NT-proBNP indicates left ventricular impairment and adverse clinical outcome in patients with Tetralogy of Fallot and pulmonary regurgitation

Background: The goal of this study was to interrelate N-terminal B-type natriuretic peptide (NT-proBNP) levels and cardiac magnetic resonance imaging-derived ventricular function, mass, and volumes in adults with pulmonary regurgitation after Fallot repair and to evaluate the prognostic relevance of these parameters regarding adverse clinical outcome. Methods: Eighty-one patients (aged 26.3 +/- 7.4 years; male sex, 45.7%; New York Heart Association class I, 72.8%; pulmonary valve velocity, < 3 m/s) were included. At baseline cardiac magnetic resonance imaging and NT-proBNP measurements were performed. Results: During a mean observation time of 6.9 +/- 2.6 years, 13 patients (16.1%) had sustained supraventricular arrhythmias or heart failure (2.4 per 100 patient-years). Multivariate Cox analysis identified NT-proBNP, left ventricular (LV) end-systolic volume index and LV ejection fraction, right ventricular (RV) end-diastolic volume index, and tricuspid regurgitation as independent predictors of adverse events. NT-proBNP correlated with LV but not with RV parameters. In receiver operating characteristic curve analysis using significant variables of the multivariate analysis, NT-proBNP was superior to all other parameters to detect patients at risk (area under the curve [AUC], 0.873; 95% confidence interval, 0.772-0.974). LV end-systolic volume index (AUC, 0.734), RV end-diastolic volume index (AUC, 0.645) und tricuspid regurgitation (AUC, 0.747) showed lower diagnostic accuracy. Conclusions: Even in mildly symptomatic patients with pulmonary regurgitation after Fallot repair NT-proBNP is a strong predictor of adverse outcome. It is rather associated with LV but not with RV impairment. In severe pulmonary regurgitation an increase in the level of NT-proBNP and LV impairment seem to provide additional useful information for the timing of pulmonary valve replacement.