Quest for a detrusor overactivity index

A pilot study assessing average detrusor pressure garnered from area under a urodynamic curve: Evaluation of clinical outcomes

INTRODUCTION

The management of neurogenic bladder mostly relies on urodynamic studies; however, several studies have shown low interobserver reproducibility. The aim of this study was to evaluate if a new objective cystometric parameter was superior to other cystometric measures.

PATIENTS AND METHODS

A new parameter (pressure adjusted area under curve ratio, PAUC) was formulated from the ratio of area under the cystometry curve to a DLPP-adjusted total area (A_T). A_T was figured from a rectangle designed on the cystometrogram curve with a fixed height of 200 cmH₂O and a width defined by the filling phase (figure). Two different estimated pressure measures derived from this (upper mean static pressure, UMSP and theoretical end filling pressure TEFP) were then calculated. Medical records of myelomeningocele patients with ultrasonography and renal scintigraphy performed at the time of urodynamics (with an interval of >5 years) were reviewed. Hydronephrosis and new scars in scintigraphy were used as the outcome measures.

RESULTS

The study group consisted of 115 subjects with a median age of 4 (0-23) years at the time of the first urodynamic study. The median follow-up was 6 (5-14) years. PAUC and its derivatives (UMSP and TEFP) had the best discriminative power in predicting high grade hydronephrosis (0.830, 95% CI:0.732-0.927, p < 0.001), worsening in hydronephrosis (0.827, 95% CI:0.723-0.931, p < 0.001), and new scar formation (0.704, 95% CI: 0.576-0.832, p = 0.002). PAUC>0.1 significantly correlated with urinary tract dilatation (p < 0.001) and new scar formation (p = 0.002). In the multivariate analysis, our three parameters and having scars at admission were the only independent risk factors for new scars (p = 0.001 and p = 0.002, respectively) and worsening in hydronephrosis (p < 0.001 and p = 0.001, respectively).

DISCUSSION

Our results show that our three parameters derived from area under the urodynamic curve are more reliable than other urodynamic measures. Their major theoretical advantage is to incorporate all the pressure during filling phase giving a more accurate picture of what the intravesical pressure milleu is. Using these measures, we demonstrated their superiority in predicting clinical outcomes. Major limitations of this study are the retrospectively collected data and lack of longitudinal follow-up starting from infancy in each patient.

CONCLUSION

Our new parameters (PAUC, UMSP and TEFP) which incorporate the impact of entire filling phase pressure changes in the analysis, may be useful tools to identify those patients who are under the risk of kidney damage with neurogenic lower urinary tract dysfunction.

A Novel Alternative in the Treatment of Detrusor Overactivity? In Vivo Activity of O-1602, the Newly Synthesized Agonist of GPR55 and GPR18 Cannabinoid Receptors

The aim of the research was to assess the impact of O-1602—novel GPR55 and GPR18 agonist—in the rat model of detrusor overactivity (DO). Additionally, its effect on the level of specific biomarkers was examined. To stimulate DO, 0.75% retinyl acetate (RA) was administered to female rats’ bladders. O-1602, at a single dose of 0.25 mg/kg, was injected intra-arterially during conscious cystometry. Furthermore, heart rate, blood pressure, and urine production were monitored for 24 h, and the impact of O-1602 on the levels of specific biomarkers was evaluated. An exposure of the urothelium to RA changed cystometric parameters and enhanced the biomarker levels. O-1602 did not affect any of the examined cystometric parameters or levels of biomarkers in control rats. However, the O-1602 injection into animals with RA-induced DO ameliorated the symptoms of DO and caused a reversal in the described changes in the concentration of CGRP, OCT₃, BDNF, and NGF to the levels observed in the control, while the values of ERK1/2 and VAChT were significantly lowered compared with the RA-induced DO group, but were still statistically higher than in the control. O-1602 can improve DO, and may serve as a promising novel substance for the pharmacotherapy of bladder diseases.

What predicts and what mediates the response of urge urinary incontinence to biofeedback?

AIMS

To better target a behavioral approach for urge urinary incontinence (UUI) and enhance its efficacy by (1) identifying predictors of response to biofeedback-assisted pelvic muscle training (BFB), and (2) determining factors that mediate response.

METHODS

BFB (four biweekly visits) was administered to 183 women > 60 years (mean = 73.6). Before and after intervention, all underwent comprehensive evaluation and videourodynamic testing. Postulated predictors and mediators from four urodynamic domains, specified a priori, were correlated with reduction in UUI frequency.

RESULTS

Median UUI frequency decreased from 3.2/day to 1/day (P =0.0001). UUI improved by ≥50% in 55% of subjects and by 100% in 13% of subjects. Frequent UUI predicted poor response (P < 0.01). Of the urodynamic parameters, only high amplitude and briskness of detrusor overactivity (DO) predicted decreased response (P < 0.05 and P < 0.01) and these could be measured only in the 43% of subjects with elicitable DO. Decreased DO elicitability was the only urodynamic variable that changed in concert with improvement and thus was a candidate mediator. Response was neither predicted nor mediated by proprioception/warning, cystometric capacity, detrusor contractility, sphincter strength, or baseline DO elicitability.

CONCLUSIONS

Severe DO predicts poor response to BFB. Good response is mediated by reduction in DO elicitability. Other than baseline UUI frequency, there are no other clinically or urodynamically important predictors or mediators of BFB response in this population. BFB may be best for patients with less severe DO. Future research to enhance its efficacy might better focus on the brain than on the lower urinary tract.

Novel biomarkers for overactive bladder

Biomarkers constitute any objectively measurable indicator of a biological process. The classic biomarker used in the diagnosis of overactive bladder (OAB) has been detrusor overactivity, which is assessed urodynamically. In the search for a reliable, noninvasive alternative to urodynamics, interest has focused on genetic, imaging, and urinary factors. Along with other cytokines detectable in urine, prostaglandin E2 and nerve growth factor are indicators of low-grade inflammation. Although they correlate with OAB symptom severity, they have not been shown to have independent prognostic benefit. Imaging biomarkers have been investigated since the earliest days of video urodynamics. Despite extensive research on the ultrasonographic estimation of bladder wall thickness, further standardization of the technique is required before conclusions can be reached regarding diagnostic accuracy. Genetic factors contribute approximately half of the total risk for urgency incontinence. Functional polymorphisms of the cytochrome P450 IID6 gene significantly alter the metabolism of some commonly used anticholinergic drugs, but no genetic loci that influence risk of OAB have been definitively identified. The first genome-wide association studies for OAB are in progress, and should identify new susceptibility genes. Although current putative biomarkers correlate with OAB severity, much future work is required to assess their prognostic value, and establish their role in clinical practice.

Executive summary: The International Consultation on Incontinence 2008--Committee on: "Dynamic Testing"; for urinary incontinence and for fecal incontinence. Part 1: Innovations in urodynamic techniques and urodynamic testing for signs and symptoms of urinary incontinence in female patients

AIMS

The members of The International Consultation on Incontinence 2008 (Paris) Committee on Dynamic Testing' provide an executive summary of the chapter 'Dynamic Testing' that discusses (urodynamic) testing methods for patients with signs and or symptoms of urinary incontinence. Testing of patients with signs and or symptoms of faecal incontinence is also discussed.

METHODS

Evidence based and consensus committee report.

RESULTS

The chapter 'Dynamic Testing' is a continuation of previous Consultation-reports added with a new systematic literature search and expert discussion. Conclusions, based on the published evidence and recommendations, based on the integration of evidence with expert experience and discussion are provided separately, for transparency.

CONCLUSION

This first part of a series of three articles summarizes the committees recommendations about the innovations in urodynamic study techniques 'in general', about the test characteristics and normal values of urodynamic studies as well as the assessment of female with signs and or symptoms of incontinence and includes only the most recent and relevant literature references.

Triple therapy in refractory detrusor overactivity: a preliminary study

PURPOSE

To evaluate in a prospective study the impact of the "three-drug therapy" (antimuscarinic, alpha-blocker and tricyclic antidepressants) on the treatment of refractory detrusor overactivity (DO).

METHODS

Data from 27 consented patients with refractory DO were available for study. They were asked to complete a daily urinary chart and underwent urodynamic evaluation (UD) before and 60 days after treatment. Response to treatment was considered the presence of one or less involuntary detrusor contractions (IDC) on post-treatment UD. Statistical analysis was performed with Fisher and Mann-Whitney tests, besides Spearman's correlation. P values <0.05 were considered significant.

RESULTS

The mean follow-up was 15 months. The comparison of the daily urinary chart before and after treatment showed significant increase on bladder capacity and decreases on urgency, urge-incontinence and frequency. Objective data from UD showed that the mean maximum bladder capacity (MBC) ranged from 200 to 300 mL (P < 0.001) with treatment. The same trend was observed with the other UD variables. When compared to baseline, the questionnaire OAB-v8 showed significant improvement (P < 0.01). Main side effects comprised dry mouth and constipation (40%), with average scores of 5.16 and 3.08, respectively (visual scale from 0 to 10).

CONCLUSIONS

Triple therapy may be an effective, easily employed and well-tolerated option to refractory DO treatment. More studies are necessary to achieve more consistent data on the matter.

Parameters of bladder function in pre-, peri-, and postmenopausal continent women without detrusor overactivity

AIMS

To determine normative data for lower urinary tract function in asymptomatic continent women without detrusor overactivity (DO) across the age span.

METHODS

Healthy female volunteers aged > or =20 years were recruited from the community. Comprehensive assessment included bladder diary, physical examination, uroflowmetry, and video-urodynamics. Continent women without history of frequent urgency and without DO were selected. Data on bladder storage, voiding and urethral sphincter function, urine output and frequency are presented for pre-, peri-, and postmenopausal women.

RESULTS

Twenty-four asymptomatic women (mean age 50.2 years, range 22-80 years) met the inclusion criteria, including 7 pre- (29.2 years), 7 peri- (48.8 years), and 10 postmenopausal (66.0 years) women. For all subjects, maximum single voided volume in bladder diary was 500 ml and maximum cystometric capacity was 580 ml (median values). Strong desire to void (SDV) was reported at 287, 366, and 425 ml for pre-, peri-, and postmenopausal groups, respectively. The maximum flow rate was 25, 32, and 23 ml/sec in uroflowmetry and 23, 24, and 18 ml/sec in pressure-flow study, respectively. Median post-void residual volume (PVR) was below 20 ml in all groups. At maximum flow rate subjects voided with detrusor pressures of 29, 26, and 24 cm H(2)O, respectively. Maximum urethral closure pressure was 94, 74, and 42 cm H(2)O, respectively.

CONCLUSIONS

We provide normative data on bladder function in asymptomatic, continent, pre-, peri-, and postmenopausal women without DO.

Prognostic Significance of Micturition Disturbances After Acute Stroke

OBJECTIVES

To investigate the prevalence, incidence, clinical types, and prognostic effect of micturition disturbances in acute stroke.

DESIGN

Prospective observational study.

SETTING

Geriatric department (stroke and rehabilitation unit) in a community hospital (acute phase); outpatient clinic, patients' own homes, or nursing homes (3 months follow-up).

PARTICIPANTS

Three hundred fifteen patients (mean age 77) with acute first-ever or recurrent stroke consecutively admitted to the hospital stroke unit.

MEASUREMENTS

Premorbid basic and instrumental activities of daily living (ADLs) and mental functioning; comorbidity; previous and actual micturition symptoms; stroke syndromes; medication use; and poststroke mobility, ADLs, and cognition.

RESULTS

One hundred forty-seven patients (46%) had preexisting micturition disturbances (urinary incontinence (UI), n = 98; urgency/frequency, n = 37; voiding difficulties, n = 12). Seventy-eight developed new symptoms (UI, n = 65; urgency/frequency, n = 4; sustained retention, n = 9). There were two UI types: urge UI (n = 27) and UI with impaired awareness of bladder needs (IA UI, n = 38). In regression analyses, IA UI was the only micturition disturbance predicting mortality and need for nursing home care at 3 months (odds ratio (OR) = 27.5, 95% confidence interval (CI) = 7.0-108.2), together with poor mobility (OR = 8.2, 95% CI = 2.6-26.2), and partial or total anterior circulation stroke type (OR = 3.6, 95% CI = 1.4-9.0).

CONCLUSION

New-onset poststroke UI with impaired awareness of bladder needs is a strong and independent risk factor for poor outcome at 3 months. This probably reflects more serious brain damage, affecting sustained attention and information processing. Valid clinical tools to detect such dysfunction in stroke victims are needed. Clinical classification of poststroke UI is likely to improve management.

The Impact of Detrusor Overactivity on Bladder Function in Younger and Older Women

PURPOSE

We examined the relationship of DO and aging, and bladder function in female volunteers.

MATERIALS AND METHODS

We recruited 85 cognitively competent, fully functional female volunteers who were 22 to 90 years old (median age 54) with and without symptoms suggestive of DO. Comprehensive assessment included a bladder diary, uroflowmetry and videourodynamics. We examined predefined urodynamic and diary variables for associations with DO and age, summarizing results in the 3 subgroups no DO, intermediate DO and clinically relevant DO.

RESULTS

Compared to women without DO those with DO showed a decrease in maximum cystometric capacity (558 vs 448 ml), mean daytime voided volume (260 vs 175 ml) and volume at strong desire to void (363 vs 283 ml) but an increase in maximum isovolumetric pressure (41 vs 64 cm H2O) and maximum detrusor pressure during involuntary contraction (intermediate and relevant DO 22 and 37 cm H2O, respectively). The positive association between increased detrusor contraction strength and DO was present at younger ages but absent in older subjects. Maximum urethral closure pressure and detrusor contraction strength decreased significantly with age.

CONCLUSIONS

From young adulthood to old age DO appears to affect bladder function parameters. It is associated with decreased bladder capacity and increased bladder sensation. Moreover, in younger adults DO is also associated with increased detrusor contraction strength, which is an association not seen in older individuals. This age associated loss of muscle function may be related to sarcopenia, implying that different treatments may be appropriate in older adults.

The Effect of Age on Lower Urinary Tract Function: A Study in Women

OBJECTIVES

To identify age-associated changes in female lower urinary tract function across a wide age spectrum, controlling for detrusor overactivity (DO).

DESIGN

Secondary analysis of a cross-sectional study of DO and aging. Eligible volunteers were stratified by age group and presence of DO.

SETTING

Community-based volunteers, evaluated in research laboratory.

PARTICIPANTS

Eighty-five ambulatory, nondemented, community-dwelling female volunteers, with and without bladder symptoms suggestive of DO, recruited by advertising, mean age 54 (range 22-90); 75% Caucasian, 21% African American.

MEASUREMENTS

Comprehensive assessment included bladder diary, uroflowmetry, and detailed videourodynamics. Predefined urodynamic and diary variables were examined for association with age and DO. Mean values of these variables were calculated for subgroups aged 20 to 39, 40 to 59, and 60 and older (14 subjects > or =70).

RESULTS

Maximum urethral closure pressure, detrusor contraction strength, and urine flow rate declined significantly with age (P<.001, P<.001, P=.006, respectively), regardless of whether DO was present. Most elderly individuals continued to empty their bladder almost completely, with normal voiding frequency. Mean number of nocturnal voids was less than one in all age groups. Bladder capacity did not decrease with age (mean 522 mL in oldest group) but was smaller in subjects with DO. Bladder sensation diminished significantly with age (P<.001) but was stronger in subjects with DO.

CONCLUSION

Female bladder and urethral function appear to deteriorate throughout adult life, whether DO is present or not. Specifically, detrusor contractility, bladder sensation, and urethral pressure decline. The common belief that bladder capacity shrinks with age may be related to DO rather than to aging itself.

Brain control of normal and overactive bladder

PURPOSE

Bladder control problems are common but their cause is often unclear. Many investigators have sought causes in the lower urinary tract, but fewer in the supraspinal control system. We have used functional magnetic resonance imaging (fMRI) to determine brain responses to bladder filling in subjects with normal and with poor bladder control (detrusor overactivity).

MATERIALS AND METHODS

Cerebral responses to bladder infusion were recorded in 1 male and 11 females without overt neurological abnormality, aged 26 to 83 years. Six had good bladder control and 6 had poor control on prior urodynamics. fMRI was performed while repeatedly infusing and withdrawing liquid into and out of the bladder, and monitoring intravesical pressure. Measurements were made at small and large bladder volumes.

RESULTS

fMRI detected activation of many brain regions involved in bladder control, including periaqueductal gray, thalamus, insula, dorsal anterior cingulate, and ventromedial cerebellum. Orbitofrontal cortex, pontine micturition center and preoptic hypothalamus were visible in subgroup analyses. Activations outweighed deactivations and responses became stronger at large bladder volumes. Among subjects with good control, this strengthening of response was prominent in the orbitofrontal cortex. Among those with poor control cortical responses were exaggerated at larger bladder volumes, except in the orbitofrontal cortex, which remained weakly activated. This difference was not due to concurrent detrusor activity.

CONCLUSIONS

Poor bladder control is specifically associated with inadequate activation of orbitofrontal cortex. Clinically, frontal cortical lesions cause bladder control problems. This study suggests a similar neurophysiological basis for poor bladder control in the absence of overt neurological lesion.

FACTORS THAT DISTINGUISH CONTINENT FROM INCONTINENT OLDER ADULTS WITH DETRUSOR OVERACTIVITY

PURPOSE

In older adults detrusor overactivity (DO) is almost as common in continent individuals as in those with urge incontinence (UUI). Thus, UUI likely reflects the contribution of additional factors. We postulated that of functionally independent individuals in whom transient causes were excluded those in whom DO was accompanied by UUI would be more likely to have smaller functional bladder capacity, less warning and less ability to avert urine loss in the face of DO.

MATERIALS AND METHODS

While blinded to continence status, we reviewed the records of all 52 cognitively intact and nonobstructed volunteers older than 65 years who had DO associated with urgency during urodynamic testing and had been asked to try to prevent leakage for 2 minutes. Of these individuals 31 were continent at home.

RESULTS

In patients with UI mean functional bladder capacity +/- SD was smaller (313 +/- 153 vs 390 +/- 178 ml, p = 0.06) and warning was briefer (87 +/- 81 vs 120 +/- 116 ml), although the association with warning was less impressive (p = 0.14). The ability to forestall leakage for at least 2 minutes correlated strongly with being continent at home (p < 0.002). For continence detrusor suppression at the onset of DO was more important than sphincter contraction.

CONCLUSIONS

Urge incontinence in older adults involves more than simply the presence of DO. Physical function, cognitive function and medications are already known to be important for continence. Our data suggest that functional bladder capacity and the ability to suppress involuntary contraction (and possibly warning) are also potentially important covariates. These factors may represent additional potential targets for behavioral and pharmacological therapy.

DETRUSOR OVERACTIVITY. DOES IT REPRESENT A DIFFERENCE IF PATIENTS FEEL THE INVOLUNTARY CONTRACTIONS?

PURPOSE

We evaluated the differences between patients with overactive bladder (OAB) who felt involuntary detrusor contractions during cystometry (detrusor overactivity [DO]) and those who did not feel them.

MATERIALS AND METHODS

We prospectively studied 45 patients with symptoms of nonneurogenic, nonobstructed overactive bladder and with DO on cystometry. All patients underwent videourodynamics, the ice water test and electrical perception threshold determination. Continence, urodynamic parameters, data from specific sensory evaluation and outcome of drug treatment were examined.

RESULTS

Almost half of our patients did feel the contractions of DO and half did not. The groups differed significantly. Those without DO sensation were more frequently incontinent, had more involuntary detrusor contractions and these occurred earlier during bladder filling. They had involuntary start of voiding more frequently, more pathological sensation of bladder filling and lower electrical sensory thresholds. The results of drug treatment were better in the group who felt DO.

CONCLUSIONS

Contractions of DO are felt by some of the patients and they differ from those patients who do not feel such contractions. It is likely that this finding reflects the existence of different OAB conditions with a different neuropathological cause and a different treatment outcome. Therefore, we suggest that specific tests for the evaluation of sensation in the lower urinary tract should be part of the diagnosis of patients with DO and symptoms of OAB.

SACRAL NEUROMODULATION FOR REFRACTORY DETRUSOR OVERACTIVITY IN WOMEN WITH AN ARTIFICIAL URINARY SPHINCTER

PURPOSE

We assessed the efficacy of sacral neuromodulation as an alternative therapeutic option in women with an artificial urinary sphincter (AUS) who had de novo irritative urinary symptoms (urgency/frequency) refractory to conventional treatment.

MATERIALS AND METHODS

Between 1984 and 2002 we implanted an AUS in 350 women and detrusor overactivity developed in 14. Six of the 14 patients responding positively to a percutaneous nerve evaluation test (greater than 50% subjective/objective improvement) were implanted with an S3 neuromodulator within 42.8 weeks (range 21 to 106) of AUS implantation. Followup included analysis of the voiding diary, a pad test and urodynamic assessment.

RESULTS

After 30.5 months followup (range 14 to 40) 1 patient was dry, 4 were improved and treatment failed in 1. At 12 months mean voiding frequency daily had decreased from 17 (range 12 to 23) to 8 (range 4 to 12) and the mean number of leakages episodes daily had decreased from 14.7 (range 8.5 to 17) to 6 (range 4 to 10). Mean voided volume had increased from 121.7 (range 90 to 170) to 180 ml (range 120 to 225), mean first desire to void volume had increased from 117 (range 88 to 190) to 183 ml (range 130 to 275) and mean functional bladder capacity had increased from 325 (range 200 to 530) to 372 ml (range 250 to 580). Uninhibited bladder contractions had resolved in 4 of 5 patients.

CONCLUSIONS

In women who already have an AUS with urge incontinence sacral neuromodulation can help resolve symptoms. Because this therapy does not compromise the potential for future treatment, it appears to be an alternative option in these patients. It can postpone or avoid more mutilating surgery and self-catheterization.

Which stop test is best? Measuring detrusor contractility in older females

PURPOSE

Impaired detrusor contractility has an important role in geriatric voiding dysfunction but there are many competing methods of measurement. We compared the performance of 3 methods of measuring detrusor contraction strength to identify the best one.

MATERIALS AND METHODS

We retrospectively analyzed urodynamics data on 84 females 53 years old or older. All had urge incontinence and were enrolled in a placebo controlled oxybutynin trial. Stop tests (voluntary interruption, mechanical interruption and continuous mechanical occlusion of flow) were performed on each subject.

RESULTS

At baseline the voluntary stop test measured lower mean isovolumetric detrusor pressure +/- SD than the mechanical and continuous methods (31.2 +/- 16.0 versus 47.2 +/- 26.5 and 48.7 +/- 24.4 cm. water, respectively). The latter 2 values also correlated highly (r = 0.87). Followup data on 76 women confirmed these results. Based on baseline and followup values in the 20 women who received placebo the continuous occlusion test showed highest test-retest reliability (r = 0.9, p <0.01), followed by the mechanical (r = 0.69, p = 0.01) and voluntary (r = 0.67, p <0.01) stop tests. Treatment with oxybutynin decreased isovolumetric detrusor pressure in all 3 stop tests by up to 6 cm. water. However, the decrease was statistically significant only for the continuous occlusion test.

CONCLUSIONS

To assess detrusor contraction strength in elderly females with urge incontinence the mechanical stop and continuous occlusion tests are acceptable but the continuous occlusion test has better reliability and better detects slight drug induced changes. Voluntary stop tests greatly underestimate detrusor isovolumetric pressure and should no longer be used.