As physicians, we see patients on a daily basis who have complaints of chest discomfort, atypical and typical of myocardial ischemia. The burden is on us to assess not only if coronary artery disease (CAD) is responsible for the symptoms but also if present, how extensive it is and what the patient’s prognosis is. Patients are not only asking us to diagnose the underlying condition but also tell them how the disease, if present, will affect their lifestyle and the prognostic implications of the diagnosis. The diagnostic modalities that are available can grossly be divided into anatomic testing and functional testing.

In terms of functional testing the standard treadmill testing (ETT or TMT) has been in use for over 70 years and is still the most frequently used test.¹ ETT is being used for not only diagnosis but also prognostic purposes in clinically stable patients.¹ ETT is generally a safe test and is cost-effective and free of radiation or contrast exposure. ETT has maximal diagnostic value in the patient population with intermediate (10%-90%) pretest probability of CAD.² ETT is of little diagnostic value in patients with either low or high pretest probability and is generally discouraged for asymptomatic individuals.³ ETT is thought, based on meta-analysis, to have a sensitivity of 68% and a test specificity of 77%. Test accuracy (both sensitivity and accuracy) is lower in women than in men, and this is in part related to lower prevalence of CAD in women. Exercise capacity is the most important prognostic variable as patients with poor exercise capacity are at high risk for poor clinical outcome, often related to underlying left main or three-vessel CAD.⁴

The American College of Cardiology (ACC)/American Heart Association (AHA) 2002 Guideline Update for Exercise Testing identifies three CAD risk categories and allows the physician to classify the patient based on annual mortality rates: low <1%, intermediate 1% to 3%, or high >3% risk. The guidelines emphasize that low-risk patients do not need further cardiac testing and can be treated medically. The intermediate risk category may or may not require further testing, and the high risk is generally referred for coronary angiography.¹,³ Stress imaging (SPECT or ECHO) has higher sensitivity and similar specificity.²,⁵,⁶ Despite advances in noninvasive testing over the last decades, there is still no consensus on which noninvasive test is preferable, and we continue to be faced with the dilemma of how to approach the patient in the best, safest, and most cost-effective way.⁷ In part, this may also be related to which test the individual physician or institution has most experience and expertise in. Historically we have much evidence that traditional functional testing, exercise electrocardiography, exercise or dobutamine echocardiography, exercise or chemical myocardial perfusion imaging, and cardiac magnetic resonance imaging, provides excellent prognostic information. An abnormal functional test (FT) has been shown to be associated with a significantly increased (5- to 10-fold) risk of adverse cardiovascular events.