestenose (p>0.05). Também não houve correlação do processo de reestenose com a proteína C reativa, colesterol total ou a leucometria (p>0.05). O índice tornozelo-braquial mostrou boa correlação com a evolução clínica dos pacientes. Conclusão: O perfil inflamatório de pacientes submetidos à angioplastia transluminal percutânea periférica com stents de nitinol revestidos de politetrafluoretileno avaliado através das citocinas séricas IL-1?, IL-6, IL-8, IL-10, TNF-? e TGF-? mostrou significativo aumento das citocinas pró-inflamatórias logo após o procedimento. Não houve correlação de nenhuma das interleucinas estudadas ou ainda da proteína C reativa com o processo de reestenose. / Introduction: The peripheral transluminal angioplasty with the use of coated stents has become a viable option for the treatment of obstructive arterial disease in specific cases, mainly in the femoral-popliteal region, despite the significant incidence of restenosis with important role of the inflammatory process. Cytokines are proteins secreted by cells of natural and acquired immunity and participate in a fundamental way in the local and systemic inflammatory process. Objective: To evaluate the serum concentrations of IL-1?, IL-6, IL-8, IL-10, TNF-?, TGF-?1 and PCR, as well as total cholesterol and leucometry before and after the implantation of coated stents and the possible association with early restenosis in patients with peripheral femoralpopliteal arterial disease. Population and method: 38 consecutive patients from the outpatient clinic of vascular and endovascular surgery of the HCFMRP-USP were recruited with indication of peripheral transluminal angioplasty in which the stent was coated in the femoropopliteal segment for the treatment of atherosclerotic peripheral obstructive arterial disease. All patients were followed up with clinical examinations and Doppler ultrasound for up to six months after the procedure with serum levels of cytokines, as well as C-reactive protein, total cholesterol and hemogram. It was considered restenosis narrowings greater than 50% of vessel lumen, measured, initially, by the ultrasound and confirmed by arteriography. Results: Of the 27 patients included in the study, 23 did not present restenosis (85.2%) and four cases evolved with early restenosis (14.8%). None of the cytokines studied - IL-1?, IL-6, IL-8, IL-10, TNF-? and TGF-? - showed a correlation with restenosis (p> 0.05). There was also no correlation of the restenosis process with the C-reactive protein, total cholesterol or leucometry (p> 0.05). The ankle-brachial index showed a good correlation with the clinical evolution of the patients. Conclusions: The inflammatory profile of patients undergoing peripheral percutaneous transluminal angioplasty with polytetrafluoroethylene-coated nitinol stents evaluated through the serum cytokines IL-1?, IL-6, IL-8, IL-10, TNF-? and TGF-? showed a significant increase in proinflammatory cytokines soon after the procedure. There was no correlation of any of the interleukins studied or the C-reactive protein with the restenosis process.
58

Avaliação da função endotelial após o implante de stents com revestimento cerâmico e baixas doses de sirolimus: estudo prospectivo, duplo-cego e randomizado / Endothelial function evaluation after a ceramic surface coating stent with low dose of sirolimus implantation: a prospective, double-blinded and randomized trial

Almeida, Breno Oliveira 27 March 2013 (has links)
A disfunção endotelial é uma das possíveis causas relacionadas à taxa mais elevada de trombose após o implante da primeira geração de stents farmacológicos. Se a presença do polímero durável ou elevada dose de fármacos antiproliferativos, ou ambos, são responsáveis por este fenômeno não está definido. O Estudo VESTASYNC II comparou um novo stent farmacológico, com superfície revestida por uma camada porosa de hidroxiapatita e impregnado com baixa dose de sirolimus. (55?g - stent VestaSync®) com seu equivalente não farmacológico (Stent VestaCor® ). O Vestasync II é um estudo prospectivo, randomizado (2:1) e duplo-cego, que incluiu pacientes com lesões de novo em artérias nativas com extensão menor que 14mm, com diâmetro entre 3,0 e 3,5mm. Um subgrupo composto por 20 pacientes (10 em cada grupo) submeteu-se à avaliação da função endotelial, no seguimento angiográfico de oito meses. O objetivo primário foi a comparação da vasomotricidade após o implante de stents com a mesma plataforma, com e sem eluição de sirolimus, a fim de determinar o real impacto de baixa dose do sirolimus na função endotelial. O desfecho de eficácia foi a perda luminal tardia e o porcentual de obstrução intra-stent. A avaliação da função endothelial foi realizada através da estimulação atrial com marcapasso (20ppm acima da frequência cardiaca basal até alcançar 150ppm) e o diâmetro luminal foi mensurado nas extremidades proximal e distal do stent e em um segmento controle, em estágios diferentes (repouso, sucessivas fases do estímulo e após a infusão intracoronária de nitroglicerina). A eficácia deste novo dispositivo foi confirmada por angiografia coronária quantitativa (perda luminal tardia VestaSync = 0,39 mm vs. 0,78 mm, p=0,005) e ultrassom intravascular (% obstrução VestaSync 9,3% vs. 17,6%, p= 0,005). Houve variação negativa no diâmetro luminal, entre o repouso e o estímulo máximo, nas bordas proximal (10%) e distal (8%). Entre os segmentos controles esta variação não alcançou 3%. A eluição de dose baixa do sirolimus não parece interferir na função endotelial, oito meses após o implante do stent sem polímero revestido com hidroxiapatita. / Endothelium dysfunction is among the possible causes related to higher thrombosis rates after first generation drug-eluting stents implant. Whether the presence of durable polymer or high anti-proliferative drug dose, or both, can be responsible for this phenomenon is not clear. The VESTASYNC II trial compared a novel polymer-free drug-eluting stent with a nanothinmicroporous hydroxyapatite surface coating impregnated with a low-dose of sirolimus (55?g-VestaSyncTM stent) to a bare-metal equivalent also coated with a nanothin-microporous hydroxyapatite surface (VestaCorTM stent). This is a randomized (2:1), double-blinded trial which enrolled patients with single de novo lesions in native coronary arteries from 3.0 to 3.5mm diameter and less than 14mm in length. A subset of 20 patients (10 from each group) underwent to endothelial function assessment at eight-month angiographic follow-up. The primary objective was to compare the vasomotricity after implantation of stents with the same platform, with and without drug elution, to determine the real impact of low-dose sirolimus release in endothelial function. Efficacy endpoint was in-stent late loss and % of stent obstruction. Endothelial function was assessed with atrial pacemaker stimulation (20 ppm over basal cardiac frequency until reach 150 ppm) and the lumen diameter was measured at 5 mm of proximal and distal stent edges and in a control segment, in different stages (at rest, at successive phases of stimulli and after nitroglycerin intracoronary infusion). The efficacy of this new device was confirmed by means of quantitative coronary angiography (late loss VestaSync = 0.39 mm vs. 0.78 mm, p=0.005) and intravascular ultrasound (% obstruction VestaSync 9.3% vs. 17.6%, p= 0.005). There was a negative variation in luminal diameter between basal and maximum stimulli in proximal (10%) and distal (8%) edges of both groups. Among control segments this variation did not reach 3%. The elution of low-dose of sirolimus does not seem to interfere in endothelial function 8 months after polymer-free hydroxyapatite coating stent implantation.
59

Estudo do revestimento de modelos de stents coronários biorreabsorvíveis de PLLA com PLDLA/PLGA e ácido hialurônico / Study of bioresorbable coronary PLLA stents models coating with PLDLA/PLGA and hialurônic acid

Maria, Adriana Del Monaco De 04 May 2017 (has links)
A doença arterial coronariana vem sendo a maior causa de mortalidade no mundo, a angioplastia com implante de stent é uma estratégia importante nestes casos. Estudos apontam a biodegradabilidade, imobilização de antiproliferativos e moléculas bioativas nos stents, como características das futuras gerações destes dispositivos. Dentre estas, o ácido hialurônico contribui para a diminuição da agregação e proliferação de células entre as camadas da artéria e o dispositivo implantado. Foram desenvolvidos modelos de stents coronários biorreabsorvíveis de poli(-L-ácido láctico) (PLLA) com enxertia de ácido hialurônico (HA) em poli(-ácido lático co-ácido glicólico) (PLGA) e poli(L-D-ácido lático) (PLDLA). Os modelos foram caracterizados quanto suas propriedades térmicas, mecânicas e de superfície. O PLDLA e PLGA com enxertia de HA modificado com dihidrazida adípica (ADH) apresentaram características de superfície mais hidrofílicas, ideais para material de revestimento dos dispositivos. Desta forma, este trabalho possibilitou o desenvolvimento dos modelos físicos biorreabsorvíveis, com dimensões semelhantes aos stents coronários, feitos de PLLA, revestidos com PLGA e PLDLA com enxertia de HA e HAADH, e estáveis aos processos de esterilização por radiação ultravioleta e plasma de peróxido de hidrogênio. / Coronary artery disease has been world´s leading cause of death and angioplasty stent implantation is an important strategy in these cases. Studies indicate that the biodegradability, immobilization of antiproliferatives and bioactive molecules in stents are characteristics of future generations of these medical devices. Amongst them, hyaluronic acid (HA) contributes to the decrease of the aggregation and proliferation of cells between artery layers and implanted device. For this purpose, poly (L-lactic acid) (PLLA) bioresorbable coronary stents with HA grafting in poly (lactic acid-co-glycolic acid) (PLGA) and poly (LD- (PLDLA) were developed. The models were characterized as their thermal, mechanical and surface properties. PLDLA and PLGA with adipic dihydrazide (ADH) modified HA grafting presented more hydrophilic surface characteristics, ideal as coating material of this devices. This project allowed the development of bioresorbable physical models with similar dimensions to coronary stents, made of PLLA, coated with PLGA and PLDLA with hyaluronic acid grafting, stable to ultraviolet radiation and plasma sterilization with hydrogen peroxide processes.
60

Avaliação seriada por ultrassom intracoronário do suporte vascular bioabsorvível com eluição de novolimus DESolveTM / Serial assessment by intracoronary ultrasound bioresorbable coronary scaffold eluting with novolimus DESolveTM

Aguiar Filho, Gentil Barreira de 03 October 2017 (has links)
INTRODUÇÃO: Os suportes vasculares bioabsorvíveis (SVB) surgiram com a finalidade de aumentar a segurança tardia das intervenções coronárias percutâneas (ICP). Estes dispositivos liberam o fármaco antiproliferativo no local da obstrução e são absorvidos com o passar do tempo. A utilização do ultrassom intracoronário (USIC) pode ajudar na avaliação do processo de absorção deste dispositivo. OBJETIVOS: Primário: avaliar e comparar, pelo USIC, o volume e a área da luz, do vaso e do SVB imediatamente após o implante da prótese, e, tardiamente, aos 6 e 18 meses. Objetivos secundários: avaliar e comparar, pelo USIC, o volume e área da placa imediatamente após o implante da prótese, e, tardiamente, aos 6 e 18 meses e os diâmetros do vaso, lúmen e SVB após ICP e no seguimento. Percentual de estenose e perda tardia do lúmen pela angiografia no seguimento e incidência de eventos cardíacos adversos maiores (ECAM) até os 18 meses. MÉTODO: Trata-se de um estudo prospectivo, não randomizado com a inclusão de 20 pacientes que foram submetidos ao implante do SVB DESolve®. Foi realizado o USIC após o procedimento e aos 6 e 18 meses de seguimento. RESULTADOS: Dos 20 pacientes selecionados, um paciente recusou realizar o USCI aos 6 meses e dois não realizaram o exame aos 18 meses, sendo excluídos do estudo. Totalizando 17 pacientes analisados. A idade média foi de 58,59 ± 8,73 anos e 70,6% eram do sexo masculino. O quadro clínico predominante era de angina estável. A via de acesso preferencial foi a radial, todos os pacientes foram submetidos à pré e pós-dilatação e o sucesso angiográfico ocorreu em todos os casos. No seguimento, houve aumento significativo na área (6,41 ± 1,35 mm2 vs. 7,35 ± 1,53 mm2, p < 0,002), volume (101,19 ± 20,9 mm3 vs. 118,51 ± 26,6 mm3, p = 0,001) e diâmetros do dispositivo, pelo USIC, aos 6 meses quando comparado ao procedimento índice. Não houve alteração significativa nas áreas, nos volumes e nos diâmetros do vaso e lúmen, em qualquer comparação no seguimento. A perda tardia foi de 0,22 ± 0,30 mm aos 6 e de 0,33 ± 0,44 mm aos 18 meses. Não houve nenhum caso de reestenose angiográfica e trombose do dispositivo. No seguimento, não houve casos de ECAM. CONCLUSÕES: A ICP com a utilização do SVB DESolve® para o tratamento da doença arterial coronária não complexa demonstrou resultados promissores. Houve aumento do volume e área do dispositivo aos 6 meses e uma supressão eficaz da hiperplasia intimal sem ECAM no seguimento. / INTRODUCTION: The bioresorbable vascular scaffolds (BVS) emerged in order to increase late safety of percutaneous coronary interventions (PCI). These devices release the antiproliferative drug to the site of obstruction and are absorbed over time. The use of intravascular ultrasound (IVUS) can help in the evaluation of this device absorption process. OBJECTIVES: The primary endpoint was to evaluate and compare, through IVUS, the volume and the area of the lúmen, the vessel and the device immediately after its implantation, and later at 6 and 18 months. The secondary endpoints were to evaluate and compare, through IVUS, the volume and the area of the plaque immediately after its implantation, and later at 6 and 18 months and diameters of the vessel, lúmen and BVS after PCI and at follow-up. Percentage of stenosis and late lúmen loss by angiography and incidence of major adverse cardiac events (MACE) up to 18 months. METHOD: This is a prospective, non-randomized study, with the inclusion of 20 patients who underwent implantation of DESolveTM. IVUS was performed after the procedure and at 6 and 18 months of follow-up. RESULTS: Of the 20 patients selected, one patient refused to perform the USCI at 6 months and two did not undergo the exam at 18 months and were excluded from the study. In total, 17 patients were analyzed. The average age was 58.59 ± 8.73 years and 70,6% were male. The most common clinical presentation was stable angina. The preferred vascular acess was to radial, all patients underwent pre- and post-dilation and angiographic success occurred in all cases. At follow-up there was a significant increase in area (6,41 ± 1,35 mm2 vs. 7,35 ± 1,53 mm2, p < 0,002), volume (101,19 ± 20,9 mm3 vs. 118,51 ± 26,6 mm3, p = 0,001) and diameters of the device, by IVUS, at 6 months when compared to the index procedure. There was no significant change in the areas, volumes and diameters of the vessel and lúmen, in any comparison at follow-up. The late loss was 0,22 ± 0,30 mm at 6 and 0,33 ± 0,44 mm at 18 months. There were no cases of restenosis and scaffold thrombosis. During follow-up there was no case of MACE. CONCLUSIONS: PCI with the use of DESolve scaffold for the treatment of non-complex coronary artery disease has shown promising results. There was an increase in the volume and area of the device at 6 months and an effective suppression of intimal hyperplasia without MACE at follow-up.

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