ROLE OF THE PERIPHERAL RENIN PROFILE IN PREDICTING BLOOD-PRESSURE CONTROL AFTER BILATERAL-NEPHRECTOMY IN RENAL-TRANSPLANTED PATIENTS

Background. The unregulated renin release by native kidneys is one of the factors responsible for the high incidence of hypertension after r enal transplantation but, even after three decades of transplantation, there is still a lack of a method to identify it as the major cause o f hypertension. Methods. We investigated whether or not peripheral ren in activity, before and 90 min after 25 mg of captopril, can play this role. One hundred and five consecutive patients with SCr less than 2 mg/dl were studied 18+/-8 months after renal transplantation. Forty-se ven of them were considered hypertensive and 58 normotensive. All hype rtensive patients were submitted to the captopril test to analyse the peripheral renin activity profile. Results. In the hypertensive group, 17 patients (36%) were considered Renin-pos and 30 (64%) Renin-neg. A ll Renin-pos (stimulated renin=19.1+/-6.4 ng/ml/h) patients were submi tted to bilateral nephrectomy (bNx) and re-evaluated 6 months later. A ll of them normalized renin activity (4.4+/-3.0 ng/ml/h, P= 0.0001) an d 10 of 17 (60%) became normotensive and off drugs. The remaining seve n (40%) decreased the number of hypotensive drugs from 2.2+/-0.5 to 0. 5+/-0.7/pt/day. There was a correlation between b-Renin and dBP (r =0. 47, P<0.05) which was lost after bNx. an 'in situ' renal-cell carcinom a was found in two cases. Serum creatinine did not change. Conclusions . This study shows that the unregulated renin-angiotensin system from the native kidneys plays a major role in the maintenance of hypertensi on in some patients with normal graft function and that peripheral ren in activity can identify those who will benefit from bilateral nephrec tomy.