Contemporary Stress Echocardiography: Old Dog with New Tricks
By Professor Roxy Senior,
MD, DM, FRCP, FESC, FACC
Professor of Clinical Cardiology at National Heart and Lung Institute, Imperial College, London
Roxy Senior is Professor of Clinical Cardiology at the National Heart and Lung Institute, Imperial College London and Consultant Cardiologist and Director of Echocardiography at the Royal Brompton Hospital, London and Northwick Park Hospital, Harrow.
He graduated and obtained masters degree in medicine and cardiology from the University of Calcutta, India and migrated to the U.K. in 1989 when he joined Northwick Park Hospital as a research fellow. He became a Consultant Cardiologist and Director of Cardiac Research at the Northwick Park Hospital, Harrow in 1995.Following which he was appointed as Consultant Cardiologist and Director of Echocardiography at the Royal Bromtpon Hospital, London in 2010.
He is a clinician with a major interest in echocardiography. He has been involved with echocardiography for the last 25 years and has published over 250 original papers in this field. His particular interest is in heart failure, coronary artery disease, valvular heart disease and acute coronary syndrome.
He pioneered the clinical development of myocardial contrast echocardiography especially in the detection of myocardial viability and led several multicentre studies involving Contrast Echocardiography. He also pioneered the use of stress echocardiography for early discharge of patients with suspected acute coronary syndrome. Furthermore, he has utilised hand-held echocardiography for the detection of cardiac dysfunction and assessed its cost-effectiveness in comparison to BNP for the detection of heart failure. He recently completed a study assessing cardiac function and carotid atherosclerosis in Indian Asian vs European Whites which may clarify the differential outcome in these two ethnic groups. He is now actively involved in research in valvular heart disease.
Professor Senior has been awarded the “Edler Lecture” by the University of Lund for his pioneering work in echocardiography. He provided Core – Lab function for MRC sponsored study in Hibernating Myocardium.
Professor Senior is on various task force committees in the American Society of Echocardiography and European Association of Echocardiography. He is also on the editorial board of the European Journal of Echocardiography and the Indian Heart Journal and reviewer for the Lancet, Circulation, Journal of the American College of Cardiology, American Heart Journal, Heart and European Heart Journals.
Professor Roxy Senior MD, DM, FRCP, FESC, FACC
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
