Blockade of the renin-angiotensin system increases graft survival in patients with chronic allograft nephropathy

Background. Chronic allograft nephropathy (CAN) is the leading cause of late allograft failure, with only limited treatment options. Blockade of the renin-angiotensin system (RAS) decreases progression in diabetic and non-diabetic renal disease, but the effect on CAN is as yet unclear. Therefore, we have studied retrospectively the effect of RAS blockade on renal survival in patients with biopsy-proven CAN. Methods. The medical records of 72 patients with biopsy-proven CAN were evaluated with regard to time course of graft function, proteinuria, blood pressure, and antihypertensive and immunosuppressive treatment. Cox's proportional hazards model was used for analysing renal graft survival after the index biopsy. Results. On univariate analysis, histological determinants influencing renal survival were the chronic interstitial and chronic tubular score, and clinical parameters were the serum creatinine level at the time of the biopsy, the relative change in serum creatinine level between 12 months post-transplantation and at the time of the biopsy, mean systolic and diastolic blood pressure after the biopsy, and RAS blockade by angiotensin-converting enzyme inhibitor or angiotensin receptor blocker. On multivariate analysis., graft outcome was influenced by the relative change in serum creatinine level between 12 months post-transplantation and the time of the index biopsy, the urinary protein excretion, the mean diastolic blood pressure after the index biopsy, and RAS blockade. Renal graft survival after treatment with RAS blockade was 6.3 (0.9-10.9) years as opposed to 1.8 (0.1-6.7) years in untreated patients (P = 0.003). Conclusion. RAS blockade increases graft survival in CAN. In view of the limited treatment options for CAN, this finding is of importance and needs confirmation by a prospective randomized trial.