Plasma renin activity in the evaluation of hypertension in renal transplant recipients.

Plasma renin activity (PRA) was measured in nine renal transplant recipients, seven of which had transplant renal artery stenosis. Surgical correction of the stenosed renal transplant artery was performed in six patients. After corrective surgery of the stenosed artery hypertension (mean arterial pressure before operation 156 mmHg) improved (mean arterial pressure postoperatively 110 mmHg) in four patients with high peripheral PRA (17.3+/-3.9 ng/ml. hr). Two patients, one hypertensive, the other normotensive with low PRA (1.5+/-0.05 ng/ml. hr) had no change in their blood pressure after corrective surgery. In three hypertensive renal transplant recipients the PRA of the venous effluent of the own kidneys and the renal transplant were studied selectively. Selective PRA determinations revealed the source of inappropriate renin secretion offering a basis for surgical management of the assocaited hypertension.