Noninvasive assessment of coronary blood flow by transthoracic Doppler echocardiography: basic to practical use in the emergency room.

Echo Doppler is widely available in the clinical setting, and the feasibility of coronary flow detection in the left anterior descending coronary artery has been reported as >90% with the use of a high-frequency transducer. Coronary flow detection takes only a few minutes by skilled echocardiologists, and this noninvasive technique can provide useful physiological information in patients with various types of coronary artery disease. Coronary flow velocity reserve measurement by echo Doppler is a simple and easy technique. It is available in the echo laboratory as well as in the outpatient clinic, and can be used as an alternative examination to screen for significant coronary stenosis in patients with stable angina. Moreover, physiological information provided by coronary flow velocity reserve can be used in combination with other imaging modalities that can provide anatomical information of the coronary arteries such as coronary computed tomography or coronary angiography. Coronary flow velocity in patients with acute coronary syndrome (ACS) enables rapid noninvasive differentiation of TIMI-III from TIMI-II coronary reperfusion before emergency coronary intervention. Transthoracic coronary flow detection by echo Doppler contributes to the assessment of the coronary reperfusion status in the emergency room for patients with ACS, prior to invasive coronary angiography.