USE OF ATP-MGCL2 IN THE EVALUATION AND TREATMENT OF CHILDREN WITH PULMONARY-HYPERTENSION SECONDARY TO CONGENITAL HEART-DEFECTS

Background Pulmonary hypertension results in increased morbidity and m ortality in children after surgical repair of congenital heart defects . Various vasodilators have been unsuccessful in providing preferentia l pulmonary vasodilation in these patients. Identification of a more p referential pulmonary vasodilator would improve the assessment, manage ment, and outcome of these children. To determine whether ATP-MgCl2 is a preferential pulmonary vasodilator in children with pulmonary hyper tension secondary to congenital heart defects, ATP-MgCl2 was administe red during routine cardiac catheterization, and the effects were compa red with tolazoline. In addition, ATP-MgCl2 was infused intravenously during episodes of postoperative pulmonary hypertension. Methods and R esults During cardiac catheterization in 28 children, the effect of AT P-MgCl2 on the pulmonary artery pressure (PAP) and pulmonary vascular resistance index (R(p)) was compared with tolazoline. ATP-MgCl2 (0.1mg of ATP per kilogram per minute) decreased mean PAP by 24% (P<.05) and R(p) by 47% (P<.05) without changing mean systemic arterial pressure or systemic vascular resistance. These effects were comparable to thos e of tolazoline (1 mg/kg). ATP-MgCl2 produced no significant side effe cts; tolazoline caused tachycardia, nausea, and vomiting. After cardia c surgery in 7 patients, ATP-MgCl2 decreased PAP by 14% (P<.05) and sy stemic arterial pressure by 6% (P<.05) and eliminated pulmonary hypert ensive crises in 3 of 3 patients. Conclusions ATP-MgCl2 is a safe, eff ective, and preferential pulmonary vasodilator in children with pulmon ary hypertension secondary to congenital heart defects. It is useful f or evaluating pulmonary vasoreactivity during cardiac catheterization and for treating pulmonary hypertension after cardiac surgery.