Optical coherence tomography-based evaluation of in-stent neoatherosclerosis in lesions with more than 50% neointimal cross-sectional area stenosis

AIMS: To use optical coherence tomography (OCT) to evaluate the time course, risk factors, and clinical implication of in-stent neoatherosclerosis. METHODS AND RESULTS: The neointimal characteristics of 152 lesions, 128 drug-eluting stents (DESs) and 24 bare metal stents (BMSs), with >50% percent cross-sectional area (CSA) neointimal stenosis were evaluated. Neoatherosclerosis was defined as neointima with presence of lipid or calcification. Neoatherosclerosis was observed in 54 lesions (35.5%, 35 DESs and 19 BMSs). Median time to follow-up was 70.7 months in lesions with neoatherosclerosis (longer than lesions without neoatherosclerosis [13.4 months, p<0.001]): 58.7 months in DES-treated lesions and 129.5 months in BMS-treated lesions (p<0.001). The optimal cut-off time to predict neoatherosclerosis in DES-treated lesions was 30 months with a sensitivity of 91.4% and a specificity of 72.0% (area under curve: 0.839, 95% confidence interval: 0.764-0.898, p<0.001). Independent risk factors for neoatherosclerosis were stent age, use of first-generation DES and hypertension. Patients with neoatherosclerosis (versus without neoatherosclerosis) had a higher rate of target lesion revascularisation (92.6% vs. 77.6%, respectively, p=0.018) and stent thrombosis (14.8% vs. 0%, respectively, p<0.001). CONCLUSIONS: Neoatherosclerosis occurred in one-third of stented lesions with >50% percent CSA stenosis of neointima. Late-phase development of neoatherosclerosis might be associated with clinical deterioration of stented lesions.