AIMS - The natural course of post-procedural incomplete strut apposition (ISA) after the implantation of bioresorbable scaffolds (BVS) remains unknown. The purpose of the present study was to evaluate the fate of post-procedural ISA after everolimus-eluting Absorb BVS in comparison with the second-generation everolimus-eluting cobalt chromium stent (CoCr-EES).
METHODS AND RESULTS - Fate of post-procedural ISA was evaluated by serial optical coherence tomography(OCT) in the ABSORB Japan randomized trial [OCT-1 subgroup: 110 paired lesions of post-procedure and 2-year follow-up (BVS 73 lesions vs. CoCr-EES 37 lesions)] with respect to ISA distance. Post-procedure ISA struts were categorized into either 'resolved' or 'persistent' by matched OCT imaging at 2-year follow-up. Post-procedure %malapposed strut and ISA area were smaller in BVS than in CoCr-EES (%malapposed strut: 4.8 ± 6.9% vs. 9.9 ± 9.8%, P = 0.002; ISA area 0.10 ± 0.18 mm2 vs. 0.23 ± 0.26 mm2, P = 0.003). At 2-year follow-up, the difference diminished, and majority of the ISA struts spontaneously resolved in both arms (%malapposed strut: 0.10 ± 0.46% vs. 0.24 ± 0.65%, P = 0.183). Receiver operating characteristic curve analysis (BVS 661 struts vs. CoCr-EES 807 struts) demonstrated that the best cut-off value of endoluminal ISA distance post-procedure for predicting persistent-ISA at 2-year follow-up was 396 µm for BVS (sensitivity 0.875; specificity 0.851) and 359 µm for CoCr-EES (sensitivity 0.778; specificity 0.881).
CONCLUSION - BVS as compared with CoCr-EES allows larger ISA distance at post-procedure, although we should make every effort to minimize post-procedure ISA. The reported cut-off value of OCT-estimated ISA distance at post-stenting for predicting persistent-ISA would be helpful to optimize PCI with BVS and CoCr-EES.