When should I order an exercise treadmill stress test for an adult who can exercise to assess coronary artery disease?

When to Order an Exercise Treadmill Stress Test

Order an exercise treadmill stress test as the initial diagnostic test for adults with symptoms of angina who have intermediate pre-test probability of coronary artery disease (15-65%), can exercise adequately, and have an interpretable baseline ECG. 1

Primary Indications for Exercise Treadmill Testing

Symptomatic Patients with Suspected CAD

• Order exercise ECG testing for patients with chest pain symptoms and intermediate pre-test probability (15-65%) who are not taking anti-ischemic medications, can exercise, and have a normal baseline ECG. 1
• Exercise testing is the preferred initial modality because it provides physiological stress superior to pharmacological testing and correlates better with daily symptom burden. 2
• The test should be performed when patients can achieve at least 4-5 METs of physical work capacity (equivalent to routine activities of daily living). 3, 2

Risk Stratification in Specific Populations

• Order exercise testing for asymptomatic men over 40-45 years or postmenopausal women over 50-55 years with at least one coronary risk factor (hypertension, hyperlipidemia, smoking, diabetes) before vigorous competitive activities. 3
• Consider testing for all patients over 65 years old, even without risk factors or symptoms. 3
• Any patient with symptoms suggestive of coronary disease, regardless of age, should undergo exercise testing. 3

Patients with Known CAD

• Order exercise ECG testing in patients on treatment to evaluate control of symptoms and ischemia. 1
• Exercise testing can be useful in patients with obstructive CAD who have stable chest pain despite optimal medical therapy to determine if symptoms are consistent with angina and assess functional capacity. 1

When to Choose Imaging Stress Testing Instead

Switch to stress imaging (echocardiography, SPECT, PET, or CMR) rather than exercise ECG alone in these specific situations:

High Pre-Test Probability

• Order imaging stress testing as the initial test when pre-test probability is 66-85% or when left ventricular ejection fraction is <50% in patients without typical angina. 1

Uninterpretable Baseline ECG

• Do not order exercise ECG in patients with baseline ECG abnormalities that prevent accurate interpretation: left bundle branch block, paced rhythm, Wolff-Parkinson-White syndrome, left ventricular hypertrophy with strain pattern, ≥0.1 mV ST-depression at rest, or digitalis use. 1
• These conditions make ECG changes non-interpretable and produce frequent false-positive results. 1

Prior Revascularization

• Consider imaging stress testing in symptomatic patients with previous PCI or CABG to evaluate for recurrent ischemia. 1

Inconclusive Exercise ECG Results

• Order imaging stress testing when exercise ECG is inconclusive (failure to achieve 85% maximum predicted heart rate without symptoms or signs of ischemia, or when exercise is limited by orthopedic or non-cardiac problems). 1

Special Populations Requiring Modified Approach

Women

• Exercise ECG has lower sensitivity and specificity in women compared to men, with more frequent false-positive results. 1
• Despite these limitations, exercise ECG without imaging remains the preferred initial test for risk stratification in most women who can exercise and have normal baseline ECG. 1
• Women who exercise <5 METs are at increased risk of death and may be better evaluated with pharmacological stress imaging. 1
• Stress echocardiography provides significantly higher specificity and accuracy than standard exercise ECG in women. 1

Young Adults with Congenital Heart Disease

• Exercise stress testing is reasonable in asymptomatic young adults <30 years with aortic stenosis to determine exercise capability, symptoms, and blood pressure response. 1
• Testing is reasonable for those with mean Doppler gradient >30 mm Hg or peak gradient >50 mm Hg if interested in athletic participation. 1

Patients with Kawasaki Disease History

• Exercise stress echocardiography is preferred over exercise ECG alone in children with coronary artery abnormalities from Kawasaki disease, as it may identify myocardial ischemia not detected by ECG changes alone. 1

Common Pitfalls to Avoid

• Do not order exercise testing in asymptomatic patients without risk factors—testing of asymptomatic populations is generally not indicated and leads to false-positive results. 4
• Do not use 85% age-predicted maximum heart rate as a criterion to terminate testing—there is high variability in age-predicted maximum heart rate among subjects of identical age. 5, 2
• Do not order exercise stress testing for preoperative risk assessment in patients who can achieve ≥4 METs without symptoms—it is not indicated before noncardiac surgeries in this population. 4
• Do not order repeat exercise testing in asymptomatic patients with known CAD <2 years after PCI or <5 years after CABG—this is rarely appropriate without new symptoms. 4
• Exercise ECG alone may overestimate disease severity in patients with baseline abnormalities (LVH, electrolyte imbalance, intraventricular conduction abnormalities, atrial fibrillation). 1

Prognostic Value Beyond Diagnosis

• Exercise capacity alone is one of the strongest prognostic indicators for long-term risk including death. 5, 3
• Patients able to complete 9 minutes of the Bruce protocol have extremely low subsequent cardiac risk regardless of symptoms or ECG changes. 5
• High-risk features include exercise duration <6 minutes on Bruce protocol, failure to attain 90% age-predicted maximum heart rate, greater degree of ST-segment depression, and chest pain during maximal exertion. 3
• Asymptomatic men over 40 years with at least one risk factor and at least two abnormal exercise features have a 30-fold increment in 5-year cardiac risk. 3