Preoperative B-type Natriuretic Peptide as a Predictor of Postoperative Cardiac Events Following Orthopedic Elderly Patients

ABSTRACT

BACKGROUND: The aim of this study was to evaluate the value of preoperative plasma B-type natriuretic peptide (BNP) level in predicting postoperative in-hospital major adverse cardiac events (MACE, defined as atrial fibrillation, congestive heart failure, nonfatal myocardial infarction and cardiac death) in elderly patients undergoing orthopedic surgery. METHODS: Between March 2010 and September 2011, data from 156 patients (aged 65 years or older) who underwent scheduled or emergent orthopedic surgery, were investigated. Screening for postoperative in-hospital MACE was performed using clinical criteria. RESULTS: MACE occurred in 12 patients (7.7%). The BNP level was significantly higher in patients with MACE than in those without (median, 152.0; interquartile range [36.3 to 352.8] pg/mL vs. median, 36.8; interquartile range [15.5 to 98.1] pg/mL, p=0.005). The BNP level was positively correlated with the revised cardiac risk index score (r=0.300, p=0.001). In a receiver operating characteristic (ROC) analysis for MACE, the ROC for BNP was 0.746 (95% confidence interval, 0.602 to 0.891). At the optimal cut-off point (BNP=110 pg/mL), the sensitivity, specificity and positive and negative predictive values were 66.7, 81.2, 22.0% and 96.6%, respectively. On multivariate analysis, preoperative BNP was an independent predictor for MACE (odds ratio, 5.091; p=0.018) after adjusting for baseline confounding factors such as diabetes mellitus and history of cerebrovascular accident. CONCLUSION: The preoperative BNP level may be a useful tool in stratifying the risk for MACE in elderly patients undergoing orthopedic surgery.