Flow-mediated vasodilation predicts the presence and extent of coronary artery disease assessed by stress thallium imaging.
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.
Wu
Wen-Chih
WC
Division of Cardiology, Providence VA Medical Center, Brown Medical School, 830 Challkstone, Providence, RI 02908, USA.
Sharma
Satish C
SC
Choudhary
Gaurav
G
Coulter
Linda
L
Coccio
Elizabeth
E
Eaton
Charles B
CB
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
D019275:Radiopharmaceuticals; D014665:Vasodilator Agents; C027549:thallium chloride; D013793:Thallium