Stress Echocardiography Expert Consensus Statement--Executive Summary: European Association of Echocardiography (EAE) (a registered branch of the ESC)

Abstract

Stress echocardiography is the combination of echocardiography with a physical, pharmacological, or electrical stress. The diagnostic endpoint for the detection of myocardial ischaemia is the induction of a transient worsening in regional function during stress. Stress echocardiography provides similar diagnostic and prognostic accuracy to radionuclide stress perfusion imaging, but at a substantially lower cost, without environmental impact, and with no biohazards for the patient and the physician. Among different stresses of comparable diagnostic and prognostic accuracy, semisupine exercise is the most used, dobutamine the best test for viability, and dipyridamole the safest and simplest pharmacological stress and the most suitable for combined wall motion coronary flow reserve assessment. The additional clinical benefit of myocardial perfusion contrast echocardiography and myocardial velocity imaging has been inconsistent to date, whereas the possibility of performing coronary flow reserve evaluation of the left anterior descending coronary artery by transthoracic Doppler echocardiography adds another potentially important dimension to stress echocardiography. New emerging fields of application taking advantage of the versatility of the technique are Doppler stress echo in valvular heart disease and in dilated cardiomyopathy. In spite of its dependence on the operator's training, stress echocardiography is today the best (most cost-effective and risk-effective) possible imaging choice to achieve the still elusive target of sustainable cardiac imaging in the field of non-invasive diagnosis of coronary artery disease. In 1935, Tennant and Wiggers 1 demonstrated that coronary occlusion immediately resulted in instantaneous abnormality of wall motion. A large body of evidence 2–5 recognized for the first time that transient dys-synergy was an early, sensitive, specific marker of transient ischaemia, clearly more accurate than ECG changes and pain. In European clinical practice, 6–10 stress echo has been embedded in the legal and cultural framework of existing European laws and medical imaging referral guidelines. The radiation used for medical examinations and tests is the greatest man-made source of radiation exposure. 11 Small individual risks of each test performed with ionizing radiation multiplied by a billion examinations become significant population risks. For this reason, in Europe, both the law 11 and the referral guidelines for medical imaging 12 recommend a justified, optimized, and responsible use of testing with ionizing radiation. European Commission referral guidelines were released in 2001 in application of the Euratom Directive, and explicitly state that a non-ionizing technique must be used whenever it will give information grossly comparable with an ionizing investigation. For instance, ‘because MRI does not use ionizing radiation, MRI should be preferred when both CT and MRI would provide similar information and when both are available’. 12 In this perspective of the medical, as well as socio-economic and biological impact of medical imaging, it is imperative to increase all efforts to improve appropriateness 13 and minimize the radiation burden of stress imaging for the population and the individual patient. 14 The imperative of sustainability of medical imaging is likely to become increasingly important in the near future, also from a US perspective. 15 , 16 In the quest for sustainability, stress echocardiography has unsurpassed assets of low cost, absence of environmental impact, and lack of biological effects for both the patient 17 and the operator compared with equally accurate, but less sustainable, competing techniques. 18 Stress echocardiography is the combination of 2D echocardiography with a physical, pharmacological, or electrical stress. 19 The diagnostic endpoint for the detection of myocardial ischaemia is the induction of a transient change in regional function during stress. The stress echo sign of ischaemia is a stress-induced worsening of function in a region contracting normally at baseline. The stress echo sign of myocardial viability is a stress-induced improvement of function during low levels of stress in a region that is abnormal at rest. A transient regional imbalance between oxygen demand and supply usually results in myocardial ischaemia, the signs and symptoms of which can be used as a diagnostic tool. Myocardial ischaemia results in a typical ‘cascade’ of events in which the various markers are hierarchically ranked in a well-defined time sequence. 20 Flow heterogeneity, especially between the subendocardial and subepicardial perfusion, is the forerunner of ischaemia, followed by metabolic changes, alteration in regional mechanical function, and only at a later stage by electrocardiographic changes, global left ventricular (LV) dysfunction, and pain. The pathophysiological concept of the ischaemic cascade is translated clinically into a gradient of sensitivi