Bioresorbable vascular scaffold versus metallic drug-eluting stent in patients at high risk of restenosis: final 7-year results of the COMPARE-ABSORB trial

Selected in EuroIntervention Journal by E. Gallinoro

This study provides the longest available follow-up for first-generation bioresorbable vascular scaffolds and fails to demonstrate any late clinical advantage after complete scaffold resorption.

Reviewer

Emanuele Gallinoro

@EGallinoro

Interventional cardiologist / Cardiologist

Rome, Italy

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My Comment

Overview of the key elements of the "COMPARE ABSORB » study proposed by E. Gallinoro for PCRonline

Overview of the key elements of the "COMPARE ABSORB » study proposed by E. Gallinoro for PCRonline

Why this study – the rationale/objective?

Second-generation drug-eluting stents (DES) have significantly improved the outcomes of percutaneous coronary intervention; however, long-term follow-up studies show that target lesion failure continues to increase linearly over time, with an annual event rate of approximately 2 % even up to 5–10 years.

Bioresorbable vascular scaffolds (BVS) were developed to overcome the limitations of permanent metallic implants, with the expectation that complete scaffold resorption could restore vessel physiology and reduce very late adverse events.

Previous randomised trials reported higher early rates of thrombosis and target lesion failure with first-generation BVS, but follow-up was limited to 5 years and often excluded complex lesions. Whether the theoretical long-term benefit of a “leave-nothing-behind” strategy could translate into improved outcomes beyond the resorption phase, particularly in patients at high risk of restenosis, remained uncertain.

How was it executed? The methodology

COMPARE-ABSORB was a prospective, multicentre randomised trial including 1,670 patients at high risk of restenosis assigned 1:1 to bioresorbable vascular scaffolds (BVS) or everolimus-eluting stents (EES). Participants met at least one of the inclusion criteria: medically treated diabetes, multivessel disease with more than one de novo target lesion, and/or presence of at least one complex target lesion (long lesion, small vessel, total occlusion, or bifurcation).

A dedicated implantation protocol was recommended for BVS. The primary endpoint was target lesion failure (TLF), defined as cardiac death, target-vessel myocardial infarction, or clinically indicated target lesion revascularisation (CI-TLR).

Because complete resorption of the Absorb scaffold is expected to occur at approximately 3 years, the study was designed to assess non-inferiority at 1 year and superiority at 7 years using a prespecified 3-year landmark analysis, aimed at evaluating clinical outcomes after full scaffold resorption, when a potential long-term benefit of the “leave-nothing-behind” strategy was hypothesised.

What is the main result?

At 7-year follow-up, the primary endpoint of target lesion failure occurred in 15.1 % of patients treated with BVS versus 13.1 % with EES (HR 1.17, 95. % CI 0.90–1.52; p = 0.24). In the pre-specified 3-to-7-year landmark analysis, corresponding to the co-primary objective, TLF was not significantly different between groups (6.7 % vs 5.9 %; HR 1.14, 95 % CI 0.76–1.73; p = 0.53). Rates of cardiac death (2.3 % vs 2.8 %; HR 0.84, 95 % CI 0.45–1.57) and target-vessel myocardial infarction (2.0 % vs 2.2 %; HR 0.94, 95 % CI 0.46–1.90) were similar. However, clinically indicated target lesion revascularisation was significantly higher in the BVS group (4.4 % vs 2.2 %; HR 1.97, 95 % CI 1.08–3.60; p = 0.023), while definite device thrombosis rates were low and comparable between groups (0.4 % vs 0.5 %; HR 0.74, 95 % CI 0.17–3.30).

Critical reading and the relevance for clinical practice:

This study provides the longest available follow-up for first-generation bioresorbable vascular scaffolds and fails to demonstrate any late clinical advantage after complete scaffold resorption. The absence of benefit beyond 3 years challenges the original hypothesis that restoration of vessel physiology after disappearance of the scaffold would translate into lower rates of late target lesion failure compared with contemporary metallic DES.

Importantly, the higher rate of clinically indicated target lesion revascularisation observed between 3 and 7 years in the BVS arm suggests that mechanical limitations of early scaffold design, including thicker struts, limited radial strength, and suboptimal acute lumen gain, may offset the theoretical biological advantages of a temporary device.

These findings support the current standard of care favouring new-generation metallic DES, which provide excellent long-term safety and efficacy even in complex lesions. However, the concept of a “leave-nothing-behind” strategy should not be considered abandoned. Newer scaffold platforms with thinner struts, improved radial strength, and more predictable resorption kinetics may overcome the limitations of first-generation devices. In addition, alternative approaches such as drug-eluting balloon (DEB) therapy, either as standalone treatment or in combination with short stenting strategies, may allow lesion treatment while minimizing the amount of permanent metal left in the vessel. Future studies should therefore focus on patient and lesion selection, optimisation of implantation technique with routine intravascular imaging, and evaluation of newer bioresorbable technologies. The long-term goal remains the same: achieving durable revascularisation while reducing very late adverse events associated with permanent coronary implants.