Amino-Terminal Fragment of Pro-Brain Natriuretic Hormone Identifies Functional Impairment and Right Ventricular Overload in Operated Tetralogy of Fallot Patients

To evaluate the relationship between plasma concentration of amino-terminal fragment of pro-brain natriuretic peptide (NT-proBNP), functional capacity, and right ventricular overload in survivors of tetralogy of Fallot (TOF) repair, we prospectively studied 70 operated TOF patients (44 males, 21 ± 1 years old; mean ± SEM) who underwent, during the same day, echocardiography, cardiac magnetic resonance imaging, neurohormonal characterization (plasma NT-proBNP, catecholamines, plasma renin activity, and aldosterone assay), and cardiopulmonary exercise testing. Forty-eight age- and sex-matched healthy volunteers served as the control group. Compared to controls, maximal workload and peak oxygen consumption (VO₂/kg) were lower in operated TOF patients (p < 0.001), whereas NT-proBNP concentration was elevated (p < 0.001). No difference was found among the other neurohormones. In operated TOF patients, NT-proBNP showed a significant positive correlation with right ventricular (RV) end systolic and end diastolic volumes and RV systolic pressure, and it showed a negative correlation with peak VO₂/kg and RV ejection fraction. From multivariable analysis, NT-proBNP concentration was found to be an independent predictor of peak VO₂/kg, RV end systolic volume, and RV systolic pressure. These results show an association among RV overload, decrease in functional capacity, and cardiac natriuretic peptide expression in operated TOF patients. NT-proBNP plasma assay may be a useful tool for diagnostic purposes and for decision making in this setting.