Risk factors and prediction model for thrombocytopenia following coronary artery bypass graft surgery in elderly Chinese population

Background: Thrombocytopenia, a common complication of coronary artery bypass graft (CABG) surgery, is particularly prevalent among elderly individuals. This study developed a risk prediction model utilizing preoperative and intraoperative variables to identify high -risk elderly patients prone to developing thrombocytopenia. Methods: The patients were retrospectively recruited from Beijing Anzhen Hospital between February 2019 and December 2020. Postoperative thrombocytopenia was defined as a postoperative platelet (PLT) count <100x109/L as measured within 7 days after surgery. The entire population was randomly split into derivation and validation sets in a 7:3 ratio. The derivation set underwent variable screen by the least absolute shrinkage and selection operator (LASSO) regression method. To evaluate the predictive ability of the model for thrombocytopenia, decision curve analysis (DCA) and receiver operating characteristic (ROC) curves were generated in the derivation and validation sets. Results: A total of 1,773 patients were recruited in this study, with random assignment to either the derivation set (1,242 cases) or the validation set (531 cases). LASSO regression was utilized the risk factors associated with thrombocytopenia, resulting in selection of preoperative baseline variables: body mass index (BMI), estimated glomerular filtration rate (eGFR), B -type natriuretic peptide (BNP), preoperative PLT, and use of beta-blocker, and intraoperative variables: red blood cell (RBC) transfusion, plasma transfusion, use of intra-aortic balloon pump (IABP) and cardiopulmonary bypass (CPB), reoperation for bleeding, washed RBC transfusion volume, and use of epinephrine. The logistic regression was employed to establish the risk prediction. The area under the ROC curve (AUC) for the derivation set was 0.900 [95% confidence interval (CI): 0.880-0.920], while for the validation cohort, it was 0.897 (95% CI: 0.866-0.928). Conclusions: The model incorporating significant preoperative and intraoperative variables exhibited good predictive performance for thrombocytopenia in elderly patients undergoing CABG surgery.