What stress test should I order for a patient with a history of myocardial infarction (MI) who has chest pain?

Stress Testing for Patients with History of MI and Chest Pain

For patients with a history of myocardial infarction who present with chest pain, stress imaging (stress echocardiography, PET/SPECT myocardial perfusion imaging, or cardiovascular magnetic resonance) is the recommended stress test of choice rather than exercise ECG alone. 1

Rationale for Stress Imaging

Patients with prior MI have baseline ECG abnormalities that can interfere with the interpretation of exercise-induced ST-segment changes, making exercise ECG testing alone less reliable. The 2021 AHA/ACC/ASE/CHEST/SAEM/SCCT/SCMR guidelines specifically recommend:

• Class I recommendation: Exercise myocardial perfusion SPECT to identify the extent, severity, and location of ischemia in patients with baseline ECG abnormalities that interfere with interpretation of exercise-induced ST-segment changes 1

• For patients with known CAD (including prior MI), stress imaging provides superior diagnostic and prognostic information compared to exercise ECG alone 1

Specific Test Selection Algorithm

1. First-line recommendation:

   • Stress imaging test (one of the following based on availability and patient characteristics):
     • Stress echocardiography
     • Stress nuclear imaging (SPECT or PET)
     • Stress cardiovascular magnetic resonance (CMR)

2. Selection factors to consider:

   • If patient can exercise adequately: Exercise stress with imaging is preferred
   • If patient cannot exercise: Pharmacologic stress with imaging is recommended
   • If patient has left bundle branch block or paced rhythm: Pharmacologic stress with nuclear imaging is preferred 1

3. Specific advantages by modality:

   • Stress echocardiography: Provides assessment of wall motion abnormalities, valvular function, and structural heart disease; no radiation exposure 2, 3, 4
   • Nuclear perfusion imaging: Higher sensitivity for detecting ischemia, particularly with PET; less operator-dependent than echocardiography 1
   • PET over SPECT: For nuclear imaging, PET is reasonable in preference to SPECT to improve diagnostic accuracy and decrease nondiagnostic test results (Class 2a recommendation) 1

Special Considerations

• For patients with known obstructive CAD who have persistent chest pain despite guideline-directed medical therapy, invasive coronary angiography (ICA) is recommended (Class 1 recommendation) 1

• For patients with a previous stress test showing mild abnormalities (within the past year), coronary CT angiography (CCTA) is reasonable for diagnosing obstructive CAD 1

• For patients with a coronary artery stenosis of 40% to 90% on CCTA, fractional flow reserve with CT (FFR-CT) can be useful for diagnosing vessel-specific ischemia 1

Clinical Pitfalls to Avoid

• Don't rely on exercise ECG alone in patients with prior MI, as baseline ECG abnormalities reduce its diagnostic accuracy

• Don't delay testing in high-risk patients with concerning symptoms despite negative initial troponins

• Don't assume all chest pain in patients with prior MI is cardiac - consider other causes including gastrointestinal, musculoskeletal, or pulmonary etiologies

• Avoid using stress testing in patients with unstable symptoms - these patients may require direct referral for invasive coronary angiography

By following this approach, you can effectively risk-stratify your patient with a history of MI presenting with chest pain and determine the appropriate management strategy to reduce morbidity and mortality.