BACKGROUND: Small vessel diameter is associated with higher risk of target lesion revascularization (TLR) after percutaneous coronary intervention (PCI). The COMBO sirolimus-eluting biodegradable-polymer stent has a proprietary anti-CD34 antibody layer to enhance homogeneous endothelialization, which may be advantageous in treating small vessels. OBJECTIVE: We examined for differences in 1-year clinical outcomes after PCI by maximum implanted stent diameter from the COMBO collaboration. METHODS: The COMBO collaboration (n = 3614) is a patient-level pooled dataset of patients undergoing PCI with COMBO stents in the MASCOT and REMEDEE multicenter registries. Stent diameter was available in 3590 (99.3%) patients. We compared patients receiving COMBO stents <3 mm versus ≥3 mm. The primary endpoint was 1-year target lesion failure (TLF), composite of cardiac death, target vessel-myocardial infarction (TV-MI) or clinically driven TLR. Secondary outcomes included stent thrombosis (ST). Adjusted outcomes were assessed using Cox regression methods. RESULTS: The study included 792 (22%) patients with small stents <3 mm and 2798 (78%) patients with large stents ≥3 mm. Small stent patients included more women with lower body mass index and higher prevalence of diabetes but similar prevalence of acute coronary syndrome. Risk of 1-year TLF was similar in small and large stent groups (4.4% vs. 3.8%, HR 1.12, 95% CI 0.74-1.72, p = 0.58). There were no differences in the rates of cardiac death (1.7% vs. 1.5%, p = 0.74), TV-MI (1.4% vs. 1.2%, p = 0.58) or TLR (2.7% vs. 2.1%, p = 0.31). Definite or probable ST occurred in 1.3% of the small stent and 0.7% of the large stent PCI patients, p = 0.14, HR 2.13, 95% CI 0.93-5.00, p = 0.07. CONCLUSIONS: One-year ischemic outcomes after COMBO PCI were similar irrespective of stent diameter in this all-comers international cohort.
