ED stress testing, in addition to standard workup with ECG and biomarkers, led to more downstream testing (angiography) and more interventions (PCI or CABG), but this didn't translate into fewer acute myocardial infarctions at one year. The whole premise of a stress test is to find a blocked artery non-invasively, open it, and decrease future risk of acute myocardial infarction (AMI). But that is not what happened. EM Nerd has a helpful post on this article, The Case of the Failed Assumptions.
Why does this matter?
The AHA recommends stress testing in the ED or within 72 hours of ED evaluation in addition to standard ED workup with ECG and biomarkers. Studies like this continue to call into question the role of urgent stress testing. Provocative testing (exercise electrocardiography, stress echocardiography, myocardial perfusion scan, or CT coronary angiography) doesn't seem to lower risk of MI or death for patients but does seem to increase downstream invasive testing, which begs the question: Are we doing additional "objective" testing for the patients' benefit or to cover ourselves?
Stress tests are so...stressful
This study retrospectively analyzed almost 1 million patients in a health database and compared two groups: patients seen for chest pain on the weekdays and those on the weekend. Baseline characteristics and cardiac risk factors were the same whether seen on the weekday or weekend, except it was more convenient to do ED stress tests on the weekdays. As expected, more stress tests were ordered on the weekdays, which led to more downstream testing, including coronary angiography. Despite more downstream testing and more coronary interventions (PCI or even CABG), the rate of AMI wasn't lower in the group that underwent more stress tests. If stress testing was beneficial, those tested should have had lesions identified and treated, with lower rates of future MI. But that is not what this study showed. Rates of AMI were not decreased in patients who had ED stress tests ordered. In other words, testing did not have a protective effect for AMI. In fact, AMI rates were slightly worse in patients who had stress tests, though not statistically significant. Before you go crazy discharging chest pain patients, a word of caution. Patients who don't meet low-risk criteria are not appropriate for ED discharge, and hospitalization is still the best plan. Take advantage of risk stratification tools like HEART.
Cardiovascular Testing and Clinical Outcomes in Emergency Department Patients With Chest Pain. JAMA Intern Med. 2017 Jun 26. doi: 10.1001/jamainternmed.2017.2432. [Epub ahead of print]
Peer reviewed by Thomas Davis, MD.