What is the purpose and procedure of a routine stress test for patients with a high risk of cardiovascular disease?

Routine Stress Testing in High-Risk Cardiovascular Patients

Routine stress testing is NOT recommended for asymptomatic patients, even those at high cardiovascular risk, unless they have poor functional capacity (<4 METs), are planning vigorous exercise, or have specific high-risk features requiring risk stratification. 1, 2

When Stress Testing Should NOT Be Performed

Routine screening with stress testing in asymptomatic individuals provides no benefit and should be avoided. 1, 2 The 2024 AHA/ACC guidelines explicitly state that routine stress testing before noncardiac surgery is not recommended in patients who:

• Have adequate functional capacity (≥4 METs) 1
• Are at low risk for perioperative cardiovascular events 1
• Are undergoing low-risk procedures 1
• Are asymptomatic and clinically stable 1

This recommendation is based on evidence showing that preoperative revascularization does not reduce mortality or myocardial infarction risk, making routine testing unnecessary and potentially harmful through unnecessary downstream testing and surgical delays. 1

Limited Indications for Stress Testing in High-Risk Patients

Stress testing may be considered (Class IIb recommendation) only in highly selected circumstances: 1, 2

• Elevated-risk noncardiac surgery patients with poor or unknown functional capacity (<4 METs or DASI score ≤34) AND elevated perioperative risk based on validated risk tools 1
• Asymptomatic diabetic patients planning to start vigorous exercise 2
• Asymptomatic adults with diabetes who have additional very high-risk features: peripheral arterial disease, high coronary artery calcium score, proteinuria, or renal failure 2
• Asymptomatic men >45 years or women >55 years planning vigorous exercise or in occupations affecting public safety 2

The Goal of Stress Testing When Indicated

The purpose of stress testing is NOT to identify undiagnosed coronary artery disease but to identify patients with left main disease or severe multivessel disease with reduced left ventricular ejection fraction who might benefit from revascularization. 1 This represents a critical shift in thinking—stress testing should only be performed when the results would change management in ways that improve mortality, morbidity, or quality of life.

Critical Pitfall to Avoid

An abnormal stress test should NOT automatically prompt coronary angiography or revascularization unless the study shows high-risk features. 1 The CARP trial demonstrated no difference in perioperative myocardial infarction at 30 days or all-cause mortality at 2.7 years between revascularization and medical therapy groups, with the revascularization group experiencing a 36-day surgical delay. 1

Procedure Selection When Testing Is Indicated

Exercise stress testing is preferable to pharmacological stress testing if the patient can exercise. 1 For patients unable to exercise, pharmacological stress test selection should be based on:

• Patient-specific factors 1
• Local availability and expertise 1

Stress imaging (echocardiography or nuclear) is preferred over standard ECG stress testing for: 2

• Patients with prior revascularization (PCI or CABG) 2
• Uninterpretable ECG (left bundle branch block, paced rhythm, >1mm resting ST depression, left ventricular hypertrophy with strain) 2

Symptomatic Patients: A Different Scenario

The recommendations above apply to asymptomatic high-risk patients. For symptomatic patients, stress testing serves different purposes: 1, 2

• Intermediate pretest probability of CAD with symptoms: Stress testing is recommended for evaluation and risk stratification 2
• Stabilized unstable angina (intermediate or low-risk): Stress testing is appropriate 12-24 hours after clinical stabilization 1
• Post-myocardial infarction: Submaximal testing before discharge or symptom-limited testing 2-3 weeks post-event 2

Cost-Value Considerations

The 2024 guidelines emphasize that routine stress testing leads to: 1

• Unnecessary downstream testing 1
• Delays in indicated surgery 1
• Potential for overtesting and overtreatment 1
• No demonstrated reduction in perioperative major adverse cardiovascular events or cardiac mortality 1

The evidence is clear: functional capacity assessment (can the patient climb two flights of stairs or walk four blocks?) is more valuable than routine stress testing for risk stratification in asymptomatic high-risk patients. 1