Contemporary Stress Echocardiography: Old Dog with New Tricks

By Professor Roxy Senior,


Professor of Clinical Cardiology at National Heart and Lung Institute, Imperial College, London

Stress Echocardiography (SE) has a Class 1 indication according to the most recent guidelines by the European Society of Cardiology for the assessment of patients with suspected stable angina without known coronary artery disease (CAD). Its major advantages compared to other contemporary techniques are it can be performed at the bedside, without the need of ionizing radiation, wide availability and rapid performance and interpretation of the test without the need for post-processing.

In an era where the prevalence of CAD is on the decline and the population tested are generally low risk, SE is an ideal test because of the above attributes. Hitherto, SE detects the presence of CAD by evoking wall motion abnormality (WMA) during stress. Because WMA during stress appears later in the ischemic cascade, SE is generally considered to be less sensitive compared to other techniques which detects perfusion abnormalities that occurs earlier in the ischemic cascade. SE is also considered to have more non-diagnostic results because of degradation of image quality during stress. Lastly, computerised coronary tomographic angiography (CCTA) which can be performed non-invasively, by virtue of its ability to detect plaque disease confers superior prognostic power compared to ischemia based techniques.

With the development of harmonic imaging and the availability of echo-enhancing contrast agents which are microbubbles, the quality of images have improved significantly so that diagnostic images are obtained during SE in over 98% of patients consistently. The microbubbles in contrast agents have the rheology of red blood cells and remains entirely intravascular and hence is ideal for the assessment of myocardial perfusion. Myocardial perfusion during SE has been shown to provide incremental value for the diagnosis of CAD and risk stratification beyond wall motion. Indeed myocardial perfusion during SE was found to be more sensitive compared with SPECT imaging for the detection of CAD. Recent guidelines in Europe have conferred a Class1 indication for its use in SE for both to improve image quality and for the assessment of perfusion.

Finally, carotid ultrasound which can assess plaque disease has been shown in large studies to be associated with cardiac-related events. Carotid ultrasound can be performed simultaneously with SE and can therefore provide information of myocardial ischemia and atherosclerosis. In recent studies carotid ultrasound was shown to provide incremental diagnostic and prognostic value beyond SE data both during medium term and long term follow-up. Like CTCA, it showed that the greatest impact on outcome are in patients who did not demonstrate myocardial ischemia. Presence of carotid plaque disease in these patients conferred a higher risk versus those patients who did not demonstrate plaque disease. Patients with carotid plaque disease in the absence of myocardial ischemia during SE may benefit from statin therapy.

In conclusion contemporary SE in combination with carotid ultrasound can now provide information on myocardial function, perfusion and atherosclerosis—all known substrates of CAD—improving detection of CAD and risk stratification in patients presenting with suspected stable angina without known CAD. Compounded with its superior safety profile compared to contemporary techniques is an ideal test in the low risk population of suspected angina.

Contemporary Stress Echocardiography in combination with carotid ultrasound can now provide information on myocardial function, perfusion and atherosclerosis—all known substrates of CAD—improving detection of CAD.

Professor Roxy Senior