Qualitative and quantitative neointimal characterization by optical coherence tomography in patients presenting with in-stent restenosis.

AIMS: To describe optical coherence tomography (OCT) findings in patients with in-stent restenosis (ISR) and determine predictors of neointimal patterns and neoatherosclerosis. METHODS AND RESULTS: Patients undergoing OCT prior to PCI for ISR in three European centres were included. Analyses were performed in a core laboratory. Qualitative and quantitative [gray-scale signal intensity (GSI)] neointima analyses were performed on a per quadrant basis. A total of 107 patients were included. Predominantly homogeneous lesions included 4.5% (0.0-14.3) non-homogeneous quadrants, while predominantly non-homogeneous ones included 28.1% (20.3-37.5) homogeneous quadrants. Mean GSI values differed significantly between homogeneous [108.4 (92.5-123.6)], non-homogeneous [79.9 (61.2-95.9)], and neoatherosclerosis [88.3 (72.8-104.9)] quadrants (p < 0.001 for all comparisons). Stent underexpansion was observed in 48.5% and 61.1% of lesions, respectively (p = 0.225). Female sex and maximal neointimal thickness independently correlate with a non-homogeneous pattern, while angiographic pattern and diabetes mellitus inversely correlate with such pattern. Time from index stenting procedure was the only independent predictor of neoatherosclerosis. CONCLUSIONS: Different neointimal patterns coexist in a significant proportion of ISR lesions. GSI values differ significantly between neointimal categories. Neoatherosclerosis is a time-dependent phenomenon, displaying different time courses in DES compared to BMS, with earlier appearance in the former group. Stent underexpansion is a frequent finding in patients with ISR.