AJR April 2018
David C. Levin
Jefferson University Hospital
“Coronary CT Angiography: Use in Patients With Chest Pain Presenting to Emergency Departments”
Coronary CT angiography (CCTA) has been found to be more efficient than myocardial perfusion imaging (MPI) for emergency department (ED) patients presenting with acute chest pain, but far more MPI examinations are still being performed, according to a study published in the April 2018 issue of AJR.
Previously published reports have shown that CCTA is a more efficient method of diagnosis than MPI and stress echocardiography for patients presenting to EDs with acute chest pain. The group of study authors, led by David C. Levin of Jefferson University Hospital, examined recent trends in the use of these techniques in EDs.
The authors examined Medicare Part B data from 2006 to 2015. The Current Procedural Terminology, version 4, codes for CCTA, MPI, and stress echocardiography were selected. Medicare place-of-service codes were used to determine procedure volumes in EDs. Medicare specialty codes were used to ascertain how many of these examinations were interpreted by radiologists, cardiologists, and other physicians as a group.
From 2006 to 2015, there was essentially no change in the number of MPI examinations performed in EDs for patients using Medicare or in the number of stress echocardiograms. By contrast, the number of CCTA examinations increased rapidly, from 126 in 2006 to 1,919 in 2015. Despite this rapid growth, patients in EDs underwent 11.6 times as many MPI as CCTA examinations in 2015. In that last year of the study, radiologists interpreted 78% of ED MPI and 83% of ED CCTA examinations.
Another important advantage of using CCTA to evaluate patients with chest pain in the ED is that if it is performed as a so-called triple rule-out examination it can be used to exclude other causes of acute chest pain, such as pulmonary embolism, aortic dissection, pericardial effusion, and pneumothorax. MPI and stress echocardiography cannot be used for that purpose.
The results of the foregoing studies strongly support the use of CCTA early during the ED stay of a patient with chest pain. Aside from those, there are an abundance of reports in the literature [7, 12–26] documenting the general superiority of CCTA over the widely used MPI as the first imaging test for patients with suspected CAD. These studies have shown that MPI has too many false-positive and false-negative results, that CCTA has a negative predictive value close to 100%, and that too many invasive coronary angiograms are being obtained for patients who do not need them.
The American College of Radiology Appropriateness Criteria include a listing for chest pain suggestive of acute coronary syndrome. These criteria, which are well known to radiologists, rate various imaging tests on a scale of 1–9 with 7–9 considered appropriate, 4–6 possibly appropriate, and 1–3 usually not appropriate. In this particular clinical circumstance, MPI is rated 8, stress echocardiography 7, and CCTA 6. The reasons for the low rating of CCTA are not clear. In view of literature reviewed in their study, the authors said they believe the appropriateness criteria for chest pain suggestive of acute coronary syndrome should be revised to rate CCTA higher than both MPI and stress echocardiography. Radiologists, who interpret most CCTA examinations performed in EDs, should educate their emergency medicine colleagues about the greater utility of CCTA in the evaluation of patients with chest pain.
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