Incidence and short-term clinical outcomes of small side branch occlusion after implantation of an everolimus-eluting bioresorbable vascular scaffold: an interim report of 435 patients in the ABSORB-EXTEND single-arm trial in comparison with an everolimus-eluting metallic stent in the SPIRIT first and II trials.

OBJECTIVES: The aim of this study was to investigate the incidence and clinical sequelae of small side branch occlusion (SBO) after Absorb (Abbott Vascular, Santa Clara, California) bioresorbable vascular scaffold (BVS) implantation.

BACKGROUND: The thicker strut of metallic stents potentially contributes to a higher incidence of SBO.

METHODS: We performed a post-hoc angiographic assessment of 1,209 side branches in 435 patients enrolled in the ABSORB-EXTEND single-arm trial (ABSORB EXTEND Clinical Investigation: A Continuation in the Clinical Evaluation of the ABSORB Bioresorbable Vascular Scaffold [BVS] System in the Treatment of Subjects With de Novo Native Coronary Artery Lesions), in comparison with 682 side branches in 237 patients treated with the everolimus-eluting metallic stent (EES) in the SPIRIT (A Clinical Evaluation of an Investigational Device. The Abbott XIENCE V Everolimus Eluting Coronary Stent System in the Treatment of Patients With de Novo Native Coronary Artery Lesions) first and II trials. Any visible side branches originating within the device implantation site or the 5-mm proximal and distal margins were included in the angiographic assessment. The SBO was defined as a reduction in Thrombolysis In Myocardial Infarction flow grade 0 or 1.

RESULTS: Post-procedural SBO was observed in 73 side branches (6.0%) in BVS group and 28 side branches (4.1%) in EES group (p = 0.09). Patients with post-procedural SBO were significantly associated with an increased incidence of in-hospital myocardial infarction (6.5% in SBO group vs. 0.5% in non-SBO group, p < 0.01). Multivariable analysis revealed that BVS was an independent predictor of post-procedural SBO (odds ratio: 2.09; 95% confidence interval: 1.18 to 3.68). By stratified analysis, BVS demonstrated a higher incidence of post-procedural SBO compared with EES only in small side branches with a reference vessel diameter ≤0.5 mm (10.5% vs. 3.9%, p = 0.03 between the groups, p for interaction = 0.08).

CONCLUSIONS: Bioresorbable vascular scaffold was associated with a higher incidence of post-procedural SBO compared with EES. This effect was more pronounced with small side branches with a reference vessel diameter ≤0.5 mm. (ABSORB EXTEND Clinical Investigation: A Continuation in the Clinical Evaluation of the ABSORB Bioresorbable Vascular Scaffold [BVS] System in the Treatment of Subjects With de Novo Native Coronary Artery Lesions: NCT01023789).