Clinical studies were performed on 7 renovascular hypertensive patients (3 male and 4 female, mean age 50.6 +/- 18.6) with bilateral renal artery stenosis. Duration of hypertension ranged from 2 months to 24 years (mean 6.1 +/- 8.2 years) before evaluation. All had stenosis or occlusion of both main renal arteries or these branches shown by arteriography. In 4 of the 7 patients atheromatous stenosis or occlusion was present; the remaining two had aortitis syndrome and one had fibromuscular hyperplasia. Of the 7 patients operated, two who had both negative renal renin study and ureteric catheterization study; one was failure after bilateral percutaneous transluminal angioplasty (PTA), and another one was improved after axillo-femoral bypass operation. In one patient with positive results of both studies an area of focal cortical atrophy was present in upper part of the left kidney. The patient, therefore, underwent partial nephrectomy the left kidney but failed to have decrease of blood pressure and was subsequently treated with antihypertensive medications. In the remaining four patients operated, two who had both positive renin and catheterization studies preoperatively were cured or improved after PTA in negative side and nephrectomy of positive side kidney. Other two patients with contradictory results of renin and catheterization studies underwent, PTA of the renal artery of the kidney with the highest renin levels. But their hypertension was maintained despite sufficient dilatation of the renal artery and PRA from the contralateral kidney was noted to be markedly increased after PTA. Therefore, nephrectomy of the contralateral nonfunctioning contracted kidney was performed.(ABSTRACT TRUNCATED AT 250 WORDS)