Improved Assessment of Chest pain Trial (IMPACT): assessing patients with possible acute coronary syndrome

To the Editor:

Cullen and colleagues are to be congratulated on their most recent contribution to the assessment of emergency department patients presenting with possible acute coronary syndrome.1 The ability to safely reduce length of stay for a larger proportion of patients compared with the ADAPT study, pending external validation, is promising.1

The timing of the article also presents an invaluable opportunity to remind all clinicians that despite the progressive improvements in accelerated diagnostic pathways for chest pain, not all chest pain is cardiac.

Accelerated diagnostic pathways, when used incorrectly, run the risk of introducing cognitive dispositions to respond such as availability bias (where a clinician may choose a diagnosis that is more familiar, such as acute coronary syndrome), omission bias (doing something easy and omitting something hard, such as ordering serial troponins instead of a computed tomography aortogram) and Sutton’s slip (settling on the most obvious interpretation of the problem).2 The potential for error is further compounded by error-producing conditions inherent in busy emergency departments, such as overcrowding, narrow time windows for assessment, surge phenomena and multiple transitions of care (eg, movement to short stay).3

It is pleasing to see that additional features were utilised in stratifying patients compared with previous accelerated diagnostic pathways.1 High-risk features such as prolonged duration and recurrence of chest pain as well as syncope may also be present in aortic dissection.4 It is possible that a patient presenting with an aortic dissection could be deemed low risk with criteria such as those in the ADAPT accelerated diagnostic pathway.5 Troponin levels do not provide a safeguard, as evidenced in a previous case where a 75-year-old woman was discharged home after two normal troponin test results only to die later the same day from progression of a type A aortic dissection.4

Aortic dissection is a lethal cardiovascular emergency that boasts significant morbidity and mortality.4 It has been astutely described as the “subarachnoid haemorrhage of chest pain”.4 Although it is rare and sometimes difficult to diagnose compared with acute coronary syndrome, clinicians are urged to include aortic dissection in their initial assessment of chest pain before implementing an accelerated diagnostic pathway.