Study Questions Need for Early Testing in Chest Pain Patients Without Ischemia
The vast majority of patients who present to an emergency department (ED) with chest pain in the absence of MI should not undergo immediate further testing given their low risk of future MI, according to a study published online January 26, 2015, ahead of print in JAMA Internal Medicine.
“Deferral of early noninvasive testing could allow for more appropriate and selective use of noninvasive testing in the outpatient setting,” say study author Andrew J. Foy, MD, of Penn State Milton S. Hershey Medical Center (Hershey, PA), and colleagues. Ordering further functional or anatomical tests for CAD when no abnormalities are found in the ED means that some patients undergo unnecessary catheterization and revascularization, they conclude.
The data were first presented in March 2014 at the ACC Scientific Session in Washington, DC.
Dr. Foy and colleagues reviewed private healthcare claims data from 2011 involving 693,212 ED visits of patients with a primary or secondary diagnosis of chest pain. The analysis centered on 127,986 patients who underwent testing—either stress echo, exercise ECG, myocardial perfusion scintigraphy, or coronary computed tomography angiography (CTA)—within 7 days of presentation and 293,788 patients who did not.
The mean age of tested patients was 49.9 years, and 52.7% were female. This cohort had more comorbid conditions and was older, more likely to be hospitalized on the index visit, and more likely to have undergone noninvasive testing within 6 months than patients who did not undergo testing.
Of the 4 tests, myocardial perfusion scintigraphy was used most frequently (64.8%).
At 7 and 190 days of follow-up, the percentages of patients who had been hospitalized for an MI were 0.11% and 0.33%, respectively. There were no differences in hospitalization for MI between any of the testing groups compared with those who did not undergo testing. Additionally, in subgroup analysis, there was no interaction with sex.
At 7 days, 3% of the entire cohort had undergone catheterization and 0.7% had been revascularized. Compared with those who did not undergo testing, patients who had any type of test also were more likely to receive catheterization or revascularization (table 1).
At 190 days, 5.3% of all patients had undergone catheterization and 1.3% revascularization. Those initially tested were again more likely to undergo catheterization and revascularization, except for patients who initially received stress echo.
Furthermore, patients who underwent early testing had higher rates of subsequent noninvasive testing.
Dr. Foy and colleagues point out that stress echo was associated with the lowest rate of downstream catheterizations and revascularization. “This finding suggests that, of the noninvasive testing strategies, [it] is the most efficacious in this population of patients,” they say, adding that the increase in revascularization associated with the other 3 tests “without a concomitant reduction in MI suggests that overdiagnosis is a legitimate concern in this patient population.”
Overdiagnosis Wastes Resources
According to the analysis, for every 100,000 patients who undergo scintigraphy instead of no initial testing, approximately 3,700 will have unnecessary catheterization. In addition, for every 100,000 patients who undergo coronary CTA, approximately 800 will have unnecessary revascularization.
The authors say further studies are needed to clarify which early noninvasive test is best for low-risk patients being evaluated for chest pain in the ED.
“A randomized trial comparing a no-testing strategy with different noninvasive testing strategies with an emphasis on hard endpoints could definitively address this need,” Dr. Foy and colleagues say. “Given today’s concerns regarding healthcare cost growth, especially the portion attributable to noninvasive cardiac imaging, and patient safety issues related to radiation exposure as well as overdiagnosis, performing such a study should be a priority.”
In an editor’s note, Rita F. Redberg, MD, MSc, of the University of California, San Francisco (San Francisco, CA), goes one step further, suggesting that “[it] is time to change our guidelines and practice for treatment of chest pain in low-risk patients. Such patients should be given a close follow-up appointment with a primary care physician who can determine, based on the patient’s condition, whether further evaluation is necessary.”
Only a Randomized Trial Can Decide
But in an email with TCTMD, Matthew J. Budoff, MD, of Harbor-UCLA Medical Center (Torrance, CA), highlighted the differences in baseline demographics between the 2 groups..
“The no-test group was a decade younger, had less than 50% the incidence of diabetes, less than 50% the incidence of hypertension, one-third the risk of hypercholesterolemia, and less than 50% of the history of ischemic heart disease” compared with those who underwent testing, Dr. Budoff pointed out. Although the study authors note this in the paper, he said, they did not control for it.
“You can’t correct for that many discrepancies between the groups and conclude whether there is a difference [in outcome],” Dr. Budoff stressed. Better than calling for changes in guidelines, he asserted, would be “to call for a randomized clinical trial of ‘do nothing’ or noninvasive testing. I will put my money on the latter every time.”
1. Foy AJ, Liu G, Davidson WR Jr, et al. Comparative effectiveness of diagnostic testing strategies in emergency department patients with chest pain: an analysis of downstream testing, interventions, and outcomes. JAMA Intern Med. 2015;Epub ahead of print.
2. Redberg RF. Stress testing in the emergency department: not which test but whether any test should be done [editor’s note]. JAMA Intern Med. 2015;Epub ahead of print.
- Drs. Foy and Redberg report no relevant conflicts of interest.
- Dr. Budoff reports receiving grants from GE Healthcare.