Troponin T and B-type natriuretic peptide after on-pump cardiac surgery: prognostic impact on 12-month mortality and major cardiac events after adjustment for postoperative complications.

Abstract

The independent predictive value of troponin T (TNT) after on-pump cardiac surgery was established in several studies. However, adjustment was limited to preoperative risk factors without considering perioperative complications. Data on the prognostic value of postoperative B-type natriuretic peptide (BNP) are scarce. Our aim was to assess the independent value of TNT and BNP to predict 12-month outcome after cardiac surgery with adjustment for preoperative risk estimates and postoperative complications and to report risk stratification gains when considering the European System for Cardiac Operative Risk Evaluation (EuroSCORE) combined with postoperative biomarkers. This prospective cohort study included consecutive patients undergoing on-pump cardiac surgery between 2007 and 2010. We evaluated postoperative TNT and BNP, the EuroSCORE, and postoperative complications as predictors of adverse events using Cox regression. The primary end point was death or major adverse cardiac events within 1 year after surgery. We calculated the net reclassification index of TNT and BNP in addition to the EuroSCORE. We enrolled 1559 patients, of whom 176 (11.3%) experienced an event. The adjusted hazard ratio of TNT >0.8 μg/L was 2.13 (95% confidence interval, 1.47-3.15) and of BNP >790 ng/L was 2.44 (95% confidence interval, 1.65-3.62). The net reclassification index of the addition of TNT and BNP to the EuroSCORE was 0.276 (95% confidence interval, 0.195-0.348). Postoperative TNT and BNP are strong predictors of 1-year events after on-pump cardiac surgery independent of preoperative risk factors and postoperative complications. Updating the preoperative EuroSCORE risk with postoperative TNT and BNP after surgery allows for improved prediction of 1-year death or major adverse cardiac events.