The fate of incomplete scaffold apposition of everolimus-eluting bioresorble scaffolds: A serial optical coherence tomography analysis

Background: Incomplete stent apposition (ISA) can be divided into acute and late forms. Late ISA may be due to persistent ISA or late-acquired ISA (LAISA). This study evaluated the natural course of ISA after bioresorbable vascular scaffold (BRS) implantation using optical coherence tomography (OCT).

Methods: Thirty-two patients (45 BRS) were assessed immediately after BRS implantation and 1 year thereafter using OCT. Acute ISA identified after BRS implantation but absent at follow-up was defined as resolved; otherwise, it was considered persistent. LAISA was defined as newly developed ISA that was identified at follow-up despite complete apposition immediately after BRS implantation. Intra-BRS fibrin-like material (IBF) was identified as an irregular intraluminal mass. ISA percentage was expressed as follows: (number of ISA/total number of BRS struts)×100.

Results: Among 45 BRS and 15,894 analyzed BRS struts, 34 and 882 had acute ISA post-procedure, respectively. At follow-up, 92 of 15,364 analyzed struts exhibited late ISA (64 persistent ISA and 28 LAISA). In 15 of 28 struts with LAISA, LAISA occurred at the sites adjacent to post-interventional dissection. Uncovered struts were more frequently observed in late ISA compared to apposed struts (3.7±4.8 vs. 0.58±2.2%, p=0.09). IBF was significantly more common in BRS with late ISA (62.5 vs. 8.1%, p=0.02). Receiver-operating characteristic curve analysis identified a cut-off value of 280μm for acute ISA distance predicting persistent ISA.

Conclusion: Resolution of acute ISA after BRS is common. The occurrence of LAISA may be infrequent and may be a nidus of stent thrombosis.