Association of N-terminal pro-brain natriuretic peptide and cardiac troponin T with in-hospital cardiac events in elderly patients undergoing coronary artery surgery

Background and objectives: Despite evidence of their prognostic power for non-surgical patients, the value of perioperative natriuretic peptides and cardiac troponins as markers of cardiac events is incompletely defined. This study sought to examine whether perioperative N-terminal pro-brain natriuretic peptide (NT-proBNP) and cardiac troponin T (cTnT) levels could be used for the prediction of in-hospital cardiac events in elderly patients undergoing elective coronary artery bypass grafting. Methods: Ninety-eight elderly patients (>75 yr) undergoing elective coronary artery bypass grafting with cardiopulmonary bypass were enrolled and followed up for 12-15 months. NT-proBNP and cTnT levels were measured before induction of anaesthesia and 12, 24 and 48 h after surgery. To identify the best discriminatory level of NT-proBNP and cTnT receiver operating characteristics curves were analysed. Results: Thirty-four patients experienced 54 in-hospital cardiac events. Patients with complications had significantly higher NT-proBNP and cTnT levels than those without complications. Receiver operating characteristics curve analysis revealed cut-off levels of 2361 pg mL -1 and 0.66 μg mL for NT-proBNP and cTnT (sensitivity, specificity, positive predictive value and negative predictive value of 84.3%, 89.4%, 78.9% and 92.4%, and 93.7%, 74.2%, 63.8% and 96.1%, respectively) at 24 h after surgery to be associated with in-hospital cardiac events. An elevation of both biomarkers above these threshold values was independently associated with individual postoperative complications (odds ratio, 18.9; 95%, CI, 2.3-106.1). Conclusions: In elderly patients undergoing elective coronary artery bypass grafting surgery, high values of NT-proBNP and cTnT measured 24 h after the end of surgery were independently associated with in-hospital cardiac events.