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AUA 2019

AUA 2019: TVT vs. Polyacrylamide Hydrogel Injection for Primary SUI - A Randomized Trial

Chicago, IL (UroToday.com) This podium session showcased a collection of studies primarily focused on the comparative outcomes for stress urinary incontinence (SUI) treatments. Although urethral slings still remain the most commonly used and studied surgical treatment option for SUI, intraurethral injectable bulking agents have long been an alternative or an adjunctive treatment. Polyacrylamide hydrogel (PAHG, also known as Bulkamid® or Aquamid®) has been available for use in Europe since 2001, and initial outcomes were reported in 2006.1 This is a non-particulate biocompatible homogenous gel more similar to collagen than other particulate urethral bulking agents, such as Macroplastique® and Durasphere®, but is still non-degradable, like these two. It has previously been studied in comparison to collagen and was determined to be non-inferior in 1 year follow up.2

This product has also been used for tissue reconstruction elsewhere in the body, and has also been studied in comparison to dextranomer hyaluronic acid for the treatment of vesicoureteral reflux.3 The authors of this study are responding to increasing concerns for complications for implanted mesh, and sought to determine if an intraurethral bulking agent such as PAHG could be considered a reasonable primary treatment (as opposed to salvage) alternative to tension-free vaginal tape (TVT) for the treatment or primary stress urinary incontinence.

This was a prospective, randomized, parallel-group, controlled study. The goal of the study was to demonstrate the non-inferiority of PAHG as compared to TVT at 1-year. The primary outcomes evaluated included: patient satisfaction score (0-100, >80 is considered a good level of satisfaction), effectiveness (negative cough stress test and/or pad test), and complication rate. A total of 224 women with primary SUI were included and randomized in this study, (patients with previous SUI procedures, pelvic organ prolapse, and BMI>35 were excluded) with 111 patients in the TVT group, and 113 in the PAHG group. Both procedures were performed in the outpatient setting and included local anesthesia. The PAHG procedure was done with 4 injections, 1.5cm from bladder neck, at the 2, 4, 8, and 10 o'clock positions. On average a 1.8cc volume for the procedure.

In regards to patient satisfaction and effectiveness, the PAHG group did not demonstrate non-inferiority. Median satisfaction scores (0-100) for the TVT and PAHG group were 99 and 85 respectively. Similarly, there was a 95% negative cough test with TVT and 66% with PAHG. The TVT group achieved both a negative cough and pad stress test in 91% of patients, whereas this was appreciated in 54% of the PAHG group.

In regards to complications, the majority (such as hematoma, perforation, or urinary retention) were reported in the TVT group. The PAHG did not have any reported re-operations for complications, which the TVT group did (3 for urinary retention, 1 for hematoma), and at 1 year the TVT group also had an incidence of erosion (2 patients), pelvic pain (5 patients), and difficulty emptying the bladder (8 patients), whereas the PAHG had none of these complications reported at 1-year. At the 1 year follow up de novo urgency was appreciated in 6 patients in the TVT group and in 10 patients in the PAHG group.

Although the authors were not able to demonstrate non-inferiority, they still demonstrate and argue that this specific intraurethral bulking agent offers patients a potentially safer, though less effective at 1-year, an alternative to a mesh sling. For a number of patients, this will be an attractive option, particularly those who are very risk-averse, or who are a higher risk for perioperative complications. Based on these conclusions, offering patients an intraurethral bulking agent for primary SUI is valid, provided that they understand there is a 1/3 chance that it will not be effective. Further research, perhaps from this same patient cohort, could be utilized on how to risk stratify patients or prepare them for, or avoid, complications from TVT or failures from intraurethral bulking with PAHG.


Presented by: Tomi Mikkola MD, Associate Professor Department of Obstetrics and Gynecology, Helsinki University Central Hospital

Written by: Ross Moskowitz, MD; Assistant Clinical Professor of Urology, University of California Irvine Medical Center; @rossmosk1 at the American Urological Association's 2019 Annual Meeting (AUA 2019), May 3 – 6, 2019 in Chicago, Illinois

References:
  1. Lose G, Mouritsen L, Nielsen JB. A new bulking agent (polyacrylamide hydrogel) for treating stress urinary incontinence in women. BJU Int. 2006 Jul;98(1):100-4.
  2. Sokol ER, Karram MM, Dmochowski R. Efficacy and safety of polyacrylamide hydrogel for the treatment of female stress incontinence: a randomized, prospective, multicenter North American study. J Urol. 2014 Sep;192(3):843-9.
  3. Ramsay S, Blais AS, Morin F, Moore K, Cloutier J, Bolduc S. PolyacrylamideHydrogel as a Bulking Agent for the Endoscopic Treatment of Vesicoureteral Reflux: Long-Term Results and Safety. J Urol. 2017 Mar;197(3 Pt 2):963-967.