Optical coherence tomographic analysis of drug-eluting in-stent restenosis at different times: A STROBE compliant study

The imaging characteristics of drug-eluting in-stent restenosis (ISR) at different times varied; however, the mechanism had not yet been elucidated. To analyze the imaging characteristics of drug-eluting ISR at different time points by optical coherence tomography (OCT) and investigate the cause of the stent treatment failure. A total of 70 patients with drug-eluting ISR undergoing OCT were enrolled (intimal hyperplasia ≥50% of stent area) and implanted with drug-eluting stents. According to stent implantation time, the patients were divided into 2 groups: early in-stent restenosis group (E-ISR group) (group A, n = 35, stent age ≤12 months) and late in-stent restenosis group (L-ISR group) (group B, n = 35, stent age ≥24 months). A qualitative analysis of the restenosis tissue included the nature of restenosis tissue (homogeneous and heterogeneous), neoatherosclerosis, thin-cap fibroatheroma (TCFA), and microvessels. The ratio of ≥75% cross-sectional area stenosis between the L-ISR and E-ISR groups was (60.00% vs 34.28%, P < .05). The heterogeneous intima, neoatherosclerosis, TCFA, and microvessels were more prevalent in the L-ISR group as compared to the E-ISR group (71.43% vs 45.71%, P < .05; 48.57% vs 22.86%, P < .05; 25.71% vs 5.71%, P < .05; 22.86% vs 2.86%, P < .05, respectively). The morphological characteristics of L-ISR were significantly different from those in the E-ISR; the former was closer to the atherosclerotic plaque, which provided a new approach for the treatment of drug-eluting ISR.