Prepared by: Dr. Ramazan Furkan Demirkıran

Name of study: Bioresorbable vascular scaffold versus metallic drug-eluting stent in patients at high risk of restenosis: the COMPARE-ABSORB randomised clinical trial

Presented at: EuroPCR 2025

Objective:
The COMPARE-ABSORB trial was designed to assess the clinical efficacy and safety of bioresorbable vascular scaffolds (BVS) compared to metallic everolimus-eluting stents (EES) in patients at high risk for restenosis. BVS represents a new-generation technology offering temporary vascular support and drug delivery while eventually dissolving, potentially avoiding the long-term drawbacks of permanent metal stents. The study sought to evaluate both short-term non-inferiority and potential long-term advantages of BVS.

Methods:
This was an investigator-initiated, prospective, single-blind, randomized controlled multicenter trial conducted in 45 centers across Europe. A total of 1,670 patients aged 18 to 75 years with high-risk features for restenosis due to diabetes, multivessel disease, long or small-vessel lesions, or bifurcations were randomized 1:1 to receive either BVS (n=848) or EES (n=822). A dedicated implantation protocol involving pre-dilatation, post-dilatation with high-pressure balloons, and strict sizing criteria was mandated in the BVS group. The primary endpoint was target lesion failure (TLF), defined as a composite of cardiac death, target vessel myocardial infarction (TVMI), or clinically driven target lesion revascularization within one year.

Results:
At one year, TLF occurred in 5.1% of BVS patients and 4.2% of EES patients, confirming non-inferiority (absolute difference 0.9%, 95% CI: –1.2% to 3.0%, p for non-inferiority <0.001). However, device thrombosis was significantly higher in the BVS group (2.0% vs 0.6%, p=0.012), as was TVMI (4.0% vs 2.1%, p=0.020). The majority of thrombotic events (76%) occurred within the first 30 days after implantation, indicating procedural causes. Despite protocol-defined optimal implantation techniques, post-hoc analysis revealed many lesions did not meet precise sizing criteria. Additionally, device success was lower in the BVS group (92.4% vs 96.8%), driven by lower delivery success.

Discussion and Conclusion:
The COMPARE-ABSORB trial demonstrates that in patients at high risk for restenosis, BVS is non-inferior to EES in terms of TLF at one year. However, BVS carries a significantly higher risk of early device thrombosis and myocardial infarction, even with optimal implantation techniques. These risks are primarily due to limitations in precise vessel sizing and scaffold compatibility. Visual assessment was insufficient, and future BVS deployment should consider mandatory intravascular imaging. While the short-term safety profile of BVS is a concern, long-term follow-up (up to 7 years) is necessary to determine whether complete scaffold resorption will result in improved outcomes. Further scaffold design improvements are essential for the safe clinical use of BVS.