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 NT-proBNP levels and cardiac magnetic resonance imaging (CMR) derived ventricular function, mass and volumes in adults with pulmonary regurgitation after Fallot repair and to evaluate the prognostic relevance of these factors regarding adverse clinical outcome.

Methods: 81 patients (age 26.3 ± 7.4, male 45.7%, NYHA class I 72.8%, pulmonary valve velocity < 3 m/sec) were included. At baseline CMR and NT-proBNP measurement were performed.

Results: During a mean observation time of 6.9 ± 2.6 years 13 (16.1%) patients had sustained supraventricular arrhythmias or heart failure (2.4/100 patient years). Multivariate Cox analysis identified NT-proBNP (HR: 5.492; 95% CI: 1.751–17.230), left ventricular (LV) end systolic volume index (4.156 (95% CI: 2.255–11.44); p = 0.006) and LV ejection fraction (HR: 0.211; 95%CI: 0.065–0.680), right ventricular (RV) end diastolic volume index (HR: 5.046; 95% CI: 1.636–15.558) and tricuspid regurgitation (HR: 7.618; 95% CI: 2.555–22.707) as independent predictors of adverse events. NT-proBNP correlated with LV but not with RV parameters. Using ROC in significant variables of multivariate analysis NT-proBNP was superior to all other parameters to detect patients at risk (AUC: 0.873; 95% CI: 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.

Conclusion: 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 than with RV impairment. Observation of both NT-proBNP and LV parameters during follow-up provide additional information regarding risk stratification potentially influencing subsequent therapeutic decisions.