Key Imaging Takeaways From the 2021 Chest Pain Guidelines

Mar 14, 2022   |  Chad Gier, MD; Mohammed Al-Sadawi, MB ChB; Ryan Heslin, MD; Andrew Van Tosh, MD, FACC; Smadar Kort, MD, FACC

Expert Analysis

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Quick Takes

  • New guidelines for the evaluation of acute or stable chest pain.
  • The choice of imaging modality depends on the diagnostic yield and guided by clinical decision pathways.
  • Patients presenting with acute chest pain who are stratified as low risk (<1% MACE), do not warrant routine admission or urgent cardiac testing. However, outpatient CAC score can provide valuable information for long term risk stratification.
  • Decision to proceed with anatomic versus functional imaging testing depend on clinical presentation (acute vs. stable chest pain) and risk stratification (low, intermediate, high risk).
  • In general, CCTA is favored in younger patients (<65 years of age) or if non-obstructive CAD is suspected.
  • In general, stress testing is favored in older patients (≥65 years of age) or if obstructive CAD is suspected.
  • Functional testing such as FFR-CT or stress testing is indicated if anatomic testing shows obstructive disease (>50%).
  • Anatomic testing is indicated if stress imaging is equivocal or non-diagnostic.
  • In cases of suspected ischemia and INOCA, functional testing with stress imaging is advisable.

Chest pain is one of the most common chief concerns for patients to seek evaluation in the outpatient clinics and emergency departments in the United States. The American Heart Association (AHA)/American College of Cardiology (ACC) 2021 Chest Pain Guidelines1 aims to provide guidance for evaluating acute or stable chest pain in these settings. The following are key imaging guideline perspectives:

  • The choice of imaging is influenced by cost, availability, site expertise, pretest probability, test specific contraindications, prior testing, need for certain indication like viability, pre-treatment planning and anatomical considerations. In general, coronary computed tomography angiography (CCTA) is favored in patients <65 years of age or when less obstructive coronary artery disease (CAD) is suspected, and stress testing is favored in patients >65 years of age or when more obstructive CAD suspected.2,3
  • The "warranty" period varies for different cardiac imaging modalities. CCTA warranty period is 2 years due to the low number of events with patients with normal testing (no stenosis or plaque). Stress testing warranty period is only 1 year as patients with a normal stress test may still have significant amounts of coronary artery plaque and have high event rates.
  • Imaging modalities can be divided into anatomic testing or functional testing.
  • Anatomic testing is recommended in the following circumstances:
    • For patients with stable chest pain with no history of CAD deemed to be low risk, coronary artery calcium (CAC) or exercise testing without imaging are reasonable first line studies. CAC can be used to identify patients in which no further testing is needed (CAC score of zero) or can guide selective follow up testing (detectable CAC). Exercise electrocardiogram (ECG) testing can also effectively rule out myocardial ischemia and can help give information about a patient's functional capacity.4,5
    • For patients with stable chest pain with no history of CAD deemed to be intermediate to high risk:
      • CCTA has high diagnostic sensitivity and can help guide further testing or treatment.
      • Patients found to have 40-90% stenosis in proximal or mid coronary segments, fractional flow reserve can be used as add-on testing to help guide further management.
      • For patients with stable chest pain deemed to be intermediate to high risk that there is high clinical suspicion for CAD despite a negative stress test, a CCTA is reasonable.
    • Patients with history of coronary artery bypass surgery (CABG) with stable chest pain should undergo CCTA or stress imaging to evaluate for ischemia or bypass graft stenosis/occlusion.
  • Stress imaging includes stress echocardiography, positron emission tomography (PET)/single-photon emission computed tomography (SPECT), myocardial perfusion imaging (MPI) or cardiac magnetic resonance imaging (CMR). Stress imaging is recommended in the following circumstances:
    • For patients with stable chest pain with no history of CAD deemed to be intermediate to high risk:
      • Transthoracic echocardiography (TTE) is recommended to evaluate for left ventricular systolic function, diastolic function, and for the presence of myocardial, valvular, or pericardial disease.
      • Stress imaging with stress echocardiography, PET/ SPECT, MPI or CMR can be used to diagnosis myocardial ischemia.
      • PET, if available, is preferred over SPECT due to better diagnostic accuracy and lower rates of non-diagnostic results.
      • For patients with stable chest pain with no history of CAD deemed to be intermediate to high risk with inconclusive CCTA, subsequent testing with stress imaging is reasonable.
    • For patients with stable chest pain with known obstructive CAD:
      • Stress imaging is recommended to diagnosis myocardial ischemia, to risk stratify and to guide clinical decision making.
      • PET, if available, is preferred over SPECT due to better diagnostic accuracy and lower rates of non-diagnostic results.
      • For patients undergoing stress PET MPI or stress CMR, myocardial blood flow reserve (MBFR) should be added.
    • Patients with history of CABG with stable chest pain should undergo CCTA or stress imaging to evaluate for ischemia or bypass graft stenosis/occlusion.
    • For patients with suspected ischemia and no obstructive coronary artery disease (INOCA):
      • Stress PET MPI with MBFR, stress CMR with MBFR or stress echocardiography with coronary flow velocity reserve are reasonable choices to diagnose microvascular disease and assist with risk stratification.

References

  1. Gulati M, Levy PD, Mukherjee D, et al. 2021 AHA/ACC/ASE/CHEST/SAEM/SCCT/SCMR guideline for the evaluation and diagnosis of chest pain: a report of the American College of Cardiology/American Heart Association Joint Committee on Clinical Practice Guidelines. J Am Coll Cardiol 2021:78:e187-e285.
  2. Dilsizian V, Bacharach SL, Beanlands RS, et al. ASNC imaging guidelines/SNMMI procedure standard for positron emission tomography (PET) nuclear cardiology procedures. J Nucl Cardiol 2016;23:1187–1226.
  3. Narula J, Chandrashekhar Y, Ahmadi A, et al. SCCT 2021 expert consensus document on coronary computed tomographic angiography: a report of the Society of Cardiovascular Computed Tomography. J Cardiovasc Comput Tomogr 2021;15:192–217.
  4. Pellikka PA, Arruda-Olson A, Chaudhry FA, et al. Guidelines for performance, interpretation, and application of stress echocardiography in ischemic heart disease: from the American Society of Echocardiography. J Am Soc Echocardiogr 2020;33:1–41.e8.
  5. Juarez-Orozco LE, Saraste A, Capodanno D, et al. Impact of a decreasing pre-test probability on the performance of diagnostic tests for coronary artery disease. Eur Heart J Cardiovasc Imaging 2019;20:1198–1207.

Clinical Topics: Cardiac Surgery, Cardiovascular Care Team, Invasive Cardiovascular Angiography and Intervention, Noninvasive Imaging, Atherosclerotic Disease (CAD/PAD), Interventions and Coronary Artery Disease, Interventions and Imaging, Angiography, Computed Tomography, Echocardiography/Ultrasound, Magnetic Resonance Imaging, Nuclear Imaging

Keywords: Exercise Test, Calcium, Fractional Flow Reserve, Myocardial, Coronary Artery Disease, Myocardial Perfusion Imaging, Computed Tomography Angiography, Echocardiography, Stress, American Heart Association, Constriction, Pathologic, Follow-Up Studies, Chest Pain, Tomography, Emission-Computed, Single-Photon, Magnetic Resonance Imaging, Electrocardiography, Positron-Emission Tomography, Emergency Service, Hospital, Coronary Artery Bypass, Clinical Decision-Making, Risk Assessment, Ambulatory Care Facilities, Contraindications, Ischemia, Coronary Angiography


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