The utility or disutility of non-invasive diagnostic testing for chest pain – CT coronary angiograms, treadmill stress testing, myocardial perfusion imaging and the like – in the Emergency Department remains controversial. A couple days ago, the daily ACEP News Bulletin e-mail referenced an article regarding non-invasive testing featuring the following statement:
“Patients who underwent noninvasive diagnostic testing after evaluation for chest pain in the” emergency department (ED) appeared to have “a lower observed rate of CV death or MI,” researchers concluded.
While this statement is not strictly untrue, it is dramatically clarified by including the next sentence from the authors’ own abstract conclusion:
“This lower rate was driven by the high-risk subgroup.”
The study cited is a propensity-matched cohort of 370,863 patients discharged from the ED after a visit for chest pain in Ontario, Canada. They created matched cohorts featuring 96,457 patients who each either underwent non-invasive cardiac testing in the Emergency Department or did not. Interestingly enough, at 90 days, those who underwent testing had a higher risk of their combined endpoint of cardiovascular death or myocardial infarction. However, by 1 year, the rate of the combined endpoint in those who underwent testing had dropped below the rate for those who did not. The hazard difference was small, however, and driven by small absolute differences in outcomes for those in the high-risk and intermediate-risk cohorts.
Rather than try and read into this study some general advantage to non-invasive testing in the Emergency Department, it would only imply testing of value would be for those who are at intermediate- or high-risk for adverse cardiovascular outcomes. Next, it also does not specifically mandate or imply the testing should be done in the ED or, based on the 90 day outcomes data, even urgently upon discharge. Finally, the newsworthy snippet also does not mention dramatic increases in downstream invasive angiography, PCI, and cardiology visits associated with those in those who underwent non-invasive testing.
The ultimate conclusion is not practice changing in the least: appropriately selected patients may be candidates for the appropriately selected test. Individualized decisions need to be made for those at intermediate- and high-risk for cardiovascular outcomes. Likewise, the relative urgency of testing ought to be determined on an individual basis – and not routinely in the ED. This is, in fact, the authors’ own conclusion – just not well-reflected by the ACEP News Bulletin.
“Clinical Effectiveness of Cardiac Noninvasive Diagnostic Testing in
Patients Discharged From the Emergency Department for Chest Pain”
https://www.ahajournals.org/doi/10.1161/JAHA.119.013824