Immunosenescence biomarkers and outcomes in isolated coronary artery bypass grafting.

OBJECTIVES: Preoperative inflammation and immune dysregulation drive perioperative complications and long-term adverse outcomes in coronary artery bypass grafting (CABG). Routine blood count-derived immunosenescence biomarkers offer accessible measures of systemic immune status, but their prognostic value in CABG is not fully established. METHODS: We conducted a retrospective cohort study of adults undergoing isolated CABG from 2010 to 2025. Preoperative immunosenescence biomarkers, including neutrophil-to-lymphocyte ratio, platelet-to-lymphocyte ratio, monocyte-to-lymphocyte ratio, systemic immune-inflammation index, systemic inflammation response index, and aggregate index of systemic inflammation, were derived from routine blood counts collected within 30 days before surgery. Outcomes included 30-day mortality, perioperative complications, postoperative atrial fibrillation, all-cause mortality, and 5-point major adverse cardiovascular and cerebrovascular events. Associations were assessed using univariable and multivariable logistic and Cox regression adjusted for clinical covariates. RESULTS: Among 9046 patients (median age 67 years; 24.3% female), 30-day perioperative mortality was 2.27%. Greater standardized preoperative biomarker levels were significantly associated with increased perioperative mortality (P < .001) and complications (P < .001), with modest predictive performance (area under the receiver operating curve, 0.534-0.656). Although postoperative atrial fibrillation occurred in 29.4% of patients, the biomarkers were not predictive after multivariable adjustment (P = .357). Over 14 years of follow-up, greater biomarker levels were independently associated with increased all-cause mortality (P < .001 for all) and major adverse cardiovascular and cerebrovascular events (P < .001 for all). CONCLUSIONS: Preoperative immunosenescence biomarkers are independently associated with adverse outcomes in patients who undergo CABG. These accessible biomarkers may identify high-risk patients scheduled to undergo CABG and guide future individualized perioperative and immunomodulatory strategies.