Activated Partial Thromboplastin Time and Mortality in Coronary Artery Bypass Grafting Patients

BACKGROUND: To evaluate the prognostic value of preoperative activated partial thromboplastin time (APTT) in patients who underwent coronary artery bypass grafting (CABG). METHODS: All data were extracted from the Medical Information Mart for Intensive Care III (MIMIC-III) database. The study population was divided to two groups according to the optimal cut-off value of APTT calculated by X-tile software, and Cox proportional hazard model was used to define independent effect of APTT on 4-year mortality. Survival curves were estimated by the Kaplan-Meier method, and the area under the receiver-operating characteristic curve (AUC) was calculated to compare APTT with other severity scores. Propensity score matching (PSM) analysis were applied to ensure the robustness of this study. RESULTS: A total of 2,706 patients were included. The optimal cut-off value of APTT for 4-year mortality was 44 seconds. The Cox proportional hazard model showed that patients with APTT ≥ 44 had a significantly higher risk of all-cause death than those with APTT < 44 both before (HR (95% CI), 1.42 (1.16-1.74), P < 0.001) and after PSM (HR (95% CI), 1.47 (1.14-1.89), P = 0.003). The survival curves showed that patients with longer APTT had a significantly lower 1-year and 4-year cumulative survival probability. The ROC of APTT combined with other severity scores significantly increased predictive ability for 1-year and 4-year mortality. CONCLUSIONS: A longer APTT (≥44) was associated with a higher risk of mortality and can serve as a prognostic predictor in CABG patients.