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Christos V Bourantas - One of the best experts on this subject based on the ideXlab platform.
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impact of local endothelial shear stress on Neointima and plaque following stent implantation in patients with st elevation myocardial infarction a subgroup analysis of the comfortable ami ibis 4 trial
International Journal of Cardiology, 2015Co-Authors: Christos V Bourantas, Lorenz Raber, Serge Zaugg, Antonis I Sakellarios, Masanori Taniwaki, Dik Heg, Aris Moschovitis, Maria D Radu, Michail I PapafaklisAbstract:Abstract Background Numerous studies have demonstrated an association between endothelial shear stress (ESS) and Neointimal formation after stent implantation. However, the role of ESS on the composition of Neointima and underlying plaque remains unclear. Methods Patients recruited in the Comfortable AMI–IBIS 4 study implanted with bare metal stents (BMS) or biolimus eluting stents (BES) that had biplane coronary angiography at 13month follow-up were included in the analysis. The intravascular ultrasound virtual-histology (IVUS-VH) and the angiographic data were used to reconstruct the luminal surface, and the stent in the stented segments. Blood flow simulation was performed in the stent surface, which was assumed to represent the luminal surface at baseline, to assess the association between ESS and Neointima thickness. The predominant ESS was estimated in 3-mm segments and was correlated with the amount of Neointima, Neointimal tissue composition, and with the changes in the underlying plaque burden and composition. Results Forty three patients (18 implanted with BMS and 25 with BES) were studied. In both stent groups negative correlations were noted between ESS and Neointima thickness in BMS ( P P =0.002). In BMS there was a negative correlation between predominant ESS and the percentage of the Neointimal necrotic core component ( P =0.015). In BES group, the limited Neointima formation did not allow evaluation of the effect of ESS on its tissue characteristics. ESS did not affect vessel wall remodeling and the plaque burden and composition behind BMS ( P >0.10) and BES ( P >0.45). Conclusions ESS determines Neointimal formation in both BMS and BES and affects the composition of the Neointima in BMS. Conversely, ESS does not impact the plaque behind struts irrespective of stent type throughout 13months of follow-up.
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circumferential distribution of the Neointima at six month and two year follow up after a bioresorbable vascular scaffold implantation a substudy of the absorb cohort b clinical trial
Eurointervention, 2015Co-Authors: Christos V Bourantas, Vasim Farooq, Yaojun Zhang, Takashi Muramatsu, Bill D Gogas, Leif Thuesen, Dougal Mcclean, Bernard Chevalier, Stephan Windecker, Jacques J KoolenAbstract:Aims: To investigate the extent and the circumferential distribution of the Neointima tissue developed following an Absorb bioresorbable vascular scaffold (BVS) implantation. Methods and results: Twenty-three patients who were treated with the Absorb BVS and had optical coherence tomographic examination after scaffold implantation, at six-month and at two-year follow-up, were included in the current analysis. The lumen and the scaffold borders were detected and the circumferential thickness of the Neointima was measured at one degree intervals. The symmetry of the Neointima was defined as: minimum/maximum thickness. The lumen area was decreased at six months compared to baseline but it did not change between six-month and two-year follow-up (baseline: 7.49 [6.13-8.00] mm2, six months: 6.31 (4.75-7.06) mm2, two years: 6.01 [4.67-7.11] mm2, p=0.373). However, the mean Neointima thickness (six months: 189 [173-229] μm, two years: 258 [222-283] μm, p<0.0001) and the symmetry index of the Neointima (six months: 0.06 [0.02-0.09], two years: 0.27 [0.24-0.36], p<0.0001) were increased at two years. Full circumferential coverage of the vessel wall by Neointima tissue was seen in 91% of the studied frames at two years. Conclusions: This study demonstrates that after an Absorb BVS implantation Neointima tissue develops that covers almost the whole circumference of the vessel wall. In contrast to the metallic stents, the Neointima tissue does not compromise the luminal dimensions. Further research is required to evaluate the Neointimal characteristics and assess the potential value of the device in passivating high-risk plaques.
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effect of the endothelial shear stress patterns on Neointimal proliferation following drug eluting bioresorbable vascular scaffold implantation an optical coherence tomography study
Jacc-cardiovascular Interventions, 2014Co-Authors: Christos V Bourantas, Michail I Papafaklis, Vasim Farooq, Yaojun Zhang, Takashi Muramatsu, Anna Kotsia, Josep Gomezlara, Javaid Iqbal, Fanis G Kalatzis, Katerina K NakaAbstract:Objectives This study sought to investigate the effect of endothelial shear stress (ESS) on Neointimal formation following an Absorb bioresorbable vascular scaffold (BVS) (Abbott Vascular, Santa Clara, California) implantation. Background Cumulative evidence, derived from intravascular ultrasound–based studies, has demonstrated a strong association between local ESS patterns and Neointimal formation in bare-metal stents, whereas in drug-eluting stents, there are contradictory data about the effect of ESS on the vessel wall healing process. The effect of ESS on Neointimal development following a bioresorbable scaffold implantation remains unclear. Methods Twelve patients with an obstructive lesion in a relatively straight arterial segment, who were treated with an Absorb BVS and had serial optical coherence tomographic examination at baseline and 1-year follow-up, were included in the current analysis. The optical coherence tomographic data acquired at follow-up were used to reconstruct the scaffolded segment. Blood flow simulation was performed on the luminal surface at baseline defined by the Absorb BVS struts, and the computed ESS was related to the Neointima thickness measured at 1-year follow-up. Results At baseline, the scaffolded segments were exposed to a predominantly low ESS environment (61% of the measured ESS was Conclusions The hemodynamic microenvironment appears to regulate Neointimal response following an Absorb BVS implantation. These findings underline the role of the ESS patterns on vessel wall healing and should be taken into consideration in the design of bioresorbable devices.
Toyoaki Murohara - One of the best experts on this subject based on the ideXlab platform.
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new endoplasmic reticulum stress regulator gipie regulates the survival of vascular smooth muscle cells and the Neointima formation after vascular injury
Arteriosclerosis Thrombosis and Vascular Biology, 2015Co-Authors: Tomonori Noda, Kengo Maeda, Shinji Hayano, Naoya Asai, Atsushi Enomoto, Masahide Takahashi, Toyoaki MuroharaAbstract:Objective— The accumulation of unfolded protein in the endoplasmic reticulum (ER) initiates an adaptive stress response, termed the unfolded protein response. Previous studies suggested that ER stress might be involved in the formation of Neointima after vascular injury. We recently discovered a novel regulator of ER stress, 78-kDa glucose-regulated protein–interacting protein induced by ER stress (Gipie). The objective of this study was to elucidate the role of Gipie using models of vascular disease. Approach and Results— We investigated the functions of Gipie in cultured vascular smooth muscle cells (VSMCs) and in a vascular injury model of a rat carotid artery. The expression of Gipie was predominantly detected in synthetic VSMCs and to a much lesser extent in contractile VSMCs, which was augmented by treatment with thapsigargin. Gipie knockdown increased the phosphorylation levels of c-Jun N-terminal kinase and the number of apoptotic cells under ER stress. Moreover, Gipie knockdown decreased the mature form of collagen I in synthetic VSMCs. The expression of Gipie was rarely detected in the medial VSMCs of the intact carotid artery, whereas it was detected in most of the Neointimal cells and some of the medial VSMCs after balloon injury. Depletion of Gipie in the rat carotid artery attenuated the Neointimal thickening, which was accompanied by increased cell death in the Neointima. Conversely, overexpression of Gipie augmented the Neointimal thickening. Conclusions— Gipie participates in the ER stress response in VSMCs and plays an important role in Neointima formation after vascular injury. # Significance {#article-title-30}
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Disruption of Atherosclerotic Neointima as a Cause of Very Late Stent Thrombosis After Bare Metal Stent Implantation
American Journal of Cardiology, 2011Co-Authors: Hirohiko Ando, Daiji Yoshikawa, Tetsuya Amano, Tadayuki Uetani, Hideki Ishii, Toyoaki MuroharaAbstract:A male who were implanted bare metal stent 11 years ago were admitted for acute coronay syndrome. Optical coherence tomography showed a Neointimal disruption and integrated backscatter intravascular ultrasound revealed a lipid pool around the disrupted Neointima, suggesting newly formed atherosclerotic Neointima developed after bare metal stent implantation. The disruption of atherosclerotic Neointima may represent a new potential mechanism of very late stent thrombosis after bare metal stent implantation.
Gary S Mintz - One of the best experts on this subject based on the ideXlab platform.
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atorvastatin accelerates both Neointimal coverage and re endothelialization after sirolimus eluting stent implantation in a porcine model new findings from optical coherence tomography and pathology
Circulation, 2012Co-Authors: Tianjie Wang, Yuejin Yang, Yi Tian, Bo Xu, Qian Bo-zhang, Yue Tang, Gary S MintzAbstract:BACKGROUND: Delayed vessel healing after drug-eluting stent implantation is thought to be the underlying mechanisms of late stent thrombosis (LST). METHODS AND RESULTS: In the animal model of stenting, 45 minipigs were divided into 3 groups (n=15 each): bare metal stent (BMS), sirolimus-eluting stent (SES), and SES plus atorvastatin treatment (SES+ator). Neointimal coverage and endothelium coverage were evaluated separately by optical coherence tomography (OCT), pathology, and scanning electron microscopy (SEM) at days 7, 14 and 28. OCT showed that SES significantly delayed Neointimal coverage compared with BMS and the percentage of uncovered struts in the SES+ator group was significantly decreased on days 7 (42.7±1.3% vs. 56.8±5.7%, P<0.01) and 14 (24.8±4.3% vs. 45.3±2.8%, P<0.01) compared with the SES group. However, re-endothelialization was even more seriously delayed than Neointima formation after SES deployment (P<0.05). Pathology and SEM revealed improved re-endothelialization of the Neointima with atorvastatin therapy in terms of more struts covered by endothelium, less platelet adhesion, and higher endothelial nitric oxide synthase expression of the endothelial cells in the SES+ator group. Flow cytometry illustrated that the SES+ator group had more mobilized endothelial progenitor cells (EPCs) compared with the SES group at day 7 (0.21±0.02% vs. 0.11±0.03%, P=0.022). CONCLUSIONS: Atorvastatin pretreatment can accelerate both Neointimal coverage and re-endothelialization after SES implantation, which may be mediated by the mobilization of EPC and enhancement of the endothelial function of the Neointima.
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optical coherence tomographic analysis of in stent neoatherosclerosis after drug eluting stent implantation
Circulation, 2011Co-Authors: Soojin Kang, Dukwoo Park, Takashi Akasaka, Seongwook Park, Gary S Mintz, Seungjung ParkAbstract:Background—We report findings from optical coherence tomography (OCT) of in-stent neoatherosclerosis as a cause of drug-eluting stent (DES) failure. Methods and Results—Optical coherence tomography and grayscale and virtual histology intravascular ultrasound were performed in 50 patients (30 stable, 20 unstable angina) with 50 DES in-stent restenosis lesions and intimal hyperplasia >50% of stent area. Median follow-up time was 32.2 months. Overall, 26 lesions (52%) had at least 1 OCT-defined in-stent thin-cap fibroatheroma (TCFA)–containing Neointima and 29 (58%) had at least 1 in-stent Neointimal rupture. Patients presenting with unstable angina showed a thinner fibrous cap (55 μm [interquartile range 42 to 105 μm] versus 100 μm [interquartile range 60 to 205 μm], P=0.006) and higher incidence of OCT-defined TCFA-containing Neointima (75% versus 37%, P=0.008), intimal rupture (75% versus 47%, P=0.044), thrombi (80% versus 43%, P=0.010), and red thrombi (30% versus 3%, P=0.012) than stable patients. Fibro...
Robert S Schwartz - One of the best experts on this subject based on the ideXlab platform.
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Pressure rinsing of coronary stents immediately before implantation reduces inflammation and Neointimal hyperplasia.
Journal of the American College of Cardiology, 2001Co-Authors: Antoni Bayes-genis, Michael A. Jorgenson, Allan R Camrud, Kristen L. Shogren, Janis L Donovan, David R Holmes, Robert S SchwartzAbstract:Abstract OBJECTIVES This study evaluates whether rinsing stents with high pressure immediately before implantation minimizes stent-induced inflammation and Neointimal formation. BACKGROUND Several reports indicate that manual stent manipulation before implantation results in foreign body contamination and increased Neointimal hyperplasia. METHODS A stent-cleaning chamber was developed to rinse stents at a sustained hydrodynamic pressure of 4 atm for 10 s. Commercial pre-mounted stents were examined with different levels of manipulation: 1) untouched stents: no stent manipulation before implantation; 2) handled stents: manual stent re-crimping on the balloon; 3) rinsed stents: pressure-rinsed with the stent-cleaning chamber. In vitro surface analysis was evaluated by scanning electron microscopy. Neointimal hyperplasia and inflammation around stent struts were also assessed in the pig in-stent restenosis model. RESULTS In vitro analysis revealed fewer contaminants on rinsed stents compared with untouched (p = 0.01) and handled stents (p CONCLUSIONS Rinsing stents under high pressure immediately before coronary implantation results in less inflammation around struts and thinner Neointima at 28 days in this pig model.
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artery size Neointima and remodeling time for some standards
Journal of the American College of Cardiology, 1998Co-Authors: Robert S Schwartz, Eric J Topol, Patrick W Serruys, Giuseppe Sangiorgi, David R HolmesAbstract:Controversy continues regarding the mechanism of coronary restenosis. While Neointimal thickening was initially considered the major cause, recent studies suggest that changes in arterial size, or remodeling, plays an important or even dominant role in late lumen loss. Moreover, Neointimal thickness and remodeling may be interrelated. The field has been complicated by the fact that remodeling analyses have not used consistent definitions or methods. In this editorial we thus describe a quantitative paradigm for remodeling analyses: as arterial plaque or Neointima forms in an artery, it is accompanied by luminal encroachment, artery expansion or gradations of either. In this manner, remodeling is generally defined as any arterial size change (enlargement or contraction), independent or dependent of Neointimal thickening. Standardization of definitions and quantitative methods may improve understanding of the components of restenosis resulting from artery size changes, Neointimal thickening and their impact on lumen size.
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effect of external beam irradiation on Neointimal hyperplasia after experimental coronary artery injury
Journal of the American College of Cardiology, 1992Co-Authors: Robert S Schwartz, Thomas M Koval, Allan R Camrud, Kevin Browne, Ronald E Vlietstra, William D Edwards, Kent R. Bailey, David R HolmesAbstract:Abstract Human coronary artery restenosis after percutaneous revascularization is a response to mechanical injury. Smooth muscle cell proliferation is a major component of restenosis, resulting in obstructive Neointimal hyperplasia. Because ionizing radiation inhibits cellular proliferation, this study tested in a porcine coronary injury model the hypothesis that the hyperplastic response to coronary artery injury would be attenuated by X-irradiation. Deep arterial injury was produced in 37 porcine left anterior descending coronary artery segments with overexpanded, percutaneously delivered tantalum wire coils. Three groups of pigs were irradiated with 300-kV X-rays after coil injury: Group I (n = 10), 400 cGy at 1 day; Group II (n = 10), 400 cGy at 1 day and 400 cGy at 4 days and Group III (n = 9), 800 cGy at 1 day. Eight pigs in the control group underwent identical injury but received no radiation. Treatment efficacy was histologically assessed by measuring Neointimal thickness and percent area stenosis. Mean Neointimal thickness in all irradiated groups was significantly higher than in the control groups and thickness was proportional to X-ray dose. X-irradiation delivered at these doses and times did not inhibit proliferative Neointima. Rather, it accentuated the Neointimal response to acute arterial injury and may have potentiated that injury.
Michail I Papafaklis - One of the best experts on this subject based on the ideXlab platform.
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impact of local endothelial shear stress on Neointima and plaque following stent implantation in patients with st elevation myocardial infarction a subgroup analysis of the comfortable ami ibis 4 trial
International Journal of Cardiology, 2015Co-Authors: Christos V Bourantas, Lorenz Raber, Serge Zaugg, Antonis I Sakellarios, Masanori Taniwaki, Dik Heg, Aris Moschovitis, Maria D Radu, Michail I PapafaklisAbstract:Abstract Background Numerous studies have demonstrated an association between endothelial shear stress (ESS) and Neointimal formation after stent implantation. However, the role of ESS on the composition of Neointima and underlying plaque remains unclear. Methods Patients recruited in the Comfortable AMI–IBIS 4 study implanted with bare metal stents (BMS) or biolimus eluting stents (BES) that had biplane coronary angiography at 13month follow-up were included in the analysis. The intravascular ultrasound virtual-histology (IVUS-VH) and the angiographic data were used to reconstruct the luminal surface, and the stent in the stented segments. Blood flow simulation was performed in the stent surface, which was assumed to represent the luminal surface at baseline, to assess the association between ESS and Neointima thickness. The predominant ESS was estimated in 3-mm segments and was correlated with the amount of Neointima, Neointimal tissue composition, and with the changes in the underlying plaque burden and composition. Results Forty three patients (18 implanted with BMS and 25 with BES) were studied. In both stent groups negative correlations were noted between ESS and Neointima thickness in BMS ( P P =0.002). In BMS there was a negative correlation between predominant ESS and the percentage of the Neointimal necrotic core component ( P =0.015). In BES group, the limited Neointima formation did not allow evaluation of the effect of ESS on its tissue characteristics. ESS did not affect vessel wall remodeling and the plaque burden and composition behind BMS ( P >0.10) and BES ( P >0.45). Conclusions ESS determines Neointimal formation in both BMS and BES and affects the composition of the Neointima in BMS. Conversely, ESS does not impact the plaque behind struts irrespective of stent type throughout 13months of follow-up.
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effect of the endothelial shear stress patterns on Neointimal proliferation following drug eluting bioresorbable vascular scaffold implantation an optical coherence tomography study
Jacc-cardiovascular Interventions, 2014Co-Authors: Christos V Bourantas, Michail I Papafaklis, Vasim Farooq, Yaojun Zhang, Takashi Muramatsu, Anna Kotsia, Josep Gomezlara, Javaid Iqbal, Fanis G Kalatzis, Katerina K NakaAbstract:Objectives This study sought to investigate the effect of endothelial shear stress (ESS) on Neointimal formation following an Absorb bioresorbable vascular scaffold (BVS) (Abbott Vascular, Santa Clara, California) implantation. Background Cumulative evidence, derived from intravascular ultrasound–based studies, has demonstrated a strong association between local ESS patterns and Neointimal formation in bare-metal stents, whereas in drug-eluting stents, there are contradictory data about the effect of ESS on the vessel wall healing process. The effect of ESS on Neointimal development following a bioresorbable scaffold implantation remains unclear. Methods Twelve patients with an obstructive lesion in a relatively straight arterial segment, who were treated with an Absorb BVS and had serial optical coherence tomographic examination at baseline and 1-year follow-up, were included in the current analysis. The optical coherence tomographic data acquired at follow-up were used to reconstruct the scaffolded segment. Blood flow simulation was performed on the luminal surface at baseline defined by the Absorb BVS struts, and the computed ESS was related to the Neointima thickness measured at 1-year follow-up. Results At baseline, the scaffolded segments were exposed to a predominantly low ESS environment (61% of the measured ESS was Conclusions The hemodynamic microenvironment appears to regulate Neointimal response following an Absorb BVS implantation. These findings underline the role of the ESS patterns on vessel wall healing and should be taken into consideration in the design of bioresorbable devices.
