Prevalence, predictors, and outcomes of in-stent restenosis with calcified nodules.

BACKGROUND Calcified nodules (CN) has been reported to be associated with stent failure including in-stent restenosis (ISR). However, there is no systematic study of this condition. AIMS We aimed to clarify the prevalence, predictors, and midterm results of ISR lesions with CN. METHODS We examined the clinical characteristics of 651 ISR lesions which underwent percutaneous coronary intervention (PCI) with optical coherence tomography between October 2008 and July 2016, and their 6- to 8-month follow-up angiography results. CN was defined as a high backscattering mass with small nodular calcium depositions which protruded in the vessel lumen. RESULTS Thirty-two ISR lesions (4.9%) had CN. Multivariable analysis showed that calcified lesion (odds ratio [OR] 12.441, P < 0.001), incomplete stent apposition (OR 3.228, P = 0.005), hemodialysis (OR 3.633, P = 0.024), and female gender (OR 3.212, P = 0.036) were independently associated with ISR lesions with CN. Midterm follow-up was performed on 612 ISR lesions. Both ISR and target lesion revascularization (TLR) rates were significantly higher in lesions with CN compared with those without CN (43.8% vs. 25.0%, P = 0.023; 37.5% vs. 18.8%, P = 0.020, respectively). However, multivariate analysis did not show the presence of CN as an independent predictor for re-TLR (OR 1.690, P = 0.286). CONCLUSIONS The prevalence of ISR lesions with CN was 4.9%. Calcified lesion, incomplete stent apposition, hemodialysis, and the female gender are likely associated with CN formation. ISR lesions with CN may have poor midterm outcomes compared with ISR lesions without CN.