title: Detection of right-to-left shunts may be associated with body size.
abstract: OBJECTIVE
  The aim of this study was to investigate whether physiological factors, including body mass index (BMI), are associated with detection of right-to-left shunt (RLS) by contrast transcranial Doppler ultrasonography (c-TCD).
  
  
  METHODS
  After prospective c-TCD for stroke patients, we compared clinical backgrounds between patients with positive and negative results for RLS. After counting microembolic signals (MES), RLS were functionally graded as follows (grade 0 = 0 MES, grade I = 1-10 MES, grade II = 11-30 MES, grade III = 31-100 MES if countable, grade IV = over 100 MES or uncountable like a shower.
  
  
  RESULTS
  Subjects comprised 584 patients (203 men, 381 women) with a mean age of 67.9 +/- 11.1 years. RLS was detected in 134 of 584 patients (23%). In univariate analysis, mean BMI was 22.1 in patients with RLS and 23.3 in those without RLS (P= .004). Mean BMI in concordance with RLS grade gradually decreased (grade 0; 22.7, grade I; 20.8, grade II; 20.1, grade III; 19.6, P= .001). After performing the Valsalva maneuver, mean BMI in concordance with RLS grade linearly increased (grade I; 20.6, grade II; 23.2, grade III; 24.8, grade IV; 25.8, P < .001).
  
  
  CONCLUSIONS
  Although smaller body size may be associated with detection of RLS, a patient with significant RLS (grade III or IV) had larger body.
authors.affiliation: Department of Stroke Medicine, Kawasaki Medical School, Okayama 701-0192, Japan. yigu@med.kawasaki-m.ac.jp
authors.forename: Yasuyuki
authors.initials: Y
authors.lastname: Iguchi
authors.forename: Kazumi
authors.initials: K
authors.lastname: Kimura
authors.forename: Kazuto
authors.initials: K
authors.lastname: Kobayashi
authors.forename: Junya
authors.initials: J
authors.lastname: Aoki
authors.forename: Kenichiro
authors.initials: K
authors.lastname: Sakai
authors.forename: Yuka
authors.initials: Y
authors.lastname: Terasawa
authors.forename: Junichi
authors.initials: J
authors.lastname: Uemura
authors.forename: Kensaku
authors.initials: K
authors.lastname: Shibazaki
mesh_terms: D000368:Aged; D049628:Body Size; D005260:Female; D054092:Foramen Ovale, Patent / Q000150:complications* / Q000000981:diagnostic imaging*; D006801:Humans; D015994:Incidence; D020766:Intracranial Embolism / Q000000981:diagnostic imaging* / Q000209:etiology*; D007564:Japan / Q000453:epidemiology; D008297:Male; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D013223:Statistics as Topic; D017585:Ultrasonography, Doppler, Transcranial / Q000379:methods*