People with chest pain go to the Emergency Department (ED). They get checked out. Some get diagnosed with acute coronary syndrome. Some get diagnosed with other conditions. And some get told there is nothing wrong.
Later, some die and some represent with acute coronary syndrome. For them, their ED visit can be seen as a missed opportunity to save their life. And for some, perhaps it was and for others perhaps not. Thus, ED’s job is very difficult.
Does Kawatkar et al’s retrospective cohort study published in JAMA Internal Medicine shed any light on this? They studied 79040 patients who presented to ED with chest pain and had acute myocardial infarction (MI) ruled out. They compared rates of death and MI 30 days after discharge in those who had early noninvasive cardiac testing versus those who did not have early testing. These were observational data. Whether patients had early testing was at the discretion of the treating physician i.e. differences between the groups could be explained by many factors aside from whether or not they had testing. But setting that to one side, the study found a reduction in death and MI in those who had early testing (primarily exercise ECG).
This is not surprising given that the US guidelines recommend early testing and therefore, those who did not receive it were probably inappropriate for it for other reasons or perhaps they declined it. We really have no way of knowing whether testing makes the difference or not. The authors conclude that the number needed to treat is too high for this strategy to be useful to most patients. This is a persuasive argument and it is worth evaluating real-world outcomes but no amount of observational data can replace a randomised trial.