Posterior urethral valves: Persistent renin angiotensin system activation after valve ablation and role of pre-emptive therapy with angiotensin converting enzyme-inhibitors on renal recovery

Aim: To study renin angiotensin system (RAS) activity after posterior urethral valve ablation and the role of early induction of angiotensin converting enzyme-inhibitors (ACE-I) on the outcome of renal function.

Materials and methods: Thirty four children underwent valve ablation in which therapy with ACE-I was started 40.5 ± 4.1 (range 32-47 months) formed the study group. Post-ACE-I data were collected after mean duration of 18.2 ± 4.0 (12-28 months). Plasma renin activity (PRA), urinary micro albumin, glomerular filtration rate (GFR), and serum creatinine, before and after therapy were monitored.

Results: Therapy with ACE-I resulted in a fall in micro albuminuria by 45.7% and 42.0% in patients without and with vesico ureteral reflux, respectively, and improvement in split renal function by 6.6% and 5.9% GFR respectively. A similar response was noted in patients without and with renal scars.

Conclusion: The decline in renal function after valve ablation is accompanied by activation of RAS reflected in a gradual rise in PRA. Therapy with ACE-I stabilizes and then improves renal function, thereby, retarding the pace of renal damage.