Diagnosis of ureteropelvic junction obstruction in children: role of endothelin-1 in voided urine.

OBJECTIVES

To examine the role of voided urine endothelin-1 (ET-1) in the diagnosis and follow-up of children with ureteropelvic junction obstruction.

METHODS

The study included 35 children with unilateral ureteropelvic junction obstruction who underwent pyeloplasty and 30 control children, including 10 healthy children, 10 with vesicoureteral reflux, and 10 with renal stones. Voided urine samples were obtained from the children in the study group before surgery and from the renal pelvis by needle aspiration during pyeloplasty. Bladder urine samples were also collected from the study group 1, 2, 3, 6, 9, and 12 months postoperatively. Bladder urine samples were also collected from all 30 control children. ET-1 was measured in the urine samples collected from the study and control groups.

RESULTS

The preoperative ET-1 level in the voided urine of the study group was significantly greater than its level in each of the three control groups. For the whole study group, a cutoff value of 3 fmol/mg creatinine gave a sensitivity of 74.3%, a specificity of 90%, and an overall accuracy of 81.5%. In 8 children (1 year old or younger), a cutoff value of 4 fmol/mg creatinine gave a sensitivity and specificity of 100%. Compared with the preoperative value, ET-1 had decreased significantly at 12 months after pyeloplasty.

CONCLUSIONS

The ET-1 level in voided urine is a useful marker that could be used as a noninvasive tool for the diagnosis and long-term follow-up of children with ureteropelvic junction obstruction.