title: Estimation of coronary flow reserve by transesophageal coronary sinus Doppler measurements in patients with syndrome X and patients with significant left coronary artery disease.
abstract: OBJECTIVE
  This study sought to determine the feasibility of coronary sinus flow velocity analysis by transesophageal Doppler echocardiography for estimation of coronary flow reserve in patients with syndrome X and patients with coronary artery disease.
  
  
  BACKGROUND
  Coronary flow reserve provides useful information in patients with coronary artery disease and patients with syndrome X. Current methods of measuring coronary flow reserve are invasive or require extensive laboratory equipment, or both. Transesophageal Doppler recordings of coronary sinus flow velocity before and after vasodilator application may allow noninvasive determination of coronary flow reserve.
  
  
  METHODS
  We obtained coronary sinus flow velocity recordings before and after dipyridamole administration (0.6 mg/kg body weight per 5 min) in 9 patients with syndrome X, 14 with significant left coronary artery disease and 22 age-matched control patients. We used the formula anterograde minus retrograde flow velocity time integral times heart rate as an index of coronary sinus flow. Coronary flow reserve was calculated by dividing coronary sinus flow variables after dipyridamole administration by the respective baseline values.
  
  
  RESULTS
  Technically adequate recordings were obtained in 44 (98%) of 45 patients. Compared with that in the control group (2.78 +/- 0.95 [mean +/- SD]), coronary flow reserve was significantly lower in patients with syndrome X (1.21 +/- 0.23, p < or = 0.001) as well as in those with coronary artery disease (1.47 +/- 0.7, p < or = 0.001). Using a cutoff coronary flow reserve value of 1.8, sensitivity, specificity and overall predictive value of coronary flow reserve determinations were, respectively, 100%, 91% and 94% for syndrome X and 86%, 91% and 89% for coronary artery disease.
  
  
  CONCLUSIONS
  Coronary flow reserve calculation by transesophageal coronary sinus flow velocity recordings is feasible in a large proportion of patients and might be useful for the noninvasive evaluation of patients with syndrome X and patients with severe left coronary artery disease.
authors.affiliation: Department of Cardiology, University of Vienna, Austria.
authors.forename: M
authors.initials: M
authors.lastname: Zehetgruber
authors.forename: G
authors.initials: G
authors.lastname: Mundigler
authors.forename: G
authors.initials: G
authors.lastname: Christ
authors.forename: D
authors.initials: D
authors.lastname: Mörtl
authors.forename: P
authors.initials: P
authors.lastname: Probst
authors.forename: H
authors.initials: H
authors.lastname: Baumgartner
authors.forename: G
authors.initials: G
authors.lastname: Maurer
authors.forename: P
authors.initials: P
authors.lastname: Siostrzonek
mesh_terms: D001783:Blood Flow Velocity / Q000187:drug effects / Q000502:physiology; D003326:Coronary Circulation / Q000187:drug effects / Q000502:physiology*; D003327:Coronary Disease / Q000000981:diagnostic imaging* / Q000503:physiopathology; D004176:Dipyridamole; D015150:Echocardiography, Doppler / Q000379:methods*; D017548:Echocardiography, Transesophageal / Q000379:methods*; D004562:Electrocardiography; D005240:Feasibility Studies; D005260:Female; D006801:Humans; D008297:Male; D017566:Microvascular Angina / Q000000981:diagnostic imaging* / Q000503:physiopathology; D008875:Middle Aged; D011237:Predictive Value of Tests; D012680:Sensitivity and Specificity
chemical_list: D004176:Dipyridamole