When should a stress test be performed?

When to Perform a Stress Test

Stress testing should be performed when it is anticipated that the results will affect patient management, primarily in symptomatic patients with suspected coronary artery disease at intermediate risk, and should not be conducted if the information can be obtained through other means or if the patient is already selected for cardiac catheterization. 1, 2

Primary Indications for Stress Testing

Suspected Coronary Artery Disease

• Perform stress testing in patients with chest pain at low to intermediate risk after initial evaluation shows no high-risk features (normal ECG, negative cardiac biomarkers) 2
• Testing should occur within 72 hours for low-risk outpatients, or after 8-12 hours of observation in chest pain units/emergency departments if the patient remains pain-free with normal ECGs and biomarkers 2
• Standard exercise ECG is appropriate for patients with normal resting ECG who are not taking digoxin, as it is nearly as accurate as imaging modalities for detecting left main or three-vessel disease in this population 3

Post-Acute Coronary Syndrome

• Submaximal exercise testing can be performed 4-6 days post-event for prognostic assessment and activity prescription 2
• Symptom-limited testing should be performed 14-21 days after discharge if predischarge testing was not done 2
• Stress testing is useful for cardiac rehabilitation planning and activity counseling after coronary revascularization 2

Specific Clinical Scenarios Requiring Stress Testing

Hypertrophic Cardiomyopathy (HCM):

• Exercise stress testing is reasonable for initial evaluation to determine functional capacity and provide prognostic information 1
• Exercise echocardiography is recommended for symptomatic HCM patients without resting or provocable outflow tract gradient ≥50 mm Hg on standard TTE 1
• Consider repeat testing every 2-3 years when functional capacity or symptom status is uncertain 1

Diabetes Mellitus:

• Stress testing is recommended for diabetic patients planning to start vigorous exercise, particularly those with multiple cardiovascular risk factors 1, 2
• Exercise testing should be performed in diabetic patients with symptoms suggesting cardiac disease before initiating physical activity programs 1

Preoperative Assessment:

• Stress testing is reasonable for patients undergoing vascular surgery or those with active cardiac symptoms before nonemergent noncardiac surgery 2, 4
• Testing is not indicated before noncardiac surgery in patients who can achieve 4 metabolic equivalents without symptoms 4

Transplant Candidates:

• Perform noninvasive stress testing in kidney transplant candidates with diabetes, prior CAD, or poor functional capacity 1
• Consider stress testing in liver transplant candidates with multiple risk factors or age >50 years to uncover asymptomatic ischemic heart disease 1

When to Add Imaging to Stress Testing

Add imaging modalities (echocardiography or nuclear imaging) when patients have: 2

• Resting ST-segment depression
• Left ventricular hypertrophy
• Bundle-branch block or intraventricular conduction defect
• Pre-excitation syndrome
• Digoxin therapy
• Paced rhythm

Use pharmacological stress testing with imaging when physical limitations prevent adequate exercise 2

Absolute Contraindications to Stress Testing

• Severe comorbidity limiting life expectancy or candidacy for revascularization 2
• Acute myocardial infarction patients with uncompensated heart failure, cardiac arrhythmia, or severe noncardiac conditions limiting exercise ability 2
• Patients already selected for cardiac catheterization (though stress imaging may still evaluate ischemia in borderline lesions) 2

When NOT to Perform Stress Testing

Avoid routine stress testing in: 2

• Asymptomatic men or women without risk factors (routine screening not recommended)
• Patients with known CAD and no new symptoms less than 2 years after percutaneous intervention 4
• Patients with known CAD and no new symptoms less than 5 years after coronary artery bypass grafting 4

Limited utility in young patients:

• Adults under 40 years have extremely low yield from stress testing (0.4% positive rate, with only 0.097% true positives) even with intermediate risk features 5, 6
• The 30-day cardiovascular complication rate is not different between young patients without known heart disease who do versus do not receive stress testing 6

Critical Pitfalls to Avoid

• Do not order stress tests in asymptomatic low-risk patients without risk factors 2
• Do not perform standard exercise ECG in patients with baseline ECG abnormalities—this leads to decreased accuracy and requires imaging instead 2, 3
• Do not test too early in acute MI patients who are not clinically stable 2
• Do not fail to consider pharmacologic stress testing when patients cannot achieve adequate exercise levels, as this leads to inaccurate results 2
• The physician must be immediately available during testing, and should be personally present for high-risk patients (recent acute coronary syndrome within 7-10 days, severe LV dysfunction, severe valvular stenosis, or complex arrhythmia) 1