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

Abstract

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 $\text{APTT}\ge 44$ had a significantly higher risk of all-cause death than those with $\text{APTT}<44$ 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.