title: Flow-mediated vasodilation predicts the presence and extent of coronary artery disease assessed by stress thallium imaging.
abstract: BACKGROUND
  Endothelial function can be measured by flow-mediated vasodilation (FMD) of the brachial artery and has been associated with cardiac risk factors (RF) and angiographically defined coronary artery disease (CAD). Stress single photon emission computed tomography (SPECT) imaging is commonly used to study patients with CAD. We sought to study the relationship between endothelial dysfunction by FMD and stress thallium SPECT to detect CAD.
  
  
  RESULTS
  Fifty-five consecutive patients with chest pain syndrome referred for stress SPECT and eleven healthy control subjects had FMD measured on the brachial artery by standard techniques. The main outcome was the percent of brachial artery diameter dilation from baseline and the number of perfusion defects by SPECT. In subjects with no RF, those with RF but no defects, and those with defects, the mean FMD was 18.88% +/- 2.31%, 7.85% +/- 1.66%, and 5.91% +/- 1.07%, respectively (P < .05). A significant correlation was found between the number of thallium defects and degree of FMD impairment (r = -0.40, P < .01). An FMD cutoff value of less than 7.5% had a 72.5% sensitivity and 73.1% specificity in predicting the presence of any thallium defects. After RF adjustment, FMD remained as the strongest predictor of scintigraphic CAD (odds ratio, 10.96; 95% confidence interval, 2.82-57.31).
  
  
  CONCLUSIONS
  FMD independently predicts the presence and extent of scintigraphic CAD.
authors.affiliation: Division of Cardiology, Providence VA Medical Center, Brown Medical School, 830 Challkstone, Providence, RI 02908, USA.
authors.forename: Wen-Chih
authors.initials: WC
authors.lastname: Wu
authors.forename: Satish C
authors.initials: SC
authors.lastname: Sharma
authors.forename: Gaurav
authors.initials: G
authors.lastname: Choudhary
authors.forename: Linda
authors.initials: L
authors.lastname: Coulter
authors.forename: Elizabeth
authors.initials: E
authors.lastname: Coccio
authors.forename: Charles B
authors.initials: CB
authors.lastname: Eaton
mesh_terms: D000328:Adult; D000368:Aged; D001783:Blood Flow Velocity; D001916:Brachial Artery / Q000000981:diagnostic imaging; D003324:Coronary Artery Disease / Q000000981:diagnostic imaging*; D004730:Endothelium, Vascular / Q000000981:diagnostic imaging*; D005080:Exercise Test / Q000379:methods*; D005260:Female; D006801:Humans; D015994:Incidence; D008297:Male; D019275:Radiopharmaceuticals; D015203:Reproducibility of Results; D018570:Risk Assessment / Q000379:methods; D012307:Risk Factors; D012680:Sensitivity and Specificity; D012720:Severity of Illness Index; D013793:Thallium; D015899:Tomography, Emission-Computed, Single-Photon / Q000379:methods; D014463:Ultrasonography; D014664:Vasodilation; D014665:Vasodilator Agents
chemical_list: D019275:Radiopharmaceuticals; D014665:Vasodilator Agents; C027549:thallium chloride; D013793:Thallium