Renovascular hypertension: the role of nonspecific factors in the antihypertensive effect of surgery.

Effective surgical treatment was carried out in 67 patients who were selected from a population of 336 subjects with renovascular hypertension. Split renal function studies and estimation of plasma renin activity in both renal veins were made to demonstrate the functional significance of the stenosis. The degree of disturbance of these tests did not correlate with the preoperative blood pressure level. The percentage decrease in postoperative blood pressure was directly related to the preoperative blood pressure (P less than 0.01). In 23 postoperative patients followed yearly for 5 years, the blood pressure increased progressively and was positively correlated with the duration of follow up (P less than 0.02). Patients with renovascular hypertension had a lower frequency of blood group 0 and a higher frequency of blood group A than did normotensive controls. The results of the study suggest that, in renovascular hypertension, the antihypertensive effect of surgical treatment is not exclusively related to the physiological consequence of the stenosis and that nonspecific factors, possibly of genetic origin, may determine the blood pressure response after surgical treatment.