BACKGROUND: Chronic total occlusion (CTO) percutaneous coronary intervention (PCI) has improved outcomes, yet residual cardiovascular risk persists. The neutrophil percentage-to-albumin ratio (NPAR), an integrated marker of inflammation and nutritional status, has not been examined in successfully revascularized CTO patients. We investigated whether NPAR is independently associated with long-term adverse outcomes in this population. METHODS: This single-center retrospective cohort study included 1513 consecutive patients who underwent successful CTO PCI. NPAR was calculated as (neutrophil percentage × 100)/albumin (g/dL). The primary endpoint was all-cause mortality, secondary endpoints were cardiovascular mortality and cardiovascular events (cardiovascular death, non-fatal myocardial infarction, non-fatal stroke). Multivariable Cox regression and restricted cubic splines (RCS) assessed the association between NPAR and clinical outcomes. Time-dependent Receiver operating characteristics (ROC) curves were used to evaluate the ability for NPAR to predict all-cause mortality. RESULTS: During a median follow-up of 810 days, 83 (5.5%) all-cause deaths, 53 (3.5%) cardiovascular deaths, and 73 (4.8%) cardiovascular events occurred. After multivariable adjustment, each 1-standard deviation increase in NPAR was associated with a 50% higher risk of all-cause mortality (HR 1.50, 95% CI 1.23-1.83, P<0.001), a 59% higher risk of cardiovascular mortality (HR 1.59, 95% CI 1.23-2.05, P<0.001), and a 42% higher risk of cardiovascular events (HR 1.42, 95% CI 1.13-1.79, P = 0.003). RCS analysis revealed a linear association between NPAR and all-cause mortality (P for non-linearity = 0.971), cardiovascular mortality (P for non-linearity = 0.150), and major cardiovascular events (P for non-linearity = 0.152). Time-dependent ROC analyses demonstrated that adding NPAR to a basic model comprising age, multi-vessel disease, and LVEF significantly improved discrimination for all-cause mortality at 1, 2, and 3 years (ΔAUC 0.092, 0.076, and 0.058, respectively; all P < 0.0001). The optimal NPAR cut-off values derived from the maximum Youden index were stable across all three time points (15.71, 16.18, and 15.37, respectively), yielding sensitivities of 71.8% to 72.6% and specificities of 73.2% to 75.7%. CONCLUSION: In patients undergoing successful CTO PCI, elevated NPAR is independently and linearly associated with increased long-term mortality and major cardiovascular events. This simple, objective biomarker may refine post-intervention risk stratification and identify high-risk individuals warranting intensified secondary prevention.