Effects of Alpha-Blockade on Ureteral Peristalsis and Intrapelvic Pressure in an In Vivo Stented Porcine Model.

INTRODUCTION: Clinical studies have shown beneficial role of oral alpha-blockers for ureteral stent-related morbidity. However, the in vivo effects of oral alpha-blockers on a stented ureter are unclear. We evaluated the effects of alpha-blockade on ureteral dynamics in a stented porcine ureter.

METHODS: Twenty-seven female pigs were used in this study. Fourteen pigs received oral alpha-blocker medication (silodosin, 8 mg daily), and 13 pigs received no medication. Under cystoscopic guidance, a 5F ureteral catheter was positioned in the renal pelvis and attached to a pressure monitor. A Foley catheter was placed in the bladder along with a bladder pressure transducer. A lumbotomy was performed, and the ureter was identified. A magnetic sensor was placed on the extraluminal surface of the ureter to monitor ureteral peristalsis. We measured renal pelvic and bladder pressures, urine output, and ureteral peristalsis every hour for 10 minutes for a total of 5 hours. The pigs were then euthanized.

RESULTS: The mean weight was 42.5 kg in the drug group and 45.9 kg in the nondrug group (p = 0.008). Mean hourly urine output was 140 mL in the drug group and 144 mL in the nondrug group (p = 0.76). Mean baseline renal pressure was 13.2 and 13.8 mm Hg (p = 0.69) in the drug and nondrug groups, respectively. Mean peristaltic renal pelvic pressure was 19.1 mm Hg in the drug group and 19.2 mm Hg in the nondrug group (p = 0.97). Mean number of peristalsis was 11/10 and 14/10 minutes (p = 0.03) in the drug and nondrug groups, respectively.

CONCLUSIONS: Alpha-blockade in an in vivo stented porcine ureter resulted in no significant effect on renal pelvic pressure but a significant decrease in the number of ureteral peristalsis. Further investigation of the effects of alpha-blocker on ureteral dynamics is required to better understand its effects on stent-related symptoms.