In the U.S. today, new onset chest pain accounts for around four million stress tests every year, but there is limited data to guide diagnostics for this population. While patients and providers are given the option to utilize a functional stress test or a computed tomographic scan, which produce similar outcomes in terms of death and major cardiac conditions, the scan may be better at ruling out the need for subsequent tests and procedures in patients who are free of cardiovascular disease, according to research presented Saturday, March 14 as a part of ACC.15 and simultaneously published in the New England Journal of Medicine.

In the trial, author Pamela S. Douglas, MD, MACC, et al. employed the first-ever randomized, controlled trial to compare the effectiveness of functional testing versus a coronary computed tomography angiography (CTA) or ≥64-slice multidetector, in discovering signs of coronary artery disease (CAD) in patients. The study included 10,003 symptomatic patients with no prior diagnosis of CAD, but for whom diagnostic testing was recommended, from 193 health centers in the U.S. and Canada.

The study found no difference in outcomes between patients who received a functional stress test or a CTA, and established that CTA is a viable alternative to functional testing. However, some secondary questions, such as the level of radiation exposure and the rate of subsequent testing that did not reveal significant CAD, favored CTA.

The authors note that these results are important because current clinical guidelines leave the selection of tests for patients reporting symptoms such as chest pain or shortness of breath, largely up to physician and patient preference and the real-world results that were collected in this trial should be used to inform testing choices in clinical care and provide guidance to future studies of diagnostics for suspected cardiovascular disease.

“Until this study, we have essentially been guessing on decisions about which initial test to use for this huge population of patients who need evaluation for cardiovascular symptoms,” said Douglas. “Our study shows that the prognostic outcomes are excellent and are similar regardless of what type of test you use, but there are some indications that CTA might be the safer test with fewer catheterizations without obstructive disease and lower radiation exposure when compared to nuclear testing.”

Douglas said the team plans to further investigate outcomes for different subgroups of patients to determine whether different groups might benefit from different testing approaches.

Meanwhile, a separate late-breaking clinical trial presented on Sunday, March 15, addressed the economic implications of the PROMISE trial findings. Author Daniel Mark, MD, MPH, FACC, and team conducted an economic sub-study to look the cost of CTA versus functional stress tests when evaluating patients with suspected blocked arteries. The study found that although CTA looked cheaper when testing started, additional testing and treatments ultimately resulted in minimal differences between the two tests in average costs. 

“Despite some fair differences in the prices of these different diagnostic tests, there was no statistically significant difference between the cost of first receiving an anatomic CT angiography versus a functional stress test in these patients over three years of follow-up,” said Mark. “Prior to this there was really no data that were reliable or empirically based, so this information provides tremendous value, even if the answer is that there is not much difference between the two tests. It’s an answer and a useful answer that can help drive decision making.”

Keywords: Anaphylaxis, Angina, Unstable, Angiography, Chest Pain, Constriction, Pathologic, Coronary Artery Disease, Electrocardiography, Hospitalization, Myocardial Infarction, Prospective Studies, Renal Insufficiency, Stroke, ACC Annual Scientific Session

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