Background:Despite its severity,coronary artery ectasia (CAE) is still poorly understood.High-sensitivity C-reactive protein (hs-CRP) has been recognized as a prognostic factor in some cardiovascular diseases but not assessed in CAE.The aim of this observational study was to investigate the prognostic value of hs-CRP in CAE.Methods:Our analysis evaluated the effect of the baseline hs-CRP on cardiovascular events (CVs) (cardiac death and nonfetal myocardial infarction) in consecutively enrolled stable CAE patients.We used the Cox proportional hazards regression models to examine the association between baseline hs-CRP level and follow-up CVs in CAE.The net reclassification improvement and integrated discrimination improvement (IDI) of hs-CRP were also assessed.Results:We obtained the follow-up results of 540 patients over a median follow-up period of 36 (37.41 ± 15.88) months.The multivariable Cox analysis showed that the hs-CRP was a significant predictor of adverse outcomes in CAE (hazard ratio [HR]:2.99,95％ confidence interval [CI]:1.31-6.81,P =0.0091).In Kaplan-Meier analysis,the group with hs-CRP ＞3 mg/L had a lower cumulative 66-month event-free survival rate (log-rank test for trend,P =0.0235) and a higher risk ofCVs (HR =2.66,95％ CI:1.22-5.77,P =0.0140) than the group with hs-CRP ≤3 mg/L.Hs-CRP added predictive information beyond that given by the baseline model comprising the classical risk factors (P value for IDI =0.0330).Conclusions:A higher level of hs-CRP was independently associated with cardiac death and nonfatal myocardial infarction in CAE patients.The hs-CRP level may therefore provide prognostic information for the risk stratification of CAE patients.