The natural history of postoperative renal function in patients undergoing ileal conduit diversion for cancer measured using serial isotopic glomerular filtration rate and 99m technetium-mercaptoacetyltriglycine renography.

PURPOSE: There is little consensus regarding long-term followup of renal function in patients who undergo urinary diversion. We established the usefulness of combined serial isotopic glomerular filtration rate measurement and diuresis renography in the early identification of patients at risk for deterioration of renal function following ileal conduit diversion.

MATERIALS AND METHODS: A total of 340 patients with ileal conduit diversion who were followed between 1990 and 2000 were identified. We analyzed data on 178 patients who had more than 4 years of followup. Renal function was assessed by serial estimation of serum creatinine, isotopic glomerular filtration rate and diuresis renographic measurements.

RESULTS: Of the patients 52 (29%) demonstrated a worsening glomerular filtration rate. Mean followup +/- SEM was 8.2 +/- 0.4 years (range 4 to 30) and 67% of patients had more than 6 years of followup. In this group we found that hypertension, recurrent urinary sepsis and an initial post-diversion glomerular filtration rate of less than 50 ml per minute per 1.73 m were prevalent risk factors. Hypertension was an independent predictor of a decreased glomerular filtration rate in this group. Of 52 patients with a deteriorating glomerular filtration rate 19 had type II or IIIb curves on followup renography, of whom 13 underwent revision surgery. Renal function subsequently stabilized or improved in this group.

CONCLUSIONS: Of patients with an ileal conduit 29% have renal function deterioration in the long term. No surgical cause for glomerular filtration rate deterioration was found in 18%. Important predisposing factors in nonobstructed cases were hypertension, recurrent urinary sepsis and a glomerular filtration rate of less than 50 ml per minute per 1.73 m. Hypertension was an independent predictor of a decreased glomerular filtration rate in the group with worsening glomerular filtration rates. In 11% of patients deterioration was due to upper tract obstruction. This was identifiable using renography and the glomerular filtration rate. A type IIIb curve was an early indicator of obstruction.