title: Doppler microembolic signals in children with prosthetic cardiac valves.
abstract: OBJECTIVE
  The aim of this study was the evaluation of the prevalence and counts of Doppler microembolic signals (MES) in children with prosthetic cardiac valves and their comparison to those obtained in corresponding adult patients.
  
  
  METHODS
  Nine children and 43 adults with ATS valves implanted in the aortic position were monitored over both middle cerebral arteries with transcranial Doppler ultrasound. MES were identified on-line according to standard criteria. Heart rate and rhythm, valve type, size and duration, patients' height, International Normalized Ratio, and prevalence of neurological complications were obtained from all study participants.
  
  
  RESULTS
  MES prevalence and counts were significantly higher in children compared with adult patients (100% versus 25.5% and 58 [18.5 to 115.5] versus 55 [2 to 10.5], median, 95% CI, respectively). No corresponding differences in valve duration of valve implant were evident, but children has heart rates and were significantly smaller compared with adults. A positive correlation between patients' size, heart rate, and MES counts was noted.
  
  
  CONCLUSIONS
  MES counts in children with mechanical prosthetic valves are significantly higher compared with those in corresponding adults. We hypothesize that this is due to (1) the shorter distance between aortic valve and middle cerebral artery, since cavitation bubbles have a short life span and are bound to dissolve with time, and (2) the faster heart rate in children, resulting in a higher number of valve closures per minute.
authors.affiliation: Department of Neurology, Martin-Luther University Halle-Wittenberg, Halle/Saale, Germany. dimitrios.georgiadis@medizin.uni-halle.de
authors.forename: D
authors.initials: D
authors.lastname: Georgiadis
authors.forename: M
authors.initials: M
authors.lastname: Preiss
authors.forename: A
authors.initials: A
authors.lastname: Lindner
authors.forename: Y
authors.initials: Y
authors.lastname: Gybels
authors.forename: S
authors.initials: S
authors.lastname: Zierz
authors.forename: H R
authors.initials: HR
authors.lastname: Zerkowski
mesh_terms: D000293:Adolescent; D017677:Age Distribution; D000368:Aged; D003331:Coronary Vessels; D005260:Female; D006350:Heart Valve Prosthesis / Q000009:adverse effects*; D006801:Humans; D002542:Intracranial Embolism and Thrombosis / Q000000981:diagnostic imaging* / Q000453:epidemiology / Q000209:etiology*; D008297:Male; D008875:Middle Aged; D015588:Observer Variation; D015995:Prevalence; D017585:Ultrasonography, Doppler, Transcranial / Q000706:statistics & numerical data