Biodegradable polymer drug-eluting stents versus second-generation drug-eluting stents in patients with and without diabetes mellitus:a single center study

Objective It remains undetermined whether biodegradable polymer drug-eluting stents(BP-DES)are superior to second generation drugeluting stents(G2-DES)in patients with and without diabetes mellitus(DM).The study aims to evaluate the efficacy and safety of G2-DES and BP-DES in patients with and without DM in a high-volume cardiovascular center in China.

Effect of nonionic surfactants in release media on accelerated in-vitro release profile of sirolimus eluting stents with biodegradable polymeric coating

It is a well-known fact that sirolimus(SRL) undergoes degradation process via hydrolysis in aqueous media, leading to incorrect assessment of drug amount and thus release characteristics of formulations.The main objective of the present study was to evaluate the effect of nonionic surfactants in media on invitro release profiles for sirolimus eluting stents(SES) coated with biodegradable polymeric matrix.Phosphate buffer and acetate buffer incorporating nonionic surfactants with varying concentrations were examined for adequate solubility and stability(by RP-HPLC). Good sink condition was achieved in phosphate buffer(at pH 4.0) with 1.0% Tween 20, 1.0% Brij 35% and 0.5% Brij 58. Hydrodynamic size(by DLS) and the micelle-water partition coefficient(P) with standard free energy of solubilization(ΔGs°) of drug were evaluated to get some understanding about the solubilization phenomena. About 80% of drug release during the period of 48 h was achieved in optimized drug release media which was 1.0% Tween20 in phosphate buffer pH 4.0. The obtained accelerated SRL release profile in optimized medium correlated well with the real time in-vitro release in phosphate buffer(pH 7.4). Surface morphology changes(by SEM), changes in gravimetric weights and molecular weight change(by GPC) were examined before and after drug release to understand the drug release mechanism which explains that the polymer did not undergo degradation during the drug release.

Safety and Efficacy of Ultra-Thin, Biodegradable Polymer Coated Sirolimus-Eluting Supralimus-Core Stents in Real-World Patients: Outcomes at 24-Month Follow-Up

Aim: The purpose of this registry was to establish long-term safety and efficacy through implantation of Supralimus-Core sirolimus-eluting stents (SES) in real-world patients with coronary artery disease (CAD). Methods:The present registry was a retrospective, singe-arm, single-centre, investigator-initiated registry. A total of 372 consecutive patients were implanted with Supralimus-Core SES between January 2015 and November 2016. The primary endpoints were major adverse cardiac events (MACE), a composite of cardiac death, myocardial infarction (MI), target lesion revascularization (TLR) and target vessel revascularization (TVR) at 24 months. The secondary endpoints were all-cause death and all separate components of the primary endpoint. Additional endpoints included events of stent thrombosis classified as definite, probable, and possible stent thrombosis. Follow-ups were conducted at 30-days, 6-months, 12-months and 24-months after the index procedure. Results: The mean age of the registry population was 56.3 ± 11.1 years. Males constituted 276 (74.2%) patients. Hypertensives, diabetics, alcoholics, tobacco chewers and smokers comprised 198 (53.2%), 160 (43.0%), 93 (25.0%), 91 (24.5%) and 88 (23.7%) of the registry population, respectively. The mean length and diameter of stents implanted was 19.3 ± 8.8 mm and 2.9 ± 0.3 mm, respectively. At the 24-month follow-up, MACE was reported in 14 (3.8%) patients. Cardiac death, MI, TLR and TVR was reported in 7 (1.9%), 4 (1.1%), 3 (0.8%) and 4 (1.1%) patients, respectively. Overall stent thrombosis occurred in 4 (1.1%) patients. Conclusions: The low MACE rate of 3.8% at the 24-month follow-up indicates favorable long-term results after implantation of the ultra-thin strut Supralimus-Core SES in all-comer, real-world patients.

All-Comers Study of Percutaneous Coronary Interventions with Ultrathin Strut Biodegradable-Polymer Sirolimus-Eluting Stents—ORSHINE Registry

Current new generation stent technology has made remarkable progress in stent design, structure, and component material to improve its performance in reducing stent thrombosis, and restenosis compared to earlier DES and BMS. Orsiro-Sirolimus eluting stent is new generation ultra-thin strut stent with biodegradable abluminal coating that leaves a polymer free stent after drug release enhances coverage of stent struts and prevents excess neo intimal proliferation. A retrospective data analysis was done to see safety and efficacy of Orsiro in patients treated with ultra-thin DES with Orsiro stents at Sunshine Hospitals, Hyderabad. A total of 331 patients with 525 lesions were treated with 506 Orsiro stents and the major adverse cardiac events (MACE) rate and stent thrombosis (ST) at 2 years’ follow-up were analysed. MACE rate was 1.6% for an average follow-up at 2 years. Out of 2 patients who developed ST, one presented with definite acute stent thrombosis and one with possible, late stent thrombosis and 1.8% non-cardiac death reported during the follow-up. Despite many patients with complex PCI in the ACS subset, Orsiro reduced significant reduction in MACE rate in all spectrum of coronary artery disease patients with excellent acute and long-term results similar to other established FDA-approved current generations stents.

Five-year outcomes of biodegradable versus second-generation durable polymer drug-eluting stents used in complex percutaneous coronary intervention

Background:There are few data comparing clinical outcomes of complex percutaneous coronary intervention(CPCI)when using biodegradable polymer drug-eluting stents(BP-DES)or second-generation durable polymer drug-eluting stents(DP-DES).The purpose of this study was to investigate the safety and efficacy of BP-DES and compare that with DP-DES in patients with and without CPCI during a 5-year follow-up.Methods:Patients who exclusively underwent BP-DES or DP-DES implantation in 2013 at Fuwai Hospital were consecutively enrolled and stratified into two categories based on CPCI presence or absence.CPCI included at least one of the following features:unprotected left main lesion,≥2 lesions treated,≥2 stents implanted,total stent length>40 mm,moderate-to-severe calcified lesion,chronic total occlusion,or bifurcated target lesion.The primary endpoint was major adverse cardiac events(MACE)including all-cause death,recurrent myocardial infarction,and total coronary revascularization(target lesion revascularization,target vessel revascularization[TVR],and non-TVR)during the 5-year follow-up.The secondary endpoint was total coronary revascularization.Results:Among the 7712 patients included,4882(63.3%)underwent CPCI.Compared with non-CPCI patients,CPCI patients had higher 2-and 5-year incidences of MACE and total coronary revascularization.Following multivariable adjustment including stent type,CPCI was an independent predictor of MACE(adjusted hazard ratio[aHR]:1.151;95%confidence interval[CI]:1.017–1.303,P=0.026)and total coronary revascularization(aHR:1.199;95%CI:1.037–1.388,P=0.014)at 5 years.The results were consistent at the 2-year endpoints.In patients with CPCI,BP-DES use was associated with significantly higher MACE rates at 5 years(aHR:1.256;95%CI:1.078–1.462,P=0.003)and total coronary revascularization(aHR:1.257;95%CI:1.052–1.502,P=0.012)compared with that of DP-DES,but there was a similar risk at 2 years.However,BP-DES had comparable safety and efficacy profiles including MACE and total coronary revascularization compared with DP-DES in patients with non-CPCI at 2 and 5 years.Conclusions:Patients underwent CPCI remained at a higher risk of mid-to long-term adverse events regardless of the stent type.The effect of BP-DES compared with DP-DES on outcomes was similar in CPCI and non-CPCI patients at 2 years but had inconsistent effects at the 5-year clinical endpoints.

Six-month results of a biodegradable polymer and rapamycin-coating stent for coronary artery disease

Objective To assess the safety and efficacy of a novel biodegradable polymer and rapamycin-coating stent, the EXCEL stent, in the treatment of coronary artery disease (CAD), as compared with the CypherTM stent. Methods In this prospective, non-randomized study, 60 consecutive patients with symptomatic CAD received either an EXCEL stent (n=32), or a CypherTM stent(n=28),according to their respective treatment intention. Follow-up angiography was performed at a mean of 180±40 days. The primary endpoint of the study was the occurrence of a major adverse cardiac event (MACE), including death, myocardial infarction, or target-vessel revascularization during the 6 months after stenting. The secondary end points included the in-stent late luminal loss (LLL), percentage of in-stent stenosis of the luminal diameter, and the rate of restenosis (luminal narrowing of 50 percent or more) at 6 months. Results There were no significant differences between the two groups in baseline characteristics, including the distribution of target vessel and lesion types. During the follow up period of 6 months, there were no occurrences of MACE in either group. Twenty-seven patients(84%) in the EXCEL group and 10 (36 %) in the CypherTM group underwent quantitative coronary angiography at 6 months. For these patients, no restenosis occurred, and there were no differences in the in-stent stenosis of the luminal diameter (5.98±5.52% vs 5.21 ±6.3%,P＞0.05) and the LLL (-0.02±0.09 mm vs -0.01±0.07 mm, P＞0.05). Conclusions Compared with the CypherTM stent, the EXCEL Stent with biodegradable polymer and rapamycin-coating showed similar efficacy in the prevention of neointimal proliferation, restenosis, and associated clinical events in CAD patients.

Safety and Performance of Sirolimus-Eluting Coronary Stent System with Biodegradable Polymer: A Retrospective Analysis in Real-World Patient Population

Background and Aim: Newer generation coronary stent systems with low profile metallic frame, biodegradable polymer coating and potent but safe anti-restenosis drug from “limus family” are emerging as safe and effective stents. To evaluate the safety and performance of Metafor SES (Meril life Sciences Pvt. Ltd., Vapi, India) in consecutive patients in a real-world population. Methods: The study was a retrospective, non-randomized, single-center study which evaluated the data of 127 patients who underwent percutaneous coronary intervention (PCI) treated with Metafor SES from February 2012 to February 2015 and mean follow-up period of those patients was 3.6 ± 0.6 years. The primary endpoint was a major adverse cardiac event (MACE) including cardiac death, myocardial infarction (MI), and target lesion revascularization (TLR). In addition, Stent thrombosis (ST) was analyzed at respective follow-up period. Results: A total of 127 patients (mean age: 53.70 ± 8.41 years and 99 males) were included. Among those 80 (63%) patients had hypertension and 58 (45.7%) patients with diabetes mellitus.At follow-up, MACE in form of TLR was observed in 2 (1.6%) patients only. No cardiac death or stent thrombosis was reported in any patient. A total of 169 lesions were treated with the Metafor SES (1.3 stents per lesion). The 38.4% of patients treated with the Metafor SES with lesion length ≥24 mm, and the procedural success was 100%. Conclusions: The lower incidence of MACE in uncontrolled and real world population at long term follow-up clearly depicts the prolonged safety and performance of the Metafor SES.

Safety evaluation of the biodegradable polymer-based sirolimus-eluting stent with faster drug eluting rate and polymer absorption kinetics in complex patient and lesion subgroup

Background and Objective Previous reports from PANDA III trial had proven that BuMA biodegradable polymer(BP)sirolimus-elutingstents(SES),with faster drug eluting rate and polymer absorption kinetics,was non-inferior to the Excel SES in an all-comers population for 1-year target lesion failure(TLF),with a lower incidence of stent thrombosis(ST).The aim of the present study was to perform a safety evaluation of BuMA SES in the complex patient and lesion subgroup.

Clinical Performance of the Cobalt-Chromium Biodegradable Polymer Coated Sirolimus-Eluting Stent in an Unselected Real-World Population

OBJECTIVE: The primary objective of the S-CORE registry was to assess the safety and efficacy of the Supralimus-Core? sirolimus-eluting stent deployment for the treatment of coronary artery disease and event-free survival of patients treated with this coronary stent. METHODS: S-CORE Registry is an observational, single-arm, non-randomized, post-marketing surveillance multicenter registry in which 562 patients undergoing single or multi-vessel percutaneous coronary intervention were enrolled. The pre-specified primary outcome was the rate of major adverse cardiac events (MACE), defined as the composite of cardiac death, myocardial infarction (MI), target lesion revascularisation (TLR) and target vessel revascularisation (TVR) at 12-month post-procedure. Stent thrombosis (ST) served as the safety endpoint. RESULTS: A total of 640 lesions were treated in 562 enrolled patients (mean age 57.4 ± 10.7 years) with average stent length of 25.0 ± 9.0 mm. Stent delivery was successful in 99% cases. A total of 554 (98.6%) patients have been followed up to 12 months. The incidence of MACE at 30 days and 6 months was 7 (1.2%) and 12 (2.1%) respectively. The composite rate of MACE at a 12-month clinical follow-up was 19 (3.4%), consisting of 12 (2.1%) cardiac deaths, 0 (0%) MI, 6 (1.1%) TLR and 1 (0.2%) TVR. The long-term follow-up of this registry is going on to confirm safety and efficacy profiles. CONCLUSIONS: This multicenter registry demonstrated satisfactory safety and efficacy profiles, as evidenced by low rates of major adverse cardiac events up to 12 months, for the cobalt-chromium biodegradable polymer-based sirolimus-eluting Supralimus-Core? stent in a “real-world” setting.

Preliminary Clinical Outcomes after Implantation of Newer-Generation Biodegradable Polymer-Coated Everolimus-Eluting Stent in “Real-World” Patients with Coronary Artery Disease

Background and Objective: In the contemporary practice, the use of drug-eluting stents is still associated with low mortality benefits, restenosis and stent thrombosis. To address these issues, newer generation, thin-strut, biodegradable polymer coated stents has been designed. Thus, the aim of the study is to assess the safety and clinical performance of the Everoflex (Sahajanand Medical Technologies Pvt. Ltd., Surat, India), a newer generation biodegradable polymer coated everolimus-eluting stent, in unselected “real-world” patients with coronary artery disease. Methods: It is a multicentre, retrospective, non-randomized, single-arm study enrolling all the consecutive patients who underwent implantation with the Everoflex for coronary artery disease from April 2014 to March 2016. The primary end-point of the study is 30-day major adverse cardiovascular events (MACE) rate, which consists of cardiac death, myocardial infarction, target lesion revascularization and target vessel revascularization. Stent thrombosis was also analyzed and reported. Results: A total of 340 patients were intervened successfully with 395 everolimus eluting stents (1.3 ± 0.6 stents per patient). Out of total patients (58.7 ± 10.5 years), 77.9% were male and comorbidities like diabetes and hypertension were observed in 31.2% and 35.3% patients, respectively. According to ACC/AHA classification, there were 34.4% type B lesions and 53.2% type C lesions, indicating a higher proportion of complexity involved. Moreover, 57.9% patients had multivessel disease and there were 15.4% total occlusions. At 30 days, follow-up was completed in 100% patients. The MACE was found to be 1.5%, which is a composite of 1.2% cardiac death and 0.3% target lesion revascularization. Stent thrombosis at 30 days was found to be 0.3%. Conclusion: The low incidence of MACE and stent thrombosis clearly depicts excellent safety and clinical performance of the Everoflex in unselected real world patients with coronary artery disease.

Advantages and disadvantages of biodegradable platforms in drug eluting stents

Coronary angioplasty with drug-eluting stent(DES)implantation is currently the most common stent procedure worldwide.Since the introduction of DES,coronary restenosis as well as the incidence of target vessel and target lesion revascularization have been significantly reduced.However,the incidence of very late stent thrombosis beyond the first year after stent deployment has more commonly been linked to DES than to baremetal stent(BMS)implantation.Several factors have been associated with very late stent thrombosis after DES implantation,such as delayed healing,inflammation,stent mal-apposition and endothelial dysfunction. Some of these adverse events were associated with the presence of durable polymers,which were essential to allow the elution of the immunosuppressive drug in the first DES designs.The introduction of erodable polymers in DES technology has provided the potential to complete the degradation of the polymer simultaneously or immediately after the release of the immunosuppressive drug,after which a BMS remains in place.Several DES designs with biodegradable(BIO)polymers have been introduced in preclinical and clinical studies, including randomized trials.In this review,we analyze the clinical results from 6 observational and randomized studies with BIO polymers and discuss advantages and disadvantages of this new technology.

Impact of biodegradable versus durable polymer drug-eluting stents on clinical outcomes in patients with coronary artery disease： a meta-analysis of 15 randomized trials

Background Drug eluting stents （DESs） made with biodegradable polymer have been developed in an attempt to improve clinical outcomes.However,the impact of biodegradable polymers on clinical events and stent thrombosis （ST） remains controversial.Methods We searched Medline,the Cochrane Library and other internet sources,without language or date restrictions for articles comparing clinical outcomes between biodegradable polymer DES and durable polymer DES.Safety endpoints were ST （definite,definite/probable）,mortality,and myocardial infarction （MI）.Efficacy endpoints were major adverse cardiac event （MACE） and target lesion revascularization （TLR）.Results We identified 15 randomized controlled trials （n=17 068） with a weighted mean follow-up of 20.6 months.There was no statistical difference in the incidence of definite/probable ST between durable polymer-and biodegradable polymerDES; relative risk （RR） 0.83; 95% confidence interval （CI） 0.62-1.11; P=0.22.Biodegradable polymer DES had similar rates of definite ST （RR 0.94,95% CI 0.66-1.33,P=0.72）,mortality （RR 0.94,95% C/0.82-1.09,P=0.43）,MI （RR 1.08,95% CI 0.92-1.26.P=0.35）,MACE （RR 0.99,95% CI 0.91-1.09,P=0.85）,and TLR （RR,0.94,95% CI 0.83-1.06,P=0.30） compared with durable polymer DES.Based on the stratified analysis of the included trials,the treatment effect on definite ST was different at different follow-up times：≤1 year favoring durable polymer DES and 〉1 year favoring biodegradable polymer DES.Conclusions Biodegradable polymer DES has similar safety and efficacy for treating patients with coronary artery disease compared with durable polymer DES.Further data with longer term follow-up are warranted to confirm the potential benefits of biodegradable polymer DES.

A Randomized Controlled Trial of a Biodegradable Polymer,Microcrystalline Sirolimus-Eluting Stent(MiStent)versus Another Biodegradable Polymer Sirolimus-Eluting Stent(TIVOLI):The DESSOLVE-C Trial

Objective::Data comparing the outcomes of MiStent(Micell Technologies,Durham,North Carolina,USA)microcrystalline biodegradable polymer(BP)drug-eluting stent(DES)and those of another post-marketing BP-DES,TIVOLI(EssenTech,Beijing,China)are rare.This study sought to compare the angiographic efficacy and clinical outcomes of the microcrystalline BP sirolimus-eluting stent(SES)system MiStent and those of TIVOLI BP-SES.Methods::The DESSOLVE-C trial was a prospective,single-blinded,multicenter,randomized trial(NCT02448524),which randomly assigned patients with de novo coronary lesions to receive MiStent or TIVOLI BP-SES by a 1:1 ratio.The primary endpoint was a non-inferiority comparison of in-stent late lumen loss(LLL)by quantitative coronary angiography at 9 months.The secondary endpoint was device-related clinical cardiovascular composite events(target lesion failure(TLF),composite of cardiac death,target vessel myocardial infarction(MI),and clinically driven target lesion revascularization)and 1-year outcomes.Results::A total of 428 patients(216 patients in the MiStent group and 212 patients in the TIVOLI group)were enrolled and included in an intention-to-treat analysis.MiStent was not only non-inferior but superior to TIVOLI for in-stent LLL at 9 months((0.23±0.37)mm vs.(0.34±0.48)mm,P for non-inferiority<0.001,P for superiority=0.02).Although without significant difference,the rate of TLF in MiStent was quantitatively lower than that in TIVOLI(3.70%vs.6.60%;P=0.17).Conclusion::Compared with TIVOLI BP-SES,the MiStent system was superior in in-stent LLL at 9 months and had a comparable clinical benefit at 1 year in de novo coronary lesions.

Efficacy and safety of FIREHAWK abluminal groove filled biodegradable polymer sirolimus-eluting stents for the treatment of long coronary lesions： nine-month angiographic and one-year clinical results from TARGET I trial lona cohort

Background Previous studies indicated that long coronary lesions are one of the key predictors of drug-eluting stent （DES） failure. The purpose of this study was to evaluate the efficacy and the safety of the long length FIREHAWK stent in long coronary artery disease. Methods The long cohort of TARGET I was a prospective, multicenter, single arm trial. It was planned to enroll 50 patients undergoing percutaneous coronary intervention （PCI） for the treatment of de novo long lesions in a native coronary artery. The major inclusion criteria of the trial was that patients were intended to undergo the treatment of a long target lesion（s） with diameter stenosis 〉70% and reference vessel diameter 2.5 mm to 4.0 mm by visual estimate, that needed to be covered by at least one 33 mm or 38 mm stent or multiple long stents overlapped. The angiographic follow-up was planned at 9-month and the clinical follow-up will be up to 5 years. The primary end point was in-stent late lumen loss at 9-month. Results Fifty patients （mean age （57.6±10.2） years） with 59 de novo long lesions （reference vessel diameter （2.85±0.44） mm, lesion length （35.2±9.4） mm, and stent length （41.8±11.3） mm） were enrolled. The angiographic follow-up rate was 92% at 9-month. The in-stent late loss was （0.16±0.16） mm. Proximal edge, distal edge and in-segment late loss （mm） were 0.21±0.35, 0.03±0.33, and 0.07±0.26, respectively. No in-segment binary restenosis was observed. At 1-year no death, Q wave myocardial infarction （MI）, or stent thrombosis occurred. Non-Q-wave MI occurred in two patients （4%） due to procedural complications. Conclusions Treatment of long coronary lesions with the FIREHAWK stent is able to produce similar results as observed in the FIREHAWK~ FIM clinical trial. Based on this result, we are confident in the treatment prospect of the FIREHAWK for long coronary lesions.

Long-term effects of biodegradable versus durable polymer-coated sirolimus-eluting stents on coronary arterial wall morphology assessed by virtual histology intravascular ultrasound

Background The durable presence of polymer coating on drug-eluting stent （DES） surface may be one of the principal reasons for stent thrombosis. The long-term coronary arterial response to biodegradable polymer-coated sirolimus-eluting stent （BSES） in vivo remained unclear.Methods Forty-one patients were enrolled in this study and virtual histology intravascular ultrasound （VH-IVUS） was performed to assess the native artery vascular responses to BSES compared with durable polymer-coated SES （DSES） during long-term follow-up （median： 8 months）. The incidence of necrotic core abutting to the lumen was evaluated at follow-up.Results With similar in-stent late luminal loss （0.15 mm （0.06-0.30 mm） vs. 0.19 mm （0.03-0.30 mm）, P=0.772）, the overall incidence of necrotic core abutting to the lumen was significantly less in BSES group than in DSES group （44% vs.63%, P 〈0.05） （proximal 18%, stented site 14% and distal 12% in BSES group, proximal 19%, stented site 28% and distal 16% in DSES group）. The DSES-treated segments had a significant higher incidence of necrotic core abutting to the lumen through the stent struts （73% vs. 36%, P 〈0.01）. In addition, more multiple necrotic core abutting to the lumen was observed in DSES group （overall： 63% vs. 36%, P 〈0.05）. Furthermore, when the stented segments with necrotic core abutting to the lumen had been taken into account only, DSES-treated lesions tended to contain more multiple necrotic core abutting to the lumen through the stent struts than BSES-treated lesions （74% vs. 33%）, although there was no statistically significant difference between them （P=0.06）.Conclusions By VH-IVUS analysis at follow-up, a greater frequency of stable lesion morphometry was shown in lesions treated with BSESs compared with lesions treated with DSESs. The major reason was BSES produced less toxicity to the arterial wall and facilitated neointimal healing as a result of polymer coating on DES surface biodegraded as time went by.

3D Printing of Biodegradable Polymer Vascular Stents:A Review

Biodegradable polymer vascular stents(BPVSs)have been widely used in percutaneous coronary interventions for the treatment of coronary artery diseases.The development of BPVSs is an integrated process that combines material design/selection,manufacturing,and performance characterization.Three-dimensional(3D)printing technology is a powerful tool for polymer stent fabrication.Current review studies have focused primarily on the material and structural design of polymer stents but have failed to comprehensively discuss different 3D printing approaches and stent characterization techniques.In this paper,we address these shortcomings by discussing 3D printing methods and their application in BPVSs.First,some commonly used 3D printing methods(including material extrusion,vat polymerization,and powder bed fusion)and potential 3D printing strategies(including material jetting and binder jetting)for fabricating BPVSs are discussed;furthermore,the main post-treatments are summarized.Then,techniques to characterize the morphology,mechanical properties,and biological prop-erties of the printed BPVSs are introduced.Subsequently,representative commercial BPVSs and lab-grade BPVSs are compared.Finally,based on the limitations of stent printing and characterization processes,future perspec-tives are proposed,which may help develop new techniques to fabricate more customized stents and accurately evaluate their performance.

Novel completed biodegradable polymer sirolimus-eluting stent versus durable polymer sirolimus-eluting stent in de novo lesions： nine-month angiographic and three-year clinical outcomes of HOPE trial

Background Drug-eluting stents（DES） with durable polymer have significantly reduced restenosis and target vessel revascularization compared with bare metal stents. Durable polymer has been linked with persistent inflammation of vessel wall and delayed endothelial healing that may increase the risk of late and very late stent thrombosis. This study sought to evaluate the efficacy and safety of HELLOS completed biodegradable polymer sirolimus-eluting stent （SES） in de novo coronary lesions.Methods Totally, 287 patients with one or two de novo coronary lesions （lesion length ≤38 mm and reference vessel diameter 2.5-4.0 mm） were enrolled in the HOPE study, a prospective, multicenter, randomized, non-inferiority trial. Patients were randomized to treatment either with HELIOS completed biodegradable polymer SES （n=142） or PARTNER durable polymer SES （n=145）. The primary endpoint was angiographic in-stent late lumen loss （LLL） at 9-month follow-up. The secondary endpoint included stent thrombosis and major adverse cardiac events including cardiac death, myocardial infarction （MI） and target lesion revascularization （TLR）.Results The 9-month in-stent LLL in the HELIOS group was similar to the PARTNER group, （0.16±0.22） mm vs. （0.19±0.30） mm （P=0.28）. The difference and 95% confidence interval were -0.03 （-0.09, 0.04）, and the P value for non-inferiority 〈0.01. Major adverse cardiovascular event （MACE） occurred in 7.9% vs. 8.2%, MI in 2.4% vs. 3.0%, TLR in 5.5% vs. 3.0%, and stent thrombosis in 0 vs. 1.5%; and events were comparable between the HELIOS group and PARTNER aroup at three-year follow-up （all P 〉0.05）. The three-year cardiac death was lower in the HELIOS group, butwith no significant difference, 0 vs. 3.0% （P=0.12）. Conclusions In the HOPE trial, the novel completed biodegradable polymer SES HELIOS was non-inferior to the durable polymer SES PARTNER with respect to nine-month in-stent LLL in de novo coronary lesions. The incidence of other clinical endpoints was low for both of the stents in three-year follow-up.

Long-term clinical outcomes after bioabsorbable polymer- and durable polymer-based sirolimus-eluting stents implantation： two-year follow-up results from a large single-center database

Background Several clinical trials have shown that sirolimus-eluting stents significantly reduce the risk of restenosis after percutaneous coronary intervention （PCI）. The FIREBIRD stent （coated with durable polymer） and the EXCEL stent （coated with bioabsorbable polymer） are two different types of sirolimus-eluting stents made in China; both have been approved for clinical use in China by the State Food and Drug Administration. The mid-term （6-month） angiographic and clinical results of both stents have been confirmed exciting perspective outcomes. However, it is unclear whether there are differences in the long-term safety and efficacy between the two types of stents in daily practice.Methods All consecutive patients undergoing elective PCI with EXCEL or FIREBIRD stents between June 1,2006 and December 31, 2006 at Fu Wai Hospital in Beijing were included. Patients were classified from the index admission according to stent types （EXCEL or FIREBIRD） used. Clinical and procedural risk factors were collected prospectively. With propensity score matching without replacement, the frequency of major adverse cardiac events （MACE, a composite of death, myocardial infarction or target vessel revascularization） and stent thrombosis during a 2-year follow-up period were compared between the two groups.Results A total of 474 patients were treated with EXCEL, and 640 were treated with FIREBIRD. Three hundred and ninety-seven EXCEL patients were matched to 397 FIREBIRD patients, 2-year risk-adjusted MACE rates were 6.1% in EXCEL group and 7.6% in FIREBIRD group （HR 0.84, 95%CI0.50-1.43）, whereas the respective rates for mortality, myocardial infarction and target-vessel revascularization were 2.3% vs 2.8% （HR 0.74, 95%CI0.30-0.85）, 1.8% vs 1.3% （HR 1.41,95%CI 0.45-4.43） and 2.5% vs 4.0% （HR 0.62, 95%CI0.28-0.37）, respectively. Cumulative incidence of stent thrombosis at 2 years was 1.8% in the EXCEL group vs 1.3% in the FIREBIRD group （P=0.5610）, whereas the rate of very late stent thrombosis was 0.5% vs 1.3% （P=0.2550）.Conclusions Results from this long-term, relatively large size, single-center study showed that both of the EXCEL and the FIREBIRD sirolimus-eluting stent had similar and lower incidence of MACE after PCI in daily practice.

4D printing of personalized shape memory polymer vascular stents with negative Poisson’s ratio structure:A preliminary study

Four-dimensional(4D)printing,integrates transformation information into three-dimensional(3D)-printed structures,which means that 3D-printed structures are able to change their shapes,properties,or functionalities over time.Here,two types of shape memory personalized vascular stents with negative Poisson’s ratio structure are developed via 4D printing.The genetic algorithm is used to optimize the structure.Axial compression tests,radial compression tests and three-point bending tests are carried out to study the mechanical properties of the stents.In addition,fluid-structure interaction and stress distribution during the shape recovery process are investigated based on finite element method.The shape memory behaviors of the stents are excellent and in vitro feasibility tests demonstrate that the stents can expand the simulated narrow blood vessel rapidly.Therefore,4D printed shape memory stents with negative Poisson’s ratio structure are highly promising for the treatment of vascular stenosis.

A review on biodegradable biliary stents: materials and future trends

Biliary stricture is defined as the reduction and narrowing of the bile duct lumen, which can be caused by many factors such as cancer and inflammation. Biliary stent placement can effectively alleviate benign and malignant biliary strictures. However, the commonly used plastic or metallic biliary stents are far from ideal and do not satisfy all clinical requirements,although several types of biodegradable biliary stents have been developed and used clinically. In this review, we summarized current development status of biodegradable stents with the emphasis on the stent materials. We also presented the future development trends based on the published literature.