Relation between peripheral vascular endothelial function and coronary flow reserve in patients with chest pain and normal coronary angiogram

To evaluate the relation between peripheral vascular endothelial function and coronary flow reserve (CFR), we assessed flow mediated dilation (FMD) of brachial artery and the intima-media thickness (IMT) of the carotid artery in 32 subjects (mean age 58 ± 9 years, M/F = 9:23 ) with chest pain and normal coronary angiogram. The subjects were divided into 2 groups according to CFR ≥ 2.1 or < 2.1 measured with transthoracic echocardiography in distal left anterior descending coronary artery. We found % FMD was decreased in the group with CFR < 2.1 than those of CFR ≥ 2.1 and CFR was correlated with peripheral FMD. However, IMT was not different between two groups. These results suggest that microvascular dysfunction is primarily related to endothelial dysfunction rather than advanced atherosclerosis and because it is a generalized process that involves the whole arteries, the measurement of brachial FMD can be a useful diagnostic tool to evaluate microvascular dysfunction in patients with chest pain and normal coronary angiogram.