Ultrathin Bioresorbable Polymer Sirolimus-Eluting Stents Versus Thin Durable Polymer Everolimus-Eluting Stents

A Review of the Ultrathin Orsiro Biodegradable Polymer Drug-eluting Stent in the Treatment of Coronary Artery Disease

Drug-eluting stents (DES) have revolutionised the treatment of coronary artery disease (CAD) in patients undergoing percutaneous coronary intervention. In recent years, there has been a focus on a new generation of DES, such as biodegradable polymer DES (BP-DES). This novel stent platform was developed with the hope of eliminating the risk of very late stent thrombosis associated with the current gold-standard durable polymer DES (DP-DES). Ultrathin Orsiro BP-DES (Biotronik, Bülach, Switzerland) are based on a cobalt-chromium stent platform that is coated with a bioresorbable polymer coating containing sirolimus. These devices have one of the thinnest struts available in the current market and have the theoretical benefit of reducing a chronic inflammatory response in the vessel wall. In 2019, the United States Food and Drug Administration (FDA) approved the use of Orsiro BP-DES in patients with CAD based on promising results in recent landmark trials, such as BIOFLOW V and BIOSTEMI. The aim of the present review article was to discuss the history of stent technology and the continued opportunities for improvements, focusing on the potential benefits of Orsiro BP-DES.

Prospective multicentre open-label randomised controlled trial of 3-month versus 12-month dual antiplatelet therapy after implantation of the new generation biodegradable polymer sirolimus TARGET-eluting coronary stent: protocol of the TARGET DAPT trial

INTRODUCTION

Dual antiplatelet therapy (DAPT) with aspirin and thienopyridine is required after placement of coronary stents to prevent thrombotic complications. However, current recommendation for duration of DAPT remains controversial. Firehawk is a biodegradable polymer applied to recessed abluminal grooves, sirolimus target-eluting stent associated with early excellent healing response and almost complete strut coverage, as well as possibly reduced myocardial ischaemic events. But the optimal DAPT duration for such a new generation stent is less known. Therefore, the present trial seeks to evaluate the safety and efficacy of 3-month versus 12-month DAPT in broad patients receiving Firehawk stents.

METHODS AND ANALYSIS

The TARGET DAPT study is designed to access the benefits and risks of short-term (3 months) versus long-term (12 months) DAPT in preventing stent thrombosis or major adverse cardiovascular and cerebrovascular events in subjects undergoing percutaneous coronary intervention for the treatment of coronary artery obstructive lesions. The TARGET DAPT trial is a large, prospective, multicentre, randomised (1:1) non-inferiority clinical trial that will enrol 2446 subjects treated with Firehawk stents. The primary endpoint is net adverse clinical and cerebral events, a composite of all-cause death, myocardial infarction, cerebral vascular accident and major bleeding (BARC 2,3 or 5) at 18 months clinical follow-up postindex procedure.

ETHICS AND DISSEMINATION

Ethics approval was obtained from the Ethics Committee of Zhongshan Hospital, Shanghai. The reference number is B2018-146R. Study findings will be made available to interested participants. Study results will be submitted for publication in a peer-reviewed journal. Also the protocol will be submitted and approved by the institutional Ethics Committee at each participating clinical centre.

TRIAL REGISTRATION

NCT03008083.

Biodegradable polymer sirolimus-eluting stents versus durable polymer everolimus-eluting stents in patients with ST-segment elevation myocardial infarction (BIOSTEMI): a single-blind, prospective, randomised superiority trial

BACKGROUND

Newer-generation drug-eluting stents that combine ultrathin strut metallic platforms with biodegradable polymers might facilitate vascular healing and improve clinical outcomes in patients with acute myocardial infarction undergoing primary percutaneous coronary intervention (PCI) compared with contemporary thin strut second-generation drug-eluting stents. We did a randomised clinical trial to investigate the safety and efficacy of ultrathin strut biodegradable polymer sirolimus-eluting stents versus thin strut durable polymer everolimus-eluting stents in patients with acute ST-segment elevation myocardial infarction (STEMI) undergoing primary PCI.

METHODS

The BIOSTEMI trial was an investigator-initiated, multicentre, prospective, single-blind, randomised superiority trial at ten hospitals in Switzerland. Patients aged 18 years or older with acute STEMI who were referred for primary PCI were eligible to participate. Patients were randomly allocated (1:1) to either biodegradable polymer sirolimus-eluting stents or durable polymer everolimus-eluting stents. Central randomisation was done based on a computer-generated allocation sequence with variable block sizes of 2, 4, and 6, which was stratified by centre, diabetes status, and presence or absence of multivessel coronary artery disease, and concealed using a secure web-based system. Patients and treating physicians were aware of group allocations, whereas outcome assessors were masked to the allocated stent. The experimental stent (Orsiro; Biotronik; Bülach, Switzerland) consisted of an ultrathin strut cobalt-chromium metallic stent platform releasing sirolimus from a biodegradable polymer. The control stent (Xience Xpedition/Alpine; Abbott Vascular, Abbott Park, IL, USA) consisted of a thin strut cobalt-chromium stent platform that releases everolimus from a durable polymer. The primary endpoint was target lesion failure, a composite of cardiac death, target vessel myocardial reinfarction (Q-wave and non-Q-wave), and clinically-indicated target lesion revascularisation, within 12 months of the index procedure. All analyses were done with the individual participant as the unit of analysis and according to the intention-to-treat principle. The trial was registered with ClinicalTrials.gov, number NCT02579031.

FINDINGS

Between April 26, 2016, and March 9, 2018, we randomly assigned 1300 patients (1623 lesions) with acute myocardial infarction to treatment with biodegradable polymer sirolimus-eluting stents (649 patients and 816 lesions) or durable polymer everolimus-eluting stents (651 patients and 806 lesions). At 12 months, follow-up data were available for 614 (95%) patients treated with biodegradable polymer sirolimus-eluting stents and 626 (96%) patients treated with durable polymer everolimus-eluting stents. The primary composite endpoint of target lesion failure occurred in 25 (4%) of 649 patients treated with biodegradable polymer sirolimus-eluting stents and 36 (6%) of 651 patients treated with durable polymer everolimus-eluting stents (difference -1·6 percentage points; rate ratio 0·59, 95% Bayesian credibility interval 0·37-0·94; posterior probability of superiority 0·986). Cardiac death, target vessel myocardial reinfarction, clinically-indicated target lesion revascularisation, and definite stent thrombosis were similar between the two treatment groups in the 12 months of follow-up.

INTERPRETATION

In patients with acute STEMI undergoing primary PCI, biodegradable polymer sirolimus-eluting stents were superior to durable polymer everolimus-eluting stents with respect to target lesion failure at 1 year. This difference was driven by reduced ischaemia-driven target lesion revascularisation in patients treated with biodegradable polymer sirolimus-eluting stents compared with durable polymer everolimus-eluting stents.

FUNDING

Biotronik.

Clinical Outcomes Following Implantation of Thin-Strut, Bioabsorbable Polymer-Coated, Everolimus-Eluting SYNERGY Stents

Background:

The thin-strut SYNERGY stent has an abluminal everolimus-eluting bioabsorbable polymer coating designed to facilitate vascular healing and reduce risk of stent thrombosis. In the multicenter, randomized EVOLVE II trial (The EVOLVE II Clinical Trial to Assess the SYNERGY Stent System for the Treatment of Atherosclerotic Lesion[s]), SYNERGY was noninferior to the durable polymer PROMUS Element Plus everolimus-eluting stent for the primary end point of 1-year target lesion failure. Longer-term clinical follow-up will support the relative efficacy and safety of SYNERGY.

Methods:

Patients with ≤3 native coronary lesions (reference vessel diameter ≥2.25–≤4.00 mm; length ≤34 mm) in ≤2 major epicardial vessels were randomized 1:1 to SYNERGY (N=838) or PROMUS Element Plus (N=846). EVOLVE II included a Diabetes substudy which pooled patients with diabetes mellitus from the randomized controlled trial (n=263) and from a sequential, single-arm substudy (N=203).

Results:

The 5-year target lesion failure rate was 14.3% for SYNERGY and 14.2% for PROMUS Element Plus ( P =0.91). Landmark analysis demonstrated similar rates of target lesion failure from discharge to 1-year ( P =0.90) and from 1 to 5 years ( P =0.94). Definite/probable stent thrombosis was infrequent in both arms (SYNERGY 0.7% versus PROMUS Element Plus 0.9%; P =0.75). There were no significant differences in the rates of cardiac death, myocardial infarction, or revascularization. Among patients with diabetes mellitus, the target lesion failure rate to 1-year was noninferior to a prespecified performance goal and to 5 years was 17.0%.

Conclusions:

SYNERGY demonstrated comparable outcomes to PROMUS Element Plus, with low rates of stent thrombosis and adverse events through 5 years of follow-up. Five-year clinical outcomes were favorable in patients with diabetes mellitus. These data support the long-term safety and effectiveness of SYNERGY in a broad range of patients.

Clinical Trial Registration:

URL: https://www.clinicaltrials.gov . Unique identifier: NCT01665053.

Biodegradable vs. permanent polymer drug-eluting stents: the need for a new nomenclature to classify drug-eluting stent technology

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Long-Term Effect of Ultrathin-Strut Versus Thin-Strut Drug-Eluting Stents in Patients With Small Vessel Coronary Artery Disease Undergoing Percutaneous Coronary Intervention

Background:

Randomized trials evaluating the Orsiro biodegradable polymer sirolimus-eluting stent (BP-SES; 60 and 80 μm strut thickness for stent diameters ≤3 and >3 mm, respectively) did not stratify according to vessel size and failed to specify the impact of ultrathin-strut thickness on long-term clinical outcomes compared with durable polymer everolimus-eluting stents (DP-EES). We sought to assess the long-term effect of ultrathin-strut (60 μm) BP-SES versus thin-strut (81 μm) DP-EES on long-term outcomes in patients undergoing percutaneous coronary revascularization for small vessel disease.

Methods:

In a subgroup analysis of the randomized, multicenter, noninferiority BIOSCIENCE trial, patients with stable coronary artery disease or acute coronary syndrome randomly assigned to treatment with BP-SES or DP-EES were stratified according to vessel size (≤3 mm versus >3 mm) as a surrogate to compare patients treated with ultrathin-strut versus thin-strut drug-eluting stent. The primary end point was target lesion failure, a composite of cardiac death, target vessel myocardial infarction, and clinically indicated target lesion revascularization, within 5 years.

Results:

Among 2109 patients, 1234 (59%) were treated for small vessel disease. At 5 years, target lesion failure occurred in 124 patients (cumulative incidence, 22.3%) treated with ultrathin-strut BP-SES and 109 patients (18.3%) treated with thin-strut DP-EES (rate ratio, 1.22; 95% CI, 0.94–1.58; P =0.13). Cumulative incidences of cardiac death, target vessel myocardial infarction, and clinically indicated target lesion revascularization and definite stent thrombosis at 5 years were similar in patients treated with ultrathin-strut BP-SES and thin-strut DP-EES. After adjustment for potential confounders, there was no significant interaction between vessel size and treatment effect of BP-SES versus DP-EES.

Conclusions:

We found no significant difference in clinical outcomes throughout 5 years between patients with small vessel disease treated with ultrathin-strut BP-SES versus thin-strut DP-EES.

Clinical Trial Registration:

URL: https://www.clinicaltrials.gov . Unique identifier: NCT01443104.

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.

Clinical and angiographic outcomes of bioabsorbable vs. permanent polymer drug-eluting stents in Sweden: a report from the Swedish Coronary and Angioplasty Registry (SCAAR)

Aims

Randomized clinical trials have consistently demonstrated the non-inferiority of bioabsorbable polymer drug-eluting stents (BP-DES) with respect to DES having permanent polymers (PP-DES). To date, the comparative performance of BP- and PP-DES in the real world has not been extensively investigated.

Methods and results

From October 2011 to June 2016, we analysed the outcomes associated with newer generation DES use in Sweden. After stratification according to the type of DES received at the index procedure, a total of 16 504 and 79 106 stents were included in the BP- and PP-DES groups, respectively. The Kaplan–Meier estimates for restenosis at 2 years were 1.2% and 1.4% in BP- and PP-DES groups, respectively. Definite stent thrombosis (ST) was low in both groups (0.5% and 0.7% in BP- and PP-DES groups, respectively). The adjusted hazard ratio (HR) for either restenosis or definite ST did not differ between BP- and PP-DES [adjusted HR 0.95, 95% confidence interval (CI) 0.74–1.21; P = 0.670 and adjusted HR 0.79, 95% CI 0.57–1.09; P = 0.151, respectively]. Similarly, there were no differences in the adjusted risk of all-cause death and myocardial infarction (MI) between the two groups (adjusted HR for all-cause death 1.01, 95% CI 0.82–1.25; P = 0.918 and adjusted HR for MI 1.05, 95% CI 0.93–1.19; P = 0.404).

Conclusion

In a large, nationwide, and unselected cohort of patients, percutaneous coronary intervention with BP-DES implantation was not associated with an incremental clinical benefit over PP-DES use at 2 years follow-up.

Recurrent atherosclerosis complications as a mechanism for stent failure

Stents are an indispensable tool in the percutaneous treatment of symptomatic coronary artery disease. Yet, stent failure due to restenosis or thrombosis may compromise their clinical benefit, carrying substantial morbidity and mortality. Despite improvements in device design and adjunctive medical treatment, stent failure still occurs during long-term follow-up, suggesting that this may be an issue that persists for many years, perhaps indefinitely. Numerous studies during the last decade have highlighted the previously underappreciated pivotal role of atherosclerosis in stent failure. We review evolving evidence on the role of atherosclerosis in stent restenosis and thrombosis, differentiating between de novo in-stent atherosclerosis development (i.e., neoatherosclerosis) and progression of pre-existing underlying atherosclerosis (i.e., paleoatherosclerosis), a distinction with potentially important clinical implications. We conclude with a concept that provides a unifying pathophysiology for these significant problems in the field of interventional cardiology based on the progression and destabilization of atherosclerosis.