A intervenção percutânea com implante de stents constitui-se na principal forma de revascularização miocárdica empregada, e associa-se à redução de sintomas, à melhoria na qualidade de vida e ao aumento da sobrevida em pacientes acometidos por síndrome coronária aguda. Entretanto, o implante de stents pode acompanhar-se de exagerada hiperplasia intimal, principal determinante da reestenose destes dispositivos. Diversos fatores clínicos, anatômicos e técnicos associam-se a maiores taxas de reestenose, porém a hipótese de que o tipo ou a composição da lesão aterosclerótica tratada possa correlacionar-se com o fenômeno ainda não foi esclarecida. Determinar a relação entre a composição da placa aterosclerótica tratada conforme análise pela Histologia Virtual® - e a magnitude da hiperplasia intimal após o implante de stents farmacológicos e não-farmacológicos. No período de setembro de 2008 a novembro de 2009, selecionamos 52 pacientes prospectivos com o diagnóstico de síndrome coronária aguda com ou sem supra ST, submetidos à cinecoronariografia e candidatos à intervenção percutânea. Estes foram randomizados para o tratamento com stents farmacológicos com sirolimus (Cypher® Cordis, Johnson & Johnson) ou com stents não-farmacológicos (Driver®,Medtronic Inc.). O ultra-som com Histologia Virtual® foi realizado antes do tratamento das lesões culpadas, e correlacionou-se o porcentual dos componentes fibrótico, fibrolipídico, núcleo necrótico e cálcio com o grau de hiperplasia intimal, em reestudo ultrasonográfico realizado aos 9 meses. A média de idades foi de 55,3 anos (DP 4,9 anos), sendo 77% homens. Não foram verificadas diferenças significativas entre os grupos no que se refere às variáveis clínicas e angiográficas. A maioria dos pacientes apresentava obstrução coronária uniarterial, e o vaso mais freqüentemente tratado foi a descendente anterior. À Histologia Virtual®, não foram detectadas diferenças em relação ao tipo de placa tratada, sendo predominantes as lesões do tipo fibroateroma e fibroateroma calcificado. O tecido fibrótico foi o componente preponderante [59,6% (DP 15,8%) do volume total das placas analisadas], e cerca de 20% do volume das lesões era composto por núcleo necrótico. Após 9 meses, o reestudo ultrasonográfico foi realizado em 49 (94%) dos pacientes. Tanto o volume como o porcentual de hiperplasia intimal foram significativamente maiores no grupo tratado com stents não-farmacológicos [60,8 mm3 [DP 32 mm3] versus 14 mm3 (DP 9,2 mm3), p<0,0001 e [31,9% (DP 12,9%) versus 8,2% (DP 7,6%) , p<0,0001, respectivamente]. Contudo, não foi observada associação entre os porcentuais dos componentes fibrótico (corr. 0,038, p=0,81), fibrolipídico (corr. 0,109, p=0,49), cálcio (corr. -0,073, p=0,64) e núcleo necrótico (corr. -0,062, p=0,69) das lesões tratadas com o tecido neointimal intra-stent. Os resultados desta investigação prospectiva e randomizada indicam que as informações providas pela Histologia Virtual® na caracterização das placas ateroscleróticas não auxiliam na identificação de lesões mais propensas à reestenose, após o implante de stents farmacológicos e não-farmacológicos. / To the present, little is known about the correlation between modifications in plaque composition at stent edges and the changes in vessel geometry. This study sought to evaluate, by serial grey-scale intravascular ultrasound (IVUS) and Virtual Histology(TM), the modifications in plaque composition at the edges of drug-eluting and bare-metal stents and the correlation of these findings with changes in the measuremntes of vessel, lumen and plaque area at those segments. Single-center, prospective and randomized (1:1) evaluation of 40 patients with acute coronary syndrome treated with bare-metal (Driver(TM), n=20 patients) or drug-eluting stents (Cypher(TM), n=20 patients). Following stent deployment, all individuals underwent gray scale IVUS and Virtual Histology(TM) evaluation, which were repeated at nine months. Primary endpoint included the modification in vessel, lumen and plaque area and in the composition of the plaque in the mean time between the baseline and follow-up procedure. Additionally, we tried to determine a correlation between plaque composition variation and changes in vessel geometry. At the proximal edge of both drug-eluting and bare-metal stents there was a trend to positive vessel remodeling which compensated the modest increase in plaque area. At the distal edge, patients treated with drug-eluting stents had less plaque growth resulting in a larger lumen area at follow-up. By Virtual Histology, there was a marked reduction in the % of fibrotic tissue and necrotic core in both edges of the two stents and a positive, strong correlation was seen between increase in % of fibrofatty component and augmentation in plaque area(r=0.78, p=0.01). The use of drug-eluting stents was not associated with \"edge effect\". On the contrary, patients treated with these devices experienced less plaque growth, especially at the distal edge of the stents. Modifications in plaque composition, with increase in fibrofatty content, might partially explain these findings.

O acidente vascular cerebral (AVC) e a primeira causa de obito no Brasil e a principal de incapacidade no mundo. A doenca aterosclerotica carotidea esta associada a cerca de 15% dos AVC. A endarterectomia cirurgica e o tratamento padrao-­ouro para as estenoses carotideas sintomaticas. A angioplastia carotidea com stent via endovascular (ACS) e uma alternativa terapeutica a endarterectomia. O desenvolvimento de dispositivos de protecao embolica levou a reducao das taxas de complicacao durante a ACS. A tecnica de protecao mais utilizada na pratica clinica e a protecao distal com filtro. As estrategias de protecao proximal, por bloqueio ou reversao do fluxo carotideo, tem revelado resultados promissores em relacao a protecao distal com filtro durante a ACS. Assim, o objetivo do estudo foi comparar a reversao de fluxo e o filtro de protecao durante a ACS. Os objetivos primarios foram a incidencia, o numero e o tamanho das lesoes cerebrais isquemicas por ressonancia magnetica pela sequencia diffusion-­weighted-­imaging (DWI) apos a ACS. Os objetivos secundarios foram as complicacoes cardiacas e eventos cerebrovasculares (CCEC), ataque isquemico transitorio (AIT) e as lesoes cerebrais isquemicas definitivas na imagem por ressonancia magnetica pela sequencia fluid-­attenuated inversion recovery (FLAIR) no seguimento de tres meses. As lesoes isquemicas foram obtidas por ressonancia magnetica (RM) de campo 3 Tesla. Os pacientes foram avaliados quanto aos desfechos neurologicos atraves das escalas do National Institutes of Health Stroke Scale (NIHSS) e modified Rankin Scale (mRS). Quarenta pacientes foram incluidos randomicamente no estudo. Comparado a reversao de fluxo (n=21) o filtro de protecao (n=19) resultou em uma reducao significativa na incidencia (15,8% vs. 47,6%, p=0,03), no numero (0,73 vs. 2,6, p=0,05) e no tamanho (0,81 vs. 2,23 mm, p=0,05) das novas lesoes cerebrais isquemicas. Dois pacientes, um de cada grupo, apresentaram AIT no seguimento de tres meses. Nao foram observadas CCEC na internacao ou no seguimento de tres meses. Neste estudo, o filtro de protecao mais eficaz que a reversao de fluxo na protecao cerebral durante a angioplastia carotidea com stent por acesso femoral. / Objectives: Carotid artery stenting (CAS) has become an alternative treatment for patients presenting symptomatic carotid artery stenosis. The improvement in clinical outcomes with CAS has been associated with the development of embolic protection devices. The trial aim is to compare flow-­reversal versus filter protection during CAS through femoral access. Methods: Patients were randomly enrolled in CAS using flow-­reversal or filter protection. The primary endpoints were the incidence, number and size of new ischemic brain lesions after CAS. The secondary endpoints included major adverse cardiac and cerebrovascular events (MACCE), transient ischemic attack (TIA) and definitive ischemic brain lesions on fluid-­attenuated inversion recovery magnetic resonance image (FLAIR-­MRI) at a three-­month follow-­up. Ischemic brain lesions were assessed by a 3T-­MRI. Neurological outcomes were evaluated by means of the National Institutes of Health Stroke Scale (NIHSS) and the modified Rankin Scale (mRS). Results: Forty consecutive patients were randomly assigned. Compared to flow-­reversal (n=21), filter protection (n=19) resulted in a significant reduction in the incidence (15.8% vs. 47.6%, p=0.03), number (0.73 vs. 2.6, p=0.05) and size (0.81 vs. 2.23 mm, p=0.05) of new ischemic brain lesions. Two patients, one from each group, presented TIA at the three-­month follow-­up. There were no MACCE in the hospital or at the three-­month follow-­up. Conclusions: In this small sample size trial, filter protection was more effective than flow-­reversal in reducing ischemic brain lesions during CAS through femoral approach.

Abstract Endovascular aneurysm repair (EVAR) is a minimally invasive alternative to open surgery to exclude an abdominal aortic aneurysm from the circulation to avert a rupture. The aim of this thesis was to evaluate the early and mid-term results of EVAR using the Zenith® stent-graft (Cook Inc, Bloomington, IN, USA) in asymptomatic and symptomatic abdominal aortic aneurysm (AAA) patients in three Finnish university hospitals. Furthermore, the aim was to study whether preoperative embolization of the inferior mesenteric artery (IMA) before EVAR decreases the incidence of a type II endoleak or has an effect on the aneurysm sac shrinkage. Finally, the results after secondary interventions for a type II endoleak were evaluated. Two hundred six patients underwent elective endovascular repair of an intact AAA. The use of the Zenith® stent-graft was associated with good early and mid-term results. The thirty-day mortality rate (2.9%) was in accordance with other EVAR studies. Only one late aneurysm-related death occurred in this series, whilst no patients died of a late aneurysm rupture. No stent-graft migrations or fractures were observed. Endoleak, defined as persistent blood flow outside the graft and within the aneurysm sac, remains a long-term problem with EVAR. The overall endoleak incidence was 34.6%. A type II endoleak (retrograde perfusion via aortic side branches) occurred in 52 patients (25.4%). EVAR was performed for 14 patients with a symptomatic, unruptured AAA. The median delay from admission to intervention was 4 days. EVAR of a symptomatic, unruptured AAA was associated with a favourable outcome even in patients with a very high operative risk. There were no perioperative deaths. Altogether forty patients treated at Kuopio University Hospital had a patent IMA on preoperative computed tomography (CT) and were treated successfully with coil embolization before EVAR. Thirty-nine patients who underwent EVAR at Oulu University Hospital without preoperative embolization of a patent IMA served as a control group. Preoperative coil embolization of the IMA significantly reduced the incidence of type II endoleaks after EVAR, but the present study failed to show any influence on late postoperative aneurysm sac shrinkage. Overall, 14 patients underwent a secondary intervention to repair the type II endoleak. Ten patients had transarterial embolization and four patients had translumbar embolization. The results were unsatisfactory; clinical success after the first secondary intervention was achieved in only two patients in the transarterial embolization group and three patients in the translumbar embolization group. These results seem to favour direct translumbar embolization rather than transarterial embolization. In conclusion, EVAR with the Zenith® stent-graft is effective in excluding AAAs from the circulation and is associated with good mid-term results.

Objectifs : caractériser (1) la morphométrie de la crosse afin d’examiner les critères favorisant les complications et la faisabilité d’endoprothèses (EP) standards. (2) les propriétés mécaniques de l’aorte ascendante (AA) chez le porc, homme sain et en cas de dissection aortique (DAo).Matériels et méthodes :Caractérisation morphométrique : A partir d’angioscanner aortiques les paramètres: (1) morphométriques élémentaires (2) géométriques ; (3) troncs supra-aortiques (TSAo), sont mesurésCaractérisation mécanique : In vivo : à partir de données échographiques et hémodynamiques, les paramètres élastiques sont calculés.In vitro : tests de traction bi-axiale sur l’AA plus une analyse histomorphométrique et microstructurale.Résultats :Caractérisation morphométrique : > de75% des patients ont une orientation des TSAo à ± 15° par rapport à la moyenne, et une variabilité de la distance entre les ostia TSAo de ± 4 mm.Les facteurs indépendants associés aux endofuites, défaut d’apposition et mal-positionnement sont respectivement:(1) collet proximal court; (2) angulation de la zone d’ancrage (valeur seuil 51°); et (3) indice tortuosité (valeur seuil 1.68) Caractérisation mécanique : In vivo : une grande compliance de l’aorte porcine comparé à l’homme et une rigidification en cas de DAo.In vitro : l’aorte porcine a un comportement linéaire comparé au caractère non linéaire chez l’homme. Conclusion : Ce travail montre :- le lien entre morphométrie et complications après EP, et la faisabilité d’EP standards pour la crosse.- le modèle porcin est inapproprié pour tester les EP de l’AA. - la rigidification de la paroi en cas de DAo influencera le choix des futurs EP. / Objectives: characterize (1) arch morphometry to examine criteria favoring complications after thoracic endovascular aortic repair (TEVAR) and feasibility of « off-the-shelf » fenestrated devices.(2) mechanical properties of ascending aorta (AA) in swine and humans, with and without aortic dissection.Materials and methods : Morphometric characterization : Computed tomographic angiography were analysed to calculate elementary morphometric, geometric and supra-aortic trunks data Mechanical characterization : In vivo: arterial pressure and diameters measured with echocardiophy are used to calculate elastic parameters.Ex vivo: biaxial tensile testing performed on AA plus histological and microstructural analysis. Results :Morphometric characterization : In > 75% of cases supra-aortic branches are positioned within 15° of each other and distances between them have a variability of ± 4 mm.Independant factors associated with endoleak, bird beak and mis-positioning are respectively : (1) short proximal neck (2) landing zone angulation (cut-off value: 51°); and (3) tortuosity index (cut-off value: 1.68). Mechanical characterization : in vivo: greater compliance of swine aorta compared to humans and a stiffer aorta in case of aortic dissectionBiaxial testing: linear stress-strain behavior of swine aorta, compared to a non linear one in human. Conclusion : our study reveals :- the impact of anatomy on complications occurrence after TEVAR, and suitable arguments for « off-the-shelf » fenestrated devices.- swine model is inappropriate to test AA dedicated stent-graft.- stiffer wall in aortic dissection has consequences on the choice of futur devices dedicated to AA.

High entropy alloys (HEAs) are alloys with five or more principal elements. Due to these distinct concept of alloying, the HEA exhibits unique and superior properties. The outstanding properties of HEA includes higher strength/hardness, superior wear resistance, high temperature stability, higher fatigue life, good corrosion and oxidation resistance. Such characteristics of HEA has been significant interest leading to researches on these emerging field. Even though many works are done to understand the characteristic of these HEAs, very few works are made on how the HEAs can be applied for commercial uses. This work discusses the application of High entropy alloys in biomedical applications. The coronary heart disease, the leading cause of death in the United States kills more than 350,000 persons/year and it costs $108.9 billion for the nation each year in spite of significant advancements in medical care and public awareness. A cardiovascular disease affects heart or blood vessels (arteries, veins and capillaries) or both by blocking the blood flow. As a surgical interventions, stent implants are deployed to cure or ameliorate the disease. However, the high failure rate of stents has lead researchers to give special attention towards analyzing stent structure, materials and characteristics. Many works related to alternate material and/or design are carried out in recent time. This paper discusses the feasibility of CoCrFeNiMn and Al0.1CoCrFeNi HEAs in stent implant application. This work is based on the speculation that CoCrFeNiMn and Al0.1CoCrFeNi HEAs are biocompatible material. These HEAs are characterized to determine the microstructure and mechanical properties. Computational modeling and analysis were carried out on stent implant by applying CoCrFeNiMn and Al0.1CoCrFeNi HEAs as material to understand the structural behavior.

OBJECTIVES The aim of this analysis was to assess the 7-year long-term safety and effectiveness of a randomized comparison of percutaneous coronary intervention (PCI) with sirolimus-eluting stents (SES) versus minimally invasive direct coronary artery bypass (MIDCAB) surgery for the treatment of isolated proximal left anterior descending lesions. BACKGROUND Long-term follow-up data comparing PCI by SES and MIDCAB surgery for isolated proximal left anterior descending lesions are sparse. METHODS Patients were randomized either to PCI with SES (n ¼ 65) or MIDCAB (n ¼ 65). Follow-up data were obtained after 7 years with respect to the primary composite endpoint of death, myocardial infarction, and target vessel revas- cularization. Angina was assessed by the Canadian Cardiovascular Society classification and quality of life with Short Form 36 and MacNew quality of life questionnaires. RESULTS Follow-up was conducted in 129 patients at a median time of 7.3 years (interquartile range: 5.7, 8.3). There were no significant differences in the incidence of the primary composite endpoint between groups (22% PCI vs. 12% MIDCAB; p ¼ 0.17) or the endpoints death (14% vs. 17%; p ¼ 0.81) and myocardial infarction (6% vs. 9%, p ¼ 0.74). However, the target vessel revascularization rate was higher in the PCI group (20% vs. 1.5%; p < 0.001). Clinical symptoms and quality of life improved significantly from baseline with both interventions and were similar in magnitude between groups. CONCLUSIONS At 7-year follow-up, PCI by SES and MIDCAB in isolated proximal left anterior descending lesions yielded similar long-term outcomes regarding the primary composite clinical endpoint and quality of life. Target vessel revascularization was more frequent in the PCI group. (Randomied Comparison of Minimally Invasive Direct Coronary Artery Bypass Grafting and Percutaneous Coronary Intervention With Drug-Eluting Stents in Patients With Proximal Stenosis of the Left Anterior Descending Coronary Artery; NCT00299429) (J Am Coll Cardiol Intv 2014;-:-–-) © 2014 by the American College of Cardiology Foundation.

No description available.

The coronary heart disease kills more than 350,000 persons/year and it costs $108.9 billion for the United States each year, in spite of significant advancements in clinical care and education for public, cardiovascular diseases (CVD) are leading cause of death and disability to the nation. A cardiovascular disease involves mainly heart or blood vessels (arteries, veins and capillaries) or both, and then mainly occurs in selected regions and affects heart, brain, kidney and peripheral arteries. As a surgical interventions, stent implantation is deployed to cure or ameliorate the disease. However, the high failure rate of stents used in patients with peripheral artery diseases has lead researchers to give special attention towards analyzing stent structure and characteristics. In this research, the mechanical properties of a stent based on the rhombus structure were analyzed and verified by means of analytical and numerical approaches. Theoretical model based on the beam theory were developed and numerical models were used to analyze the response of these structures under various and complex loading conditions. Moreover, the analysis of the stent inflation involves a model with large deformations and large strains, nonlinear material properties need to be considered to accurately capture the deformation process. The maximum stress values were found to occur in localized regions of the stent. These regions were generally found along the inner radii of each of the connected links connecting each of the longitudinal struts. Stress values throughout the whole stent were typically much lower. The peak engineering stress values were found to be less than the material ultimate strength (limit stress 515Mpa), indicating a safe stent design throughout expansion range. Lastly, the rheological behavior of blood can be quantified by non-Newtonian viscosity. Carreau model is introduced and simulates the situation in the artery, then the available shear stress in the model would help to the future analysis in the contact analysis of stent and the artery.

Background: Single-cohort studies suggest that second-generation stents (SGS; “mesh stents”) may improve carotid artery stenting (CAS) outcomes by limiting peri- and postprocedural cerebral embolism. SGS differ in the stent frame construction, mesh material, and design, as well as in mesh-to-frame position (inside/outside). Objectives: To compare clinical outcomes of SGS in relation to first-generation stents (FGSs; single-layer) in CAS. Methods: We performed a systematic review and meta-analysis of clinical studies with FGSs and SGS (PRISMA methodology, 3302 records). Endpoints were 30-day death, stroke, myocardial infarction (DSM), and 12-month ipsilateral stroke (IS) and restenosis (ISR). A random-effect model was applied. Results: Data of 68,422 patients from 112 eligible studies (68.2% men, 44.9% symptomatic) were meta-analyzed. Thirty-day DSM was 1.30% vs. 4.11% (p < 0.01, data for SGS vs. FGS). Among SGS, both Casper/Roadsaver and CGuard reduced 30-day DSM (by 2.78 and 3.03 absolute percent, p = 0.02 and p < 0.001), whereas the Gore stent was neutral. SGSs significantly improved outcomes compared with closed-cell FGS (30-day stroke 0.6% vs. 2.32%, p = 0.014; DSM 1.3% vs. 3.15%, p < 0.01). At 12 months, in relation to FGS, Casper/Roadsaver reduced IS (−3.25%, p < 0.05) but increased ISR (+3.19%, p = 0.04), CGuard showed a reduction in both IS and ISR (−3.13%, −3.63%; p = 0.01, p < 0.01), whereas the Gore stent was neutral. Conclusions: Pooled SGS use was associated with improved short- and long-term clinical results of CAS. Individual SGS types, however, differed significantly in their outcomes, indicating a lack of a “mesh stent” class effect. Findings from this meta-analysis may provide clinically relevant information in anticipation of large-scale randomized trials.

No description available.