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Accelerated protocol identifies chest pain patients at low risk for major cardiac events

Clinical Question:
Can an accelerated protocol using troponin testing at 0 and 2 hours identify patients with suspected acute coronary syndrome who are safe for early discharge from the emergency department?

Bottom Line:
This protocol -- a combination of Thrombolysis in Myocardial Infarction (TIMI) score of 0, negative electrocardiogram, and negative troponins at 0 and 2 hours -- can accurately identify emergency department patients with symptoms suggestive of acute coronary syndrome (ACS) who are at low risk for major cardiac events and who can therefore be discharged early with outpatient follow-up. (LOE = 2b)

Than M, Cullen L, Aldous S, et al. 2-hour accelerated diagnostic protocol to assess patients with chest pain symptoms using contemporary troponins as the only biomarker. J Am Coll Cardiol 2012;59(23):2091-2098.  [PMID:22578923]

Study Design:
Cohort (prospective)

Industry + govt


Emergency department

These investigators evaluated whether an accelerated diagnostic protocol consisting of a TIMI score of 0, an initial electrocardiogram without ischemic changes, and negative troponin-I at 0 and 2 hours could identify patients with suspected ACS who are safe for early discharge from the emergency department. Adult patients presenting to the emergency department with symptoms suggestive of ACS were enrolled (N = 1975). The study population was 90% white, with an average age of 60 years, and 20% of the group had known history of coronary artery disease. Patients received usual care according to local hospital protocols. A 2-hour troponin was also drawn but results were not used for clinical care. The primary outcome was a major cardiac adverse event within 30 days, including cardiac-related death, cardiac arrest, acute myocardial infarction, and cardiogenic shock. This occurred in 15% of the overall cohort. Of the 392 patients deemed low risk (20%) per the accelerated diagnostic protocol, only 1 patient had a major cardiac adverse event, which translates to a sensitivity and negative predictive value of this protocol of 99.7% and a specificity of 23.4%. As this was an observation study, a major limitation is that many of these low-risk patients still underwent hospital admission and further diagnostics and treatments that may have led to their better outcomes.


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