462 THE CORRELATION OF PLASMA RENIN ACTIVITY WITH RENAL BIOPSY IN PEDIATRIC URTEROPELVIC-JUNCTION OBSTRUCTION

INTRODUCTION AND OBJECTIVES: Plasma renin activity (PRA) has been known to be increased in urinary tract obstruction to compensate decreased local renal blood flow. In pediatric ureteropelvic-junction obstruction (UPJO), PRA has been reported to be increased than control and decreased after surgical correction of UPJO. We compared PRA with the histologic change of renal cortex to analyze the clinical meaning of PRA in pediatric UPJO patients. METHODS: We analyzed 42 consecutive pediatric patients who had been diagnosed with UPJO and undergone pyeloplasty or simple nephrectomy between March 2011 and October 2011. Age at operation, differential renal function (DRF) on diuretric renogram, PRA, and renal histologic change were analyzed. In all patients undergone pyeloplasty, kidney needle biopsies were performed simultaneously. When there was interstitial fibrosis or glomerulosclerosis in renal cortex, it was defined as unfavorable histology. RESULTS: Median age at operation was 5.4 (IQR: 3.3-12.5) months. Pyeloplasty was performed in 40 patients and laparoscopic simple nephrectomy was in 2 patients. Renal cortical histology showed unfavorable histology in 12 patients (28.6%) (Table 1). Gender, laterality, age at operation, blood pressure, serum creatinine, glomerular filtration rate showed no significant difference. Preoperative DRF and PRA were significantly higher in favorable histologic group. CONCLUSIONS: Preoperative DRF and PRA reflected renal histologic change in pediatric UPJO patients. In UPJO, higher PRA was correlated with higher renal function and that could be considered in the management of UPJO patients.