Proximal and distal maximal luminal diameters as a guide to appropriate deployment of the ABSORB everolimus-eluting bioresorbable vascular scaffold: A Sub-Study of the ABSORB Cohort B and the On-Going ABSORB EXTEND Single Arm Study

Objectives: Due to the limited distensibility of the everolimus-eluting bioresorbable vascular scaffold (ABSORB) compared to metallic platform stents, quantitative coronary arteriography (QCA) is a mandatory requirement for ABSORB deployment in the on-going ABSORB EXTEND Single-Arm Study. Visual assessment of vessel size in the ABSORB Cohort B study often lead to under and over-sizing of the 3 mm ABSORB in coronary vessels (recommended range of the vessel diameter ≥2.5 mm and ≤3.3 mm), with an increased risk of spontaneous incomplete scaffold apposition post ABSORB deployment. We report whether mandatory QCA assessment of vessel size pre-implantation, utilizing the maximal luminal diameter (Dmax) and established interpolated reference vessel diameter (RVD) measurements, has improved device/vessel sizing. Methods: Pre-implantation post-hoc QCA analyses of all 101 patients from ABSORB Cohort B (102 lesions) and first consecutive 101 patients (108 lesions) from ABSORB EXTEND were undertaken by an independent core-laboratory; all patients had a 3 mm ABSORB implanted. Comparative analyses were performed. Results: Within ABSORB Cohort B, a greater number of over-sized vessels (>3.3 mm) were identified utilizing the Dmax compared to the interpolated RVD (17 vessels, 16.7% vs. 3 vessels, 2.9%; P = 0.002). Comparative analyses demonstrated a greater number of appropriate vessel-size selection (75 vessels, 69.4% vs. 48 vessels, 47.1%; P = 0.001), a trend towards a reduction in implantation in small (3.3 mm) vessels (4 vessels, 3.7% vs. 17 vessels, 16.7%; P = 0.002) in ABSORB EXTEND. Bland-Altman plots suggested a good agreement between operator and core-laboratory calculated Dmax measurements. Conclusions: The introduction of mandatory Dmax measurements of vessel size prior to ABSORB implantation significantly reduced the under-sizing of the 3.0 mm scaffold in large vessels validating the use of this technique in vessel sizing prior to ABSORB implantation.