Predictive value of high-sensitivity troponin T in addition to EuroSCORE II in cardiac surgery

Plasma troponins, measured by fourth-generation assays, are associated with increased mortality and morbidity after cardiac surgery. They also offer predictive information in addition to EuroSCORE, a widely used risk model after cardiac surgery. However, preoperatively measured troponin has provided no additional information to postoperative values. Whether these facts hold true also for the high-sensitivity fifth-generation troponin assay and the better calibrated risk model, EuroSCORE II, is unknown. We hypothesized that preoperative and/or postoperative high-sensitivity troponin T (hs-TnT) would increase the predictive value of EuroSCORE II.

Consecutive coronary artery bypass grafting (CABG) and other cardiac surgical patients were prospectively enrolled in a university hospital. Plasma samples and EuroSCORE II variables were collected. The primary and secondary end-points were 180-day mortality and any major adverse event within 30 days, and 961-day mortality. The data were analysed by Kaplan-Meier survival curves, regression analyses, receiver operator characteristic curves and decision curve analysis.

Mortality rates in 180 days were 3.5% (15/428) in CABG and 6.4% (14/220) in other cardiac surgical patients. Survival curves differed only in patients with not only high postoperative hs-TnT value (>500 ng/l), but also high preoperative hs-TnT value (>14 ng/l), compared with patients with both hs-TnT values low. Adding hs-TnT to EuroSCORE II improved the prediction of 180-day mortality in other cardiac surgical patients (maximum net benefit of 1.5%), but not in CABG patients. Regarding major adverse events, adding hs-TnT to EuroSCORE II improved the prediction in both CABG patients and other cardiac surgical patients (maximum net benefits of 3 and 7%).

Elevated postoperative hs-TnT was predictive of mortality only when combined with elevated preoperative hs-TnT. Hs-TnT measurements added information to the EuroSCORE II regarding major adverse events in all cardiac surgical patients and regarding 180-day mortality in non-CABG patients.