Usefulness of the urodynamic study of the lower urinary tract in renal transplantation

OBJECTIVES: To analyze the indications, diagnostic cost-effectiveness and therapeutic implications of urodynamic assessment of the lower urinary tract in two groups of patients: 1) those awaiting renal transplantation and those with a functioning renal graft and voiding disturbances. METHODS: The first group comprised 22 patients who were evaluated before renal transplantation for a total of 32 urodynamic studies. The second group comprised 10 patients with a functioning renal graft for a total of 14 post-transplant urodynamic studies. The etiology of the chronic renal failure, indications for urodynamic assessment and videourodynamic findings in both groups were compared. RESULTS: Interstitial nephropathy associated with vesicoureteral reflux was the most common cause of chronic renal failure in the pre-transplant group, whereas glomerular nephropathy was the most common cause of chronic renal failure in the posttransplant group. Vesicoureteral reflux was the most frequent videourodynamic finding and was associated with other urodynamic disturbances in 75% of the cases. Lower urinary tract obstruction was the most common finding in the posttransplant group. CONCLUSIONS: The indications for urodynamic study in patients awaiting renal transplantation are: 1) interstitial nephropathy associated with vesicoureteral reflux, neurogenic bladder and congenital malformations; 2) patients aged 45 or older with a flowmetry suggesting obstruction; 3) those with urinary diversion, and 4) systemic diseases potentially associated with neurological damage.