Coronary flow: a new asset for the echo lab?

Non-invasive imaging of coronary blood flow by transthoracic Doppler echocardiography is an emerging diagnostic tool to study the left anterior descending (LAD) and posterior descending (PD) coronary arteries. With this new clinical application of echocardiography, we can directly measure changes in coronary flow velocity reserve (CFVR) at the very beginning of the ischaemic cascade, instead of looking at the consequences of ischaemia on myocardial contraction, as it is routinely done with dobutamine stress echocardiography and other stress tests. Since its introduction in 1997, it has been clear that transthoracic coronary Doppler ultrasound could provide useful information in the diagnosis of coronary artery disease (CAD) follow-up of percutaneous coronary interventions, coronary recanalization in acute myocardial infarction (AMI), and coronary microcirculation.. The importance of measuring CFVR in routine clinical practice has been anticipated over 20 years ago by the physiologist Carl Honig: ‘‘One of the principal tasks of a physician is to estimate the patient’s reserves. . . Prognosis is an estimate of the rate at which this reserve may disappear, and therapy is designed to increase this reserve and to prevent or eliminate stresses that might compromise it’’. With this teaching in mind we have planned our seven-year work on transthoracic coronary Doppler ultrasound. In this review we will focus on the main clinical applications of transthoracic coronary Doppler ultrasound, and discuss the advantages, limitations and technical pitfalls of the method.