The 2021 AHA/ACC/ASE/CHEST/SAEM/SCCT/SCMR chest pain guideline highlights the exclusive use of high sensitivity troponin assays to diagnosis myocardial infarction, a greater emphasis on care path utilization and structured risk assessment in acute chest pain, the role of shared decision making in clinically stable chest pain patients prior to testing, and the recommendation to defer additional cardiac testing for low risk patients presenting with acute chest pain.¹ One potentially impactful change in the guideline that was not mentioned in its preamble is the newly prominent role of coronary computed tomography angiography (CCTA) and CT fractional flow reserve (FFR-CT) in the evaluation of patients with both acute and stable chest pain.

In patients presenting with acute and stable chest pain who are felt to have intermediate-to-high pretest risk for ischemic heart disease, CCTA with FFR-CT as necessary to evaluate epicardial stenoses between 50-99% have been given a class 1 recommendation, level of evidence (LOE) A for risk stratification and coronary disease diagnosis. Functional imaging studies such as myocardial positron emission tomography (PET) and single photon emission computed tomography (SPECT) are also recommended for use in similar patients, with a lower level of recommendation (class 1, LOE B based on non-randomized data).^2-5 The new guideline also suggests that myocardial PET imaging may be preferable to SPECT given the lower radiation exposure and the potential to assess coronary flow reserve with the former.⁶

This change in the current chest pain guideline will likely have a significant impact on clinical practice, as myocardial SPECT has long been the 'work horse' for risk stratification for emergency department (ED) patients with chest pain and for those presenting in the office setting with stable angina symptoms. Many cardiology practitioners are board certified to interpret SPECT studies and large group practices often have their own nuclear medicine imaging equipment. In contrast, CCTA and FFR-CT is currently not as broadly available as SPECT, and far fewer cardiologists are specifically trained to interpret CCTA with FFR-CT. At the present time CCTA and FFR-CT are typically available in larger medical centers, with studies often interpreted by radiologists or cardiologists who have done dedicated training in cardiac CT interpretation.

The dynamic between SPECT and CCTA described above is likely to change. In addition to having contemporary randomized clinical trial data supporting its use, CCTA has also been shown to decrease ED diagnosis times and reduce ED costs by as much as 40% when compared to stress myocardial SPECT.⁴ Thus, there are both scientific and economic pressures at play that might shift the focus of cardiovascular providers away from SPECT imaging and in the direction of CCTA and FFR-CT. Expect to see greater CCTA availability and larger numbers of cardiologists seeking additional training and expertise in cardiac CT imaging in the years to come.

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: executive summary: 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. Ferencik M, Lu MT, Mayrhofer T, et al. Non-invasive fractional flow reserve derived from coronary computed tomography angiography in patients with acute chest pain: subgroup analysis of the ROMICAT II trial. J Cardiovasc Comput Tomogr 2019;13:196-202.
3. Ferencik M, Mayrhofer T, Puchner SB, et al. Computed tomography-based high-risk coronary plaque score to predict acute coronary syndrome among patients with acute chest pain--results from the ROMICAT II trial. J Cardiovasc Comput Tomogr 2015;9:538-45.
4. Goldstein JA, Chinnaiyan KM, Abidov A, et al. The CT-STAT (Coronary Computed Tomographic Angiography for Systematic Triage of Acute Chest Pain Patients to Treatment) trial. J Am Coll Cardiol 2011;58:1414-22.
5. Hoffmann U, Ferencik M, Udelson JE, et al. Prognostic value of noninvasive cardiovascular testing in patients with stable chest pain: insights from the PROMISE Trial (Prospective Multicenter Imaging Study for Evaluation of Chest Pain). Circulation 2017;135:2320-32.
6. Gould KL, Johnson NP, Bateman TM, et al. Anatomic versus physiologic assessment of coronary artery disease. Role of coronary flow reserve, fractional flow reserve, and positron emission tomography imaging in revascularization decision-making. J Am Coll Cardiol 2013;62:1639-53.

Clinical Topics: Cardiovascular Care Team, Invasive Cardiovascular Angiography and Intervention, Noninvasive Imaging, Stable Ischemic Heart Disease, Interventions and Imaging, Angiography, Computed Tomography, Nuclear Imaging, Chronic Angina

Keywords: Fractional Flow Reserve, Myocardial, Computed Tomography Angiography, Angina, Stable, Constriction, Pathologic, Decision Making, Shared, Nuclear Medicine, Tomography, Emission-Computed, Single-Photon, Positron-Emission Tomography, Myocardial Infarction, Emergency Service, Hospital, Risk Assessment, Radiation Exposure, Coronary Disease, Group Practice, Radiologists, Cardiologists, Patient Care Planning, Troponin, Coronary Angiography, Myocardial Perfusion Imaging

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