Plasma levels of B-type natriuretic peptide in patients with tetralogy of Fallot after surgical repair.

OBJECTIVE

To evaluate the utility of plasma BNP measurement in the long term follow-up of patients with surgically repaired tetralogy of Fallot (TOF).

METHODS

From 2002 to 2008, plasma BNP concentration was measured in 130 patients with TOF at the age of mean 16.1+/-7.1 years and mean 13.0+/-6.5 years after surgically repair. BNP levels were compared to age and gender-specific normal values, results of exercise testing, clinical, electrocardiographic, and echocardiographic data.

RESULTS

BNP was <200 pg/ml in all and elevated in 60% of patients. Higher values were found in females (p=0.001), in patients waiting for pulmonary valve replacement (p<0.001), and in NYHA class II compared to NYHA I patients (p=0.012) with an inverse correlation between BNP and exercise time (r=-0.59, p<0.001). BNP was correlated with right ventricular dilatation (r=0.29, p=0.005) and severity of both tricuspid (r=0.22, p=0.015) and pulmonary regurgitation (r=0.20, p=0.029). Longitudinal data revealed increasing BNP levels before (p=0.04) and a BNP decrease after pulmonary valve replacement (p=0.03), but no change in patients without surgery.

CONCLUSIONS

In patients with surgically repaired TOF, plasma BNP is significantly correlated with right ventricular volume load. In clinical practice a considerable overlap limits the estimation of right ventricular volume load by BNP, but longitudinal evaluation helps to appoint the appropriate timing of pulmonary valve replacement.