Emergency physicians see more than 8 million patients a year with a chief complaint of chest pain. Of those, more than half are admitted for further evaluation. A quarter of admitted patients are discharged with alternative diagnoses, resulting in more than $6 billion of additional cost. On the other hand, missed acute coronary syndrome is one of the top five reasons emergency physicians are sued for malpractice, accounting for 20% of malpractice costs.

On a daily basis, emergency physicians face this dichotomy of the expensive, low-prevalence, but high-risk clinical syndrome known as acute coronary syndrome (ACS), and in particular for non-ST-elevation myocardial infarction (NSTEMI).

Cardiac markers are often a key component in the evaluation of chest pain. Numerous studies, guidelines, and vendors propose a variety of approaches based on markers and clinical presentation. Options such as point of care testing exist that could theoretically speed throughput, although recent studies have shown no improvement.

Four markers are frequently referenced in the evaluation of patients to identify the presence and severity of acute myocardial infarction: troponin, CK-MB, myoglobin, and BNP. Choice of marker depends on time of onset of symptoms and desired clinical information. The American College of Emergency Physicians’ 2006 Clinical Policy “Critical Issues in the Evaluation and Management of Adult Patients with Non-ST Segment Elevation Acute Coronary Syndromes” provides an in-depth analysis and review of these markers (see summary below).

To obtain a sense of how emergency physicians are actually using these recommendations, the authors surveyed 98 emergency department physician leaders in 21 academic and 77 community emergency departments to ascertain which markers are commonly used and their current practice regarding bedside cardiac marker testing.

The first question of our survey asked which marker combination physicians utilized of the three markers ACEP recommends (troponin, CK-MB, and myoglobin) as a routine or by protocol in the emergency department. Results shown in Table 1 show the vast majority of respondents choose the combination of troponin and CK-MB. The next popular combination was troponin, CK-MB and myoglobin, with troponin alone following as a close third. Of note, academicians preferred the troponin-only model in a 7:1 ratio, compared with the all-three-marker combination. The least popular combination was troponin and myoglobin, although academicians once again preferred this over the three-marker combination.

The authors asked respondents if they routinely performed serial cardiac markers in the emergency department. As Table 2 shows, the majority of our respondents did not perform serial markers. Some of the “no” respondents commented that the patient went to an ED observation/clinical decision unit for serial testing, or that serial markers were done when patients were held in the emergency department awaiting an inpatient bed. For those who answered yes to serial markers, some respondents commented that it was done only for low-risk patients, with the intent to discharge for outpatient evaluation, and others commented that serial markers were performed only if the patient was admitted to the hospital.