The Impact of Post-Procedural Asymmetry, Expansion, and Eccentricity of Bioresorbable Everolimus-ElutingScaffold and Metallic Everolimus-Eluting Stent on Clinical Outcomes in the ABSORB II Trial.


                    OBJECTIVES: The study sought to investigate the relationship between post-procedural asymmetry, expansion, and eccentricity indices ofmetallic everolimus-eluting stent (EES) and bioresorbable vascular scaffold (BVS) and their respective impact on clinical events at 1-year follow-up.

                      BACKGROUND: Mechanical properties of a fully BVS are inherently different from those of permanent metallic stent.

                      METHODS: The ABSORB II (A bioresorbable everolimus-eluting scaffold versus a metallic everolimus-eluting stent for ischaemic heart disease caused by de-novo native coronary artery lesions) trial compared the BVS and metallic EES in the treatment of a de novo coronary artery stenosis. Protocol-mandated intravascular ultrasound imaging was performed pre- and post-procedure in 470 patients (162 metallic EES and 308 BVS). Asymmetry index (AI) was calculated per lesion as: (1 -minimum scaffold/stent diameter/maximum scaffold/stent diameter). Expansionindex and optimal scaffold/stent expansion followed the definition of the MUSIC (Multicenter Ultrasound Stenting in Coronaries) study.Eccentricity index (EI) was calculated as the ratio of minimum and maximum scaffold/stent diameter per cross section. The incidence of device-oriented composite endpoint (DoCE) was collected.

                      RESULTS: Post-procedure, the metallic EES group was more symmetric and concentric than the BVS group. Only 8.0% of the BVS arm and 20.0% of the metallic EES arm achieved optimal scaffold/stent expansion (p < 0.001). At 1 year, there was no difference in the DoCE between both devices (BVS 5.2% vs. EES 3.1%; p = 0.29). Post-procedural devices asymmetry and eccentricity were related to higher event rates while there was no relevance to the expansion status. Subsequent multivariate analysis identified that post-procedural AI >0.30 is an independent predictor of DoCE (hazard ratio: 3.43; 95% confidence interval: 1.08 to 10.92; p = 0.037).

                      CONCLUSIONS: BVS implantation is more frequently associated with post-procedural asymmetric and eccentric morphology compared tometallic EES. Post-procedural devices asymmetry were independently associated with DoCE following percutaneous coronary intervention. However, this approach should be viewed as hypothesis generating due to low event rates.