title: Noninvasive quantification of coronary blood flow reserve in humans using myocardial contrast echocardiography.
abstract: BACKGROUND
  We hypothesized that coronary blood flow (CBF) reserve could be quantified noninvasively in humans using myocardial contrast echocardiography (MCE).
  
  
  RESULTS
  Eleven patients with normal epicardial coronary arteries (group I) and 19 with single-vessel coronary stenosis (group II) underwent quantitative coronary angiography, MCE, and CBF velocity measurements at rest and during intravenous adenosine infusion. In group I patients, MCE-derived myocardial blood flow (MBF) velocity reserve (2.4+/-0.08) was similar to CBF velocity reserve using a Doppler flow wire (2.4+/-1.1). Patients with a single risk factor had a significantly higher MBF reserve (3.0+/-0.89) than those with >/=2 risk factors (1.7+/-0.22). In group II patients, significant differences were found in MBF velocity reserve in patients with mild (<50%), moderate (50% to 75%), or severe (>75%) stenoses (2.2+/-0.40, 1.6+/-0.65, and 0.55+/-0.19, respectively; P=0.005). A linear relation was found between flow velocity reserve determined using the 2 methods (r=0.76, P<0.001), and a curvilinear relation was noted between the percent coronary stenosis measured using quantitative coronary angiography and velocity reserve using both methods.
  
  
  CONCLUSIONS
  CBF reserve can be measured in humans using MCE. This method may allow the noninvasive assessment of coronary stenosis severity and the detection of microvascular dysfunction.
authors.affiliation: Cardiac Imaging Center and the Cardiovascular Division, University of Virginia School of Medicine, Charlottesville, VA, USA. kw6n@virginia.edu
authors.forename: K
authors.initials: K
authors.lastname: Wei
authors.forename: M
authors.initials: M
authors.lastname: Ragosta
authors.forename: J
authors.initials: J
authors.lastname: Thorpe
authors.forename: M
authors.initials: M
authors.lastname: Coggins
authors.forename: S
authors.initials: S
authors.lastname: Moos
authors.forename: S
authors.initials: S
authors.lastname: Kaul
mesh_terms: D000328:Adult; D003326:Coronary Circulation; D003327:Coronary Disease / Q000473:pathology / Q000503:physiopathology*; D003331:Coronary Vessels / Q000502:physiology / Q000503:physiopathology; D004452:Echocardiography / Q000379:methods*; D005260:Female; D006439:Hemodynamics; D006801:Humans; D008297:Male; D008875:Middle Aged; D012720:Severity of Illness Index