The role of brain natriuretic peptide in prognostication and reclassification of risk in patients undergoing vascular surgery*

Abstract

The aim of this study was to determine whether measurement of pre-operative brain natriuretic peptide can significantly improve risk stratification of vascular surgical patients. The study endpoint was postoperative raised troponins. Net reclassification improvement was determined for risk categories based on the Revised Cardiac Risk Index. Two reclassifications were conducted based on either the optimal discriminatory point or brain natriuretic peptide tertiles. Two hundred and sixty-seven patients were studied of whom 36 (13.5%) had raised postoperative troponin. The Revised Cardiac Risk Index score and the pre-operative brain natriuretic peptide were independent predictors of postoperative troponin elevation (p = 0.02 and p = 0.001, respectively). Reclassification based on the optimal discriminatory point significantly improved risk stratification (net reclassification improvement 38.3% (95% CI 9.3-67.3%), p = 0.01 for the entire cohort and 70.3% (95% CI 27.1-113.6%), p = 0.002 for intermediate risk patients). The brain natriuretic peptide tertiles only improved stratification of intermediate risk patients (net reclassification improvement 50.0% (95% CI 16.7-83.3%), p = 0.01). We have shown that measurement of pre-operative brain natriuretic peptide is relevant in the context of risk assessment in this cohort of patients.