Usefulness of coronary flow reserve measured by transthoracic coronary Doppler ultrasound to detect severe left anterior descending coronary artery stenosis.

Transthoracic coronary Doppler ultrasound during venous adenosine infusion showed damped (<1) coronary flow velocity reserve in patients with severe left anterior descending coronary artery stenosis. Damped coronary flow reserve discriminated severe from nonsevere stenosis with high sensitivity, specificity, and positive predictive accuracy, and is a unique noninvasive tool to identify high-risk patients.