title: Plasma renin activity: An early marker of progressive renal disease in posterior urethral valves.
abstract: BACKGROUND
  A significant number of children with posterior urethral valves (PUV) develop chronic renal failure (CRF) due to activation of the renin angiotensin system (RAS). We investigated the role of plasma renin activity (PRA) in these cases and sought to establish a relationship between the accepted criteria of renal damage and PRA.
  
  
  OBJECTIVE
  The aim of this study is to establish the relationship between PRA and CRF.
  
  
  METHODS
  The records of 250 patients with PUV were reviewed. Multiple linear regression analysis was used to assess correlations between PRA, grade of reflux, presence of scars and raised creatinine and decrease in glomerular filtration rates (GFR). A P < 0.5 was considered as significant.
  
  
  RESULTS
  A total of 58 patients were included. Their mean age was 16 years, range 5.3-24.2 years, mean follow-up period was 12.6 ± 3.6 years. At diagnosis, 22/58 (38%) patients were in CRF and 36/58 (62%) patients had normal renal function (RF). The mean PRA after treatment was higher in those who developed CRF than in those with normal RF (12.6 ± 10.2 vs. 34.6 ± 14.2 ng/ml/24 h, P = 0.02). Mean GFR at 1 year of age were 48 ± 9.8 ml/min/1.73 m(2) and 86 ± 12.5 ml/min/1.73 m(2) respectively (P = 0.005). PRA correlated negatively with GFR, t = -2.816.
  P = 0. 007. In the temporal plot over a period of 14 years, a rise in PRA preceded the fall in GFR in patients who developed CRF.
  
  
  CONCLUSIONS
  This study shows that RAS is activated earlier in kidneys susceptible to damage. PRA could be investigated as a marker for the early detection and prevention of ongoing renal damage.
authors.affiliation: Department of Pediatric Surgery, All India Institute of Medical Sciences, New Delhi, India.
authors.forename: Minu
authors.initials: M
authors.lastname: Bajpai
authors.affiliation: Department of Pediatric Surgery, All India Institute of Medical Sciences, New Delhi, India.
authors.forename: Amit
authors.initials: A
authors.lastname: Singh
keywords: Plasma renin activity; posterior urethral valves; renal failure; renin angiotensin system; valve fulguration