Accuracy of Exercise Stress Test for Coronary Artery Disease
Coronary artery disease (CAD) is the largest cause of disease burden globally, both in terms of mortality and morbidity. Timely diagnosis via exercise testing may enable efficient use of health resources when compared with interventions such as coronary angiography which are more expensive and more invasive.
Coronary arteries supply oxygenated blood to the myocardium. Narrowing attributable to atherosclerosis is the main underlying pathology of CAD, presenting with a spectrum of disease from stable angina and unstable angina to myocardial infarction (MI). The particular syndrome is determined by history, ECG findings and cardiac enzyme levels (troponins I and T) as per current guidelines. Coronary angiography is the reference standard investigation for visualising the coronary vasculature and diagnosing CAD. However, it is an invasive procedure with associated risks, and costs in terms of both finances and manpower. Investigation of all patients with signs and symptoms suggestive of CAD to coronary angiography may therefore be an inefficient use of healthcare resources without proper risk stratification of these patients.
Exercise stress testing offers a non-invasive, less expensive way of risk stratification prior to coronary angiography, and a negative stress test may actually avoid angiography. Exercise stress testing has been used to assess risk of CAD for over 60 years. There have been successive guidelines regarding the value of exercise testing and how it should be administered, but concern and confusion exist. For instance, a recent guideline from the National Institute for Health and Clinical Excellence (NICE) states, "Do not use exercise ECG to diagnose or exclude stable angina for people without known CAD", and yet exercise ECG testing is still commonly used in this clinical setting.
Individual studies have shown the value of exercise test modalities, but have been restricted by modality, by setting, and previous reviews have not been restricted to prospective studies. Therefore, we set out to systematically review the diagnostic accuracy of all exercise testing modalities by evaluating their value in ruling in or ruling out CAD in patients without known CAD. The major modalities of exercise testing included are treadmill ECG, treadmill echo, bicycle ECG, bicycle echo and myocardial perfusion imaging (MPI). Panel 1 shows the general considerations for all exercise testing in terms of contraindications and reasons for stopping tests.Panel 2 provides a brief summary of how to perform each test.
Background
Why is Exercise Stress Testing Important in Evaluating Coronary Artery Disease?
Coronary artery disease (CAD) is the largest cause of disease burden globally, both in terms of mortality and morbidity. Timely diagnosis via exercise testing may enable efficient use of health resources when compared with interventions such as coronary angiography which are more expensive and more invasive.
Pathophysiology
Coronary arteries supply oxygenated blood to the myocardium. Narrowing attributable to atherosclerosis is the main underlying pathology of CAD, presenting with a spectrum of disease from stable angina and unstable angina to myocardial infarction (MI). The particular syndrome is determined by history, ECG findings and cardiac enzyme levels (troponins I and T) as per current guidelines. Coronary angiography is the reference standard investigation for visualising the coronary vasculature and diagnosing CAD. However, it is an invasive procedure with associated risks, and costs in terms of both finances and manpower. Investigation of all patients with signs and symptoms suggestive of CAD to coronary angiography may therefore be an inefficient use of healthcare resources without proper risk stratification of these patients.
Exercise Stress Testing
Exercise stress testing offers a non-invasive, less expensive way of risk stratification prior to coronary angiography, and a negative stress test may actually avoid angiography. Exercise stress testing has been used to assess risk of CAD for over 60 years. There have been successive guidelines regarding the value of exercise testing and how it should be administered, but concern and confusion exist. For instance, a recent guideline from the National Institute for Health and Clinical Excellence (NICE) states, "Do not use exercise ECG to diagnose or exclude stable angina for people without known CAD", and yet exercise ECG testing is still commonly used in this clinical setting.
Individual studies have shown the value of exercise test modalities, but have been restricted by modality, by setting, and previous reviews have not been restricted to prospective studies. Therefore, we set out to systematically review the diagnostic accuracy of all exercise testing modalities by evaluating their value in ruling in or ruling out CAD in patients without known CAD. The major modalities of exercise testing included are treadmill ECG, treadmill echo, bicycle ECG, bicycle echo and myocardial perfusion imaging (MPI). Panel 1 shows the general considerations for all exercise testing in terms of contraindications and reasons for stopping tests.Panel 2 provides a brief summary of how to perform each test.
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