Christopher H Fry1, Andrew Gammie2, Marcus John Drake2,3, Paul Abrams2, Darryl Graham Kitney1, Bahareh Vahabi2,4. 1. School of Physiology, Pharmacology and Neuroscience, University of Bristol, Bristol, United Kingdom. 2. Bristol Urological Institute, Southmead Hospital, Bristol, United Kingdom. 3. School of Clinical Sciences, University of Bristol, Bristol, United Kingdom. 4. Department of Biological, Biomedical and Analytical Sciences, University of the West of England, Bristol, United Kingdom.
Abstract
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.
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.
Authors: Andrew Gammie; Becky Clarkson; Chris Constantinou; Margot Damaser; Michael Drinnan; Geert Geleijnse; Derek Griffiths; Peter Rosier; Werner Schäfer; Ron Van Mastrigt Journal: Neurourol Urodyn Date: 2014-01-04 Impact factor: 2.696
Authors: Nadir I Osman; Christopher R Chapple; Paul Abrams; Roger Dmochowski; François Haab; Victor Nitti; Heinz Koelbl; Philip van Kerrebroeck; Alan J Wein Journal: Eur Urol Date: 2013-10-26 Impact factor: 20.096