Noninvasive Studies of Coronary and Peripheral Arterial Blood-flow.

Noninvasive vascular imaging may identify the high-risk, asymptomatic atherosclerotic patient who will substantially benefit from aggressive preventive therapies. Endothelium is a key player in the early stages of atherogenesis. Positron emission tomography (PET) and ultrasound-measured brachial artery vasoreactivity have emerged as potentially useful tools for the identification of endothelial dysfunction and, as such, early atherosclerosis. Both have been used successfully to demonstrate the association between endothelial dysfunction and established coronary artery disease risk factors, as well as clinically evident coronary artery disease. Abnormal coronary endothelial function recently has been associated with poor clinical outcomes in long-term follow-up studies. Given the close association between endothelial function in the coronary and peripheral circulation, there is particular promise for the validation of brachial artery vasoreactivity as a clinically useful tool. Finally, surveillance of endothelial function with these techniques may prove helpful in guiding aggressiveness of antiatherosclerotic therapy and effectiveness of new regimens.