Presentation Authors: Zachary Cullingsworth*, Andrea Balthazar, Naveen Nandanan, Anna Nagle, Adam Klausner, John Speich, Richmond, VA
Introduction: Reversible strain softening, or dynamic elasticity, is a bladder material property quantified using comparative-fill urodynamic (UD) studies, and may play a role in the bladder&[prime]s ability to accommodate large volumes and variable fill rates. This study aimed to test whether acute dynamic elasticity allowed bladders to accommodate larger volumes during UD filling compared to bladders that were not identified with dynamic elasticity.
Methods: This prospective study included individuals with and without urgency based on ICIq-OAB survey question 5a (â‰¥3 and =0, respectively).They completed a 3-day void diary and vesical pressure (Pves) data were collected during a repeat fill-and-empty UDS protocol. This protocol used three fills (1-3) to quantify dynamic elasticity. Fill 1 occurred after an active void and was used to quantify baseline average pressure before strain softening. Fill 2 occurred after passive emptying via syringe aspiration at the end of Fill 1 and quantified the degree of dynamic elasticity lost to strain softening. Fill 2 concluded with an active void to restore any lost elasticity before Fill 3, and Fill 3 quantified how much dynamic elasticity was recovered due to the active void. Average Pves was calculated was calculated for each fill and dynamic elasticity was defined as occurring in individuals that showed a decrease in Pves from Fill 1 to Fill 2 and an increase in Pves from Fill 2 to Fill 3.
Results: 6/7 participants without OAB exhibited dynamic elasticity while only 5/12 participants with OAB showed dynamic elasticity. Furthermore, a significant association (Fisher&[prime]s exact test, p < 0.05) was identified between the presence of quantifiable dynamic elasticity and the bladder&[prime]s ability to accommodate larger volumes during UDS. In 9/12 individuals with dynamic elasticity, the maximum UDS volume exceeded the 3-day maximum voided volume, while only 1/7 that did not show dynamic elasticity exceeded their 3-day maximum.
Conclusions: Dynamic elasticity was identified in most healthy bladders and in some with OAB. Bladders with dynamic elasticity could accommodate larger volumes compared to void diaries during superphysiological UD fill rates. In contrast, bladders without observed dynamic elasticity were unable to adapt to a faster filling. This difference suggests a defect in the bladder&[prime]s ability to regulate elasticity may contribute to OAB. Subtyping of OAB and targeted therapies could be possible through further quantification of dynamic elasticity.
Source of Funding: This study was supported by National Institutes of Health award R01DK101719.