Noninvasive cardiac testing comes in multiple forms. There is the dobutamine or exercise stress echocardiography (DSE/ExSE), myocardial perfusion scintigraphy (MPS)–single photon emission computed tomography (SPECT), and cardiac magnetic resonance imaging (CMR). There is also a growing imaging technique CTA coronary studies which have come about due to the advances in CT technology allowing for faster scanners with increased image acquisition at lower radiation levels. Multiple studies have shown comparison of CT imaging as non-inferior to the other modalities of noninvasive testing, and some studies actual show an increased sensitivity at detecting clinically relevant lesions requiring invasive catheterization when compared to classic stress testing. So why do we still admit our chest pains for stress and echo?
While there don’t seem to be official AHA/ACC guidelines in the US for CTA coronary studies as a first line testing modality, the National Institute of Health and Care Excellence (NICE) in the UK has released guidelines as of last year making such a change. This is based on large meta analysis studies as well as multi-center trials internationally which have shown that CTA coronary studies are not only highly effective as imaging for risk stratification but also can be a very cost effective option. The cost effective analysis for the NICE guidelines are based on the UK health system, but there are multiple smaller studies done in the ED settings in the US which do show a positive cost effective analysis when compared with stress/echo as a first line testing modality.
So who can you use this on? Based on the studies done, the exclusion criteria is quite minimal. Those with contraindications to IV contrast (allergies, renal issues, etc.) or those with known arrhythmias (CT image acquisition timing is based on a regular rhythm) cannot undergo this type of imaging. There is also an increased risk of radiation exposure compared to the other studies and should be taken into account in younger or pregnant populations.
As of today, however, this form of imaging should be done/ordered in conjunction with the institution’s cardiology department as current national guidelines have not (yet) defined it has a first line imaging modality for CAD workup.
Bottom Line: CTA coronary studies are a sensitive and cost effective first line imaging technique for most patients requiring cardiac risk stratification/workup and may be becoming a guideline in the US as it already has in the UK.
Moss, Alastair J., et al. “The Updated NICE Guidelines: Cardiac CT as the First-Line Test for Coronary Artery Disease.” Current Cardiovascular Imaging Reports, Springer US, 27 Mar. 2017, www.ncbi.nlm.nih.gov/pmc/articles/PMC5368205/.
Foy, A J, et al. “Coronary Computed Tomography Angiography vs Functional Stress Testing for Patients With Suspected Coronary Artery Disease: A Systematic Review and Meta-Analysis.” JAMA Internal Medicine., U.S. National Library of Medicine, 1 Nov. 2017, www.ncbi.nlm.nih.gov/pubmed/28973101.
Rahsepar, Amir Ali, and Armin Arbab-Zadeh. “Cardiac CT vs. Stress Testing in Patients with Suspected Coronary Artery Disease: Review and Expert Recommendations.” Current Cardiovascular Imaging Reports, U.S. National Library of Medicine, Aug. 2015, www.ncbi.nlm.nih.gov/pmc/articles/PMC4613789/.