title: Detrusor after-contraction is associated with bladder outlet obstruction.
abstract: OBJECTIVE
  The aims of this study were to determine how we can differentiate detrusor after-contraction (DAC) from artifacts, and to understand the clinical implications and significance of DAC.
  
  
  METHODS
  A retrospective analysis was performed on 2,309 patients with neurogenic or non-neurogenic voiding dysfunction. Investigators asked patients to cough when detrusor contraction occurred following cessation of urinary flow. No simultaneous change of detrusor pressure (P(det) ) could confirm that P(det) increase could be regarded as true DAC. Patients were subcategorized according to the presence of large postvoid urine volume, increase of electromyographic activity, the amount of P(det) change, and multiplicity.
  
  
  RESULTS
  Detrusor contraction occurred after cessation of urinary flow in 245 patients (10.6%). The contractions of 57 patients (23.3%) were regarded as artifacts. DAC was identified in 188 patients (132 males, 5.7% and 56 females, 2.4%). The mean increase in P(det) from the initiation of DAC to the maximal P(det) of DAC was 22.6 ± 11.2 cmH(2) O in males, and 18.6 ± 7.9 cmH(2) O in females. DAC occurred more frequently as males became older. Detrusor pressures at maximal flow were higher in patients with DAC. Patients of both genders with bladder outlet obstruction (BOO) had an increased risk of developing DAC. Males with benign prostatic hyperplasia had an increased risk of developing DAC.
  
  
  CONCLUSIONS
  DAC should be differentiated from artifacts using cough test and the presence of DAC was significantly correlated to the presence of BOO.
authors.affiliation: Department of Urology, Seoul National University College of Medicine, Seoul, Korea.
authors.forename: Sung Yong
authors.initials: SY
authors.lastname: Cho
authors.forename: Jun-Seok
authors.initials: JS
authors.lastname: Yi
authors.forename: Ji Hyun
authors.initials: JH
authors.lastname: Park
authors.forename: Min Su
authors.initials: MS
authors.lastname: Jeong
authors.forename: Seung-June
authors.initials: SJ
authors.lastname: Oh
mesh_terms: D000368:Aged; D016477:Artifacts; D016009:Chi-Square Distribution; D003371:Cough / Q000503:physiopathology; D003950:Diagnostic Techniques, Urological; D004576:Electromyography; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009119:Muscle Contraction; D016017:Odds Ratio; D011237:Predictive Value of Tests; D011312:Pressure; D056910:Republic of Korea; D012189:Retrospective Studies; D001743:Urinary Bladder / Q000503:physiopathology*; D001748:Urinary Bladder Neck Obstruction / Q000175:diagnosis / Q000503:physiopathology*; D053201:Urinary Bladder, Overactive / Q000175:diagnosis / Q000503:physiopathology*