Ultrathin strut biodegradable polymer sirolimus-eluting stent versus durable polymer everolimus-eluting stent for percutaneous coronary revascularisation (BIOSCIENCE): a randomised, single-blind, non-inferiority trial

Orsiro: ultrathin bioabsorbable polymer sirolimus-eluting stent

Recent stent developments aimed to reduce and eliminate the long-term inflammatory response include thinner struts, modifications to stent design and the development of bioresorbable polymers (BP). We aimed to summarize the main findings and to discuss the established and the potential benefits of the Orsiro BP sirolimus-eluting stents in everyday clinical use. We have reviewed the available evidence on the clinical performance of the Orsiro BP drug-eluting stents. Orsiro BP sirolimus-eluting stents is clinically proven and showed noninferiority against major drug-eluting stents and provides high safety and efficacy profile at long-term follow-up. Furthermore, it may be the preferred treatment option in specific subgroups as acute coronary syndrome, as shown in the BIOFLOW V trial.

Comparison of the polymer-free biolimus-coated BioFreedom stent with the thin-strut biodegradable polymer sirolimus-eluting Orsiro stent in an all-comers population treated with percutaneous coronary intervention: Rationale and design of the randomized SORT OUT IX trial

BACKGROUND

In patients with increased bleeding risk during dual antiplatelet therapy, the biolimus A9-coated BioFreedom, a stainless steel drug-coated stent devoid of polymer, has shown superiority compared to a bare-metal stent. The aim of this study was to investigate whether the polymer-free biolimus A9-coated BioFreedom is noninferior to a modern thin-strut biodegradable polymer cobalt-chromium sirolimus-eluting Orsiro stent in an all-comers patient population treated with percutaneous coronary intervention.

METHODS

The multicenter SORT OUT IX trial (NCT02623140) randomly assigned all-comers patients to treatment with the BioFreedom drug-coated stent or the biodegradable polymer Orsiro stent in 4 Danish University Hospitals. The primary end point target lesion failure is a composite of cardiac death, myocardial infarction (not related to other than index lesion), or target lesion revascularization within 12 months. Clinically driven event detection based on Danish registries will be used and continue through 5 years. Assuming an event rate of 4.2% in each stent group, 1,563 patients in each treatment arm will provide 90% power to detect noninferiority of the drug-coated BioFreedom stent with a noninferiority margin of 2.1%.

RESULTS

A total of 3,150 patients have been randomized and enrolled in the study.

CONCLUSIONS

The SORT OUT IX trial will determine whether the drug-coated BioFreedom stent is noninferior to a modern biodegradable polymer Orsiro stent.

High Bleeding Risk Patients Treated with Very Thin-Strut Biodegradable Polymer or Thin-Strut Durable Polymer Drug-Eluting Stents in the BIO-RESORT Trial

Purpose

Patients with high bleeding risk (HBR) who undergo percutaneous coronary intervention also have an increased risk of ischemic events and represent an overall high-risk population. The coating of durable polymer drug-eluting stents (DP-DES) may induce inflammation and delay arterial healing, which might be reduced by novel biodegradable polymer DES (BP-DES). We aimed to evaluate the safety and efficacy of treating HBR patients with very thin-strut BP-DES versus thin-strut DP-DES.

Methods

Participants in BIO-RESORT (NCT01674803), an investigator-initiated multicenter, randomized all-comers trial, were treated with very thin-strut BP-DES (Synergy or Orsiro) or thin-strut DP-DES (Resolute Integrity). For the present analysis, patients were classified following HBR criteria based on previous trials. The primary endpoint was target vessel failure: a composite of cardiac death, target vessel-related myocardial infarction, or target vessel revascularization at 1 year.

Results

Of all 3514 patients, 1009 (28.7%) had HBR. HBR patients were older (p < 0.001) and had more co-morbidities than non-HBR patients (p < 0.001). At 1-year follow-up, HBR patients had significantly higher rates of target vessel failure (6.7 vs. 4.2%, p = 0.003), cardiac death (1.9 vs. 0.4%, p < 0.001), and major bleeding (3.3 vs. 1.5%, p = 0.001). Of all 1009 HBR patients, 673 (66.7%) received BP-DES and 336 (33.3%) had DP-DES. The primary endpoint was met by 43/673 (6.5%) patients treated with BP-DES and 24/336 (7.3%) treated with DP-DES (HR 0.88 [95%CI 0.54–1.46], p = 0.63). There were no significant between-group differences in the most global patient-oriented clinical endpoint (9.7 vs. 10.5%, HR 0.92 [95%CI 0.61–1.39], p = 0.69) and other secondary endpoints.

Conclusions

At 1-year follow-up, very thin-strut BP-DES showed similar safety and efficacy for treating HBR patients as thin-strut DP-DES.

Electronic supplementary material

The online version of this article (10.1007/s10557-018-6823-9) contains supplementary material, which is available to authorized users.

Long-term safety of bioresorbable scaffolds: insights from a network meta-analysis including 91 trials

AIMS

The aim of this study was to investigate the long-term safety and efficacy of biodegradable scaffolds and metallic stents.

METHODS AND RESULTS

We analysed a total of 91 randomised controlled trials with a mean follow-up of 3.7 years in 105,842 patients which compared two or more coronary metallic stents or biodegradable scaffolds and reported the long-term clinical outcomes (≥2 years). Network meta-analysis showed that patients treated with the Absorb bioresorbable vascular scaffold (BVS) had a significantly higher risk of definite or probable scaffold thrombosis (ScT) compared to those treated with metallic DES. The risk of very late ScT was highest with the Absorb BVS among comparators. Pairwise conventional meta-analysis demonstrated that the elevated risk of ScT with Absorb BVS compared to cobalt-chromium everolimus-eluting stents was consistent across the time points of ≤30 days (early), 31 days - 1 year (late) and >1 year (very late) ScT. In addition, target lesion failure rates were significantly higher in the Absorb BVS cohort, driven by both increased risk of target vessel myocardial infarction and ischaemia-driven target lesion revascularisation.

CONCLUSIONS

Absorb BVS implantation was associated with increased risk of long-term and very late ScT compared to current-generation metallic DES. The risk of ScT occurred with a rising trend beyond one year.

The BIOFLOW-III Italian Satellite Registry: 18-month results of the Orsiro stent in an all-comer high-risk population

AIMS

We aimed to corroborate clinical evidence on the safety and efficacy of the ultrathin-strut biodegradable-polymer sirolimus-eluting Orsiro stent in an all-comer population including high-risk subgroups.

METHODS

The nationwide, prospective, all-comer BIOFLOW-III Satellite Registry was conducted at 18 Italian sites. High-risk subgroups [diabetes, small vessels (≤2.75 mm), acute myocardial infarction (AMI), and chronic total occlusions (CTOs)] were prespecified. The primary endpoint was target lesion failure (TLF) at 12 months, a composite of cardiac death, target vessel myocardial infarction (MI), emergent coronary artery bypass graft, and clinically driven target lesion revascularization (TLR).

RESULTS

In all, 601 patients were enrolled (31.9% diabetes, 34.6% AMIs) with 736 lesions (37.2% small vessels, 5.7% CTOs, and 15.5% bifurcation lesions). Cumulative TLF rate at 12 months was 4.6% [95% confidence interval (CI) 3.2-6.6]: 6.9% (95% CI 4.1-11.6) in the diabetic patients, 5.0% (95% CI 2.7-9.1) in acute MI subgroup, 4.2% (95% CI 2.3-7.7) in small vessels, and 5.3% (95% CI 1.4-19.7) in CTOs. At 18-month follow-up, TLF, target vessel revascularization, and clinically driven TLR rates in the overall population were 5.2% (95% CI 3.7-7.4), 1.8% (95% CI 1.0-3.3), and 1.6% (95% CI 0.8-3.1), respectively. Probable stent thrombosis rate was 0.5% (95% CI 0.1-1.4), whereas no definite stent thrombosis was observed.

CONCLUSIONS

The study results confirmed the excellent clinical performance of the Orsiro drug-eluting stents at 18 months in the whole all-comer population and in the prespecified high-risk subgroups.

Impact of left ventricular function on clinical outcomes among patients with coronary artery disease

AIMS

To investigate the clinical relevance of contemporary cut-offs of left ventricular ejection fraction (LVEF) including an intermediate phenotype with mid-range reduced ejection fraction among patients with coronary artery disease undergoing percutaneous coronary intervention.

METHODS AND RESULTS

Patient-level data were summarized from five randomized clinical trials in which 6198 patients underwent clinically indicated percutaneous coronary intervention in different clinical settings. We assessed all-cause mortality as primary endpoint at five-year follow-up. According to the proposed LVEF cut-offs, 3816 patients were included in the preserved LVEF group (LVEF ≥ 50%), 1793 in the mid-range reduced LVEF group (LVEF 40-49%) and 589 patients in the reduced LVEF group (LVEF < 40%). Patients in the reduced LVEF group were at increased risk for the primary outcome of all-cause mortality compared with both, preserved and mid-range LVEF throughout five years of follow-up (adjusted hazard ratio 2.39 (95% confidence interval 1.75-3.28, p < 0.001) and 1.68 (95% confidence interval 1.34-2.10, p < 0.001), respectively). The risk of cardiac death and the composite endpoint of cardiac death, myocardial infarction, or stroke were higher for patients in the reduced LVEF group compared with the preserved and mid-range reduced LVEF groups, but also for the mid-range LVEF compared with preserved LVEF group (adjusted p < 0.05 for all comparisons) throughout five years. Irrespective of clinical presentation at baseline (stable coronary artery disease or acute coronary syndrome), patients with reduced or mid-range LVEF were at increased risk of all-cause mortality and cardiac death up to five years compared with the other group (adjusted p < 0.05 for all comparisons).

CONCLUSION

Patients with reduced LVEF <40% or mid-range LVEF 40-49% in the context of coronary artery disease undergoing clinically indicated percutaneous coronary intervention are at increased risk of all-cause mortality, cardiac death and the composite of cardiac death, stroke and myocardial infarction throughout five years of follow-up. The recently proposed LVEF cut-offs contribute to the differentiation and risk stratification of patients with ischaemic heart disease.

Randomised evaluation of a novel biodegradable polymer-based sirolimus-eluting stent in ST-segment elevation myocardial infarction: the MASTER study

AIMS

The MASTER study was designed to compare the performance of a new biodegradable polymer sirolimus-eluting stent (BP-SES) with a bare metal stent (BMS) in patients with ST-segment elevation myocardial infarction (STEMI).

METHODS AND RESULTS

The study was a prospective, randomised (3:1), controlled, single-blind multicentre trial that enrolled 500 STEMI patients within 24 hours of symptom onset during 2013-2015. Three hundred and seventy-five patients were treated with BP-SES and 125 with BMS. One hundred and four (104) randomised patients underwent angiographic follow-up at six months. The primary clinical endpoint was target vessel failure (TVF), defined as cardiac death, MI not clearly attributable to a non-target vessel, or clinically driven target vessel revascularisation (TVR) at 12 months. The primary angiographic endpoint was in-stent late lumen loss (LLL) at six months in the angiographic cohort. The major secondary endpoint for safety was a composite of all-cause death, recurrent MI, unplanned infarct-related artery revascularisation, stroke, definite stent thrombosis (ST) or major bleeding at one month. At 12 months, TVF had occurred in 6.1% of BP-SES and 14.4% of BMS patients (pnon-inferiority=0.0004), mainly driven by a higher rate of repeat revascularisation in BMS patients. The safety endpoint occurred in 3.5% of BP-SES and 7.2% of BMS patients (p=0.127). In-stent LLL demonstrated the superiority (p=0.0125) of BP-SES (0.09±0.43 mm) over BMS (0.79±0.67 mm).

CONCLUSIONS

The study showed clinical non-inferiority and angiographic superiority of BP-SES versus a comparator BMS, suggesting that this novel DES may be a potential treatment option in STEMI.

Use of Mortality as an Endpoint in Noninferiority Trials May Lead to Ethically Problematic Conclusions

BACKGROUND

Noninferiority trials are becoming more common. Their design often requires investigators to "trade" a secondary benefit for efficacy. Use of mortality as an outcome of interest leads to important ethical conflicts whereby researchers must establish a minimal clinically important difference for mortality, a process which has the potential to result in problematic conclusions.

OBJECTIVE

We sought to investigate the frequency of the use of mortality as an outcome in noninferiority trials, as well as to determine the average pre-specified noninferiority ("delta") values.

DESIGN

We searched MEDLINE for reports of parallel-group randomized controlled noninferiority trials published in five high-impact general medical journals.

MAIN OUTCOME MEASURES

Data abstracted from articles including trial design parameters, results, and interpretation of results based on CONSORT recommendations.

RESULTS

One hundred seventy-three manuscripts reporting 196 noninferiority comparisons were included in our analysis. Of these, over a third (67 trials) used mortality either as their sole endpoint (11 trials) or as part of a composite endpoint (56 trials). Nine trials were consort A, 21 trials consort B, 19 trials consort C, 12 were consort F, 4 consort G, and 2 were consort H. Four analyses showed statistically significant more deaths in the new treatment arm, while meeting consort criteria as "inconclusive" (consort G), (Behringer et al. in Lancet. 385(9976):1418-1427, 2015; Kaul et al. in N Engl J Med. 373(18):1709-1719, 2015; Bwakura-Dangarembizi et al. in N Engl J Med. 370(1):41-53, 2014) and thirteen trials utilizing mortality as an endpoint and had an absolute increase of > 3%, and six had an absolute increase of > 5%.

CONCLUSIONS

The use of mortality as an outcome in noninferiority trials is not rare and scenarios where the new treatment is statistically worse, but a conclusion of noninferiority or inconclusive do occur. We highlight these issues and propose simple steps to reduce the risk of ethically dubious conclusions.

Safety and efficacy of a sirolimus-eluting coronary stent with ultra-thin strut for treatment of atherosclerotic lesions (TALENT): a prospective multicentre randomised controlled trial

BACKGROUND

Supraflex is a sirolimus-eluting stent with a biodegradable polymer coating and ultra-thin struts. We aimed to compare Supraflex with the standard of care, Xience, an everolimus-eluting stent with a durable polymer coating, regarding clinical outcomes with a randomised trial in an all-comer population.

METHODS

We did a prospective, randomised, single-blind, multicentre study (TALENT) across 23 centres in Europe (the Netherlands, Poland, the UK, Spain, Bulgaria, Hungary, and Italy). Eligible participants were aged 18 years or older, had one or more coronary artery stenosis of 50% or greater in a native coronary artery, saphenous venous graft, or arterial bypass conduit, and had a reference vessel diameter of 2·25-4·50 mm. Patients underwent percutaneous coronary intervention in an all-comer manner. We randomly assigned patients (1:1) to implantation of either a sirolimus-eluting stent with a biodegradable polymer coating and ultra-thin struts (Supraflex) or an everolimus-eluting stent with a durable polymer coating (Xience). Randomisation was done by local investigators by use of a web-based software with random blocks according to centre. The primary endpoint was a non-inferiority comparison of a device-oriented composite endpoint-cardiac death, target-vessel myocardial infarction, or clinically indicated target lesion revascularisation-between groups at 12 months after the procedure, assessed in an intention-to-treat population. On assumption of 1-year composite endpoint prevalence of 8·3%, a margin of 4·0% was defined for non-inferiority of the Supraflex group compared with the Xience group. This trial is registered with ClinicalTrials.gov, number NCT02870140.

FINDINGS

Between Oct 21, 2016, and July 3, 2017, 1435 patients with 1046 lesions were randomly assigned to Supraflex, of whom 720 received the index procedure, and 715 patients with 1030 lesions were assigned to Xience, all receiving the index procedure. At 12 months, the primary endpoint had occurred in 35 patients (4·9 %) in the Supraflex group and in 37 patients (5·3%) in the Xience group (absolute difference -0·3% [one-sided 95% upper confidence bound 1·6%], p_{non-inferiority}<0·0001). Definite or probable stent thrombosis prevalence, a safety indicator, was low in both groups and did not differ between them.

INTERPRETATION

The Supraflex stent was non-inferior to the Xience stent for a device-oriented composite clinical endpoint at 12 months in an all-comer population. Supraflex seems a safe and effective alternative drug-eluting stent to other stents in clinical practice.

FUNDING

European Cardiovascular Research Institute.

Newer-generation Metallic Stents: Design, Performance Characteristics, and Outcomes

Several new coronary stents have been, or soon will be, introduced in the United States. These stents incorporate certain characteristics, such as polymer-free drug coatings, ultrathin stent struts, bioresorbable polymers, and composite materials, that address currently unmet clinical needs to enhance acute stent performance, improve longer-term clinical outcomes, and obviate obligatory prolonged dual antiplatelet therapy. This article reviews the key and novel features of these stents.

Materials and Devices for Biodegradable and Soft Biomedical Electronics

Biodegradable and soft biomedical electronics that eliminate secondary surgery and ensure intimate contact with soft biological tissues of the human body are of growing interest, due to their emerging applications in high-quality healthcare monitoring and effective disease treatments. Recent systematic studies have significantly expanded the biodegradable electronic materials database, and various novel transient systems have been proposed. Biodegradable materials with soft properties and integration schemes of flexible or/and stretchable platforms will further advance electronic systems that match the properties of biological systems, providing an important step along the path towards clinical trials. This review focuses on recent progress and achievements in biodegradable and soft electronics for biomedical applications. The available biodegradable materials in their soft formats, the associated novel fabrication schemes, the device layouts, and the functionality of a variety of fully bioresorbable and soft devices, are reviewed. Finally, the key challenges and possible future directions of biodegradable and soft electronics are provided.

Comparison between two biodegradable polymer-based sirolimus-eluting stents with differing drug elution and polymer absorption kinetics: two-year clinical outcomes of the PANDA III trial

AIMS

In the PANDA III trial, the novel poly-lactide-co-glycolide polymer-based BuMA sirolimus-eluting stent (SES) was non-inferior to the polylactide polymer-based Excel SES for the primary endpoint of one-year target lesion failure (TLF), with a lower incidence of stent thrombosis. We sought to investigate whether the effectiveness profile of BuMA SES, with more rapid drug elution and polymer absorption kinetics, would persist at two years.

METHODS AND RESULTS

A total of 2,348 patients (mean age, 61.2±10.6 years; 24.3% diabetics; 31.2% with acute myocardial infarction within one month) were randomly assigned to receive either BuMA SES (n=1,174) or Excel SES (n=1,174) in the "all-comer" PANDA III trial. Two-year clinical follow-up was available for 2,262 (96.3%) patients. The incidence of TLF and the patient-oriented composite endpoint (PoCE) was low and similar between the BuMA and Excel groups (7.4% vs. 6.9%, p=0.67, and 13.1% vs. 10.9%, p=0.11, respectively). The rate of any revascularisation was significantly higher with the BuMA SES (6.8% vs. 4.6%, p=0.03). Definite and probable thrombosis occurred in 0.7% and 1.4% of patients in the BuMA and Excel groups, respectively (p=0.10).

CONCLUSIONS

Two-year rates of TLF and PoCE events were low and similar between the two biodegradable polymer-based SES.

Thin composite wire strut, durable polymer-coated (Resolute Onyx) versus ultrathin cobalt-chromium strut, bioresorbable polymer-coated (Orsiro) drug-eluting stents in allcomers with coronary artery disease (BIONYX): an international, single-blind, randomised non-inferiority trial

BACKGROUND

During the past decade, many patients had zotarolimus-eluting stents implanted, which had circular shape cobalt-chromium struts with limited radiographic visibility. The Resolute Onyx stent was developed to improve visibility while reducing strut thickness, which was achieved by using a novel composite wire with a dense platinum-iridium core and an outer cobalt-chromium layer. We did the first randomised clinical trial to assess the safety and efficacy of this often-used stent compared with the Orsiro stent, which consists of ultrathin cobalt-chromium struts.

METHODS

We did an investigator-initiated, assessor-blinded and patient-blinded, randomised non-inferiority trial in an allcomers population at seven independently monitored centres in Belgium, Israel, and the Netherlands. Eligible participants were aged 18 years or older and required percutaneous coronary intervention with drug-eluting stents. After guide wire passage with or without predilation, members of the catheterisation laboratory team used web-based computer-generated allocation sequences to randomly assign patients (1:1) to either the Resolute Onyx or the Orsiro stent. Randomisation was stratified by sex and diabetes status. Patients and assessors were masked to allocated stents, but treating clinicians were not. The primary endpoint was target vessel failure at 1 year, a composite of cardiac death, target-vessel-related myocardial infarction, and target vessel revascularisation, and was assessed by intention to treat (non-inferiority margin 2·5%) on the basis of outcomes adjudicated by an independent event committee. This trial is registered with ClinicalTrials.gov, number NCT02508714.

FINDINGS

Between Oct 7, 2015, and Dec 23, 2016, 2516 patients were enrolled, 2488 of whom were included in the intention-to-treat analysis (28 withdrawals or screening failures). 1243 participants were assigned to the Resolute Onyx group, and 1245 to the Orsiro group. Overall, 1765 (70·9%) participants presented with acute coronary syndromes and 1275 (51·2%) had myocardial infarctions. 1-year follow-up was available for 2478 (99·6%) patients. The primary endpoint was met by 55 (4·5%) patients in the Resolute Onyx group and 58 (4·7%) in the Orsiro group. Non-inferiority of Resolute Onyx to Orsiro was thus established (absolute risk difference -0·2% [95% CI -1·9 to 1·4]; upper limit of the one-sided 95% CI 1·1%; p_{non-inferiority}=0·0005). Definite or probable stent thrombosis occurred in one (0·1%) participant in the Resolute Onyx group and nine (0·7%) in the Orsiro group (hazard ratio 0·11 [95% CI 0·01-0·87]; p=0·0112).

INTERPRETATION

The Resolute Onyx stent was non-inferior to Orsiro for a combined safety and efficacy endpoint at 1-year follow-up in allcomers. The low event rate in both groups suggests that both stents are safe, and the very low rate of stent thrombosis in the Resolute Onyx group warrants further clinical investigation.

FUNDING

Biotronik and Medtronic.

Targeted therapy with a localised abluminal groove, low-dose sirolimus-eluting, biodegradable polymer coronary stent (TARGET All Comers): a multicentre, open-label, randomised non-inferiority trial

BACKGROUND

The FIREHAWK is a drug-eluting stent with a fully biodegradable sirolimus-containing polymer coating localised to recessed abluminal grooves on the stent surface. We investigated clinical outcomes with this targeted, low-dose, biodegradable polymer, sirolimus-eluting stent compared with XIENCE durable polymer, everolimus-eluting stents in an all-comers population.

METHODS

The TARGET All Comers study was a prospective, multicentre, open-label randomised non-inferiority trial done at 21 centres in ten European countries. Patients with symptomatic or asymptomatic coronary artery disease and objective evidence of myocardial ischaemia who qualified for percutaneous coronary intervention were randomised 1:1 to undergo implantation of a FIREHAWK or XIENCE. Randomisation was web-based, with random block allocation and stratification by centre and ST elevation myocardial infarction. Outcome assessors were masked to treatment allocation, but treating physicians and patients were not. The primary endpoint was target lesion failure at 12 months, a composite of cardiac death, target vessel myocardial infarction, or ischaemia-driven target lesion revascularisation. The control event rate for XIENCE was assumed to be 7%, the non-inferiority margin was 3.5%, and the primary analysis was in the intention-to-treat population, censoring patients who did not have either an event before 365 days or contact beyond 365 days. Late lumen loss was the primary endpoint of an angiographic substudy designed to investigate the non-inferiority of the FIREHAWK compared with the XIENCE stent. This trial is registered with ClinicalTrials.gov, number NCT02520180.

FINDINGS

From Dec 17, 2015, to Oct 14, 2016, 1653 patients were randomly assigned to implantation of the FIREHAWK (n=823) or XIENCE (n=830). 65 patients in the FIREHAWK group and 66 in the XIENCE group had insufficient follow-up data and were excluded from the analyses. At 12 months, target lesion failure occurred in 46 (6·1%) of 758 patients in the FIREHAWK group and in 45 (5·9%) of 764 patients in the XIENCE group (difference 0·2%, 90% CI -1·9 to 2·2, p_{non-inferiority}=0·004, 95% CI -2·2 to 2·6, p_superiority=0·88). There were no differences in ischaemia-driven revascularisation or stent thrombosis rates at 12 months. 176 patients were included in the angiographic substudy, in which in-stent late lumen loss was 0·17 mm (SD 0·48) in the FIREHAWK group and 0·11 mm (0·52) in the XIENCE group (p=0·48), with an absolute difference of 0·05 mm (95% CI -0·09 to 0·18, p_{non-inferiority}=0·024).

INTERPRETATION

In a broad all-comers population of patients requiring stent implantation for myocardial ischaemia, the FIREHAWK was non-inferior to the XIENCE as assessed with the primary endpoint of target lesion failure at 12 months and in-stent late lumen loss at 13 months. The FIREHAWK is a safe and effective alternative stent to treat patients with ischaemic coronary artery disease in clinical practice.

FUNDING

Shanghai Microport Medical.

Ultrathin-strut, biodegradable-polymer, sirolimus-eluting stents versus thin-strut, durable-polymer, everolimus-eluting stents for percutaneous coronary revascularisation: 5-year outcomes of the BIOSCIENCE randomised trial

BACKGROUND

Drug-eluting stents combining an ultrathin cobalt-chromium stent platform with a biodegradable polymer eluting sirolimus have been shown to be non-inferior or superior to thin-strut, durable-polymer, everolimus-eluting stents in terms of 1 year safety and efficacy outcomes.

METHODS

In the randomised, single-blind, multicentre, non-inferiority BIOSCIENCE trial, we compared biodegradable-polymer sirolimus-eluting stents with durable-polymer everolimus-eluting stents in patients with chronic stable coronary artery disease or acute coronary syndromes. Here, we assess the final 5-year clinical outcomes of BIOSCIENCE with regards to the primary clinical outcome of target lesion failure, which was a composite of cardiac death, target vessel myocardial infarction, and clinically indicated target lesion revascularisation. The primary analysis was done by intention to treat. The BIOSCIENCE trial is registered with ClinicalTrials.gov, number NCT01443104.

FINDINGS

2008 (95%) of 2119 patients recruited between March 1, 2012, and May 31, 2013, completed 5 years of follow-up. Target lesion failure occurred in 198 patients (cumulative incidence 20·2%) treated with biodegradable-polymer sirolimus-eluting stents and in 189 patients (18·8%) treated with durable-polymer everolimus-eluting stents (rate ratio [RR] 1·07, 95% CI 0·88-1·31; p=0·487). All-cause mortality was significantly higher in patients treated with biodegradable-polymer sirolimus-eluting stents than in those treated with durable-polymer everolimus-eluting stents (14·1% vs 10·3%; RR 1·36, 95% CI 1·06-1·75; p=0·017), driven by a difference in non-cardiovascular deaths. We observed no difference between groups in cumulative incidence of definite stent thrombosis at 5 years (1·6% in both groups; 1·02, 0·51-2·05; p=0·950).

INTERPRETATION

5-year risk of target lesion failure among all-comer patients undergoing percutaneous coronary intervention is similar after implantation of ultrathin-strut, biodegradable-polymer, sirolimus-eluting stents or thin-strut, durable-polymer, everolimus-eluting stents. Higher incidences of all-cause and non-cardiovascular mortality in patients treated with biodegradable-polymer stents eluting sirolimus than in those treated with durable-polymer stents eluting everolimus warrant careful observation in ongoing clinical trials.

FUNDING

Clinical Trials Unit of the University of Bern and Biotronik.

Long-term clinical outcomes with biodegradable polymer sirolimus-eluting stents versus durable polymer sirolimus-eluting stents

AIMS

The purpose of this study was to compare the long-term outcomes of a biodegradable polymer, sirolimus-eluting stent (Orsiro) with a durable polymer, sirolimus-eluting stent (CYPHER) to determine if late failure of the CYPHER is caused by the polymer or sirolimus.

METHODS AND RESULTS

A total of 447 patients who underwent percutaneous coronary intervention (PCI) with one of the study stents were retrospectively analysed. The composite of cardiac death, stent thrombosis, and clinically driven target lesion revascularisation (TLR) within two years after PCI occurred in 3.0% of the Orsiro group and 9.6% of the CYPHER group. Multivariable Cox regression results indicated that the Orsiro stent was a significant independent predictor of a lower occurrence of the composite outcome (adjusted HR 0.37, 95% CI: 0.14-0.87), stent thrombosis (adjusted HR 0.07, 95% CI: 0.00-0.65), clinically driven TLR (adjusted HR 0.26, 95% CI: 0.09-0.69), and stent failure (adjusted HR 0.26, 95% CI: 0.09-0.69) within two years after PCI.

CONCLUSIONS

This study has demonstrated that late CYPHER failure is attributable more to its durable polymer than to the antiproliferative drug, sirolimus. This suggests that sirolimus-based, new-generation drug-eluting stents are relatively safe and are expected to show long-term outcomes superior to those of the CYPHER.

Mortality Following Nonemergent, Uncomplicated Target Lesion Revascularization After Percutaneous Coronary Intervention: An Individual Patient Data Pooled Analysis of 21 Randomized Trials and 32,524 Patients

OBJECTIVES

This study sought to investigate the impact of nonemergent, uncomplicated target lesion revascularization (TLR) on the risk of long-term mortality after percutaneous coronary intervention (PCI).

BACKGROUND

Restenosis requiring TLR after PCI is generally considered a benign event.

METHODS

The study pooled patient-level data from 21 randomized trials. Subjects dying the same day as or the day after the TLR procedure as well as those with myocardial infarction (MI) the day before, the same day as or the day after TLR were excluded. The primary endpoint of the study was all-cause mortality.

RESULTS

The dataset included 32,524 patients who were stratified according to whether repeat TLR was performed during follow-up. During a median follow-up of 37 months, 2,330 (7.2%) patients underwent a nonemergent, uncomplicated TLR procedure. After adjusting for potential confounders, TLR was an independent predictor of mortality (hazard ratio: 1.23, 95% confidence interval: 1.04 to 1.45; p = 0.02). Patients undergoing nonemergent, uncomplicated TLR had significantly higher rates of non-procedure-related MI compared with those without TVR. Among patients undergoing elective TLR, MI occurring after TLR was an independent predictor of mortality (hazard ratio: 3.82; 95% confidence interval: 2.44 to 5.99; p < 0.0001).

CONCLUSIONS

Nonemergent, uncomplicated TLR after PCI is an independent predictor of long-term mortality, an association in part explained by higher rates of MI occurring after TLR. Efforts aimed at reducing TLR risk may translate into prognostic benefits including reduced rates of MI and survival.

Three-months optical coherence tomography analysis of a biodegradable polymer, sirolimus-eluting stent

OBJECTIVE

We aimed to assess early neointimal healing by optical coherence tomography (OCT) 3 months after implantation of the ultrathin Orsiro® sirolimus-eluting stent with biodegradable polymer.

BACKGROUND

New generations of drug-eluting stents with biodegradable polymer have been developed to avoid the continued vascular irritation of durable polymers.

METHODS

In this prospective, open-label study, 34 patients received an Orsiro® sirolimus-eluting stent with biodegradable polymer. In a subgroup of patients (n = 15), the intervention was performed under OCT guidance. All patients underwent OCT-examination at three months. The primary endpoint was 3-month neointimal healing (NIH) score, calculated by weighing the presence of filling defects, malapposed and uncovered struts. Secondary endpoint was maturity of tissue coverage at 3 months.

RESULTS

At 3 months, NIH score was 13.7 (5.4-22), covered struts per lesion were 90% (84-97%), malapposed struts were 2.7% (0.8-5.4%) and rate of mature tissue coverage was 47% (42-53%). No target lesion failure occurred up to 12 months. Patients with OCT-guided stent implantation demonstrated a trend toward earlier stent healing as demonstrated by superior NIH scores (angio guided: 17.6% [8.8-26.4]; OCT-guided: 9.8% [4.0-15.5]; mean difference -8, [95%CI: -18.7-2.9], P = 0.123). This group had significantly more covered struts per lesion (angio-guided: 86% [82-90]; 95% [92-99]; mean difference 9% [95%CI: 3-15], P = 0.001).

CONCLUSION

The Orsiro® sirolimus-eluting stent with biodegradable polymer shows early vascular healing with a high rate of strut coverage at 3-month follow-up. OCT guided stent implantation had a positive impact on early vascular healing.

Bioresorbable Polymer-Coated Orsiro Versus Durable Polymer-Coated Resolute Onyx Stents (BIONYX): Rationale and design of the randomized TWENTE IV multicenter trial

AIM

The aim was to compare in a noninferiority trial the efficacy and safety of 2 contemporary drug-eluting stents (DESs): a novel, durable polymer-coated stent versus an established bioabsorbable polymer-coated stent.

METHODS AND RESULTS

The BIONYX trial (ClinicalTrials.gov-no.NCT02508714) is an investigator-initiated, prospective, randomized, patient- and assessor-blinded, international, multicenter study in all-comer patients with all types of clinical syndromes and lesions who require percutaneous coronary interventions with DES. Patients at 7 study sites in the Netherlands, Belgium, and Israel were randomly assigned (1:1, stratified for gender and diabetes mellitus) to treatment with the novel, zotarolimus-eluting, durable polymer-coated Resolute Onyx stent that has a radiopaque, thin-strut, CoreWire stent platform versus the sirolimus-eluting, bioresorbable polymer-coated Orsiro stent (reference device) that has a very thin-strut, cobalt-chromium stent backbone. The primary end point is the 1-year incidence of the composite clinical end point target vessel failure consisting of cardiac death, target vessel-related myocardial infarction, or clinically indicated target vessel revascularization. A power calculation, assuming a target vessel failure rate of 6.0% (noninferiority margin 2.5%), revealed that 2,470 study patients would give the study 80% power (α level 5%), allowing for up to 3% loss to follow-up. The first patient was enrolled on October 7, 2015; on December 23, 2016, the last patient entered the study.

CONCLUSIONS

BIONYX is a large-scale, prospective, randomized, international, multicenter trial comparing a novel DES with durable coating versus a reference DES with biodegradable coating in all-comers. The study is the first randomized assessment of the Resolute Onyx stent, which is an often-used DES outside the United States.

A sirolimus-eluting bioabsorbable polymer-coated stent (MiStent) versus an everolimus-eluting durable polymer stent (Xience) after percutaneous coronary intervention (DESSOLVE III): a randomised, single-blind, multicentre, non-inferiority, phase 3 trial

BACKGROUND

MiStent is a drug-eluting stent with a fully absorbable polymer coating containing and embedding a microcrystalline form of sirolimus into the vessel wall. It was developed to overcome the limitation of current durable polymer drug-eluting stents eluting amorphous sirolimus. The clinical effect of MiStent sirolimus-eluting stent compared with a durable polymer drug-eluting stents has not been investigated in a large randomised trial in an all-comer population.

METHODS

We did a randomised, single-blind, multicentre, phase 3 study (DESSOLVE III) at 20 hospitals in Germany, France, Netherlands, and Poland. Eligible participants were any patients aged at least 18 years who underwent percutaneous coronary intervention in a lesion and had a reference vessel diameter of 2·50-3·75 mm. We randomly assigned patients (1:1) to implantation of either a sirolimus-eluting bioresorbable polymer stent (MiStent) or an everolimus-eluting durable polymer stent (Xience). Randomisation was done by local investigators via web-based software with random blocks according to centre. The primary endpoint was a non-inferiority comparison of a device-oriented composite endpoint (DOCE)-cardiac death, target-vessel myocardial infarction, or clinically indicated target lesion revascularisation-between the groups at 12 months after the procedure assessed by intention-to-treat. A margin of 4·0% was defined for non-inferiority of the MiStent group compared with the Xience group. All participants were included in the safety analyses. This trial is registered with ClinicalTrials.gov, number NCT02385279.

FINDINGS

Between March 20, and Dec 3, 2015, we randomly assigned 1398 patients with 2030 lesions; 703 patients with 1037 lesions were assigned to MiStent, of whom 697 received the index procedure, and 695 patients with 993 lesions were asssigned to Xience, of whom 690 received the index procedure. At 12 months, the primary endpoint had occurred in 40 patients (5·8%) in the sirolimus-eluting stent group and in 45 patients (6·5%) in the everolimus-eluting stent group (absolute difference -0·8% [95% CI -3·3 to 1·8], p_{non-inferiority}=0·0001). Procedural complications occurred in 12 patients (1·7%) in the sirolimus-eluting stent group and ten patients (1·4%) in the everolimus-eluting stent group; no clinical adverse events could be attributed to these dislodgements through a minimum of 12 months of follow-up. The rate of stent thrombosis, a safety indicator, did not differ between groups and was low in both treatment groups.

INTERPRETATION

The sirolimus-eluting bioabsorbable polymer stent was non-inferior to the everolimus-eluting durable polymer stent for a device-oriented composite clinical endpoint at 12 months in an all-comer population. MiStent seems a reasonable alternative to other stents in clinical practice.

FUNDING

The European Cardiovascular Research Institute, Micell Technologies (Durham, NC, USA), and Stentys (Paris, France).

Satisfactory arterial repair 1 year after ultrathin strut biodegradable polymer sirolimus-eluting stent implantation: an angioscopic observation

The ultrathin strut biodegradable polymer sirolimus-eluting stent (Orsiro, O-SES) exhibits satisfactory clinical outcomes. However, no report to date has documented the intravascular status of artery repair after O-SES implantation. We examined 5 O-SES placed in 4 patients (age 65 ± 12 years, male 75%) presenting with stable angina pectoris due to de novo lesions in native coronary arteries. Coronary angioscopy was performed immediately after percutaneous coronary intervention and 1 year later. Angioscopic images were analyzed to determine the following: (1) dominant grade of neointimal coverage (NIC) over the stent; (2) maximum yellow plaque grade; and (3) existence of thrombus. Yellow plaque grade was evaluated both immediately after stent implantation and at the time of follow-up observation. The other parameters were evaluated at the time of follow-up examination. NIC was graded as: grade 0, stent struts exposed; grade 1, struts bulging into the lumen, although covered; grade 2, struts embedded in the neointima, but translucent; grade 3, struts fully embedded and invisible. Yellow plaque severity was graded as: grade 0, white; grade 1, light yellow; grade 2, yellow; and grade 3, intensive yellow. Angioscopic findings at 1 year demonstrated the following: dominant NIC grade 1, grade 2, and grade 3 in 1, 2, and 2 stents, respectively; all stents were covered to some extent; focal thrombus adhesion was observed in only 1 stent. Yellow plaque grade did not change from immediately after stent implantation to follow-up. O-SES demonstrated satisfactory arterial repair 1 year after implantation.

Distilling complexity to advance cardiac tissue engineering

The promise of cardiac tissue engineering is in the ability to recapitulate in vitro the functional aspects of a healthy heart and disease pathology as well as to design replacement muscle for clinical therapy. Parts of this promise have been realized; others have not. In a meeting of scientists in this field, five central challenges or "big questions" were articulated that, if addressed, could substantially advance the current state of the art in modeling heart disease and realizing heart repair.

Stent Polymers: Do They Make a Difference?

The necessity of polymers on drug-eluting stent (DES) platforms is dictated by the need of an adequate amount and optimal release kinetic of the antiproliferative drugs for achieving ideal DES performance. However, the chronic vessel wall inflammation related to permanent polymer persistence after the drug has been eluted might trigger late restenosis and stent thrombosis. Biodegradable polymers have the potential to avoid these adverse events. A variety of biodegradable polymer DES platforms have been clinically tested, showing equal outcomes with the standard-bearer permanent polymer DES within the first year of implantation. At longer-term follow-up, promising lower rates of stent thrombosis have been observed with the early generation biodegradable polymer DES platforms compared to first-generation DES. Whether this safety benefit still persists with newer biodegradable polymer DES generations against second-generation permanent polymer DES needs to be explored.

Randomized Comparison of a Biodegradable Polymer Ultrathin Strut Sirolimus-Eluting Stent With a Biodegradable Polymer Biolimus-Eluting Stent in Patients Treated With Percutaneous Coronary Intervention: The SORT OUT VII Trial

BACKGROUND

Coronary drug-eluting stents with biodegradable polymers have been designed to improve safety and efficacy.

METHODS AND RESULTS

The Scandinavian Organization for Randomized Trials With Clinical Outcome (SORT OUT) VII trial-a large-scale registry-based randomized, multicenter, single-blind, 2-arm, noninferiority trial-compared 2 biodegradable polymer drug-eluting stents: the thin-strut cobalt-chromium sirolimus-eluting Orsiro stent and the stainless steel biolimus-eluting Nobori stent in an all-comer patient population. The primary end point target lesion failure was a composite of cardiac death, myocardial infarction (not related to other than index lesion), or target lesion revascularization within 1 year, analyzed by intention to treat (noninferiority margin of 3.0%). Clinically driven event detection based on Danish registries was used. A total of 1261 patients were assigned to receive the sirolimus-eluting stent (1590 lesions) and 1264 patients to the biolimus-eluting stent (1588 lesions). At 1 year, the composite end point target lesion failure occurred in 48 patients (3.8%) in the sirolimus-eluting group and in 58 patients (4.6%) in the biolimus-eluting group (absolute risk difference, -0.78% [upper limit of 1-sided 95% confidence interval, 0.61%]; P<0.0001). Rates of definite stent thrombosis occurred in 5 (0.4%) of the sirolimus-eluting group compared with 15 (1.2%) biolimus-eluting stent-treated patients (rate ratio, 0.33; 95% confidence interval, 0.12-0.92; P=0.034), which largely was attributable to a lower risk of subacute definite stent thrombosis: 0.1% versus 0.6% (rate ratio, 0.12; 95% confidence interval, 0.02-1.00; P=0.05).

CONCLUSIONS

The thin-strut sirolimus-eluting Orsiro stent was noninferior to the biolimus-eluting Nobori stent in unselected patients for target lesion failure at 1 year.

CLINICAL TRIAL REGISTRATION

URL: http://www.clinicaltrials.gov. Unique identifier: NCT01879358.

Very Late Pathological Responses to Cobalt-Chromium Everolimus-Eluting, Stainless Steel Sirolimus-Eluting, and Cobalt-Chromium Bare Metal Stents in Humans

Background

The “very late” clinical outcomes for durable polymer drug‐eluting stents and bare metal stents (BMSs) have been shown to be dissimilar in clinical studies. Conceptually, the long‐term vascular compatibility of BMSs is still regarded to be superior to drug‐eluting stents; however, no pathologic study to date has specifically addressed this issue. We evaluated the very late (≥1 year) pathologic responses to durable polymer drug‐eluting stents (cobalt–chromium [CoCr] everolimus‐eluting stents [EESs] and stainless steel sirolimus‐eluting stents [SS‐SESs]) versus BMSs (CoCr‐BMSs).

Methods and Results

From the CVPath stent registry, we studied a total of 119 lesions (40 CoCr‐EESs, 44 SS‐SESs, 35 CoCr‐BMSs) from 92 autopsy cases with a duration ranging from 1 to 5 years. Sections of stented coronary segments were pathologically analyzed. Inflammation score and the percentage of struts with giant cells were lowest in CoCr‐EESs (median inflammation score: 0.6; median percentage of struts with giant cells: 3.8%) followed by CoCr‐BMSs (median inflammation score: 1.3 [P<0.01]; median percentage of struts with giant cells: 8.9% [P=0.02]) and SS‐SESs (median inflammation score: 1.7 [P<0.01]; median percentage of struts with giant cells: 15.3% [P<0.01]). Polymer delamination was observed exclusively in SS‐SESs and was associated with increased inflammatory and giant cell reactions. The prevalence of neoatherosclerosis with CoCr‐EESs (50%) was significantly less than with SS‐SESs (77%, P=0.02) but significantly greater than with CoCr‐BMSs (20%, P<0.01).

Conclusions

CoCr‐EESs, SS‐SESs, and BMSs each demonstrated distinct vascular responses. CoCr‐EESs demonstrated the least inflammation, near‐equivalent healing to BMSs, and lower neointimal formation. These results challenge the belief that BMSs have superior biocompatibility compared with some polymeric coated drug‐eluting stents and may have implications for future stent design.

Rationale of a novel study design for the BIOFLOW V study, a prospective, randomized multicenter study to assess the safety and efficacy of the Orsiro sirolimus-eluting coronary stent system using a Bayesian approach

BACKGROUND

Traditional study design submitted to the Food and Drug Administration to test newer drug-eluting stents (DES) for marketing approval is the prospective randomized controlled trial. However, several DES have extensive clinical data from trials conducted outside the United States that have led to utilization of a novel design using the Bayesian approach. This design was proposed for testing DES with bioresorbable polymer compared with DES most commonly in use today that use durable polymers for drug elution.

STUDY DESIGN AND OBJECTIVES

This prospective, multicenter, randomized, controlled trial is designed to assess the safety and efficacy of the Orsiro bioresorbable polymer sirolimus-eluting stent (BP SES). Up to 1,334 subjects with up to 3 de novo or restenotic coronary artery lesions who qualify for percutaneous coronary intervention with stenting will be randomized 2:1 to the BP SES versus the Xience durable polymer everolimus-eluting stent (DP EES). Data from this trial will be combined with data from 2 similarly designed trials that also randomize subjects to BP SES and DP EES (BIOFLOW II, N=452 and BIOFLOW IV, N=579) by using a Bayesian approach. The primary end point is target lesion failure at 12 months post index procedure, defined as cardiac death, target vessel myocardial infarction, or clinically driven target lesion revascularization, and the primary analysis is a test of noninferiority of the BP SES versus DP EES on the primary end point according to a noninferiority delta of 3.85%. Secondary end points include stent thrombosis and the individual components of target lesion failure. Subjects will be followed for 5 years after randomization.

CONCLUSIONS

The BIOFLOW V trial offers an opportunity to assess clinical outcomes in patients treated with coronary revascularization using the Orsiro BP SES relative to a commonly used DP EES. The use of a Bayesian analysis combines a large randomized cohort of patients 2 two smaller contributing randomized trials to augment the efficiency of the comparison.

Ultrathin, bioresorbable polymer sirolimus-eluting stents versus thin, durable polymer everolimus-eluting stents in patients undergoing coronary revascularisation (BIOFLOW V): a randomised trial

BACKGROUND

The development of coronary drug-eluting stents has included use of new metal alloys, changes in stent architecture, and use of bioresorbable polymers. Whether these advancements improve clinical safety and efficacy has not been shown in previous randomised trials. We aimed to examine the clinical outcomes of a bioresorbable polymer sirolimus-eluting stent compared with a durable polymer everolimus-eluting stent in a broad patient population undergoing percutaneous coronary intervention.

METHODS

BIOFLOW V was an international, randomised trial done in patients undergoing elective and urgent percutaneous coronary intervention in 90 hospitals in 13 countries (Australia, Belgium, Canada, Denmark, Germany, Hungary, Israel, the Netherlands, New Zealand, South Korea, Spain, Switzerland, and the USA). Eligible patients were those aged 18 years or older with ischaemic heart disease undergoing planned stent implantation in de-novo, native coronary lesions. Patients were randomly assigned (2:1) to either an ultrathin strut (60 μm) bioresorbable polymer sirolimus-eluting stent or to a durable polymer everolimus-eluting stent. Randomisation was via a central web-based data capture system (mixed blocks of 3 and 6), and stratified by study site. The primary endpoint was 12-month target lesion failure. The primary non-inferiority comparison combined these data from two additional randomised trials of bioresorbable polymer sirolimus-eluting stent and durable polymer everolimus-eluting stent with Bayesian methods. Analysis was by intention to treat. The trial is registered with ClinicalTrials.gov, number NCT02389946.

FINDINGS

Between May 8, 2015, and March 31, 2016, 4772 patients were recruited into the study. 1334 patients met inclusion criteria and were randomly assigned to treatment with bioresorbable polymer sirolimus-eluting stents (n=884) or durable polymer everolimus-eluting stents (n=450). 52 (6%) of 883 patients in the bioresorbable polymer sirolimus-eluting stent group and 41 (10%) of 427 patients in the durable polymer everolimus-eluting stent group met the 12-month primary endpoint of target lesion failure (95% CI -6·84 to -0·29, p=0·0399), with differences in target vessel myocardial infarction (39 [5%] of 831 patients vs 35 [8%] of 424 patients, p=0·0155). The posterior probability that the bioresorbable polymer sirolimus-eluting stent is non-inferior to the durable polymer everolimus-eluting stent was 100% (Bayesian analysis, difference in target lesion failure frequency -2·6% [95% credible interval -5·5 to 0·1], non-inferiority margin 3·85%, n=2208).

INTERPRETATION

The outperformance of the ultrathin, bioresorbable polymer sirolimus-eluting stent over the durable polymer everolimus-eluting stent in a complex patient population undergoing percutaneous coronary intervention suggests a new direction in improving next generation drug-eluting stent technology.

FUNDING

BIOTRONIK.

Extracellular Matrix Proteomics Reveals Interplay of Aggrecan and Aggrecanases in Vascular Remodeling of Stented Coronary Arteries

Supplemental Digital Content is available in the text.

Background:

Extracellular matrix (ECM) remodeling contributes to in-stent restenosis and thrombosis. Despite its important clinical implications, little is known about ECM changes post–stent implantation.

Methods:

Bare-metal and drug-eluting stents were implanted in pig coronary arteries with an overstretch under optical coherence tomography guidance. Stented segments were harvested 1, 3, 7, 14, and 28 days post-stenting for proteomics analysis of the media and neointima.

Results:

A total of 151 ECM and ECM-associated proteins were identified by mass spectrometry. After stent implantation, proteins involved in regulating calcification were upregulated in the neointima of drug-eluting stents. The earliest changes in the media were proteins involved in inflammation and thrombosis, followed by changes in regulatory ECM proteins. By day 28, basement membrane proteins were reduced in drug-eluting stents in comparison with bare-metal stents. In contrast, the large aggregating proteoglycan aggrecan was increased. Aggrecanases of the ADAMTS (a disintegrin and metalloproteinase with thrombospondin motifs) family contribute to the catabolism of vascular proteoglycans. An increase in ADAMTS-specific aggrecan fragments was accompanied by a notable shift from ADAMTS1 and ADAMTS5 to ADAMTS4 gene expression after stent implantation. Immunostaining in human stented coronary arteries confirmed the presence of aggrecan and aggrecan fragments, in particular, at the contacts of the stent struts with the artery. Further investigation of aggrecan presence in the human vasculature revealed that aggrecan and aggrecan cleavage were more abundant in human arteries than in human veins. In addition, aggrecan synthesis was induced on grafting a vein into the arterial circulation, suggesting an important role for aggrecan in vascular plasticity. Finally, lack of ADAMTS-5 activity in mice resulted in an accumulation of aggrecan and a dilation of the thoracic aorta, confirming that aggrecanase activity regulates aggrecan abundance in the arterial wall and contributes to vascular remodeling.

Conclusions:

Significant differences were identified by proteomics in the ECM of coronary arteries after bare-metal and drug-eluting stent implantation, most notably an upregulation of aggrecan, a major ECM component of cartilaginous tissues that confers resistance to compression. The accumulation of aggrecan coincided with a shift in ADAMTS gene expression. This study provides the first evidence implicating aggrecan and aggrecanases in the vascular injury response after stenting.