Evidence for the autoregulation of vesical circulation by intravesical potassium chloride and distension in the normal human bladder

Abstract

Objectives To determine the in¯uence of distension and intravesical KCl on vesical blood¯ow in the normal human bladder. Subjects and methods Nine normal volunteers underwent comparative cystometry (NaCl vs 0.2 mol/L KCl; ®lling rate 50 mL/min). Peak systolic blood¯ow velocity (PSBFV) and end-diastolic blood¯ow velocity (EDBFV) were measured in several intramural arteries at a ®lling volume of 50 mL and at maximum cystometric capacity (Cmax). For these measurements a colour Doppler unit ®tted with an endorectal probe was used. The resistance index (RI) was de®ned as (PSBFVxEDBFV)/PSBFV. Results In the presence of NaCl, the mean PSBFV increased signi®cantly from 9 cm/s at 50 mL to 17 cm/s at Cmax (512 mL). Compared with NaCl, KCl induced a signi®cantly higher mean PSBFV at 50 mL (15 cm/s). With increasing distension the rise in PSBFV with KCl ®lling (Cmax 478 mL) was nearly parallel to that obtained on NaCl ®lling (mean 22 cm/s); the RI did not change. Conclusions Bladder distension and intravesical KCl signi®cantly increased the PSBFV. The unchanged RI indicated a concomitant increase in perfusion rates. Hence, the composition of urine (high potassium concentrations and hyperosmolarity) and its storage govern the autoregulation (independent of cardiac output) of vesical circulation, probably by re¯exive pathways. These ®ndings provide further evidence for prevesical arteriovenous shunts.

α‐blockers improve chronic ischaemia of the lower urinary tract in patients with lower urinary tract symptoms

“…Age‐dependent changes in the regulation of perfusion in the urinary bladder as well as changes of bladder urothelium might lead to higher excitability of afferent and efferent neurones as well as muscle cells in the LUT, as has been postulated previously [18,23]. This higher excitability would inevitably result in irritative bladder symptoms, the main component of LUTS.…”

“…Written informed consent was obtained from all participants. In the present human study, again, 0.2 m KCl was used to fill the urinary bladder [18]. The filling speed for all measurements was 50 mL/min.…”

“…Furthermore, experimental data support the hypothesis that pelvic arterial insufficiency and chronic ischaemia are associated with marked changes in detrusor compliance and contractility of the bladder as well as changes of the prostate [15–17]. Recently, it was shown that bladder distension as well as the composition of urine, especially filling with 0.2 m KCl, which resembles highly concentrated urine, increased perfusion of the urinary bladder in humans [18,19]. Local regulation of human bladder blood flow and adaptive changes of perfusion are essential for normal function of the LUT [20].…”

“…Besides urodynamic variables, vesical and prostatic blood flows were investigated using transrectal colour Doppler ultrasound (TRCDUS) and measurement of the colour pixel density (CPD). TRCDUS is an excellent and minimally invasive technique for measuring normal and pathological perfusion in the LUT [18,21,22].…”

Assessment of microheterogeneity of blood flow in the rat urinary bladder by high‐resolution digital radiography

“…There is a significant difference in bladder microcirculation between the empty and full bladder. Hohlbrugger et al [11] reported on the autoregulation of vesical circulation in the human full bladder, using Doppler ultrasonography. In future work we will clarify the heterogeneity of blood flow in the full bladder at the microvascular level using the present method.…”