Abstract 15562: Left Ventricular Rest and Reserve Function is an Important Determinant of BNP Level in Patients with Surgically-Repaired Tetralogy of Fallot
Background Right ventricular (RV) dysfunction caused by volume and/or pressure overload due to residual pulmonary lesion is an important prognostic factor in patients with surgically-repaired tetralogy of Fallot (TOF). Plasma B-type natriuretic peptide (BNP) levels are thought to reflect the severity of RV pathophysiology. Recent studies have also emphasized the prognostic importance of left ventricular (LV) function in this disease. We hypothesized that impaired rest and reserve LV function also contributes to increased BNP levels observed in patients with repaired TOF.
Methods and Results Plasma BNP levels were measured in 41 consecutive patients with surgically-repaired TOF (age at study, 6.6±4.8 years, time interval after surgery, 5.7±4.9 years, mean±SD). Ventricular function was assessed by invasive pressure-area relationship during caval occlusion, both at rest and under β-adrenergic stimulation with dobutamine. Univariate regression analysis showed that RV end-diastolic volume (EDV) and RV/LV systolic pressure ratio correlated significantly with BNP levels (r=0.45/p<0.005, r=0.59/p<0.0001, respectively). In addition to these parameters indicating RV volume and pressure overload, impaired LV contractility (LV dp/dtmax) and relaxation (Tau) at rest correlated significantly with elevated plasma BNP levels (p<0.05). In addition, impaired inotropic and lusitropic responses to β-adrenergic stimulation correlated significantly with elevated plasma BNP levels (p<0.05). Multivariate analysis identified these parameters of LV rest and reserve function for contractility and relaxation as significant determinants of plasma BNP levels, independent of age, RV volume and RV pressure overload.
Conclusions In pediatric patients with repaired TOF, plasma BNP levels correlate with not only RV volume and pressure load but also systolic and diastolic LV function including reserve function. These data highlight the pathophysiologic importance of LV function in TOF-repaired patients, and emphasize the importance of LV dysfunction in any interpretation of high serum BNP levels in these patients.
- © 2011 by American Heart Association, Inc.