What is the best pre-operative risk stratification tool for major adverse cardiac events following elective vascular surgery? A prospective observational cohort study evaluating pre-operative myocardial ischaemia monitoring and biomarker analysis.

Although brain natriuretic peptide has been shown to be superior to the revised cardiac risk index for risk stratification of vascular surgical patients, it remains unknown whether it is superior to alternative dynamic risk predictors, such as other pre-operative biomarkers (C-reactive protein and troponins) or myocardial ischaemia monitoring. The aim of this prospective observational study was to determine the relative clinical utility of these risk predictors for the prediction of postoperative cardiac events in elective vascular surgical patients. Only pre-operative troponin elevation (OR 56.8, 95% CI 6.5-496.0, p < 0.001) and brain natriuretic peptide above the optimal discriminatory point (OR 6.0, 95% CI 2.7-12.9, p < 0.001) were independently associated with cardiac events. Both brain natriuretic peptide and troponin risk stratification significantly improved overall net reclassification (74.6% (95% CI 51.6%-97.5%) and 38.5% (95% CI 22.4-54.6%, respectively)); however, troponin stratification decreased the correct classification of patients with cardiac complications (-59%, p < 0.001). Pre-operative brain natriuretic peptide evaluation was the only clinically useful predictor of postoperative cardiac complications. Anaesthesia