Urodynamic Effect of Acute Alpha-Receptor Blockade in Patients With Bladder Neck Dysfunction

Abstract

Forty-nine male patients, median age 35 years (range 16–59) with bladder neck dysfunction (BND) were investigated before and after intravenous administration of phentolamine to evaluate the effect of acute alpha-blockade on micturition parameters and to identify patients, who might benefit from alpha-blocking therapy. Under the influence of phentolamine we found a significant decrease in the mean values of maximal urethral closure pressure (MUCP), pressure at the bladder neck and prostatic profile length (PPL), a decreased bladder capacity, a more complete bladder emptying, and a small but significant improvement in peak flow rate (PFR). However, according to a flow-rate nomogram analysis with correction for voided volume, only two patients significantly improved their PFR. A subgroup of 20 “responders”, defined as patients with any improvement of PFR after phentolamine, not caused by increased detrusor pressure was characterized by significantly longer opening time and lesser maximal flow rate before phentolamine (more severe BND). All other pressure-flow parameters as well as the static pressure at bladder neck niveau were not different. We conclude that it is not possible before phentolamine administration to select a group of patients, which might benefit from alpha-blockade and it is suggested that this procedure might be included in the evaluation of patients with suspected BND.

Key Words:

• Bladder neck dysfunction
• Alpha-blockade
• Uro-dynamics