Durable polymer noninferior to biodegradable drug-eluting stent in ACS

Durable polymer drug-eluting stents (DES) appeared noninferior to biodegradable polymer DES in patients with acute coronary syndrome (ACS) with stenosis scheduled for percutaneous coronary intervention (PCI), results of the Korea-based HOST-Reduce-Polytech-ACS* trial showed. However, the device-oriented outcome appeared to side with the durable stent. 

In this multicentre, open-label trial, 3,413 adults (mean age 63 years) with ACS with significant stenosis, a culprit lesion in a native coronary artery or a graft vessel, eligible for stent implantation, and who underwent PCI, were randomized 1:1 to receive durable or biodegradable polymer DES.

Slightly more than half of the patients had multivessel disease and culprit lesion was most often in the left anterior descending artery (50.3 percent). About 13 percent had ST-segment elevation myocardial infarction (MI), while 45 percent had diabetes. About 30 percent of patients received multi-lesion intervention.

At 12 months, the patient-oriented composite outcome comprising all-cause death, nonfatal MI, stent thrombosis, and any repeat revascularization occurred in a comparable proportion of patients who received the durable or biodegradable polymer DES (5.2 percent vs 6.4 percent; hazard ratio [HR], 0.81, 95 percent confidence interval [CI], 0.61–1.08; p=0.146), with an absolute risk difference of -1.2 percent between the two groups (p_{noninferiority}<0.001). [TCT Connect 2020, Late-Breaking Clinical Trial Session IV]

The device-oriented composite outcome of cardiac death, target vessel MI, and target lesion revascularization at 12 months was reduced in patients who received the durable vs biodegradable polymer DES (2.6 percent vs 3.9 percent; HR, 0.67, 95 percent CI, 0.46–0.98; p=0.038). This appeared to be driven by the almost halving of target lesion revascularization rates with the durable vs biodegradable polymer DES (1.0 percent vs 1.8 percent; HR, 0.54, 95 percent CI, 0.29–0.99; p=0.049).

While the two stent types were comparable for the patient-oriented outcome, we observed signs of more clinical events with the biodegradable than durable polymer DES for the device-oriented outcome, noted study author Professor Hyo-Soo Kim, director of Coronary Intervention and Transcatheter Aortic Valve Implantation, Seoul National University Hospital, Seoul, Korea, at TCT Connect 2020.

Stent thrombosis incidence at 12 months was low, occurring in two patients in the durable and six in the biodegradable polymer DES groups.

The patient-oriented findings were consistent in a post hoc analysis of thin strut stents (5.2 percent [durable DES] vs 6.9 percent [biodegradable DES]; HR, 0.75, 95 percent CI, 0.55–1.02; p=0.069).

Although DES have improved PCI outcomes, the polymers used in first-generation DES were blamed as the cause of a chronic inflammatory response that leads to stent-oriented adverse clinical outcomes such as stent thrombosis, said Kim. Biocompatible durable and biodegradable polymers were developed in an attempt to avoid these outcomes.

“Most clinicians and industrial companies believe that biodegradable polymer DES would be better than durable polymer DES [but that was] not confirmed by this study. On the other hand, the [benefits] of durable polymer, such as thromboresistance, may be real,” he said.

“Clinicians’ choice of stent for given patients can be broader and more appropriate, considering not polymer but stent design or mechanical properties such as strut thickness, deliverability, trackability, or visibility under fluoroscopy,” he continued.

Acknowledging the relatively short follow-up period, Kim pointed out that the study is ongoing to identify differences in outcomes between the two DES that may emerge over time.