Results of Temporary Drainage of Poorly Functioning Kidneys With Ureteropelvic Junction Obstruction: Does the Histology of Persistent Poor Functioning Kidneys Indicate an Increased Risk of Hypertension?

ABSTRACT

OBJECTIVE: To review our experience with managing poorly functioning kidneys with ureteropelvic junction obstruction (PFK-UPJO) with differential renal function (DRF) <10% by a trial of temporary drainage, as the management of such kidneys is controversial. We also studied the histopathologic changes in the nephrectomy specimens of persistent PFK-UPJO, as tubulointerstitial damage may predispose to hypertension. METHODS: A retrospective review of cases undergoing treatment for unilateral UPJO over 5-year period in 2 centers was conducted. In PFK-UPJO, 4-6 weeks trial of drainage with double J stent or percutaneous nephrostomy was employed. Those kidneys that improved DRF to >10% underwent pyeloplasty, while persistent PFK underwent nephrectomy; the specimens were studied for interstitial fibrosis/tubular atrophy (IF/TA), arterial lesions, and arteriole lesions. RESULTS: Of 402 patients with unilateral UPJO that underwent surgical management, 17 (4.1%) had PFK-UPJO. After 4-6 weeks trial of drainage, 6 kidneys (35.2%) with improved DRF underwent pyeloplasty, while 11 kidneys with persistent PFK underwent nephrectomy; significant IF/TA, arterial, and arteriolar changes were noted in 9 (82%), 9 (82%), and 4 (36%) kidneys, respectively, including 7 kidneys in normotensive children. Two (11.7%) children had hypertension at presentation; 1 child remains hypertensive even after nephrectomy. CONCLUSION: In PFK-UPJO, trial of temporary drainage seems appropriate to decide plan of management; 35% of such kidneys improved function after drainage. Most persistent PFK demonstrated severe and irreversible histologic changes that may predispose to hypertension if they are preserved, and we suggest that such kidneys may be removed. Long-term follow-up of all preserved PFK-UPJO is strongly recommended.