Factors associated with the outcomes of children with unilateral ureteropelvic junction obstruction

PURPOSE: Children with congenital unilateral ureteropelvic junction obstruction were evaluated with 99mtechnetium-labeled diethylenetriaminepentaacetic acid furosemide renal scans (DTPA) to determine the correlation of tubular function tests, growth factors and renal function. MATERIALS AND METHODS: A total of 38 children diagnosed with congenital unilateral ureteropelvic junction obstruction and recipients of dismembered pyeloplasty were prospectively studied. Before pyeloplasty split renal tubular function, creatinine clearance, urinary growth factors and a marker for apoptosis of each kidney were examined. Renal function of the obstructed kidney was evaluated by DTPA before and after pyeloplasty. Initially patients with DTPA greater than 40% were designated group 1 and those with DTPA 40% or less were assigned to group 2. After surgery followup patients with DTPA greater than 40% were designated the well preserved group and those with DTPA 40% or less were assigned to the poorly preserved group. Statistical analyses were performed to determine the best predictive variable for treatment. RESULTS: Mean initial DTPA split renal function values of groups 1 and 2 were 47.3% and 28.8%, respectively and subsequently, they were 48.4% and 35.3%. Initial DTPA on the obstructed side of less than 35% had a 100% sensitivity and 100% positive predictive rate for a poorly preserved renal outcome. Among the various tubular functions, only percent fractional excretion of sodium and percent fractional excretion of chloride correlated with post-pyeloplasty DTPA. Urinary epidermal growth factor/creatinine correlated with preservation of renal function on postoperative DTPA renal scans. Although urinary transforming growth factor/creatinine levels and apoptosis ratios were higher on the obstructed side, they were not significantly different between the groups. CONCLUSIONS: Proximal tubular dysfunction, such as increased percent fractional excretion of sodium and chloride, and initial DTPA 35% or less, suggest a high possibility of poorly preserved renal outcome. Urinary transforming growth factor-beta1 and apoptosis are not correlated with renal outcome. A high urinary level of epidermal growth factor might be a potential indicator of preservation of renal growth.