Urodynamic evaluation and management prior to renal transplantation

To evaluate the indications for urodynamics studies (UDS) previous to renal transplantation (RT) and the results of bladder cycling (BC), performed in selected cases.

Among 475 RT, 33 patients (6.9%) required UDS according our protocol. Indications were: (1) low urinary tract symptoms (LUTS); (2) defunctionalized bladder (DB), and (3) complex urologic history (reflux, neurogenic bladder, urethral valves, etc.). DB was defined as a total urinary output of <300 ml/24 h. Patients with DB underwent BC through a suprapubic catheter, undergoing UDS after BC. The rate and type of urodynamic anomalies were compared among the 3 groups. Cystometric capacity (CysCap) and compliance were evaluated according to the etiology of renal failure, diuresis, and number of previous bladder surgeries.

Fifteen patients (45%) showed abnormal UDS, Increased pressure at cystometry was the most frequent finding (46%). The rate of abnormal UDS among the 3 groups was not statistically significant (66.6% in DB, 42.8% in LUTS, and 35% in those with complex urologic history). Compliance and CysCap were significantly lower in the patients with DB, showing a significant correlation with diuresis. These parameters did not correlate with the number of previous bladder surgeries. BC resulted in normal UDS in 3 patients (33%) and a change in diagnosis in 2 patients (22%).

Our indications gave a good diagnostic yield. Patients with DB represent a group with different urodynamic findings. BC provides a more precise diagnosis or normalization of UDS in some cases.