Clinical and demographic factors associated with valsalva leak point pressure among women undergoing burch bladder neck suspension or autologous rectus fascial sling procedures

Aims: Many parameters have been utilized to try to estimate severity of stress urinary incontinence (SUI). Valsalva leak point pressure (VLPP) measurements, have been proposed as a reliable means of gauging the severity of SUI during urodynamic studies (UDS). Certain, non-invasive, measures of incontinence severity have been proposed, but the correlation of these measures with VLPP is not known. In addition, the correlation of other important UDS measures and VLPP has not been evaluated. In this study we sought to define the relationship between demographic characteristics, physical exam findings, and non-sphincteric UDS measures with VLPP in a large multicenter randomized surgical trial comparing Burch urethropexy and fascial sling for the treatment of SUI. Materials and Methods: Pre-surgical, standardized urodynamic measures were obtained in all participants in the Stress Incontinence Treatment Efficacy Trial (SISTEr) trial. All UDS were assessed for quality assurance and protocol compliance. VLPP was assessed using a <8 Fr water transducer catheter during graded Valsalva maneuvers at 200 ml, and then at 100 ml intervals and bladder capacity if no SUI was noted earlier. Only data from women who had SUI on at least two of three consecutive valsalva maneuvers was utilized for this analysis. Delta VLPP was determined as the average value, and the baseline vesical pressure was subtracted from the absolute vesical pressure to arrive at the reported VLPP value. Independent variables studied to assess their relationship to VLPP value included demographic characteristics (age, number of pregnancies, # vaginal deliveries, hormone usage, previous hysterectomy, previous SUI surgery), physical exam parameters [body mass index - BMI, Pelvic Organ Prolapse-Quantified POPQ stage, POPQ Aa measurement, Q-tip angle (rest) and Q-tip angle (strain), and change in angle], and other urodynamic parameters (volume of first leakage, volume at first sensation, presence of detrusor overactivity, maximum cystometric capacity - MCC, maximum flow rate - Q _max, and detrusor pressure at maximum flow rate - pdet.Q _max). Results: Among the 655 women randomized, 424 were found to have evaluable VLPPs. Thirty-four had stage 3 or 4 prolapse and were excluded from the VLPP analysis. The remaining 390 women had a mean VLPP of 81.1 cm H ₂O. On bivariate analysis, there were significant positive associations with VLPP and BMI (P = 0.026), Q-tip straining angle (P = 0.0002) change in Q-tip angle (P = 0.0046), MCC (P < 0.0001) and pdet.Q_max (P = 0.0003). Age was negatively associated with VLPP (P < 0.0001). For categorical values, lower POPQ stage (0/1), post menopausal status, and use of hormones were all associated with lower VLPP values. For example, patients with stage 2 had, on the average, VLPP values that were more than 10 cm H ₂O greater than those with stage 0/1. On multivariate analysis, however, only lower age, greater BMI, greater MCC, greater pdet.Q_max, and lower Q_max were found to be independent associated with higher delta VLPP. Conclusions: Advancing age, lower BMI, higher maximum flow rate, and lower voiding pressures are all independently associated with lower VLPP in women undergoing surgery for SUI. Lower voiding pressures and higher flow rates among women with more severe SUI may reflect the chronic loss of urethral resistance associated with SUI. Interestingly, urethral hypermobility as assessed by Q-tip testing angle does not achieve a statistically significant association with VLPP on multivariate testing when controlling for POP-Q stage. Thus, as clinically suspected, the Q-tip test is not predictive of VLPP in women with urethral hypermobility and SUI.