Estimation of bladder contractility from intravesical pressure–volume measurements

Fry, Christopher H.; Gammie, Andrew; Drake, Marcus John; Abrams, Paul; Kitney, Darryl Graham; Vahabi, Bahareh

Abstract

© 2016 Wiley Periodicals, Inc. Aims: To describe parameters from urodynamic pressure recordings that describe urinary bladder contractility through the use of principles of muscle mechanics. Methods: Subtracted detrusor pressure and voided flow were recorded from patients undergoing filling cystometry. The isovolumetric increase of detrusor pressure, P, of a voluntary bladder contraction before voiding was used to generate a plot of (dP/dt)/P versus P. Extrapolation of the plot to the y-axis and the x-axis generated a contractility parameter, vCE (the maximum rate of pressure development) and the maximum isovolumetric pressure, P0, respectively. Similar curves were obtained in ex vivo pig bladders with different concentrations of the inotropic agent carbachol and shown in a supplement. Results: Values of vCE, but not P0, diminished with age in female subjects. vCE was most significantly associated with the 20–80% duration of isovolumetric contraction t20–80; and a weaker association with maximum flow rate and BCI in women. P0 was not associated with any urodynamic variable in women, but in men was with t20–80 and isovolumetric pressure indices. Conclusions: The rate of isovolumetric subtracted detrusor pressure (t20–80) increase shows a very significant association with indices of bladder contractility as derived from a derived force–velocity curve. We propose that t20–80 is a detrusor contractility parameter (DCP). Neurourol. Urodynam. 36:1009–1014, 2017. © 2016 Wiley Periodicals, Inc.

• Journal Article Type: Article
• Acceptance Date: May 17, 2016
• Online Publication Date: Jun 6, 2016
• Publication Date: Apr 1, 2017
• Deposit Date: May 19, 2016
• Publicly Available Date: Jun 6, 2017
• Journal: Neurourology and Urodynamics
• Print ISSN: 0733-2467
• Electronic ISSN: 1520-6777
• Publisher: Wiley
• Peer Reviewed: Peer Reviewed
• Volume: 36
• Issue: 4
• Pages: 1009-1014
• DOI: https://doi.org/10.1002/nau.23047
• Keywords: bladder, contractility, force–velocity relationship, urodynamics
• Public URL: https://uwe-repository.worktribe.com/output/888633
• Publisher URL: http://dx.doi.org/10.1002/nau.23047
• Additional Information: Additional Information : This is the peer reviewed version of the following article: Fry, C. H., Gammie, A., Drake, M., Abrams, P., Kitney, D. and Vahabi, B. (2016) Estimation of bladder contractility from intravesical pressure-volume measurements. Neurourology and Urodynamics, which has been published in final form at http://dx.doi.org/10.1002/nau.23047. This article may be used for non-commercial purposes in accordance with Wiley Terms and Conditions for Self-Archiving.
• Contract Date: May 19, 2016