Comparison of three methods of quantifying urethral resistance in men

ICS-SUFU standard: Theory, terms, and recommendations for pressure-flow studies performance, analysis, and reporting. Part 2: Analysis of PFS, reporting, and diagnosis

AIMS

The Working Group (WG), initiated by the International Continence Society (ICS) Standardisation Steering Committee and supported by the Society of Urodynamics, Female Pelvic Medicine and Urogenital Reconstruction, has revised the ICS Standard for pressure-flow studies of 1997.

METHODS

Based on the ICS standard for developing evidence-based standards, the WG developed this new ICS standard in the period from May 2020 to December 2022. A draft was posted on the ICS website in December 2022 to facilitate public discussion and the comments received have been incorporated into this final release.

RESULTS

The WG has recommended analysis principles for the diagnosis of voiding dysfunction for adult men and women without relevant neurological abnormalities. New standard terms and parameters for objective and continuous grading of urethral resistance (UR), bladder outflow obstruction (BOO) and detrusor voiding contraction (DVC) are introduced in this part 2 of the standard. The WG has summarized the theory and recommendations for the practice of pressure-flow study (PFS) for patients in part 1. A pressure-flow plot is recommended for the diagnosis of every patient, in addition to time-based graphs. Voided percentage and post void residual volume should always be included in PFS analysis and diagnosis. Only parameters that represent the ratio or subtraction of pressure and synchronous flow are recommended to quantify UR and only parameters that combine pressure and flow in a product or sum are recommended to quantify DVC. The ICS BOO index and the ICS detrusor contraction index are introduced in this part 2 as the standard. The WG has suggested clinical PFS dysfunction classes for male and female patients. A pressure-flow scatter graph including every patient's pdet at maximum flow (pdetQmax ) with maximum flow rate (Qmax ) point should be included in all scientific reports considering voiding dysfunction.

CONCLUSION

PFS is the gold standard used to objectively assess voiding function. Quantifying the dysfunction and grading of abnormalities are standardized for adult males and females.

Work Capacity of the Bladder During Voiding: A Novel Method to Evaluate Bladder Contractile Function and Bladder Outlet Obstruction

Background:

Work in voiding (WIV) of the bladder may be used to evaluate bladder status throughout urination rather than at a single time point. Few studies, however, have assessed WIV owing to the complexity of its calculations. We have developed a method of calculating work capacity of the bladder while voiding and analyzed the associations of bladder work parameters with bladder contractile function and bladder outlet obstruction (BOO).

Methods:

The study retrospectively evaluated 160 men and 23 women, aged >40 years and with a detrusor pressure at maximal flow rate (P_det Q_max) of ≥40 cmH₂O in men, who underwent urodynamic testing. The bladder power integration method was used to calculate WIV; WIV per second (WIV/t) and WIV per liter of urine voided (WIV/v) were also calculated. In men, the relationships between these work capacity parameters and P_det Q_max and Abrams-Griffiths (AG) number were determined using linear-by-linear association tests, and relationships between work capacity parameters and BOO grade were investigated using Spearman's association test.

Results:

The mean WIV was 1.15 ± 0.78 J and 1.30 ± 0.88 J, mean WIV/t was 22.95 ± 14.45 mW and 23.78 ± 17.02 mW, and mean WIV/v was 5.59 ± 2.32 J/L and 2.83 ± 1.87 J/L in men and women, respectively. In men, WIV/v showed significant positive associations with P_det Q_max (r = 0.845, P = 0.000), AG number (r = 0.814, P = 0.000), and Schafer class (r = 0.726, P = 0.000). Conversely, WIV and WIV/t showed no associations with P_det Q_max or AG number. In patients with BOO (Schafer class > II), WIV/v correlated positively with increasing BOO grade.

Conclusions:

WIV can be calculated from simple urodynamic parameters using the bladder power integration method. WIV/v may be a marker of BOO grade, and the bladder contractile function can be evaluated by WIV and WIV/t.

Invasive urodynamic studies for the management of lower urinary tract symptoms (LUTS) in men with voiding dysfunction

BACKGROUND

Invasive urodynamic tests are used to investigate men with lower urinary tract symptoms (LUTS) and voiding dysfunction to determine a definitive objective diagnosis. The aim is to help clinicians select the treatment that is most likely to be successful. These investigations are invasive and time-consuming.

OBJECTIVES

To determine whether performing invasive urodynamic investigation, as opposed to other methods of diagnosis such as non-invasive urodynamics or clinical history and examination alone, reduces the number of men with continuing symptoms of voiding dysfunction. This goal will be achieved by critically appraising and summarising current evidence from randomised controlled trials related to clinical outcomes and cost-effectiveness. This review is not intended to consider whether urodynamic tests are reliable for making clinical diagnoses, nor whether one type of urodynamic test is better than another for this purpose.The following comparisons were made.• Urodynamics versus clinical management.• One type of urodynamics versus another.

SEARCH METHODS

We searched the Cochrane Central Register of Controlled Trials (CENTRAL) (2014, issue 10), MEDLINE (1 January 1946 to Week 4 October 2014), MEDLINE In-Process and other non-indexed citations (covering 27 November 2014; all searched on 28 November 2014), EMBASE Classic and EMBASE (1 January 2010 to Week 47 2014, searched on 28 November 2014), ClinicalTrials.gov and the World Health Organization International Clinical Trials Registry Platform (WHO ICTRP) (searched on 1 December 2014 and 3 December 2014, respectively), as well as the reference lists of relevant articles.

SELECTION CRITERIA

Randomised and quasi-randomised trials comparing clinical outcomes in men who were and were not investigated with the use of invasive urodynamics, or comparing one type of urodynamics against another, were included. Trials were excluded if they did not report clinical outcomes.

DATA COLLECTION AND ANALYSIS

Three review authors independently assessed trial quality and extracted data.

MAIN RESULTS

We included two trials, but data were available for only 339 men in one trial, of whom 188 underwent invasive urodynamic studies. We found evidence of risk of bias, such as lack of outcome information for 24 men in one arm of the trial.Statistically significant evidence suggests that the tests did change clinical decision making. Men in the invasive urodynamics arm were more likely to have their management changed than men in the control arm (proportion with change in management 24/188 (13%) vs 0/151 (0%), risk ratio (RR) 39.41, 95% confidence interval (CI) 2.42 to 642.74). However, the quality of the evidence was low.Low-quality evidence indicates that men in the invasive urodynamics group were less likely to undergo surgery as treatment for voiding LUTS (164/188 (87%) vs 151/151 (100%), RR 0.87, 95% CI 0.83 to 0.92).Investigators observed no difference in urine flow rates before and after surgery for LUTS (mean percentage increase in urine flow rate, 140% in invasive urodynamic group vs 149% in immediate surgery group, P value = 0.13). Similarly, they found no differences between groups with regards to International Prostate Symptom Score (IPSS) (mean percentage decrease in IPSS score, 58% in invasive urodynamics group vs 59% in immediate surgery group, P value = 0.22).No evidence was available to demonstrate whether differences in management equated to improved health outcomes, such as relief of symptoms of voiding dysfunction or improved quality of life.No evidence from randomised trials revealed the adverse effects associated with invasive urodynamic studies.

AUTHORS' CONCLUSIONS

Although invasive urodynamic testing did change clinical decision making, we found no evidence to demonstrate whether this led to reduced symptoms of voiding dysfunction after treatment. Larger definitive trials of better quality are needed, in which men are randomly allocated to management based on invasive urodynamic findings or to management based on findings obtained by other diagnostic means. This research will show whether performance of invasive urodynamics results in reduced symptoms of voiding dysfunction after treatment.

The diagnostic accuracy and lower cutoff value of three methods for quantifying urethral resistance in men

INTRODUCTION

We estimated the diagnostic accuracy of Abrams-Griffiths number (AG), urethral resistance factor (URA) and detrusor-adjusted mean passive urethral resistance relation factor (DAMPF) for bladder outlet obstruction (BOO) in benign prostate hyperplasia (BPH) patients.

MATERIALS AND METHODS

AG, URA and DAMPF were obtained by pressure-flow studies from BPH patients. Receiver operating characteristic (ROC) curves were used to analyze the diagnostic accuracy of the AG, URA and DAMPF in the diagnosis of BOO.

RESULTS

Among the 172 cases there were 154 classified as obstructed (89.5%) and 18 as unobstructed (10.5%). There were statistically significant differences in AG, URA and DAMPF between the obstructed and the unobstructed cases. The ROC curve demonstrated a similar diagnostic accuracy in the diagnosis of BOO for AG and URA values, and the least was seen for the DAMPF value. An AG cutoff of >33 provided a sensitivity of 89.61% and a specificity of 100%. A URA cutoff of >28 provided a sensitivity of 91.56% and a specificity of 100%. A sensitivity of 93.51% and the weakest specificity of 77.78% were recorded for DAMPF values of >52. AG and URA had a similar accuracy, while the efficacy of DAMPF is significantly lower in the diagnosis of BOO.

CONCLUSIONS

AG or URA appeared to be the best discriminating parameters of BOO in BPH patients. The DAMPF could be used to aid the BOO diagnosis. Lower cutoff values were suggested for these BOO parameters.

Noninvasive urodynamic evaluation of bladder outlet obstruction using Doppler ultrasonography

OBJECTIVES

Previously we had developed a new method of noninvasive urodynamics using color Doppler ultrasound. Using this technique, we attempted to identify parameters that would diagnose bladder outlet obstruction (BOO).

METHODS

Twenty-two men who underwent pressure-flow urodynamic studies were included. Color scale transperineal ultrasound and uroflowmetry data were analyzed by custom-made software. The maximum flow velocities in the entire prostatic urethra (V(0)), in the distal prostatic urethra just proximal to the external urethral sphincter (V(1)), and in the membranous urethra (V(2)) were obtained. Corresponding functional cross-sectional areas of the urethra at these three sites (A(0), A(1), and A(2)) were calculated as Qmax/V. The velocity ratio (VR), which was equal to V(1)/V(2), was also calculated as a parameter. All these parameters obtained by the velocity-flow urodynamics were compared with the Abrams-Griffiths number (AG).

RESULTS

From the x-y plots obtained, VR correlated best with AG, with Spearman's rho of 0. 728. A(0) and A(1) had rho values of -0.461 and -0.708 against AG, respectively. All men with VR exceeding 1.6 had obstruction, whereas those with VR less than 1.1 did not.

CONCLUSIONS

The VR was found to be the best parameter for diagnosing BOO. When prostatic urethral obstruction was present, the velocity in the prostatic urethra would be high but the velocity slows down to 62.5% or greater immediately below the sphincter. We believe that noninvasive pressure-flow-like urodynamic evaluation based on Doppler ultrasound has clear potential for diagnosing BOO.