THE EFFECT OF RAMIPRIL - A NEW ANGIOTENSIN-CONVERTING ENZYME-INHIBITOR ON CORTICAL NEPHRON FLOW AND EFFECTIVE RENAL PLASMA-FLOW IN PATIENTS WITH ESSENTIAL-HYPERTENSION

A placebo-controlled study of Ramipril on total and intrarenal flow distribution was carried out in 7 patients with essential hypertension. Cortical nephron flow was measured using radiolabelled tubular secreted radiopharmaceuticals 123I orthoidohippurate or 99mTc mercaptoacetyl triglycine by the transit time distribution technique. Both systolic and diastolic blood pressure were reduced significantly by Ramipril without significant changes in an index of cardiac output or in effective renal plasma flow. Cortical nephron flow increased from 207 ± 7 to 257 ± 21 ml/min (mean ± SEM) p < 0.05 and the percentage of flow to cortical nephrons increased by 6% (p = 0.05). Ramipril corrects the reduced cortical nephron flow found in essential hypertension.