Incremental value of B-type natriuretic peptide for early risk prediction of infective endocarditis.

Background: Early and accurate risk prediction is an unmet clinical need in patients with infective endocarditis (IE). The aim of this study was to determine the value of B-type natriuretic peptide (BNP) levels obtained on admission for the prediction of in-hospital death in IE patients.

Methods: Between 2009 and 2011, consecutive patients with IE diagnosed using the revised Duke criteria and admitted to the emergency department were evaluated prospectively. BNP levels were measured on admission. Death during hospitalization was the primary endpoint.

Results: Among 104 consecutive patients with IE and with available BNP levels, 34 (32.7%) died in hospital. BNP levels were significantly higher in patients who died as compared to survivors (709.0 pg/ml vs. 177.5 pg/ml, p<0.001). The accuracy of BNP to predict death as quantified by the area under the receiver operating characteristics curve was 0.826 (95% confidence interval (CI) 0.747-0.905). The value of BNP was additive to that provided by clinical, microbiological, and echocardiography assessment. On multivariate analysis, new heart failure (hazard ratio (HR) 2.02, 95% CI 1.15-3.57, p=0.015), sepsis (HR 2.10, 95% CI 1.25-3.55, p=0.005), Staphylococcus aureus endocarditis (HR 2.67, 95% CI 1.60-4.45, p<0.001), left ventricular ejection fraction ≤55% (HR 1.63, 95% CI 1.00-2.65, p=0.047), and BNP (HR 1.04, 95% CI 1.02-1.06, p<0.001) were independent predictors of in-hospital mortality.

Conclusion: Among patients with IE, BNP levels obtained on admission provide incremental value for early and accurate risk prediction.