1. Eighteen patients with unilateral arterial stenosis or renal parenchymal lesion underwent corrective surgery for hypertension. Operative curability of hypertension was compared with pre-operative plasma renin activity (PRA) determined in three different veins; affected side renal (A), contralateral renal (C), and peripheral veins (P).
2. Those with renal arterial stenosis in whom the PRA in the affected side renal vein was significantly higher (more than 14 ng/ml) than that in both the contra-lateral side and peripheral veins, i.e. those with PRA values showing a pattern of A > C=P were found surgically curable without exception.
3. Patients with unilateral renoparenchymal lesions showed either A, C > P or A = C=P pattern and these were all found not curable. A similar pattern was found in four controls.