Determinants of NT-proBNP Levels in patients with a systemic right ventricle: a new cut-off level for risk stratification?

Abstract

Abstract Introduction The role of N-terminal natriuretic peptide (NT-proBNP) in the risk prediction of patients with a systemic left ventricle is indisputable. However, its value in patients with a systemic right ventricle (sRV) is not well defined. Method Ninety-eight patients with NT-proBNP values at baseline from the randomized clinical trial SERVE were included. The correlation between baseline NT-proBNP values and parameters of bi-ventricular volumes and function quantified by cardiac magnetic resonance was assessed by means of adjusted linear regression models. The prognostic value of NT-proBNP and other established prognostic markers were assessed by means of adjusted cox proportional hazards model, survival analysis and c-statistic. The primary outcome was defined as the occurrence of either clinically relevant arrhythmia, heart failure or death. Results Median age [interquartile range, IQR] at baseline was 39 years [32,48] and 32% were female. Median NT-proBNP was 238 [137,429] ng/L. Coefficients of determination for the relationship between NT-proBNP levels and right ventricular end-systolic and end-diastolic volume index, and ejection fraction (RVEF) were +0.481, p<0.001; +0.427, p<0.001; and -0.561, p<0.001, respectively. The sex and age adjusted hazard ratio [95% confidence interval, CI] for NT-proBNP values above the 75th percentile (429ng/L) showed an exponential increase (Figure) and there was a significant difference in survival comparing the group above our cut-off value and the group below it (Table). After adjusting for age and sex, the prognostic value of NT-proBNP was comparable to the prognostic value of RVEF and predicted VO2 max (C-statistic: 0.71, 0.72 and 0.71, respectively). Conclusion NT-proBNP levels correlated significantly with right ventricular parameters assessed by means of CMR. Measurement of NT-proBNP is a reliable and convenient tool for the prediction of adverse outcomes in patients with a sRV and using the cut-off value of 429ng/L could assist in the risk stratification for this population.