ObjectiveHypertension in pediatric patients after surgical repair of coarctation of the aorta can be difficult to control and may lead to morbidity. The renin-angiotensin system mediates at least part of this hypertension. Enalaprilat, the only intravenous angiotensin-converting enzyme inhibitor, is used to treat hypertension in pediatric patients in other settings. However, its effect on postoperative hypertension during the early postoperative period in patients undergoing surgical repair of coarctation of the aorta is unknown.DesignProspective, randomized, double-blind study.SettingOperating room and the pediatric intensive care unit.PatientsFourteen consecutive pediatric patients between the ages of 1 and 18 yrs scheduled to undergo surgical repair of coarctation of the aorta.InterventionsPatients were randomized to receive enalaprilat or saline placebo. Infusions were begun intraoperatively within 15 mins of aortic repair and repeated every 6 hrs.Measurements and Main ResultsPlasma renin activity was measured at baseline and on postoperative day 1. Blood pressure was determined at 30 mins and at 2, 4, and 6 hrs after infusion and scored relative to the preoperative blood pressure. The blood pressure in the enalaprilat group was consistently lower at 30 mins, 2 hrs, and 4 hrs after infusion (p< .05), but not at 6 hrs. Plasma renin activity was significantly lower in the placebo group on postoperative day 1. Length of stay in the pediatric intensive care unit trended shorter in the treated group.ConclusionsConclusions are limited by a small cohort. Angiotensin-converting enzyme inhibitor therapy resulted in improved blood pressure control after coarctation repair. Further improvement of blood pressure control may be achievable by use of a larger dose of enalaprilat or a 4-hr enalaprilat-dosing interval.