Relationship Between Optical Coherence Tomography–Derived In‐Stent Neoatherosclerosis and the Extent of Lipid‐Rich Neointima by Near‐Infrared Spectroscopy and Intravascular Ultrasound: A Multimodal Imaging Study

BACKGROUND: In‐stent restenosis, especially for neoatherosclerosis, is a major concern following percutaneous coronary intervention. This study aimed to elucidate the association of features of in‐stent restenosis lesions revealed by optical coherence tomography (OCT)/optical frequency domain imaging (OFDI) and the extent of lipid‐rich neointima (LRN) assessed by near‐infrared spectroscopy (NIRS) and intravascular ultrasound, especially for neoatherosclerosis. METHODS AND RESULTS: We analyzed patients undergoing percutaneous coronary intervention for in‐stent restenosis lesions using both OCT/OFDI and NIRS–intravascular ultrasound. OCT/OFDI‐derived neoatherosclerosis was defined as lipid neointima. The existence of large LRN (defined as a long segment with 4‐mm maximum lipid core burden index ≥400) was evaluated by NIRS. In 59 patients with 64 lesions, neoatherosclerosis and large LRN were observed in 17 (26.6%) and 21 lesions (32.8%), respectively. Naturally, large LRN showed higher 4‐mm maximum lipid core burden index (median [interquartile range], 623 [518–805] versus 176 [0–524]; P<0.001). In OCT/OFDI findings, large LRN displayed lower minimal lumen area (0.9±0.4 versus 1.3±0.6 mm(2); P=0.02) and greater max lipid arc (median [interquartile range], 272° [220°–360°] versus 193° [132°–247°]; P=0.004). In the receiver operating characteristic curve analysis, 4‐mm maximum lipid core burden index was the best predictor for neoatherosclerosis, with a cutoff value of 405 (area under curve, 0.92 [95% CI, 0.83–1.00]). In multivariable logistic analysis, only low‐density lipoprotein cholesterol (odds ratio, 1.52 [95% CI, 1.11–2.08]) was an independent predictor for large LRNs. CONCLUSIONS: NIRS‐derived large LRN was significantly associated with neoatherosclerosis by OCT/OFDI. The neointimal characterization by NIRS–intravascular ultrasound has potential as an alternative method of OCT/OFDI for in‐stent restenosis lesions.