Special Urodynamic Tests:Ambulatory Urodynamics

Urodynamic investigations are an important tool in the diagnostic route of patients with lower urinary tract dysfunction. Despite the advantages of ambulatory UDS, conventional UDS is the “gold standard” for the investigation of lower urinary tract symptoms as it is a highly standardized and validated measurement tool. Novel techniques such as telemetric monitoring, catheter-free bladder pressure measurements and real-time bladder volume estimation are currently under development. Ambulatory UDS is more versatile and represents more a natural situation compared to conventional urodynamics. A few studies present results on treatment evaluation using ambulatory UDS as a diagnostic tool. Voiding dysfunction can have different causes related to the bladder outlet or intrinsic bladder characteristics self. Ongoing research focuses on extending the application possibilities, with particularly increasing attention to the role of ambulatory urodynamics in the assessment of bladder contractility and in mixed urinary incontinence

Detrusor contraction power parameters (BCI and W (max)) rise with increasing bladder outlet obstruction grade in men with lower urinary tract symptoms: results from a urodynamic database analysis

To investigate to what extent detrusor work during voiding is influenced by bladder outlet obstruction (BOO) in adult men with lower urinary tract symptoms (LUTS). We reviewed data of patients with LUTS suggestive of benign prostatic hyperplasia who received computer-urodynamic investigations as part of their baseline clinical assessment. BOO was defined by the Schafer classification and detrusor work during voiding was quantified by calculation of the bladder contractility index (BCI) and maximum Watt factor (W (max)) obtained by pressure-flow analysis. A total of 786 men with medians of 64 years, IPSS 16 and prostate volume of 35 ml, were included in the study. A total of 462 patients (58.8 %) had BOO (Schafer 2-6). Both detrusor contraction power parameters continuously increased with rising BOO grade. Median BCI increased from 73.3 in Schafer 0 to 188.0 in Schafer 6, whereas W (max) increased from 9.6 to 23.4 W/m(2) (p <0.001). Results of BCI and W (max) correlated well (p <0.001). With increasing BOO grade, there was a significant decrease of voiding efficiency (p <0.001). In adult male LUTS patients, detrusor contraction power parameters-BCI and W (max)-continuously increase with rising BOO grade. According to our results, it is impossible to determine a single threshold value for detrusor contraction power to diagnose detrusor underactivity in a group of LUTS patients with different BOO grades. The study is limited to men with non-neurogenic LUTS. Future studies should evaluate exact threshold values for BCI and W (max) in BOO subgroups to adequately define detrusor underactivity and investigate men with other bladder conditions

The role of phosphodiesterases in bladder pathophysiology

Nitric oxide and the cyclic nucleotide monophosphates cAMP and cGMP have a role in control of the micturition process and hence, are suggested to be involved in the pathophysiology of storage and voiding disorders. Phosphodiesterase enzymes (PDEs) hydrolyse cAMP and cGMP. Inhibition of PDEs increases cAMP and cGMP levels and relaxes urinary bladder smooth musculature. Although many preclinical studies have been conducted, to date, only PDE1 and PDE5 inhibitors have been tested clinically for the management of storage and voiding disorders. Treatment with PDE1 inhibitors might improve micturition frequency in patients with overactive bladder, whereas inhibition of PDE5 improves lower urinary tract symptoms in men, either with or without BPH and erectile dysfunction (ED). Furthermore, the combination of a PDE5 inhibitor and an a-adrenoceptor antagonist has superior efficacy to monotherapy with either agent. However, the role of PDE5 inhibitors in the treatment of women with detrusor overactivity remains unclear. The clinical application of agents that inhibit other PDEs, including PDE4, also certainly merits scientific attention. PDE inhibitors seem likely to become a valuable alternative treatment for patients with storage and voiding disorders in the future