Fate of post-procedural malapposition of everolimus-eluting polymeric bioresorbable scaffold and everolimus-eluting cobalt chromium metallic stent in human coronary arteries: sequential assessment with optical coherence tomography in ABSORB Japan trial

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 mm(2) vs. 0.23 +/- 0.26 mm(2), 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 mu m for BVS (sensitivity 0.875; specificity 0.851) and 359 mu m 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