Optical coherence tomography-based predictors for creatine kinase-myocardial band elevation after elective percutaneous coronary intervention for in-stent restenosis

Objectives: We evaluated whether morphological characteristics of neointimal tissue of instent restenosis (ISR) lesions assessed by optical coherence tomography (OCT) affect periprocedural elevation of creatine kinase-myocardial band (CK-MB). Background: The impact of neointimal characteristics of ISR lesions on periproceduralmyocardial injury has not been sufficiently investigated. Methods: A total of 125 patients with ISR lesions underwent elective percutaneous coronary intervention (PCI) and pre-PCI OCT examination. Measurements of CK-MB were performed upon hospitalization, before PCI, and every 8 hr for 24 hr after PCI. CK-MB elevation was defined as levels above the 99^th percentile of the upper reference limit. Neoatherosclerosis was defined as neointima with lipid or calcification. Results: Post-PCI CK-MB elevation was observed in 20 (16.0%) patients. The maximum length of consecutive cross-sections with neoatherosclerosis on the longitudinal axis of the stent was significantly larger in patients with post-PCI CK-MB elevation than in those without [8.8 mm (1.5-10.4) vs. 0.0 mm (0.0-1.0), P < 0.001], and thin-cap fibroatheroma (TCFA) were more frequently observed at the site of minimal lumen cross-sectional area in patients with post-PCI CK-MB elevation (55.0% vs. 1.9%, P < 0.001). Multivariate analysis revealed that the maximum length of segments with neoatherosclerosis [odds ratio (OR), 1.463; 95% confidence interval (CI), 1.090-1.962; P 5 0.011] and TCFA (OR, 14.328; 95% CI, 1.118-183.628; P 5 0.041) were independent predictors for post-PCI CK-MB elevation. Conclusions: A greater axial length of neoatherosclerosis and the presence of TCFA at the most stenotic site were significantly associated with post-PCI CK-MB elevation in ISR lesions.