The Utility of Preoperative Plasma N-Terminal Pro-BNP as a Predictor of Postoperative Heart Failure in Patients Undergoing Elective Major Non-Cardiac Surgery

The prediction of perioperative cardiovascular complications is important in the management of patients undergoing elective non-cardiac surgery. Clinical evaluations alone may be insufficient to assess the cardiac risks. Recent studies demonstrated that elevated serum BNP levels could predict post-operative cardiovascular complications in cardiac surgery. Thus pre-operative NT-pro BNP can predict post-operative cardiac complications in non-cardiac surgery Objectives: This study was designed to determine whether the pre-operative plasma N-terminal pro-brain natriuretic peptide (NT-proBNP) level could be used to predict the postoperative heart failure and cardiovascular events in patients who underwent elective major non-cardiac surgery. Methods: This study was a prospective cohort trial. Sixty seven patients aged between 50-75 years, underwent elective vascular surgery or intermediate risk non-cardiac surgery. This study excluded patients who were previously documented with heart failure or myocardial infarction. The plasma NT-proBNP, an electrocardiogram, chest radiograph and left ventricular systolic and diastolic functions were measured before surgery. The postoperative cardiac outcomes were clinical signs and symptoms, chest roentgenogram and 12-lead electrocardiogram were taken during the 48 hours following each operation. Results: Patients were predominantly women (59.7%). The mean age was 63.9 ± 7.7 years. The mean level of plasma preoperative NT-proBNP was 121.9 pg/ml. Postoperative heart failure did not occur in this study. For the secondary end point, four patients (6%) had post-operative cardiac events; three patients (4.5%) had dynamic ST-T changes and one patient (1.5%) had new onset AF. The sensitivity, specificity, positive predictive value and negative predictive value of NT-proBNP that levels less than 400 pg/ml were 25%, 96.8%, 33.3%, and 95.3% respectively for the secondary end point. Nevertheless, fatal myocardial infarction and fatal arrhythmia did not occur in the post operative period. Normal level of plasma NT-pro BNP (< 400 pg/ml) correlated well with normal left ventricular systolic function (p < 0.05). Conclusions: Post-operative heart failure did not occur in patients with normal levels of preoperative NT-pro BNP. Measurement of NT-pro BNP in patients undergoing elective major non-cardiac surgery may be useful as a predictor for post-operative cardiovascular outcomes