BACKGROUND The neutrophil to lymphocyte ratio(NLR) has been reported as a novel predictor for atherosclerosis and cardiovascular outcomes. This study aimed to determine the effects of NLR on long-term clinical outcomes of chronic total occlusion(CTO) patients.METHODS A total of 670 patients with CTO who met the inclusion criteria were included at the end of the follow-up period.Patients were divided into tertiles according to their baseline NLR levels at admission: low(n = 223), intermediate(n = 223), and high(n = 224). The incidence of major adverse cardiac events(MACEs) during the follow-up period, including all-cause death,nonfatal myocardial infarction(MI), or ischemia-driven revascularization, were compared among the three groups.RESULTS Major adverse cardiac events were observed in 27 patients(12.1%) in the low tertile, 40(17.9%) in the intermediate tertile, and 61(27.2%) in the high NLR tertile(P < 0.001). Kaplan-Meier analysis demonstrated a significantly higher incidence of MACE, ischemia-driven coronary revascularization, non-fatal MI, and mortality in patients within the high tertile than those in the low and intermediate groups(all P < 0.001). Multivariable COX regression analysis showed that the high tertile of baseline NLR level showed a strong association with the risk of MACE(hazard ratio [HR] = 2.21; 95% confidence interval [CI]: 1.21–4.03;P = 0.009), ischemia-driven coronary revascularization(HR = 3.19; 95% CI: 1.56–6.52; P = 0.001), MI(HR = 2.61; 95% CI: 1.35–5.03;P = 0.043) and mortality(HR = 3.78; 95% CI: 1.65–8.77; P = 0.001).CONCLUSION Our findings suggest that NLR is an inexpensive and readily available biomarker that can independently predict cardiovascular risk in patients with CTO.