Allograft renal-artery stenosis: increased peripheral plasma renin activity as an early indicator of uncontrollable hypertension.

We measured indices of the renin-aldosterone system and body-fluid spaces in 11 adolescents who had received a renal transplant after removal of their own diseased kidneys. None had hypervolemia but 6 had hypertension. Renal angiography revealed greater than 50% luminal occlusion by allograft renal-artery stenosis (RAS) in only the 3 patients who had severe hypertension refractory to conventional medical therapy. Excessive peripheral plasma renin activity (PRA) distinguished these patients from those who had less severe stenosis or normal angiogram, and diuretic stimulation heightened the PRA differences. We conclude that significant allograft RAS does not necessarily act like a typical single-kidney Goldblatt model until after volume depletion. Our findings indicate that peripheral PRA values can be used to assess the degree of graft ischemia clinically. This permits early identification of patients who have severe RAS that probably will be difficult to control medically, and, therefore, should be followed closely with a view of reconstructive vascular surgery before further deterioration of renal function.