Effect of Captopril on Blood Pressure and on the Renin-Angiotensin-Aldosterone System in Coarctation of the Aorta

UNLABELLED: To investigate the role of the renin-angiotensin-aldosterone system in hypertension due to coarctation of the aorta (COA), upright mean arterial pressure (MAP), plasma renin activity (PRA) and plasma aldosterone (Aldo) were determined before and 90 minutes after a single oral dose of captopril (25 mg) in eight patients with COA and in fourteen with essential hypertension (EH). There was no significant difference in MAP, PRA or Aldo values between the two groups in baseline conditions. After captopril administration, MAP and Aldo decreased significantly in both groups (p less than 0.01), whereas PRA showed a marked increase in patients with COA (p less than 0.001) and no significant changes in EH patients (from 1.5 +/- 2.2 to 49.7 +/- 9.8 and from 5.6 +/- 0.9 to 8 +/- 1.5 ng/ml/3h respectively). CONCLUSIONS: 1) MAP reduction and marked renin increase after captopril in COA patients support the view that systemic hypertension in COA is, at least in part, renin mediated and 2) the evaluation of PRA after captopril could be helpful in the decision to proceed with more invasive procedures in patients with suspicious clinical features of COA or with residual post-coarctectomy hypertension.