Effective renal plasma flow (ERPF) of the individual kidney and renal venous renin activity (RVRA) determined simultaneoulsy before and after the administration of dihydralazine in renovascular hypertension.

Effective renal plasma flow (ERPF) and renal venous renin activity (RVRA) were determined for the two kidneys separately before and after intravenous administration of dihydralazine in 50 cases of suspected unilateral renovascular hypertension. A ratio above 1.4 between the ERPFs of the two kidneys and an RVRA ratio above 1.5 were used as signs of lateralization. The two procedures showed agreement about presence or absence of lateralization in 36 cases before and 44 after dihydralazine administration. Eleven patients underwent surgery. ERPF and the changes in ERPF induced by dihydralazine gave important prognostic and preoperative information. Data on renin release rates are presented.