High-sensitivity troponin T levels before and after cardiac surgery and the 30-day mortality: a retrospective cohort study

BackgroundThe suggested threshold level of cardiac troponin T elevation after cardiac surgery is not very clear, and the values recommended by various guidelines and literature reports are quite different.MethodsIn this retrospective cohort study, we collected clinical data of patients who underwent heart surgery at Tsinghua University First Hospital between January 2015 and December 2022. Using the high-sensitivity cardiac troponin T levels (reference upper limit: 14 ng/L) measured at 1-3 days postoperation, the relationship between the cardiac troponin T level and the 30-day mortality risk was evaluated using Cox regression analysis.ResultsAmong the 3,128 patients included in this study, the types of operations mainly consisted of coronary artery bypass graft (CABG, 1,164, 37.2%), aortic valve replacement (AVR, 735, 23.5%), and other cardiac operations (1,229, 39.3%). Within 30 days postoperation, 57 patients (1.8%) died and 72 patients (2.3%) developed major vascular complications. In patients undergoing CABG or AVR, the cardiac troponin T threshold level measured within one day postoperation related to an increased 30-day mortality was determined to be 3,012 ng/L (95% CI: 1,435-3,578 ng/L), which is 218 times higher than the reference upper limit. In patients undergoing other cardiac operations, this threshold was 5,876 ng/L (95% CI: 2,458-8,119 ng/L), which is 420 times higher than the reference upper limit.ConclusionThe high-sensitivity cardiac troponin T level associated with an increased 30-day mortality risk after cardiac surgery is significantly higher than the current recommendations for defining clinically important perioperative myocardial injury.