Role of N-terminal pro B-type natriuretic peptide in identifying patients at high risk for adverse outcome after emergent non-cardiac surgery

Abstract

Patients undergoing emergency surgery continue to be at very high risk, but accurate risk identification for the individual patient remains difficult. This study tested the usefulness of perioperative N-terminal pro B-type natriuretic peptide (NT-proBNP) for in-hospital and long-term risk stratification. We conducted a prospective single-centre observational cohort study in an Austrian university hospital. Two hundred and ninety-seven consecutive patients >50 yr of age undergoing a variety of emergency non-cardiac procedures were included. The primary endpoint was a composite of non-fatal myocardial infarction (MI), acute heart failure, or death between index surgery and 3 yr follow-up. The secondary endpoint was in-hospital major adverse cardiac events (MACE), defined as non-fatal MI, acute heart failure, or cardiac death. During a median follow-up of 34 months (inter-quartile range: 16-39), 31% of subjects reached the primary endpoint. A preoperative NT-proBNP ≥725 pg ml(-1) was associated with a 4.8-fold univariate relative risk [95% confidence interval (CI): 3.1-7.6] and a postoperative NT-proBNP ≥1600 pg ml(-1) was associated with a four-fold univariate relative risk (95% CI: 2.7-6.2) for reaching the primary endpoint. Moreover, preoperative NT-proBNP remained a significant and independent (hazards ratio 1.91, 95% CI 1.08-3.37, P=0.027) predictor in a multivariate Cox proportional hazards model. A preoperative NT-proBNP ≥1740 pg ml(-1) was associated with a 6.9-fold univariate relative risk (95% CI: 3.5-13.4) for MACE during the index hospital stay, but did not remain significant in a multivariate logistic regression model. Preoperative NT-proBNP can help identify patients at high risk for adverse long-term outcome after emergency surgery.