Quantification of Spontaneous Rhythmic Contractions in Individuals With and Without Overactive Bladder: Is All Detrusor Overactivity Clinically Relevant?

Cullingsworth Z1, Li R1, Klausner A2, Speich J1

Research Type

Clinical

Abstract Category

Urodynamics

Abstract 194
Urodynamics 1
Scientific Podium Short Oral Session 13
On-Demand
Detrusor Overactivity Urodynamics Techniques Prospective Study
1. Virginia Commonwealth University, Department of Mechanical and Nuclear Engineering, 2. Virginia Commonwealth University, Department of Surgery/Division of Urology
Presenter
Z

Zachary E Cullingsworth

Links

Abstract

Hypothesis / aims of study
Spontaneous Rhythmic bladder Contractions (SRC) are thought to allow the bladder to maintain tone throughout filling and prepare for a productive active voiding contraction to occur at any volume. SRC have been shown to be elevated in muscle strips taken from patients with overactive bladder (OAB) [1] and are identified clinically in bladders with detrusor overactivity (DO) [2]. The aim of this study was to compare objectively identified SRC during the first and second halves of filling in individuals with and without OAB symptoms.
Study design, materials and methods
Individuals with and without urgency based on ICIq-OAB survey question 5a were prospectively enrolled in a urodynamics (UD) study. Participants were grouped as no/low OAB (5a=0-2) or high OAB (5a=3-4). Vesical and abdominal pressure tracings from these studies were analyzed iteratively throughout the entire filling phase to determine which volume regions contained significant rhythmic amplitude (≥1cm-H2O) in vesical pressure in the frequency range of 1.75 to 8.0 cycles/minute that was independent of rhythmic activity in abdominal pressure (S&I) using an established algorithm [3]. The maximum SRC amplitude and the corresponding frequency were recorded, along with the volumes at which S&I SRC was detected. Individuals were grouped based on whether S&I SRC occurred 1) only during the first half of filling (<50% cystometric capacity, “First Half Only”) or 2) during only the second half of filling or throughout filling (“Second Half or Throughout”).
Results
Data from 143 consecutive participants with sufficient data were analyzed and 49 (34%) were found to have S&I SRC, and these were grouped based on OAB (no/low OAB: n=31/98, 32% or  high OAB: n=18/45, 40%). The maximum S&I SRC amplitude was elevated in the high OAB group compared to the no/low OAB group (12.6 cm-H20 and 5.7 cm-H20, respectively, t-test, p<0.05), but the corresponding frequencies were not different (3.85 cycles/minutes and 4.72 cycles/minute, respectively, p>0.05). Of those found to have S&I SRC in the First Half Only of filling, only 1/14 had high OAB (Fig 1).  The presence of S&I SRC during the First Half Only was significantly associated with no/low OAB (Fisher’s exact test, p<0.05, Fig 1, *).
Interpretation of results
In this study, S&I SRC was identified in several participants with and without high OAB based on the symptom of urgency, suggesting 1) that not all quantifiable contractile activity, or DO, during UD filling necessarily leads to OAB symptoms or 2) that SRC may be an artifact of UD in some participants. Specifically, individuals with S&I SRC in the First Half Only did not have high OAB (13/14, 93%), suggesting that SRC during the First Half Only of filling may not be clinically relevant. In contrast, individuals with high OAB had S&I SRC either in the Second Half or Throughout filling.
Concluding message
This study suggests that DO identified only during early filling may not be as clinically relevant as DO identified either throughout filling or in later stage filling. Additional studies are needed to determine whether the portion of the filling phase where SRC occurs correlates with the presence of OAB or its severity.
Figure 1 Fig. 1: Number of participants with no/low OAB vs. high OAB with S&I SRC in the First Half Only or in the Second Half or Throughout Filling
References
  1. Kinder RB, Mundy AR. Pathophysiology of idiopathic detrusor instability and detrusor hyper-reflexia. An in vitro study of human detrusor muscle. Br J Urol. 1987;60(6):509-515.
  2. Colhoun AF, Speich JE, Cooley LF, Bell ED, 3rd, Barbee RW, Guruli G, Ratz PH, Klausner AP. Low amplitude rhythmic contraction frequency in human detrusor strips correlates with phasic intravesical pressure waves. World J Urol. 2017;35(8):1255-1260.
  3. Cullingsworth ZE, Kelly BB, Deebel NA, Colhoun AF, Nagle AS, Klausner AP, Speich JE. Automated quantification of low amplitude rhythmic contractions (LARC) during real-world urodynamics identifies a potential detrusor overactivity subgroup. PLoS One. 2018;13(8):e0201594.
Disclosures
Funding NIH grant R01DK101719 Clinical Trial No Subjects Human Ethics Committee Virginia Commonwealth University Institutional Review Board Helsinki Yes Informed Consent Yes
28/03/2024 00:02:56