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Objectives: We aimed to compare bare-metal stents (BMS), durable-polymer everolimus-eluting stents (DP-EES), and abluminal biodegradable-polymer sirolimus-eluting stents (ABP-SES) in the bifurcation model setup., Background: The mechanism of thrombogenicity, which differs among second-generation stents implanted using double-kissing (DK) crush or culotte stenting techniques, remains unclear. We have shown previously that setting up a porcine arteriovenous shunt model is feasible and useful to assess thrombogenicity at vessel bifurcation points., Methods: Six porcine shunt models were prepared for the comparison between DK crush and culotte stenting techniques using BMS, DP-EES, and ABP-SES. Intracoronary imaging with high-resolution optical coherence tomography (OCT) was performed to evaluate the thrombogenicity in different stent types in the bifurcation stenting model and was evaluated by a core lab., Results: Culotte stenting demonstrated more thrombogenicity at the proximal main branch (MB) with DP-EES, side branch (SB) with BMS, and the bifurcation site irrespective of the stent type, while DK crush technique exhibited thrombogenicity only at SB with BMS and ABP-SES. OCT analysis revealed malapposition of DP-EES in the proximal MB with culotte stenting. Stent expansion was generally larger in ABP-SES than BMS and DP-EES., Conclusions: The study provides hypothesis-generating findings in distinct thrombogenicity of bifurcation stenting with DP- or ABP-coated drug-eluting stents., (© 2022 Wiley Periodicals LLC.)

Background: Double kissing (DK) crush stenting has been reported as a superior bifurcation stenting strategy compared to culotte stenting. However, the mechanism associated with the reduction of clinical events by DK crush stenting remains unclear. We therefore investigated the thrombogenicity of DK crush stenting and culotte stenting with both bare-metal stents (BMS) and drug-eluting stents (DES) and the feasibility of a novel porcine arteriovenous shunt model., Methods: High-resolution intracoronary imaging with optical coherence tomography (OCT) evaluated the bifurcation stenting models for thrombogenicity., Results: All porcine models retained continuous circulation without blood leakage. Thrombus was macroscopically demonstrated around the bifurcation in all settings. The volume of thrombus (mm 3 ) with BMS using DK crush/culotte and DES using DK crush/culotte were 1.38/1.19 and 0.09/0.15, respectively. Culotte stenting had more thrombus in the proximal main branch, and DK crush stenting had more at the bifurcation. Unlike DK crush stenting, culotte stenting showed malapposition in the proximal main branch and bifurcation segments., Conclusion: The feasibility of a porcine arteriovenous shunt model to assess thrombogenicity by OCT in bifurcation stenting technique was confirmed. OCT detected less thrombogenicity in DES when used in the bifurcation model when compared to BMS., (Copyright © 2019 Elsevier Inc. All rights reserved.)

Following the December 2018 publication of a meta-analysis by Katsanos et al reporting higher rates of long-term mortality with the utilization of paclitaxel-related devices (balloons and stents) when compared to control in femoropopliteal arteries, the US Food and Drug Administration (FDA) issued a safety alert in January 2019 and further detailed the implications for future clinical use of these devices in March 2019. The FDA convened a public meeting of the Circulatory System Devices Panel of the Medical Devices Advisory Committee in June 2019. This report summarizes the proceedings of this meeting and the panel's response to the 12 questions posed by the FDA related to the potentially increased late mortality of drug-coated balloons and drug-eluting stents with paclitaxel in patients with peripheral arterial disease., (Copyright © 2019 Elsevier Inc. All rights reserved.)

The development of bare metal coronary stents revolutionized the treatment of coronary artery disease by reducing rates of acute vessel closure and restenosis associated with balloon angioplasty. However, bare metal stents (BMS) resulted in high rates of restenosis and led to the development of drug-eluting stents (DES). Those first-generation DES were followed by successive generations of DES that included improvements, such as biodegradable and more biocompatible polymers. Despite the superiority of the current DES compared to BMS, a subset of patients still receives BMS. The following paper reviews the literature comparing the safety and efficacy of newer generation DES to BMS in such patients and ultimately challenges the use of BMS in contemporary current DES era., (Copyright © 2017 Elsevier Inc. All rights reserved.)

Purpose: To report a case of a thrombosed GORE® VIABAHN® endoprosthesis stent-graft in the femoral artery (SFA) and popliteal artery managed using the pulse-spray technique and complicated by compartment syndrome of the lower leg of the affected limb., Case Report: A 61-year-old woman with three Viabahn stent grafts relining seven bare-metal stents in her right SFA and popliteal artery visited our hospital with complaint of recurrent lifestyle-limiting claudication of right leg. Angiography and intravascular ultrasound showed complete intra-stent obstruction by thrombus from the proximal right SFA to the proximal popliteal artery. Catheter-directed thrombolysis using pulse-spray technique followed by mechanical thrombectomy was performed. Despite successful recanalization, unfortunately, compartment syndrome developed on her right leg on the following day and fasciotomy was performed., Conclusion: The larger thrombus burden in Viabahn stent-grafts and its unique physicochemical properties increases the risk for distal embolic complications and potential poor clinical outcomes., (Copyright © 2016 Elsevier Inc. All rights reserved.)

Although metallic coronary stents significantly reduce angina pectoris compared with optimal medical therapy, angina after percutaneous coronary intervention (PCI) remains frequent. We, therefore, sought to compare the incidence of any angina during the 1 year after PCI among the spectrum of commercially available metallic stents. Metallic stent type was classified as bare metal stent, Cypher, Taxus Express, Xience V, Promus Element, and Resolute. The primary end point was patient-reported angina within 1 year of PCI. Multivariable logistic regression was performed to assess the independent association of stent type with any angina at 1 year. Overall, 8,804 patients were queried in regard to angina symptoms; 32.3% experienced angina at some point in the first year after PCI. Major adverse cardiovascular events, a composite of all-cause mortality, target vessel revascularization, and Q-wave myocardial infarction, increased with angina severity: 6.8% for patients without angina, 10.0% for patients with class 1 or 2 angina, and 19.7% for patients with class 3 or 4 angina (p <0.001 for trend). After multivariable adjustment, there was no significant association between stent type and angina at 1 year after PCI. Baseline Canadian Cardiovascular Society class 3 or 4 angina, history of coronary artery bypass grafting, and history of PCI were associated with a higher likelihood of angina at 1 year; increasing age, male gender, presentation with acute coronary syndrome, and higher stented length were associated with less angina. In conclusion, metallic stent type is not associated with the occurrence of angina at up to 1 year after PCI., (Copyright © 2016 Elsevier Inc. All rights reserved.)

Background: Clinical presentation of bare metal stent in-stent restenosis (ISR) in patients undergoing target lesion revascularization is well characterized and negatively affects on outcomes, whereas the presentation and outcomes of first- and second-generation drug-eluting stents (DESs) remains under-reported., Methods and Results: The study included 909 patients (1077 ISR lesions) distributed as follows: bare metal stent (n=388), first-generation DES (n=425), and second-generation DES (n=96), categorized into acute coronary syndrome (ACS) or non-ACS presentation mode at the time of first target lesion revascularization. ACS was further classified as myocardial infarction (MI) and unstable angina. For bare metal stent, first-generation DES and second-generation DES, ACS was the clinical presentation in 67.8%, 71.0%, and 66.7% of patients, respectively (P=0.470), whereas MI occurred in 10.6%, 10.1%, and 5.2% of patients, respectively (P=0.273). The correlates for MI as ISR presentation were current smokers (odds ratio, 3.02; 95% confidence interval [CI], 1.78-5.13; P<0.001), and chronic renal failure (odds ratio, 2.73; 95% CI, 1.60-4.70; P<0.001), with a protective trend for the second-generation DES ISR (odds ratio, 0.35; 95% CI, 0.12-1.03; P=0.060). ACS presentations had an independent effect on major adverse cardiac events (death, MI, and re-target lesion revascularization) at 6 months (MI versus non-ACS: adjusted hazard ratio, 4.06; 95% CI, 1.84-8.94; P<0.001; unstable angina versus non-ACS: adjusted hazard ratio, 1.98; 95% CI, 1.01-3.87; P=0.046)., Conclusions: ISR clinical presentation is similar irrespective of stent type. MI as ISR presentation seems to be associated with patient and not device-related factors. ACS as ISR presentation has an independent effect on major adverse cardiac events, suggesting that ISR remains a hazard and should be minimized., (© 2014 American Heart Association, Inc.)

Background: High on-treatment platelet reactivity (HTPR) has been shown to be associated with adverse cardiac events in patients undergoing percutaneous coronary intervention, but the effect of baseline hematologic parameters upon platelet reactivity remains controversial., Objective: The present study aims to evaluate the impact of hematocrit on 2 different assay methods used to assess on-treatment platelet reactivity to clopidogrel., Methods: We tested clopidogrel on-treatment platelet reactivity in 466 consecutive patients using VerifyNow P2Y12 (VN) and light transmission aggregometry (LTA) with adenosine diphosphate (ADP) 5 and 20 μM assays 6 to 24 hours after percutaneous coronary intervention. Patients were categorized into 4 groups according to baseline hematocrit. One-year major adverse cardiac events, including death, nonfatal myocardial infarction, and definite stent thrombosis, were collected., Results: Lower hematocrit was associated with higher P2Y12 reaction unit (PRU) and a higher rate of HTPR (P < .001) as measured by VN assay. No differences were seen among the 4 groups in platelet reactivity measured by LTA using ADP 5 μM (P = .23) and ADP 20 μM (P = .21). In a multivariable logistic regression model, baseline hematocrit was independently associated with PRU ≥208 (odds ratio [OR] 0.92, 95% CI 0.86-0.97, P = .005) but had no correlation with LTA ADP 5 μM ≥46% (OR 1.0, 95% CI 0.95-1.06, P = .88) or LTA ADP 20 μM ≥59% (OR 1.03, 95% CI 0.97-1.09, P = .39). In a logistic regression model, the addition of VN assay results, hematocrit, and interaction between the hematocrit and assay results had shown a significant influence on the area under curve for prediction of 1-year major adverse cardiac events compared with baseline clinical variables only for PRU (0.63 vs 0.76, P = .006) but not with LTA (0.64 vs 0.74, P = .13)., Conclusion: Baseline hematocrit has a differential influence on results of the ex vivo platelet functional assays. Lower baseline hematocrit was independently associated with HTPR by VN but not LTA. This may affect the interpretation of platelet function testing in patients with significant anemia., (Copyright © 2014 Mosby, Inc. All rights reserved.)

Objective: To evaluate the axial integrity of different coronary stents using intravascular ultrasound (IVUS)., Background: Longitudinal stent deformation was recently reported., Methods: Consecutive patients who underwent IVUS analysis after drug-eluting stent (DES) implantation for de novo coronary lesions were evaluated. Stent length was compared with label length for calculation of absolute change and relative difference (absolute change divided by label length)., Results: A total of 233 DES utilizing five different platforms were included. The median absolute change in stent length was 0.90 mm (interquartile range [IQR] 0.48-1.39) and the relative difference was 5.24% (IQR 2.55-8.29). There was no significant difference among the groups in median absolute or relative change: Cypher 0.89 mm/3.89%, Taxus 0.88 mm/5.39%, Endeavor 1.16 mm/6.77%, Xience V 0.86 mm/5.80%, and PROMUS Element 0.79 mm/5.34% (P = 0.085, P = 0.072, respectively). Multivariate logistic regression revealed that the Cypher stent was independently correlated with a lower change in length, whereas stent label length and deployment pressure were correlated with higher absolute change., Conclusion: The axial integrity of DES platforms examined in vivo was high, with only mild changes in stent length after implantation. While there are differences between first- and second-generation DES, axial integrity among second-generation DES was similar., (© 2013 Wiley Periodicals, Inc.)

Objective: Recent studies have suggested that metformin may inhibit endothelialization following limus-eluting stent (LES) placement and may increase the risk of stent thrombosis. Therefore, we assessed the impact of metformin on stent thrombosis and major adverse cardiovascular events (MACE) in non-insulin-dependent diabetes mellitus (NIDDM) patients who receive drug-eluting stents (DES)., Methods: We assessed the impact of metformin and stent type on stent thrombosis, MACE, and death in NIDDM patients following DES placement. Of the 1201 patients included, 74.8% received LES, 25.2% received paclitaxel-eluting stents (PES), and 55% were taking metformin., Results: There was no difference in stent thrombosis, regardless of stent type or metformin use. While Kaplan-Meier curves demonstrated reduced MACE (p = 0.007) and death (p = 0.006) with metformin use, multivariate analysis demonstrated that stent type and metformin use were not associated with outcome., Conclusion: In NIDDM patients, metformin use or stent type following DES placement did not increase stent thrombosis and MACE rates., (Copyright © 2014 Elsevier Ireland Ltd. All rights reserved.)

Percutaneous coronary intervention in the setting of acute myocardial infarction is known to predict stent thrombosis (ST). This study aims to compare the ST rates across different coronary subsets. This was an observational cohort study from a large, single-center registry. Included were 12,198 consecutive patients who underwent percutaneous coronary intervention with stenting. Patients were categorized according to their clinical presentation: stable angina pectoris (SAP, n = 3,700), unstable angina pectoris (UAP, n = 2,845), non-ST-segment elevation myocardial infarction (NSTEMI, n = 4,083), and ST-segment elevation myocardial infarction (STEMI, n = 1,570). The study end points were ST rates at 1 year. Patients with STEMI were younger with a lower prevalence of cardiovascular risk factors, except for smoking. More type C lesions were treated in STEMI, whereas drug-eluting stents were used less frequently in patients with STEMI compared with the other groups. Definite ST at 1 year was highest in patients with STEMI (1.4%; vs SAP, 0.4%; UAP, 0.5%; NSTEMI, 0.5%; p <0.001). One-year definite/probable ST rates were SAP, 0.8%; UAP, 1.1%; NSTEMI, 1.4%; and STEMI, 3.2% (p <0.001). On multivariable analysis, STEMI independently predicts definite ST (hazards ratio [HR] 3.07, 95% confidence interval [CI] 1.32 to 7.10), whereas both STEMI (HR 3.36, 95% CI 1.84 to 6.12) and NSTEMI (HR 2.04, 95% CI 1.20 to 3.07) were independent predictors of definite/probable ST. Clopidogrel cessation was the strongest predictor of ST (definite ST, HR 17.00, 95% CI 7.54 to 38.31; definite/probable ST, HR 4.69, 95% CI 2.39 to 9.20). In conclusion, in patients who underwent percutaneous coronary intervention, the acuity of clinical presentation corresponds to an increase in ST incidence. Adherence to clopidogrel is critical to prevent ST in patients who underwent percutaneous coronary intervention, especially in STEMI., (Copyright © 2014 Elsevier Inc. All rights reserved.)

Percutaneous coronary intervention (PCI) has rapidly evolved over the past 30 years as technology has sought to improve clinical outcomes by addressing pathophysiologic complications arising from the intervention. Stents were designed to resolve the drawbacks of balloon angioplasty by providing radial support to prevent vessel recoil, by sealing coronary dissections, and by preventing abrupt vessel closure. The conceptualization of an ideal drug-eluting fully bioresorbable scaffold (BRS), whether metallic or polymeric, would theoretically address the adverse aspects of permanent metallic stents. In this review of the literature, we will discuss the impact these novel fully BRS platforms have on vascular pathophysiology following PCI.

Objective: We aimed to compare neointimal tissue characteristics between bare-metal stents (BMS) and drug-eluting stents (DES) at long-term follow-up using optical coherence tomography (OCT) and virtual histology intravascular ultrasound (VH-IVUS)., Background: Neoatherosclerosis in neointima has been reported in BMS and in DES., Methods: Thirty patients with 36 stented lesions [BMS (n=17) or DES (n=19)] >3years after implantation were prospectively enrolled. OCT and VH-IVUS were performed and analyzed independently. Stents with ≥70% diameter stenosis were excluded., Results: The median duration from implantation was 126.0months in the BMS group and 60.0months in the DES group (p <0.001). Lipid-laden intima (58.8% vs. 42.1%, p=0.317), thrombus (17.6% vs. 5.3%, p=0.326), and calcification (35.3% vs. 26.3%, p=0.559) did not show significant differences between BMS and DES. When divided into 3 time periods, the cumulative incidence of lipid-laden neointima from >3years to <9years was similar between BMS and DES (42.9% vs. 42.1%, p=1.000). Furthermore, it continued to gradually increase over time in both groups. OCT-derived thin-cap fibroatheroma (TCFA) was observed in 17.6% of BMS- and 5.3% of DES-treated lesions (p=0.326). No stents had evidence of intimal disruption. The percentage volume of necrotic core (16.1% [9.7, 20.3] vs. 9.7% [7.0, 16.5], p=0.062) and dense calcium (9.5% [3.8, 13.6] vs. 2.7% [0.4, 4.9], p=0.080) in neointima tended to be greater in BMS-treated lesions. Intra-stent VH-TCFA (BMS vs. DES 45.5% vs. 18.2%, p=0.361) did not differ significantly., Conclusion: At long-term follow-up beyond 3 years after implantation, the intra-stent neointimal tissue characteristics appeared similar for both BMS and DES., (Copyright © 2014 Elsevier Inc. All rights reserved.)

Over the last decade, the introduction of drug-eluting stents has dramatically reduced restenosis and the need for repeat revascularization after implantation of metallic stents. Numerous concerns still remain, however, because of their permanent nature. Thus, the concept of bioresorbable temporary scaffolds composed of biocompatible materials has emerged as a potential alternative to permanent metal stents. Here we focus on metal alloys & discuss preclinical and clinical experiences with bioresorbable metal scaffolds., (Copyright © 2014. Published by Elsevier Inc.)

Objectives: This study aimed to compare percutaneous coronary intervention (PCI) with direct stenting (DS) to balloon predilatation (PD) for patients undergoing elective PCI to determine whether there is an independent value for DS with regard to clinical outcomes., Background: The safety of PCI with DS has been established, but the independent advantages of this technique are not entirely clear., Methods: Patients undergoing elective PCI from January 2000 to December 2010 were included. The postprocedural and late clinical outcomes of 444 patients who underwent PCI with DS were compared with a propensity-matched population of 444 subjects treated with PD., Results: The two groups were well matched to 27 baseline clinical, procedural, and angiographic characteristics, thus allowing for a more accurate evaluation of the independent value of the stenting technique. Intravascular ultrasound was used in more than 60% of interventions in both groups. PCI performed with PD were longer (DS 45 ± 19.28 vs. PD 56 ± 23.72 minutes, P = 0.001), used more contrast (DS 154 ± 65.88 vs. PD 186 ± 92.84 cc, P = 0.001), and more frequently used balloon postdilation (DS 0% vs. PD 27.3%, P = 0.001). The incidence of periprocedural myocardial infarction (PPMI) was similar between DS- and PD patients (5.3% vs. 5.4%, P = 0.91). Likewise, the 1-year rates of major adverse cardiac events (8.4% vs. 6.3%, P = 0.25), target lesion revascularization (3.9% vs. 2.5%, P = 0.24), and definite stent thrombosis (0.2% vs. 0.9%, P = 0.37) were similar among DS and PD patients, respectively., Conclusion: During elective PCI, DS decreases overall procedure time and resource utilization, but fails to reveal an independent clinical advantage as there is no demonstrable benefit in regard to the incidence of PPMI, restenosis, or overall clinical outcomes up to 1-year of follow-up., (Copyright © 2013 Wiley Periodicals, Inc.)

VIABAHN® endoprosthesis (Gore & Associates, Flagstaff, AZ), a nitinol self-expanding polytetrafluoroethylene (PTFE) lined stent, has demonstrated utility for percutaneous treatment of chronic occlusive disease involving the superficial femoral artery. In a case series communication we aimed to describe the feasibility of a PTFE-lined stent for percutaneous treatment of conditions other than chronic occlusive disease. We report the successful use of PTFE-endoprosthesis to percutaneously treat several vascular conditions, including arterio-venous fistula closure, reconstruction of a distal limb of an aorto-femoral endoprosthesis aneurysm, femoral artery perforation repair, and an exclusion of large saphenous vein graft aorto-coronary bypass aneurysm. This case series illustrates the feasibility of the "off-label" use of self-expanded PTFE endoprosthesis to percutaneously treat several conditions, which would otherwise require "open" surgical reconstructions., (Copyright © 2011 Wiley Periodicals, Inc.)

Percutaneous coronary intervention of aorto-ostial lesions is associated with high rates of major adverse cardiovascular events. Precise implantation of coronary stents in the ostium is important in order to prevent adverse clinical outcomes. The presented case demonstrates a simple technique to accurately position a stent during aorto-ostial percutaneous coronary intervention., (Copyright © 2012 Elsevier Inc. All rights reserved.)

Objectives: To evaluate the effect of a polymer-free Biolimus A9-eluting stent [BioFreedom (BF)], compared with that of a biodegradable polymer-based Biolimus A9-eluting stent [BioMatrix Flex (BMF)] and a bare metal stent (BMS) in balloon denuded and radiated hypercholesterolemic rabbit iliac arteries., Methods: Rabbits were fed with 1% cholesterol diet (n = 14) for 14 days, both iliac arteries were balloon denuded and radiated, and then rabbits were switched to 0.15% cholesterol diet. After 4 weeks, BF (n = 8), BMF (n = 8), and BMS (n = 8) were deployed in denuded and radiated areas. Four weeks later animals were euthanized, arterial segments were processed for morphometry., Results: The neointimal area in vessels implanted with BF stents was significantly less than that seen in vessels implanted with BMS (0.90 mm(2) ± 0.14 vs. 1.29 mm(2) ± 0.23, P <0.01). Percent fibrin and fibrin score were higher with BMF stents compared to BMS (P <0.03 and <0.04) and giant cell number was significantly higher with both BMF and BF stents (P < 0.01 for both). Percent endothelialization was significantly higher and % uncovered struts were lower with BMS compared to either BMF or BF stents (P < 0.05 for both)., Conclusion: This study demonstrates that compared to BMS, BF stents significantly decreased neointimal hyperplasia., (Copyright © 2011 Wiley Periodicals, Inc.)

Percutaneous coronary intervention of degenerated saphenous vein grafts remains relatively high risk when compared to native vessel interventions, despite advances in pharmacotherapy and embolic protection. This article discusses the phenomenon of distal embolization that seems to plague saphenous vein graft interventions, reviews device-based strategies for embolic protection, and offers a perspective on the utility of percutaneous saphenous vein graft intervention in both elective and acute settings.

Compared with medical therapy, percutaneous coronary intervention has been shown to reduce the rates of death and recurrent ischemia in patients presenting with acute coronary syndromes (ACS). In the current interventional era, both drug-eluting stents (DES) and bare-metal stents (BMS) have been widely used, despite the fact that the use of DES in the context of ACS was initially an "off-label" indication and that ACS has been associated with stent thrombosis (ST). In contrast to the wealth of data available for the use of DES in patients with ST-elevation myocardial infarction, data regarding the performance of DES in non-ST-elevation ACS is restricted to a handful of registries with conflicting data. The aim of this review was to summarize the safety and efficacy of DES in the entire spectrum of ACS., (Copyright © 2011. Published by Elsevier Inc.)

Covered stents have shown discouraging results when tested on saphenous vein grafts and when attempting to prevent restenosis on native coronary arteries. However, covered stents seem to be a unique tool when a coronary artery perforation complicates percutaneous coronary intervention. Because a randomized clinical trial is not likely to be conducted in this bail-out scenario, the data supporting its use come from case reports and small-size retrospective studies. This review summarizes the available evidence supporting the use of covered stents to treat coronary perforations., (Copyright © 2011 Wiley-Liss, Inc.)

Background: The process of in-stent neointimal hyperplasia (NIH) between drug-eluting stents (DES) and bare metal stents (BMS) might be different. We compared in vivo composition of in-stent NIH between DES and BMS using virtual histology-intravascular ultrasound (VH-IVUS)., Methods and Results: Volumetric VH-IVUS was used to compare in-stent NIH between 23 DES and 15 BMS in 30 patients who underwent coronary angiography because of angina. The inner and outer VH-IVUS contours were drawn in a way to avoid the stent strut artifacts. Cross-sectional analysis was done at every VH-IVUS frame within the stent, thereby allowing volumetric measurement of stent, lumen, and NIH and its components. Baseline characteristics and IVUS measurements were similar between DES and BMS groups. The duration of follow-up was similar between DES (median 38 months [interquartile range, 7-59]) vs. BMS (median 40 months [interquartile range, 7-99]), (p=0.26). % necrotic core (NC) volume was significantly higher in DES than BMS: 19.5 [16.3, 25.6] vs. 12.1 [8.2, 18.5] (p=0.006). %NC volume significantly increased with time in BMS (p=0.007), but not in DES (p=0.24) so that at any given time point, %NC in DES was greater than in BMS. After adjustment for baseline differences, only DES (p=0.003) and stent age (p=0.043) were independent predictors of %NC volume. VH-IVUS in-stent thin-cap fibroatheromas were detected only in the DES group: 34.8% vs. 0%, p=0.013., Conclusion: In vivo composition of in-stent NIH between DES and BMS was different, suggesting that the process of in-stent NIH in DES and BMS is diverse.

Optical coherence tomography (OCT) is a novel, catheter-based, invasive imaging system based on near-infrared light with high image resolution (15-20 μm). The system allows for unparalleled imaging of the coronary artery lumen, plaque characterization, assessment of coronary stent strut apposition, neointimal coverage, vascular proliferative response, complications such as focal dissection or thrombus formation, and insight into the time course of stent endothelization. This review will describe the currently available developments in OCT technology and its application in both the clinical and research arenas., (©2010, Wiley Periodicals, Inc.)

Aims: This study aimed to examine the strategy of hybrid percutaneous coronary intervention (PCI) -bare metal stent (BMS) and drug-eluting stent (DES)- versus exclusive DES implantation for patients undergoing multivessel PCI., Methods and Results: A cohort of 2,065 patients who underwent PCI (698 hybrid, 1,367 exclusive DES) were followed clinically up to one year. The primary outcome was target vessel revascularisation-major adverse cardiac events (TVR-MACE). Patients presenting with cardiogenic shock, anaemia (haematocrit <25), and bypass graft PCI were excluded. Only patients with ≥ 2 stents in two different lesions were analysed for this study. Baseline and procedural characteristics were similar. Major in-hospital complications and subacute stent thrombosis rates were similar. At one year, there was no difference in TVR-MACE (hybrid 17.2% vs. DES 14.6%, p=0.128). On multivariable analysis, hybrid PCI was not a predictor of TVR-MACE. The strongest predictors of TVR-MACE at one year were hypertension and African American race. Cumulative stent thrombosis rates at one year were similar in both groups., Conclusions: Patients who undergo hybrid PCI have similar composite in-hospital and 1-year outcomes as those who undergo exclusive DES PCI. The hybrid stent approach should be considered for patients with multivessel PCI since it can lower the procedure cost without increasing adverse events.

Angioplasty of the coronary arteries has made significant headway in the past 20 years as a treatment for atherosclerotic vascular disease. Though drug-eluting stents are effective, they appear to invoke a thrombogenic response. Biodegradable stents are a promising alternative to permanent stents and may eventually be used to solve the lingering problem of in-stent restenosis. Additionally, fully degradable stents have the ability to deliver more drugs to the target site than a thin coating of drug on metallic stents. A variety of degradable materials have been studied for stent design, including polyesters, polycarbonates, bacterial-derived polymers, and corrodible metals. The ideal biodegradable stent would be reliably deployable under fluoroscopic guidance and situate into the target lesion with minimal endovascular trauma. The stent should degrade into nontoxic byproducts and invoke a minimal degree of inflammation at the target site. Finally, the stent itself should disappear within months (to years) without significant displacement from the deployment site. Although initial data from clinical trials have been sufficient to bring biodegradable materials into the realm of feasibility, future research is undoubtedly necessary to resolve the critical issues of inflammation and mechanical stability.

BIOTRONIK's absorbable metal stent technology is based ona magnesium alloy that offers superior stent mechanics and biocompatibility. The first generation (AMS-1) showed promising results regarding mechanical properties as well as feasibility and safety in several human applications (150 cases). The second generation (AMS-2.1) shows improved scaffolding and efficacy in animals due to a more slowly degrading magnesium alloy and an optimised stent design. The preclinical results of the drug-eluting AMS-3 are encouraging and the clinical investigational program will resume in 2010.

Advances in coronary stent technology, including refinement of the stent alloy, strut thickness, stent geometry, passive coating, and drug elution, have dramatically enhanced the safety and efficacy of percutaneous coronary intervention (PCI) with stenting. Stents are currently used in over 90% of coronary interventions and the use of drug-eluting stents (DES) has been disseminated to more complex lesion subsets such as total occlusions, long lesions, bifurcation lesions, and for patients with acute myocardial infarction. DES continue to demonstrate reduction in restenosis and the need for repeat revascularisation but are associated with delayed healing and re-endothelialisation, which have led to an increased rates of late stent thrombosis, dependency on prolonged dual antiplatelet therapy, impaired in-vessel reactivity, and chronic inflammation. As scientists and clinicians better understand the mechanism for late restenosis and stent thrombosis, a variety of solutions in regard to stent technology have been proposed, including stent coating, polymer bioabsorption, and fully biodegradable stents. Bare metal stents were improved by the reduction of strut thickness, changes in stent geometry, and the addition of passive coating, which lead to improvements in efficacy and reduction of restenosis. In addition, there is continued improvement in the polymer technology for DES, including new biocompatible, thinner durable polymers, and bioabsorbable polymers that completely bioabsorb within 3-12 months after stent implantation. These features potentially minimise the chronic inflammatory response and late stent thrombosis. Finally, fully bioabsorbable stents, both polymeric and metallic, continue to be developed in order to eliminate any late stenting effects and potentially may enable complete vessel restoration. This manuscript will discuss the wide variety of new stent technologies and compare and contrast durable metallic and polymeric stents to current biodegradable stent technology.

Performance of percutaneous coronary intervention (PCI) at centers without cardiothoracic surgery is a contentious issue. Although this practice allows greater access to care, there are safety concerns. The aim was to assess the requirement for emergent coronary artery bypass grafting (CABG) after PCI and characterize patients at highest risk using independent predictors. The study population consisted of 21,957 unselected patients who underwent PCI from August 1994 (Food and Drug Administration stent approval) to January 2008 at a single medical center. Patients requiring emergent CABG (defined as within 24 hours of the index procedure) were identified. Logistic regression analysis was performed to assess for independent correlates of emergent CABG. Emergent CABG was required in 90 patients (cumulative incidence 0.41%). Indications for CABG included triple-vessel disease, dissection, acute closure, perforation, and failure to cross. These patients had significantly higher in-hospital cardiac death rates (7.8% vs 0.7%; p <0.01) and higher rates of Q-wave myocardial infarction, neurologic events, and renal insufficiency. Independent correlates of emergent CABG after PCI were acute ST-segment elevation myocardial infarction presentation, cardiogenic shock, triple-vessel disease, and type C lesion. Risk assessment based on these predictors identified 0.3% of the patient population to have a 9.3% cumulative incidence of emergent CABG. In conclusion, the need for emergent CABG after PCI in the stent era was low and was associated with poor in-hospital outcomes. Risk was nonuniform, with 0.3% of the study population, characterized by acute presentation and complex coronary disease, at heightened risk of emergent surgery.

Objectives: This study aimed to evaluate the degradation rate and long-term vascular responses to the absorbable metal stent (AMS)., Background: The AMS demonstrated feasibility and safety at 4 months in human coronary arteries., Methods: The PROGRESS-AMS (Clinical Performance and Angiographic Results of Coronary Stenting) was a prospective, multicenter clinical trial of 63 patients with coronary artery disease who underwent AMS implantation. Angiography and intravascular ultrasound (IVUS) were conducted immediately after AMS deployment and at 4 months. Eight patients who did not require repeat revascularization at 4 months underwent late angiographic and IVUS follow-up from 12 to 28 months., Results: The AMS was well-expanded upon deployment without immediate recoil. The major contributors for restenosis as detected by IVUS at 4 months were: decrease of external elastic membrane volume (42%), extra-stent neointima (13%), and intra-stent neointima (45%). From 4 months to late follow-up, paired IVUS analysis demonstrated complete stent degradation with durability of the 4-month IVUS indexes. The neointima was reduced by 3.6 +/- 5.2 mm(3), with an increase in the stent cross sectional area of 0.5 +/- 1.0 mm(2) (p = NS). The median in-stent minimal lumen diameter was increased from 1.87 to 2.17 mm at long-term follow-up. The median angiographic late loss was reduced from 0.62 to 0.40 mm by quantitative coronary angiography from 4 months to late follow-up., Conclusions: Intravascular ultrasound imaging supports the safety profile of AMS with degradation at 4 months and maintains durability of the results without any early or late adverse findings. Slower degradation is warranted to provide sufficient radial force to improve long-term patency rates of the AMS.

Background: In-stent restenosis remains the major limitation of percutaneous coronary intervention (PCI), particularly after bare-metal stent (BMS) implantation. Drug-eluting stents (DES) decrease in-stent restenosis, which is thought to have minimal clinical consequences, but may increase the risk of stent thrombosis and its attendant high mortality rate., Aims: To assess the clinical consequences of in-stent restenosis, including severity of associated illness and acute and 1-year outcomes and to compare DES and BMS in-stent restenosis., Methods: Using our prospective PCI registry, we compared data from 1958 consecutive patients hospitalized with BMS in-stent restenosis between January 2000 and April 2003 and all 190 patients with DES in-stent restenosis admitted between April 2003 and September 2006. Risk-adjusted outcomes were calculated using propensity-score matching., Results: An unstable presentation was noted in 78.1% of 2148 patients. Patients with DES in-stent restenosis presented more often with acute myocardial infarction (4.3% versus 1.6%, p<0.001). At 1 year, mortality for all patients was 5.7% and target-vessel revascularization was 21.5%. After risk adjustment, target-vessel revascularization and target-vessel revascularization-major adverse cardiac events were greater in patients with DES in-stent restenosis (respectively, 27.8% versus 19.7%, p=0.05; 32.5% versus 24.3%, p=0.06)., Conclusion: In-stent restenosis is associated with unstable presentation and a higher 1-year adverse events rate than expected in patients undergoing elective PCI. For an identical level of cardiac risk, it seems that DES in-stent restenosis outcomes are slightly worse than BMS in-stent restenosis outcomes.

Stent thrombosis (ST) is a catastrophic complication that frequently presents as an acute myocardial infarction and/or death. The most recently accepted definition established by the Academic Research Consortium classifies ST as: early (occurring within 30 days), late (30 days to 1 year) or very late (after 1 year). Very late ST has been reported following drug-eluting stent implantation with rates up to 0.6% per year and has been attributed to delayed strut endothelialization. However, very late ST is unusual after bare-metal stent (BMS) implantation. We report two cases of patients presenting with ST-elevation myocardial infarction due to very late ST 6 and 8 years after BMS implantation.

Aims: To investigate the endothelium independent coronary smooth muscle vasomotor function four months after implantation of magnesium alloy absorbable metal stents (AMS) as part of the Progress-AMS clinical trial (n = 5), compared with a control group of patients implanted with permanent metal stents (PMS) (n = 10) undergoing follow-up angiography, but who were free from angiographic restenosis., Methods and Results: Quantitative coronary angiogram (QCA) using an automated edge detection system was performed before and after the administration of 2 mg intracoronary isosorbide dinitrate (ISDN). The vessel diameter was measured at 0.2 mm intervals throughout the stented segments and a 1 cm proximal reference segment. The cross sectional area (CSA) was calculated before and after the ISDN, averaged and the percentage change measured. Reference segments demonstrated preserved vasomotor function in all cases: +13.28% (AMS) versus +17.15% (PMS), p = 0.39. The mean percentage increase in CSA for the stented segment was +6.78% for the AMS versus -1.30% for PMS, p = 0.003., Conclusion: These data demonstrate that four months after AMS implantation vasomotor function in reference segments is no different to that observed with PMS. However in contrast to PMS, within the AMS-stented segments there is demonstrable vasodilatation. These observations may have important implications for future stent design.

Background: Distal embolization during percutaneous coronary intervention (PCI) of saphenous vein graft (SVG) lesions is associated with a high rate of myonecrosis. Although direct stenting (DS) is feasible with less catheter manipulations, its ability to prevent distal embolization in SVG lesions compared with distal protection devices (DPD) is unknown., Methods: The study included 188 SVG lesions subjected to PCI, 101 patients with 101 lesions treated with DPD, and 87 patients with 87 lesions by DS without DPD. Major adverse cardiovascular events (MACE) in-hospital and at 30 days were compared., Results: Baseline characteristics were comparable, except for higher frequencies of unstable angina (53% vs. 67%, P = 0.045) and prior myocardial infarction (38% vs. 53%, P = 0.07) in the DS group. There was no difference in lesion type aside from more restenotic lesions in the DS group (7% vs. 16%, P = 0.047). Drug-eluting stent deployment was similar. Stent length in the DPD group (22.8 +/- 7.2 mm) was significantly longer than that in the DS group (17.6 +/- 8.0 mm, P < 0.001). Although maximum creatine kinase (CK)-MB value in the DPD group (2.5 +/- 5.8 ng/ml) was significantly larger than in the DS group (1.3 +/- 1.5 ng/ml, P = 0.039), the frequency of CK-MB rise >2 times the upper limit of normal did not differ (11% vs. 6%, P = 0.2). There were no differences in MACE rates in-hospital and at 30 days. By multivariate analysis, neither DPD nor DS was a significant predictor for maximum CK-MB value., Conclusion: DS should be considered an alternative treatment to PCI with DPD for selected SVG lesions., ((c) 2008 Wiley-Liss, Inc.)

Stent thrombosis remains a major pitfall of stent implantation in contemporary percutaneous coronary intervention, leading to high rates of death and nonfatal myocardial infarction (MI). Recently, the emergence of drug-eluting stents (DES) has raised concerns regarding the occurrence of late and very late stent thrombosis. Last year, a standardized definition of stent thrombosis was established to provide consistency in the reporting of this complication and to enable accurate and reliable data to be described for both types of stents: bare metal and drug eluting. Subsequent to the publication of this new definition, many updated data have been reported in the literature. On the other hand, antiplatelet therapy response variability is a recent concept and its real place in the pathogenesis of stent thrombosis is yet to be determined. In this article, we review the definition of and predictors for stent thrombosis focusing on DES use and variability in response to antiplatelet therapy, prognosis and treatment.

Background: Absorbable metallic stents (AMS) composed of magnesium alloy were designed to complete degradation within 90-120 days. Among the potential advantages of these stents, when compared to conventional stents, are the elimination of late stent thrombosis, chronic inflammation, and artifacts during noninvasive imaging., Methods: Magnesium-based AMS were deployed in juvenile domestic pig coronary arteries. Angiography, optical coherence tomography (OCT), and intravascular ultrasound (IVUS) were performed before and after implant and then at 28 days and 3 months following stenting. The animals were sacrificed at 28 days or 3 months following stent implantation. Stented vessels were harvested and analyzed by histomorphometry., Results: Over time, OCT, IVUS, and histologic images revealed a progressive degradation of the stents. Mean stent strut width in the OCT images after implantation was 0.24+/-0.032 mm, then decreased to 0.12+/-0.007 mm (P<.0001) at 28 days and to 0.151+/-0.032 mm at 3 months (P<.0001 vs. implant, P=.078 vs. 28 days)., Conclusion: Magnesium-based AMS degrade over a 3-month time period in a porcine model. Its structure is not apparent by angiography but is well-visualized by OCT and IVUS. OCT allowed quantitative assessment of stent degradation.

Conflicting data exist regarding an advantage of drug-eluting stents (DES) over bare metal stents (BMS) in catheter-based treatment of saphenous vein graft (SVG) stenoses. This study was undertaken to compare the efficacy of these modalities in that lesion subset. The DES group consisted of 138 cases with 183 lesions (sirolimus-eluting stents, n = 117; paclitaxel-eluting stents, n = 66) and the BMS group consisted of 344 cases with 478 lesions that were followed to 1 year. We examined a composite end point that comprised death, Q-wave myocardial infarction, and target lesion revascularization. More BMS were deployed per patient (p <0.001) and the diameters of BMS deployed was significantly greater (p <0.001). Peak postprocedure values of creatine kinase-MB (p = 0.003) and troponin I (p = 0.05) were higher in BMS. At 1 year there was no significant superiority of DES over BMS with regard to hard end points (death and Q-wave myocardial infarction). In conclusion, this study indicates that both DES and BMS for SVG disease provide acceptably safe and efficacious results, but unlike the case in native coronary arteries, DES use does not reduce the frequency of the need for repeat revascularization.

Background: Biocorrodible iron stents carry the potential to overcome limitations, such as chronic inflammation and premature recoil, posed by biodegradable polymer and magnesium alloy stents. This study aimed to test the safety and efficacy of biocorrodible iron stents in porcine coronary arteries., Methods: Iron stents and cobalt chromium stents were randomly deployed in the coronary arteries of juvenile domestic pigs. Animals were sacrificed at 28 days, and the vessels were fixed and processed for histochemistry., Results: At 28 days, iron stents started to show signs of degradation without evidence of stent particle embolization or thrombosis without traces of excess inflammation, or fibrin deposition. At 28 days, the surface of the iron stent struts was black to brown and the vascular wall adjacent to the iron stent had a brownish tinge. There were no statistically significant differences in any of the measured parameters between segments implanted with iron and cobalt chromium stents. There were also no adverse effects in the persistent areas., Conclusion: The current study demonstrates that stents made of biocorrodible iron are safe. In some of the measured parameters, such as intimal thickness, intimal area, and percentage occlusion, there was a trend in favor of the iron stents.