title: Usefulness of an echo-contrast agent for assessment of coronary flow velocity and coronary flow velocity reserve in the left anterior descending coronary artery with transthoracic doppler scan echocardiography.
abstract: BACKGROUND
  This study assessed the feasibility of transthoracic Doppler scan echocardiography (TTDE) combined with echo-contrast agent in measuring coronary flow velocity (CFV) and coronary flow velocity reserve (CFVR) in the left anterior descending artery.
  
  
  METHODS
  In 68 consecutive patients who underwent cardiac angiography, TTDE was recorded before and after induction of a hyperemic condition with intravenous administration of adenosine triphosphate (0.14 mg/kg/min). After CFV values returned to baseline, the same measurements were repeated while an echo-contrast agent was continuously infused. CFVR was assessed as the ratio of hyperemic to basal CFV. The pulsed wave Doppler scan quality was graded from 1 to 3 (TTDE score: 1, no signal detection; 2, poor definition of outline; 3, optimal outline definition).
  
  
  RESULTS
  Before enhancement, CFVR could not be measured in 20 patients. Prevalence of delayed stenosis (Thrombolysis In Myocardial Infarction [TIMI] II grade flow) in these patients (30%) was significantly greater than in those whose CFVRs could be measured without enhancement (2%; P <.01). TTDE scores both at baseline and after hyperemia were significantly improved with contrast enhancement (before, 2.8 +/- 0.6; after, 3.0 +/- 0.3; P <.01; before, 2.6 +/- 0.7; after, 3.0 +/- 0.3; P <.01; respectively). Overall contrast enhancement increased the rate of successful CFVR measurement from 70% to 97% (P <.01). Sensitivity and specificity of significant left anterior descending artery stenosis detection with CFVR of <2.0 were 94.4% and 87.8%, respectively.
  
  
  CONCLUSIONS
  These data suggest that administration of echo-contrast agent improves pulse wave Doppler scan quality and thus the feasibility of measuring CFVR.
authors.affiliation: Department of Cardiology, Kitaishikai Hospital, Ozu, Ehime, Japan. hiokayam@ehime.med.or.jp
authors.forename: Hideki
authors.initials: H
authors.lastname: Okayama
authors.forename: Takumi
authors.initials: T
authors.lastname: Sumimoto
authors.forename: Go
authors.initials: G
authors.lastname: Hiasa
authors.forename: Norikatsu
authors.initials: N
authors.lastname: Morioka
authors.forename: Kouzo
authors.initials: K
authors.lastname: Yamamoto
authors.forename: Hiroyuki
authors.initials: H
authors.lastname: Kawada
mesh_terms: D000368:Aged; D001810:Blood Volume; D003287:Contrast Media; D003326:Coronary Circulation; D003331:Coronary Vessels / Q000000981:diagnostic imaging / Q000502:physiology*; D003971:Diastole / Q000502:physiology; D004452:Echocardiography; D005240:Feasibility Studies; D005260:Female; D006801:Humans; D008297:Male; D015588:Observer Variation; D011134:Polysaccharides; D012039:Regional Blood Flow; D012044:Regression Analysis; D012680:Sensitivity and Specificity; D013599:Systole / Q000502:physiology
chemical_list: D003287:Contrast Media; D011134:Polysaccharides; C059891:SHU 508