PARIS – Three contemporary yet very different drug-eluting stents – two very-thin-strut biodegradable devices and one that leaves behind a durable polymer – achieved similarly low target vessel failure rates through 2 years of prospective follow-up in the large, all-comers, randomized BIO-RESORT trial, , reported at the annual meeting of the European Association of Percutaneous Cardiovascular Interventions.
That being said, the study provided an intriguing signal that the Orsiro sirolimus-eluting stent might reduce the risk of revascularization after the first year of follow-up, compared with the Synergy everolimus-eluting stent and Resolute Integrity zotarolimus-eluting stent.
“This is a signal of great interest,” noted Dr. Kok, a cardiologist at Thoraxcentrum Twente in Enschede, the Netherlands.
Thetrial was a multicenter, three-arm, patient- and assessor-blinded Dutch study in which 3,514 patients undergoing percutaneous coronary intervention (PCI) were randomized to the Resolute Integrity, Synergy, or Orsiro stent. This was an all-comers trial in which everyone who needed PCI with a drug-eluting stent was included. Most (70%) patients had an acute coronary syndrome; 31% presented with ST-segment elevation MI. At 1 year of follow-up, 86% of patients were on dual-antiplatelet therapy. The 1-year safety and efficacy outcomes, previously reported, were reassuringly similar in the three groups ( ).
This was the first randomized trial to examine the safety and efficacy of the Synergy stent in all comers. Dr. Kok presented the new 2-year results, featuring 99% patient follow-up. It’s important to look at outcomes well beyond 1 year, she said, because the three stents are so different.
The Synergy and Orsiro stents feature very-thin, flexible struts with an uncoated thickness of 74 mm and 60 mm, respectively, compared with 91 mm for the Resolute Integrity stent. While the Synergy and Orsiro stents both utilize biodegradable polymer frames, the two devices utilize different drugs with different drug-eluting and polymer-resorption times. The polymer coating of the Synergy stent is resorbed within 4 months, while the Orsiro stent’s polymer degrades after 12 months and is resorbed by 24 months. Everolimus is distributed abluminally in the Synergy stent, while the other two stents feature circumferential drug placement. The Synergy frame is platinum and chromium, while other two utilize cobalt-chromium frames.
The thinking has been that treatment of coronary artery disease with drug-eluting stents, such as the Resolute Integrity, might delay arterial healing as a consequence of the life-long presence of the polymer in the vessel. Very-thin-strut biodegradable polymer stents were developed as a means of getting around this problem. But, at 1 year, the primary endpoint of target vessel failure – a safety and efficacy composite comprising cardiac death, target vessel-related MI, or clinically driven target vessel revascularization – was 5% in all three groups.
Dr. Kok reported that, at 2 years, the target vessel failure rate remained nonsignificantly different between the three study arms: 8.3% with the zotarolimus-eluting Resolute Integrity stent, 6.8% with the everolimus-eluting Synergy stent, and 6.6% with the sirolimus-eluting Orsiro stent. Nor were there any significant differences in the individual components of the primary endpoint. However, the secondary endpoint of target lesion failure – comprising cardiac death, any MI, or clinically driven target lesion revascularization – was a different story. At 1 year, there were no significant between-group differences in this composite outcome. But, a landmark analysis showed that between years 1 and 2, the incidence was 2.4% in the Resolute Integrity group, 1.6% with the Synergy group, and 1.1% in patients randomized to the Orsiro stent. The difference in target lesion failure between the Resolute Integrity and Orsiro groups was statistically significant. This difference was driven in part by the rates of target lesion revascularization: 1.5% with the Resolute Integrity, 0.9% with the Synergy, and 0.6% with the Orsiro stent.
The 2-year rates of definite or probable stent thrombosis were low and similar in the three groups: 1.0% with the Synergy stent, 0.8% with the Resolute Integrity, and 0.6% with the Orsiro, she continued.
Longer-term follow-up is planned.
The latest BIO-RESORT results received a skeptical reception from the session’s discussion panel., of Royal Papworth Hospital in Cambridge, England, praised the study as large and well run, yet, “notwithstanding some post hoc statistical nitty-gritty, there are essentially no differences. Have we come as far as we’re going to go with metallic stents in terms of the devices, and is it now a bit more about implantation, about accuracy, about dual-antiplatelet therapy?” he asked.
, an interventional cardiologist at King Fahd Armed Forces Hospital in Jeddah, Saudi Arabia, said, “An all-comers trial design does not necessarily tell you that something is good for everyone. We try and make everything simple, and it is not that simple. I do believe that stent choice decisions should be individualized.”
The BIO-RESORT trial was funded by institutional research grants from Biotronik, Boston Scientific, and Medtronic.