RENIN SECRETION AND CAPTOPRIL STIMULATION IN HYPERTENSIVE RENAL-TRANSPLANT RECIPIENTS

Basal renin secretion and the diagnostic value of a captopril stimulat ion (captopril test) in identifying renovascular hypertension secondar y to transplant renal artery stenosis was assessed in 69 patients with hypertension after renal transplantation. An increase of plasma renin activity of 260% 1 h after captopril was considered as a positive res ult, assuming renovascular hypertension. Six of 69 patients had a posi tive captopril test, of these patients 5 had transplant renal artery s tenosis. These patients were treated with percutaneous transluminal an gioplasty (PTA) or surgery. Based on angiographic results and blood pr essure response after PTA or surgery the captopril test showed a sensi tivity of 100% and a specificity of 92% in the identification of hemod ynamically significant stenosis of the transplant artery. Therefore, t he captopril test provides a suitable screening instrument for the dif ferential diagnosis of hypertension following renal transplantation.