L’efficacité mictionnelle de la vessie est-elle utile pour évaluer la fonction vesicale chez les femmes de plus de 65 ans?

25 septembre 2019

Auteurs : F.A. Valentini, B.G. Marti, G. Robain, P.E. Zimern, P.P. Nelson
Référence : Prog Urol, 2019, 11, 29, 567-571




 




Introduction


Bladder voiding efficiency (BVE) is defined as the ratio between voided volume and total bladder capacity [1]. Although easy to calculate, this index is not widely used. Cholhanet al. [2] have evaluated bladder voiding efficiency from 2 successive free uroflowmetries (FF) in pre-menopausal women during proliferative and secretory phases of the menstrual cycle. In their study on Trans-Obturator Tape (TOT), Park et al. [3] showed a decrease of emptying efficiency in the early post-operative period.


Among these few published studies the incidence of aging was only mentioned in the study of Seong et al. [4] who underlined in women a significant increase of the prevalence of detrusor under-activity with patient age with BVE%<90 and absence of clinical obstruction.


Recently, the reliability of BVE measurement from a free flow (FF) has been demonstrated in the general population [5].


For the first time, measurement of BVE could be tested in a large cohort of non-neurological women older than 65 years. Aims of our study were first to search for the condition which had the predominant influence on evaluation of BVE (FF or intubated flow IF) and second the possible relationships with ageing, complaint and urodynamic diagnosis.


Materials and methods


Urodynamic tracings of non-neurologic women aged≥65 years who were referred for investigation of various lower urinary tract symptoms (LUTS) were retrospectively analyzed. Each urodynamic session was performed using a urodynamic unit from Laborie (Mississauga Canada). Urodynamic tests were carried out according to the International Continence Society Good Urodynamic Practices [6]. Urodynamic study included one FF in private condition (sitting position) followed by one cystometry (triple lumen urethral catheter 7F allowing for urethral pressure recording) and intubated flow (IF). Cystometry and IF were performed in sitting position, IF with maximum respect for the privacy of the patient (caregivers moving away from the urodynamic unit). Bladder was filled with saline at room-temperature at a medium filling rate of 50ml/min. Post void residual volumes (PVR) were measured using a Bladder-scan. Exclusion criteria were to be unable to void and/or expelled catheter during IF, voided volume either from FF or IF<100ml and prolapse of grade≥2.


To evaluate the role of ageing, the population was stratified in 4 age groups (65-70, 71-75, 76-80 and>80 years).


This retrospective study was conducted in accordance with the declaration of Helsinki. The local practice of our Ethics Committee does not require a formal institutional review board approval for retrospective studies.


Statistical analysis


Data are presented as mean±SD and range. The paired t-test was used for comparison of related samples, analysis of variance (Anova) to compare unrelated samples. Statistical analysis was performed using SAS, version 5.0 (SAS Institute, Inc., Cary, NC). All statistical results were considered significant at P <0.05.


Results


One hundred and ninety women met study criteria. Mean age was 74±6 years [65-96years]. Overall, the volume voided during FF (241±138ml) was significantly (P <0.0001) lower than voided volume IF (317±140ml). PVR after FF (30±59ml) was significantly lower (P <0.0001) than PVR after IF (90±113ml).


Overall, BVE IF (77.6±25.8) was significantly lower than BVE FF (90.4±15.3) (P <0.0001).


A decrease between BVE FF and BVE IF was observed whatever age sub-groups (Table 1); each decrease was significant. With ageing, there was no decrease in BVE FF and decrease of BVE IF was not significant.


Main complaint was urinary incontinence (146 women): stress (30 SUI), urge (53 UUI) and mixed (63 MUI). Forty-four women had various complaints without incontinence (among which 22 had frequency (FR) or dysuria (DYS); other complaints were recurrent urinary tract infection, interstitial cystitis, pain.


Looking at the main complaint a significant decrease in BVE IF when compared to BVE FF was observed in women with urinary incontinence whatever the sub-type (Table 2) and in the sub-group frequency-dysuria but if sub-populations without incontinence were put together, there was no significant difference between BVE FF (86.1±22.2) and BVE IF (80.1±23.6) (P =.2347).


Urodynamic diagnosis (UD) was posed according to the ICS/IUGA recommendations. From UD, 2 sub-groups were defined according with involvement of detrusor. The first (116 women) had UD related to detrusor dysfunction (21 bladder outlet obstruction BOO, 12 detrusor hyperactivity with impaired contractility DHIC, 31 detrusor overactivity DO (17 phasic and 14 terminal), 52 detrusor underactivity DU). The second sub-group (74 women) had UD found "normal" (24N), related to urethral dysfunction (38 intrinsic sphincter deficiency ISD and 12 voiding triggered by urethral relaxation URA). BVE IF was significantly lower than BVE FF except for DO, ISD, N, and URA urodynamic diagnosis (Table 3).


Looking at the influence of detrusor dysfunction BVE IF was significantly lower in the sub-group with detrusor dysfunction (73.9±26.0 vs. 86.1±20.6 p=.0008) while it is not the case for BVE FF (88.6±19.4 vs. 89.9±17.7 n.s.) (Table 4).


Discussion


Bladder voiding efficiency (BVE) quantifies the percentage of bladder emptied during voiding. If the real definition: ratio between voided volume and total bladder capacity is well respected when this index is evaluated during an intubated flow after a cystometry, but during a free uroflow as voiding is then initiated at normal desire, before maximum bladder capacity and usually long before a strong desire. That condition can explain the difference between initial bladder volumes (voided volume plus PVR). It doesn't explain the higher PVR after IF. It has been demonstrated that a 7 F urethral catheter produces no significant geometrical obstruction [7] but, on the other hand can induce a urethral reflex leading to an increased PVR [8]. BVE provides information on the bladder emptying quality while PIP [9] (BCI [1]) is used to evaluate detrusor isovolumetric pressure and IF to guide urodynamic diagnosis.


The main result is the absence of reproducibility between BVE measurement from a FF and from an IF in this post-menopause population, as observed in pre-menopause and peri-menopause populations [5]. That absence of reproducibility is similar in age sub-groups stratification. A small decrease of BVE IF with ageing is observed but is not significant. The lower values of BVE IF clearly show an inability of old women to void with a urethral catheter in place. So, BVE FF seems a more reliable index of bladder efficiency than BVE IF.


Complaint of incontinence results of significant decrease in BVE IF which could be useful information for management.


Looking at the urodynamic diagnosis, an unexpected result is observed: for patients with UD diagnosis of detrusor overactivity, BVE IF is not different from BVE FF. Two hypotheses could be proposed to explain that behavior: first a significant percentage of terminal DO would lead to complete bladder emptying and decreased PVR, second increased detrusor contractility induced by DO. The first hypothesis is not verified (14 terminal DO vs. 17 phasic DO) while the second is verified as it has been shown in a previous study that DO produce higher detrusor contractility [10]. In this study the VBN contractility parameter k is 0.57±.06 for the DO sub-group vs. 0.19±0.29 for the rest of the studied population.


The main limitation of BVE is the absence of cut off value to make a diagnosis with a reliable conclusion when evaluated from a FF or IF. Other limitation is that to our knowledge there is no use as an evaluation in bladder function. Cholhan and al. proposed BVE>90% for normal detrusor from FF in women younger than 45 years [2]. Some studies have used BVE (BVE>75%) to predicting surgical success in men with benign prostatic enlargement [11] or post-treatment large PVR after intravesical injection of by onabotulinum toxin type A (BVE<89%) in patients with overactive bladder [12]. Some authors have searched for a BVE criterion to diagnose detrusor underactivity in women; they proposed association of 3 parameters: P det.Qmax<20cmH2 O, Qmax<15mls−1 and BVE<90% [13] but without obvious superiority [4] over the association of 2 parameters pdet.Qmax<30cmH2 O, Qmax<10mls−1 [14].


So, despite these limitations and its retrospective design, our study introduces some characteristics of BVE in older female population.


Conclusion


BVE is an easily measured index. In this large cohort of old non-neurologic women studied urodynamically for a variety of LUTS, BVE is higher when evaluated from a FF whatever age and for complaint of urinary incontinence. In addition, a low BVE value from an IF could be the consequence of a detrusor dysfunction.


Disclosure of interest


The authors declare that they have no competing interest.




Table 1 - Bladder voiding efficiency (BVE) from IF vs. FF in age sub-groups.
Age (y)  n   BVE IF  BVE FF  P  
65-70  68  81.6±22.5  88.8±17.6  .0136 
71-75  54  78.3±28.1  88.4±18.9  .0445 
76-80  33  78.2±22.4  92.0±19.8  .0028 
>80  35  73.2±25.7  87.7±20.5  .0105 
P     n.s.  n.s.   



Légende :
All value of P <.05 is significant. IF: intubated flow; FF: free uroflow: n.s.; non significant.



Table 2 - Bladder voiding efficiency (BVE) from IF vs. FF for main complaint.
Complaint  n   BVE IF  BVE FF  P  
SUI  30  75.7±27.1  93.8±10.8  .0021 
MUI  63  81.3±23.5  92.4±13.9  .0004 
UUI  53  75.8±26.0  85.1±22.8  .0359 
FR-DYS  22  74.5±24.8  91.0±14.6  .0149 
Other  22  83.1±22.4  83.1±21.9  n.s. 



Légende :
IF: intubated flow; FF: free uroflow; SUI: stress urinary incontinence; MUI: mixed urinary incontinence; UUI: urge urinary incontinence; FR-DYS: frequency-dysuria; n.s.: non significant.



Table 3 - Bladder voiding efficiency (BVE) from IF vs. FF for urodynamic diagnosis.
UD  n   BVE IF  BVE FF  P  
BOO  21  59.5±25.3  87.6±23.6  .0019 
DHIC  12  67.4±32.5  94.8±7.2  .0153 
DU  52  76.4±25.3  91.0±16.1  .0001 
DO  31  82.5±21.5  84.0±22.9  n.s. 
ISD  38  87.4±20.9  92.0±11.5  n.s. 
24  83.4±21.0  85.6±25.0  n.s. 
URA  12  85.5±20.7  88.9±20.0  n.s. 



Légende :
IF: intubated flow; FF: free uroflow; UD: urodynamic diagnosis; BOO: bladder outlet obstruction; DHIC: detrusor hyperactivity with impaired contractility: DU; detrusor underactivity; DO: detrusor overactivity; ISD: intrinsic sphincter deficiency; N: normal; URA: urethral relaxation; n.s.; non significant.



Table 4 - Influence of detrusor dysfunction on bladder voiding efficiency (BVE) from IF.
  n   BVE IF  BVE FF  P  
Detrusordysfunction  117  73.9±26.0  88.6±19.4  <.0001 
No detrusordysfunction  73  86.1±20.6  89.9±17.7  n.s. 
P     .0008  n.s.   



Légende :
All value of P <.05 is significant. IF: intubated flow; FF: free uroflow; n.s.: non significant.


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