Biodegradable polymer-coated DES safe, effective at 3 years

Three-year results from the BIO-RESORT trial were reported in JACC: Cardiovascular Interventions this month, revealing that despite significant differences in stent backbone and polymer coating, the ultrathin sirolimus-eluting stent, very-thin everolimus-eluting stent and thin-strut zotarolimus-eluting stent remained equally safe and effective through follow-up.

BIO-RESORT (Comparison of Biodegradable Polymer and Durable Polymer Drug-Eluting Stents in an All Comers Population), a Dutch effort that tracked stent performance in 3,514 all-comer patients after coronary intervention, wrapped last month after nearly seven years of activity. The primary trial launched in August 2016 and was designed to measure the safety and efficacy of three drug-eluting stents (DES): the ultrathin-strut cobalt-chromium Orsiro sirolimus-eluting stent (SES) (Biotronik), the very-thin-strut platinum-chromium Synergy everolimus-eluting stent (EES) (Boston Scientific) and the durable-polymer thin-strut cobalt-chromium Resolute Integrity zotarolimus-eluting stent (ZES) (Medtronic).

Senior investigator Clemens von Birgelen, MD, PhD, and colleagues explained in JACC that DES with biodegradable polymer coatings were first developed as a safer alternative to more traditional DES, which feature durable-polymer coatings that can bind permanently to patients’ vessels. And while one-year results from the BIO-RESORT trial were favorable for both biodegradable-polymer DES, the authors said there’s still a lot to prove.

“Long-term data on contemporary devices are scarce,” von Birgelen, of Medisch Spectrum Twente and the University of Twente in Enschede, the Netherlands, and colleagues wrote.

The team’s study participants were recruited from four centers in the Netherlands, where they all underwent percutaneous coronary intervention with DES implantation between 2012 and 2015. Target vessel failure was von Birgelen and co-authors’ main concern, with the study’s primary endpoint comprising both safety (cardiac death or target vessel-related MI) and efficacy (target vessel revascularization).

The authors said three-year follow-up data were available for 3,393 patients—96.6% of the total population. Target vessel failure occurred in 8.5% of patients with the SES, 8.8% of patients with the EES and 10% of patients with the ZES. Rates of cardiac death, target vessel MI and target vessel revascularization were similar between groups.

Throughout follow-up, definite or probable stent thrombosis remained low for all three DES (1.1% for SES, 1.1% for EES, 0.9% for ZES).

“The present three-year results are of interest, because the third year is the first year during which the Orsiro SES is entirely free from its biodegradable-polymer coating,” von Birgelen and colleagues wrote. “During this third year of follow-up, the potential advantage of the two biodegradable-polymer-coated DES of leaving only a bare-metal stent behind did not translate into a lower incidence of ischemic cardiac events compared with the durable polymer-coated reference DES. Nevertheless, further follow-up is required to definitely answer the question of whether contemporary very-thin-strut or ultrathin-strut biodegradable polymer DES might improve clinical outcomes at an even later stage.”

Still, the authors acknowledged their findings to date as “remarkable” considering the major structural differences of all three stents. They said the potential benefit of biodegradable-polymer-coated DES could still be recognized—just in longer-term studies.