Clinical Value of the Quantitative Flow Ratio to Predict Long-term Target Vessel Failure in Patients with In-stent Restenosis after Drug-coated Balloon Angioplasty

Objective The study sought to investigate the clinical predictive value of quantitative flow ratio(QFR)for the long-term target vessel failure(TVF)outcome in patients with in-stent restenosis(ISR)by using drug-coated balloon(DCB)treatment after a long-term follow-up.Methods This was a retrospective study.A total of 186 patients who underwent DCB angioplasty for ISR in two hospitals from March 2014 to September 2019 were enrolled.The QFR of the entire target vessel was measured offline.The primary endpoint was TVF,including target vessel-cardiac death(TV-CD),target vessel-myocardial infarction(TV-MI),and clinically driven-target vessel revascularization(CD-TVR).Results The follow-up time was 3.09±1.53 years,and 50 patients had TVF.The QFR immediately after percutaneous coronary intervention(PCI)was significantly lower in the TVF group than in the no-TVF group.Multivariable Cox regression analysis indicated that the QFR immediately after PCI was an excellent predictor for TVF after the long-term follow-up[hazard ratio(HR):5.15×10−5(6.13×10−8−0.043);P<0.01].Receiver-operating characteristic(ROC)curve analysis demonstrated that the optimal cut-off value of the QFR immediately after PCI for predicting the long-term TVF was 0.925(area under the curve:0.886,95%confidence interval:0.834–0.938;sensitivity:83.40%,specificity:88.00;P<0.01).In addition,QFR≤0.925 post-PCI was strongly correlated with the TVF,including TV-MI and CD-TVR(P<0.01).Conclusion The QFR immediately after PCI showed a high predictive value of TVF after a long-term follow-up in ISR patients who underwent DCB angioplasty.A lower QFR immediately after PCI was associated with a worse TVF outcome.

Diagnosis and management challenges of in-stent restenosis in coronary arteries

Over the course of the 3 decades, percutaneous coronary intervention(PCI) with stent implantation transformed the practice of cardiology. PCI with stenting is currently the most widely performed procedure for the treatment of symptomatic coronary disease. In large trials, drugeluting stents(DES) have led to a significant reduction in in-stent restenosis(ISR) rates, one of the major limitations of bare-metal stents. Due to these favorable findings, DES was rapidly and widely adopted enabling more complex coronary interventions. Nevertheless, ISR remains a serious concern as late stent complications. ISR mainly results from aggressive neointimal proliferation and neoatherosclerosis. DES-ISR treatment continues to be challenging complications for interventional cardiologists.

Treatment of coronary in-stent restenosis： a systematic review

Coronary stem implantation has significantly improved percutaneous coronary intervention and enabled the management of early complications of plain balloon angioplasty. However, a new complication has accompanied these improvements： in-stent restenosis （ISR） arising from neointimal hyperplasia. ISR after coronary angioplasty is currently one of the main limitations of this method, leading to the recurrence of exertional angina pectoris or acute coronary syndromes. The clinical incidence of ISR after bare-metal stent （BMS） implantation is approximately 20%35%. The use of drug-eluting stents （DES） has led to a further decrease in the occurrence of ISR to 5%-10%. Evidence resulting from controlled clinical studies suggests that DES and drug-eluting balloon catheters （DEB） provide the best clinical and angiographic results in the treatment of ISR. We undertook a systematic review of the pathophysiology, diagnostics and treatment options for BMS- and DES-ISR. We discuss recent randomised studies, comparing different DES or DEB used for BMS or DES-ISR treatment, as well as the use of new biovascular scafolds and the topic of scafold restenosis.

New predictors of in-stent restenosis in patients with diabetes mellitus undergoing percutaneous coronary intervention with drug-eluting stent

Background Percutaneous coronary intervention （PCI） had become the major therapeutic procedure for coronary artery disease （CAD）, but the high rate of in-stent restenosis （ISR） still remained an unsolved clinical problem in clinical practice. Increasing evidences suggested that diabetes mellitus （DM） was a major risk factor for ISR, but the risk predictors of ISR in CAD patients with DM had not been well characterized. The aim of this study was to investigate the clinical and angiographic characteristic predictors significantly associated with the occurrence of ISR in diabetic patients following coronary stenting with drug-eluting stent （DES）. Methods A total of 920 patients with diabetes who diagnosed CAD and underwent coronary DES implantation at Beijing Anzhen Hospital in China were consecutively enrolled from January 2012 to December 2012. Of these, 440 patients underwent the second angiography within ≥ 6 months due to the progression of treated target lesions. Finally, 368 of these patients who met the inclusion and exclusion criteria were followed up by angiography after baseline PCI. According to whether ISR was detected at follow-up angiography, patients were divided into the ISR group （n = 74） and the non-ISR group （n = 294）. The independent predictors of ISR in patients with DM were explored by multivariate Cox＇s proportional hazards regression models. Results A total of 368 patients （260 women and 108 men） with a mean ages of 58.71 ± 10.25 years were finally enrolled in this study. Of these, ISR occurred in 74/368 diabetic patients （20.11%） by follow-up angiography. Univariate analysis showed that most baseline characteristics of the ISR and non-ISR group were similar. Patients in the ISR group had significantly higher serum very low density lipoprotein cholesterol （VLDL-C）, triglyceride （TG） and uric acid （UA） levels, more numbers of target vessel lesions, higher prevalence of multi-vessel disease, higher SYNTAX score, higher rate of previous but lower rate of drinking compared with patients in the non-ISR group. The independent predictors of ISR in patients with DM after DES implantation included VLDL-C （HR = 1.85, 95% CI： 1.24-2.77, P = 0.002）, UA （per 50 μmol/L increments, HR = 1.19, 95% CI： 1.05 1.34, P = 0.006）, SYNTAX score （per 5 increments, HR = 1.34, 95% CI： 1.03-1.74, P = 0.031） and the history ofPCI （HR = 3.43, 95% CI： 1.57-7.80, P = 0.003） by the multivariate Cox＇s proportional hazards regression analysis. Conclusions The increased serum VLDL-C and UA level, higher SYNTAX score and the history of previous PCI were independent predictors of ISR in patients with DM after coronary DES implantation. It provided new evidence for physi- cians to take measures to lower the risk oflSR for the better management of diabetic patients after PCI.

Assessment of Coronary Stents by 64-slice Computed Tomography: In-stent Lumen Visibility and Patency

Objective To assess lumen visibility of coronary stents by 64-slice computed tomography （CT） coronary angiography, and determine the value of 64-slice CT in non-invasive detecting of in-stent restenosis after coronary artery stent implantation. Methods Totally, 60 patients （54 males, aged 57.0±12.7 years） and /05 stents were investigated by 64-slice CT at a mean interval of 20.0±16.6 months after coronary stents implantation. Axial multi-planar reconstruction images of the stents and curved-planar reconstruction images through the median of the stents were reconstructed for evaluating stent image quality on a 5-point scale （1=excellent, 5=nonassessable）, and stent lumen diameter was detected. Conventional coronary angiography was performed in 18 patients, and 32 stents were evaluated. Results Image quality was good to excellent on average （score 1.71±0.76）. Stent image quality score was correlated to heart rate （r=0. 281, P〈0.01） and stent diameter （r=-0.480, P〈0.001）. All the stents were assessable in lumen visibility with an average visible lumen diameter percentage of 60.7%±13.6%. Visible lumen diameter percentage was correlated to heart rate （r=-0.193, P〈0.05）, stent diameter （r=0.403, P〈0.001）, and stent image quality score （r=-0.500, P〈0.001）. Visible lumen diameter percentage also varied depending on the stent type. In comparison with the conventional coronary angiography, 4 of 6 in-stent stenoses were correctly detected. The sensitivity and specificity for the detection of in-stent stenosis were 66.7% and 84.6%, respectively. Conclusions Using a 64-slice CT, the stent lumen is partly visible in most of the stents. And 64-slice CT may be useful in the assessment of stent patency.

Drug-eluting balloons versus new generation drug-eluting stents for the management of in-stent restenosis: an updated meta-analysis of randomized studies

Background New-generation drug-eluting stents (DES) was more effective in the treatment of in-stent restenosis (ISR) compared with the first-generation DES. Drug-eluting balloons (DEB) and new-generation DES had been available strategies in treatment of bare-metal stents/DES ISR (BMS/DES-ISR). Six new randomized trials have recently examined the angiographic outcomes and one-year clinical outcomes of DEB and new generation DES in BMS/DES-ISR. However, the optimal management for BMS/DES-ISR lesions remains controversial. Methods We searched the randomized clinical trials evaluating the angiographic outcomes and one-year clinical outcomes of DEB and new-generation DES in patients with BMS/DES-ISR. The primary endpoints were the angiographic outcomes, including the minimal luminal diameter (MLD), diameter stenosis %(DS%), late lumen loss (LLL), and binary restenosis (BR). Results A total of six randomized clinical trials with 1177 BMS/DES-ISR patients were included in our meta-analysis. For angiographic outcomes, there were significantly less MLD and more DS% with DEB compared to new-generation DES (MLD: MD =?0.18, 95% CI:?0.31– ?0.04, P < 0.001;DS%: MD = 5.68, 95% CI: 1.00–10.37, P < 0.001). Moreover, for one-year clinical outcomes, DEB was associated with a significant increase risk in target lesion revascularization (TLR)(RR = 2.93, 95% CI: 1.50–5.72, P = 0.002). However, DEB was associated with higher risks of major adverse cardiac event, target vessel revascularization, TLR, BR, and more DS% only in DES-ISR group. Conclusions DEB and new-generation DES have the similar clinical efficacy for the treatment of BMS-ISR. However, DES showed more MLD, less DS%, and a decreased risk of TLR for the treatment of DES-ISR.

Recent advances in cardiovascular stent for treatment of in-stent restenosis:Mechanisms and strategies

Treatments of atherogenesis,one of the most common cardiovascular diseases(CVD),are continuously being made thanks to innovation and an increasingly in-depth knowledge of percutaneous transluminal coronary angioplasty(PTCA),the most revolutionary medical procedure used for vascular restoration.Combined with an expanding balloon,vascular stents used at stricture sites enable the long-time restoration of vascular permeability.However,complication after stenting,in-stent restenosis(ISR),hinders the advancement of vascular stents and are associated with high medical costs for patients for decades years.Thus,the development of a high biocompatibility stent with improved safety and efficiency is urgently needed.This review provides an overview of current advances and potential technologies for the modification of stents for better treatment and prevention of ISR.In particular,the mechanisms of in-stent restenosis are investigated and summarized with the aim to comprehensively understanding the pathogenesis of stent complications.Then,according to different therapeutic functions,the current stent modification strategies are reviewed,including polymeric drug eluting stents,biological friendly stents,prohealing stents,and gene stents.Finally,the review provides an outlook of the challenges in the design of stents with optimal properties.Therefore,this review is a valuable and practical guideline for the development of cardiovascular stents.

COMPARISON OF SHORT- AND LONG-TERM OUTCOMES BETWEEN CYPHER AND TAXUS DRUG-ELUTING STENTS FOR IN-STENT RESTENOSIS

Objective To compare the short- and long-term clinical outcomes between sirolimus-eluting stent （ Cypher stent） and paclitaxel-eluting stent （TAXUS stent） in patients with in-stent restenosis （ISR） lesions of the coronary arteries. Methods From December 2002 to March 2005, 253 patients with ISR lesions of the coronary arteries were selected and divided into two groups. Cypher group （152 cases） was treated with Cypher or Cypher Select stents, and TAXUS group （101 cases） with TAXUS stents. A total of 262 ISR lesions in these patients were treated with 308 drog-eluring stents （DESs）, including 176 Cypher or Cypher Select stents and 132 TAXUS stents. All patients were followed up for 10 months. Procedure success rates of DES implantation in both groups were observed. Major adverse cardiac events （MACE） rates in hospital and at 10 months follow-up, as well as in-DES restenosis observed using coronary angiography at follow-up were compared between two groups. Results Success rate of DES implantation was 100% in both groups. No significant difference in MACE rate during hospitalization was found between the two groups. However, at 10 months follow-up, MACE rate was higher in TAXUS group than in Cypher group （ 16.00% vs. 6.67%, P =0. 031 ）. As for coronary angiography at 10 months follow-up, we observed an increasing tendency of in-DES restenosis rate in TAXUS group compared with Cypher group （29.41% vs. 14.04%, P=0.075）. Conclusions Cypher and TAXUS DESs both have good short- and long-term outcomes in treating ISR. Cypher DES proved better long-term clinical outcome than TAXUS DES.

Comparison of the efficacy of drug-eluting balloon for de novo lesions and in-stent restenosis lesions of the femoropopliteal arteries

Objective:To compare the efficacy of drug-eluting balloons for de novo and in-stent restenosis(ISR)for lesions of the femoropopliteal arteries during 12-month follow-up.Materials and methods:A retrospective analysis of 66 patients was performed.These patients had lower extremity atherosclerosis obliterans and were treated with drug-eluting balloons from June 2016 to June 2017.All the lesions were femoropopliteal,including 47 de novo lesions and 19 ISR lesions.Clinical results were followed up at 6 months and 12 months postoperatively.The primary patency rate,target lesion revascularization,Rutherford classification,ankle-brachial index,amputation rate and mortality were compared between the two groups.Results:All the 66 patients underwent the treatment of femoropopliteal artery lesions with unilateral limbs.The surgical success rates were 100%.No adverse events such as acute ischemia or amputation occurred in the hospital.There was no difference between the two groups'Rutherford classification and the ankle-brachial index at the 6-month follow-up(p>0.05).At the 12-month follow-up,the de novo group's Rutherford classification was lower than the ISR group(p=0.026),and the ankle-brachial index of the ISR group was lower(0.66±0.033 vs 0.52±0.056,p=0.036).There was no difference between the patency rate of the de novo group and the ISR group(93.6%vs 84.2%,p=0.229)at the 6-month follow-up.However,the ISR group patency rate was lower at the 12-month follow-up(63.2%vs 85.1%,p=0.048).As for revascularization there was no significant difference between the two groups at the 6-month follow-up(4.2%vs 10.5%,p=0.334),but a higher rate occurred in the ISR group at the 12-month follow-up(26.3%vs 6.4%,p=0.025).There were no significant differences in the mortality or amputation rate between the two groups(p>0.05).Conclusions:Drug-eluting balloons were effective in treating both de novo lesions and ISR lesions in the atherosclerotic femoropopliteal artery,but the 12-month follow-up results of ISR lesions were less favorable than the de novo lesions.

Comparison of the safety and efficacy of two types of drug-eluting balloons （RESTORE DEB and SeQuent Please） in the treatment of coronary in-stent restenosis： study protocol for a randomized controlled trial （RESTORE ISR China）

1 Introduction In-stent restenosis （ISR）, characterized by neointimal proliferation and/or neoatherosclerosis in the vessel of the stent, can cause a reduction in lumen diameter after stent implantation, which can directly induce the recurrence of angina symptoms or an acute coronary syndrome in patients and is usually life-threatening.

Intracoronary brachytherapy for the treatment of recurrent drugeluting stent in-stent restenosis:A systematic review and metaanalysis

BACKGROUND We performed a meta-analysis on observational studies since randomized control trials are not available.We studied intracoronary brachytherapy(ICBT)and recurrent drug eluting stent in-stent restenosis(DES-ISR)to evaluate the procedural success,target lesion revascularization(TLR),incidence of myocardial infarction(MI)and all-cause mortality at 2 years follow-up.AIM To perform meta-analysis for patients undergoing ICBT for recurrent DES-ISR.METHODS We performed a systematic search of the PubMed/MEDLINE,Cochrane and DARE databases to identify relevant articles.Studies were excluded if intracoronary brachytherapy was used as a treatment modality for initial ISR and studies with bare metal stents.We used a random-effect model with DerSimonian&Laird method to calculate summary estimates.Heterogeneity was assessed using I2 statistics.RESULTS A total of 6 observational studies were included in the final analysis.Procedural angiographic success following intra-coronary brachytherapy was 99.8%.Incidence of MI at 1-year was 2%and 4.1%at 2-years,respectively.The incidence of TLR 14.1%at 1-year and 22.7%at 2-years,respectively.All-cause mortality at 1-and 2-year follow-up was 3%and 7.5%,respectively.CONCLUSION Given the observational nature of the studies included in the analysis,heterogeneity was significantly higher for outcomes.While there are no randomized controlled trials or definitive guidelines available for recurrent ISR associated with DES,this analysis suggests that brachytherapy might be the alternative approach for recurrent DES-ISR.Randomized controlled trials are required to confirm results from this study.

Increased serum TREM-1 level is associated with in-stent restenosis,and activation of TREM-1 promotes inflammation,proliferation and migration in vascular smooth muscle cells

Background and Objective In-stent restenosis(ISR)remains a major limitation of percutaneous coronary intervention despite improvements in stent design and pharmacological agents,whereas the mechanism of ISR has not been fully clarified.In the present study,we sought to investigate the potential association of serum soluble TREM-1(sTREM-1)levels with the incidence of ISR.The role of TREM-1 was evaluated in cultured vascular smooth muscle cells(VSMCs).

Finite Element Simulation of In-Stent Restenosis with Tissue Growth Model

In this study, a finite element simulation of in-stent restenosis (ISR) is conducted to simulate the deployment and expansion of a stent in an occluded artery with a contact model and a mechanics-based growth model. A tissue growth model based on the multiplicative decomposition of deformation is applied to investigate the growth of the plaque and artery wall upon the stent’s implantation. Due to the high stresses at the contact points between the stent struts and the tissue, further tissue injury or restenosis is observed. The simulation results show that after the stent deployment, the von Mises stress is significantly larger in the plaque compared to the artery wall, especially in the region that is in contact with the stent. However, the growth of the plaque and artery tends to even out the stress concentration over time. The tissue growth is found to be more significant near the inner wall than the outer layer. A 0.77 mm restenosis is predicted, which agrees with published clinical observations. The features of the artery growth are carefully analyzed, and the underlying mechanism is discussed. This study is the first attempt to apply finite element analysis to artery restenosis, which establishes a framework for predicting ISR’s occurrence and severity. The results also provide insights into understanding the underlying mechanism of in-stent restenosis.

Clinical study about the effect of Simiao Yong'an Decoction on preventing in-stent restenosis and regulating inflammation and oxidative stress after lower extremity stent angioplasty stenting

Objective:To study the effect of Simiao Yong'an Decoction on the prevention of in-stent restenosis and the regulation of inflammation and oxidative stress after lower extremity stent angioplasty.Methods:A prospective study was conducted on 60 ASO patients who underwent lower extremity stent angioplasty in our hospital between January 2014 and January 2018.The patients were randomly divided into observation group receiving postoperative Simiao Yong'an Decoction combined with antiplatelet drug treatment and control group receiving postoperative antiplatelet drug treatment.The conditions of in-stent restenosis were followed up,and the indicators of coagulation,inflammation and oxidative stress were detected.Results:The incidence of in-stent restenosis in observation group 1 year after operation was significantly lower than that in control group;6 months and 12 months after operation,the ankle brachial index(ABI)levels,minimal lumen diameter(MLD)levels at the stent and superoxide dismutase(SOD)contents of observation group were significantly higher than those of control group,whereas D-dimer(D-D)and fibrinogen degradation product(FDP)levels as well as P-selectin,C-reactive protein(CRP),tumor necrosis factor-α(TNF-α),malondialdehyde(MDA)and inducible nitric oxide synthase(iNOS)contents were significantly lower than those of control group.Conclusions:Simiao Yong'an Decoction can prevent the in-stent restenosis and inhibit the inflammation and oxidative stress after lower extremity stent angioplasty.

雷帕霉素药物涂层支架对家猪冠状动脉NF-κB影响的研究

目的探讨核因子-κB(nuclear factor-kappa B,NF-κB)mRNA和蛋白是否参予介入后支架内再狭窄(in-stent restennosis,ISR)的发生发展以及雷帕霉素药物涂层支架(rapamycin eluting stent,RES)是否影响NF-κB mRNA和蛋白表达。方法将裸金属支架(bare metal stent,BMS)和RES按支架∶动脉比率(直径1.1～1.2∶1.0)随机植入猪冠状动脉前降支或回旋支,1个月后行冠状动脉造影并取材,冠脉定量造影术(quantity of coronary artery,QCA)分析平均血管直径、晚期血管丢失和径向狭窄,血管组织标本嗜伊红染色后测定支架血管段冠状动脉内膜最大厚度、内膜面积和支架段内血管腔面积,Rt-PCR检测NF-κB mRNA表达和Western blotting检测NF-κB蛋白表达。结果①与BMS组相比较,RES组平均血管直径显著改善(P<0.05),而晚期血管丢失和径向狭窄均显著减少(均P<0.05)。②BMS组和RES组均可见内膜完全覆盖支架,BMS组支架段内内膜最大厚度和内膜面积均显著大于RES组(均P<0.05)、血管腔面积显著小于RES组(P<0.05)。③正常血管段可见NF-κB mRNA和蛋白微量表达,与此相比,BMS组和RES组血管段NF-κBmRNA和蛋白表达均显著增强,不过,RES组血管段NF-κB mRNA和蛋白显著低于BMS组血管段。④内膜面积与NF-κB mRNA(r=0.349,P=0.001)和蛋白(r=0.417,P=0.001)呈显著正相关。结论NF-κB可能介导ISR进程,BMS可能通过促进NF-κB导致ISR而RES则可能通过抑制NF-κB减轻ISR。

紫杉醇药物涂层支架对家猪冠状动脉Egr-1影响的研究

目的探讨紫杉醇是否通过影响早期生长反应因子-1(Egr-1)抑制支架内再狭窄(ISR)。方法随机植入裸金属支架(BMS)和紫杉醇药物涂层支架(PES)于猪冠状动脉前降支或回旋支,1个月后冠状动脉造影分析平均血管直径、晚期血管丢失和径向狭窄,测定支架血管段冠状动脉内膜最大厚度、内膜面积和支架段内血管腔面积以及Egr-1表达。结果①PES组无血管丢失和径向狭窄;②BMS组和PES组内膜均完全覆盖支架,PES组支架段内内膜最大厚度和内膜面积均显著小于BMS组而血管腔面积显著大于BMS组(P<0.05);③正常血管段可见Egr-1 mRNA而无Egr-1蛋白表达,与此相比,BMS组血管段Egr-1 mRNA和蛋白表达均显著增强,而PES组血管段Egr-1 mRNA和蛋白表达显著低于BMS组血管段而高于正常血管段。结论BMS可能通过Egr-1导致ISR发生发展,而PES则可能通过抑制Egr-1表达减轻ISR。

Genetics of coronary artery disease and myocardial infarction

Atherosclerotic coronary artery disease(CAD) comprises a broad spectrum of clinical entities that include asymptomatic subclinical atherosclerosis and its clinical complications, such as angina pectoris, myocardial infarction(MI) and sudden cardiac death. CAD continues to be the leading cause of death in industrialized society. The long-recognized familial clustering of CAD suggests that genetics plays a central role in its development, with the heritability of CAD and MI estimated at approximately 50% to 60%. Understanding the genetic architecture of CAD and MI has proven to be difficult and costly due to the heterogeneity of clinical CAD and the underlying multi-decade complex pathophysiological processes that involve both genetic and environmental interactions. This review describes the clinical heterogeneity of CAD and MI to clarify the disease spectrum in genetic studies, provides a brief overview of the historical understanding and estimation of the heritability of CAD and MI, recounts major gene discoveries of potential causal mutations in familial CAD and MI, summarizes CAD and MIassociated genetic variants identified using candidate gene approaches and genome-wide association studies(GWAS), and summarizes the current status of the construction and validations of genetic risk scores for lifetime risk prediction and guidance for preventive strategies. Potential protective genetic factors against the development of CAD and MI are also discussed. Finally, GWAS have identified multiple genetic factors associated with an increased risk of in-stent restenosis following stent placement for obstructive CAD. This review will also address genetic factors associated with in-stent restenosis, which may ultimately guide clinical decision-making regarding revascularization strategies for patients with CAD and MI.

Application of drug-coated balloon in coronary artery intervention： challenges and opportunities

In recent decades, the outcomes of coronary heart disease （CHD） have markedly improved, which can be partly attributed to the use of novel drugs （especially statins and antiplatelet drugs） and partly to the evolution ofpercutaneous coronary intervention （PCI）. From percutaneous transluminal coronary angioplasty to bare-metal stent and then to drug-eluting stent, every step of PCI is attractive to interventional cardiologist, great progress has been made for patients with CHD. In the past few years, some successor devices for treating CHD have cmerged. Undoubtedly, drug-coated balloon （DCB）, which was recommended by 2014 ESC Guidelines on myocardial revascularization, is a ＂shining star＂ among them. DCB involves a semi-compliant angioplasty balloon coated with an anti-proliferative agent that can exert antirestenotic efficacy by permeating into the vessel wall during balloon contact. This review discusses the conception and merits, preclinical data, emerging clinical indications, and results from clinical trials of this novel interventional technology. Although DCB has shown authentic efficacy in the treatment ofin-stent restenosis, its use in de novo coronary lesions is still in dispute. Hence, concerns and the future direction of DCB are also covered in this paper.

Restenosis of a drug eluting stent on the previous bioresorbable vascular scaffold successfully treated with a drug-coated balloon: A case report

BACKGROUND The in-stent restenosis(ISR)rates are reportedly inconsistent despite the increased use of second-generation drug eluting stent(DES).Although bioresorbable vascular scaffold(BVS)have substantial advantages with respect to vascular restoration,the rate of scaffold thrombosis is higher with BVS than with DES.Optimal treatment strategies have not been established for DES-ISR to date.CASE SUMMARY We report on a case of a 60-year-old man patient with acute coronary syndrome.He had a history of ST-segment elevation myocardial infarction associated with very late scaffold thrombosis and treated with a DES.Coronary angiography revealed significant stenosis,suggesting DES-ISR on the previous BVS.Optical coherence tomography(OCT)identified a plaque rupture and a disrupted scaffold strut in the neointimal proliferation of DES.To treat the DES-ISR on the previous BVS,we opted for a drug-coated balloon(DCB)after a balloon angioplasty using a semi-compliant and non-compliant balloon.The patient did not experience adverse cardiovascular events on using a DCB following the use of intensive dual antiplatelet therapy and statin for 24 mo.CONCLUSION This case highlights the importance of OCT as an imaging modality for characterizing the mechanism of target lesion failure.The use of a DCB following the administration of optimal pharmacologic therapy may be an optimal strategy for the treatment and prevention of recurrent BVS thrombosis and DES-ISR.

Solid Mechanical and Hemodynamic Analyses of Different Stent Structures in a Curved Stenotic Coronary Artery

Background Coronary artery stenting is commonly used for the treatment of coronary atherosclerosis,but it causes serious clinical complications,such as the in-stent restenosis(ISR).The main reason leading to ISR is the neointimal hyperplasia(NH),which is related to the stresses of plaque and artery,and to the altered local hemodynamic environment due to the presence of stents.Different stent structures indeed have various impacts on the stresses of plaque and artery,and the local hemodynamic environment,such as the wall shear stress(WSS),average WSS(AWSS),and WSS gradient(WSSG).Thus,it is important to evaluate the performance of stents with different structures by the mechanical factors after coronary stenting.Methods Six stents implanted into a stenotic curved coronary artery were treated separately,and they included three typical commercial stents(Palmaz-Schatz,Xience,and Cypher)and three author-developed stents,which were constructed by reducing the numbers of link(C-Rlink)and crown(C-Rcrown),and aligning the strut(C-Astrut)of the commercial Cypher Solid mechanical analyses of the balloon-stent-plaque-artery system in Abaqus were first performed to assess the performance of different stent structures and provide the deformed boundary of lumen for the subsequent hemodynamic analysis.With the deformed boundary,then hemodynamic analyses in Ansys were conducted to quanti-fy the hemodynamic parameters induced by different stent structures.Combining the solid mechanical and hemodynamic analyses,the performance of the six stents was evaluated.Results The results show that among the three commercial stents,the Palmaz-Schatz stent has the least stent dogboning and recoiling,which corresponds to the greatest maximum plastic strain as well as the largest diameter.However,it induces the greatest maximum stress of plaque,intima,and media.From the viewpoint of hemodynamics,the Palmaz-Schatz stent also performs better and it has smaller areas of adverse low WSS(<0.5 Pa),high WSS(>15 Pa),low AWSS(<0.5 Pa),and high WSSG(>5 000 Pa/m).Compared to the commercial Cypher stent,the author-developed Cypher-based C-Rcrown and C-Astrut stents have smaller recoiling,greater maximum plastic stain and larger diameter,which indicates the improved mechanical performance of the Cypher stent.Moreover,both C-Rcrown and C-Astrut have smaller areas of adverse low WSS,high WSS,and low AWSS,but only C-Rcrown has smaller area of adverse high WSSG.Nevertheless,the C-Rlink stent is inferior to the commercial Cypher stent.In both senses of the solid mechanical and local hemodynamic analyses,the C-Rcrown stent is superior to the commercial Cypher stent and other Cypher-based stents.Conclusions In this study,solid mechanical and hemodynamic analyses were carried out to study the effects of six stents with different structures on their performances after stenting.It was found that the Palmaz-Schatz stent performed better than other two commercial stents,and the performance of the Cypher stent could be improved by reducing the number of crowns of its strut.The present study comparatively evaluates the performance of different stents inside a curved artery,and could be used as a guide to select a suitable commercial stent for clinical application,and provide a way to improve the performance of the existing commercial stents.