Bladder blood flow and de-obstructive open prostatectomy: correlation with clinical and urodynamic parameters

To assess the relation between tissue blood flow changes during surgery with clinical and urodynamic parameters in obstructed patients.

A prospective study was conducted in 18 symptomatic patients with bladder outlet obstruction undergoing retropubic prostatectomy. A symptom assessment and a preoperative urodynamic study were performed. To measure bladder blood flow a BLF-10 laser Doppler flowmeter and a blunt-tipped probe were used intraoperatively. Tissue flow was measured in TPU units (1 TPU unit=1 ml per minute per 100 mg of tissue). Six measurements were taken: two control in the rectus abdominis muscle and four in the detrusor, two before the incision of the prostatic capsule and two after closure. For the statistical analysis, Wilcoxon test and a regression analysis were performed.

Mean age was 70 years (range: 56-84). Six patients had an episode of acute urinary retention (AUR). No differences were found in the initial and final values of bladder blood flow of the rectus muscle and the bladder dome. A decrease of bladder blood flow in the anterior bladder wall was observed after prostate enucleation. AUR patients showed no differences in bladder blood flow values. Bladder blood flow (BBF) changes showed no correlation with any urodynamic or clinical parameter.

Laser Doppler flowmetry is useful to study BBF with low morbidity, ease of use and reproducibility. Following de-obstructive surgery, a decrease in BBF occurs, probably associated with surgery. These changes are similar in patients with and without AUR and show no correlation with other parameters studied.