A 2-Hour Diagnostic Protocol for Possible Cardiac Chest Pain in the Emergency Department: A Randomized Clinical Trial

Study Questions:

In patients presenting to the emergency department (ED) with possible cardiac chest pain, what is the effectiveness of a rapid diagnostic pathway, when compared with a standard-care cardiac chest pain pathway?


This was a single-center randomized clinical trial of adults presenting to the ED with acute chest pain consistent with acute coronary syndrome. Patients were randomized to a standard-care pathway (troponin test on arrival at hospital, prolonged observation, and a second troponin test 6-12 hours after onset of pain) or an accelerated diagnostic pathway (ADP). In the ADP, all of the following factors had to be negative for the patient to be classified as low risk and suitable for early discharge with an outpatient stress test (within 72 hours): modified Thrombolysis in Myocardial Infarction (TIMI) score = 0, negative troponin test result at 0 and 2 hours, and no new ischemic electrocardiogram changes. The primary endpoint was “successful” discharge, defined as discharge from the hospital within 6 hours of ED arrival and without a subsequent major adverse cardiovascular event (MACE) within 30 days.


In the experimental group, 52 of 270 patients were “successfully” discharged compared with 30 of 272 patients in the control group (19.3% vs. 11.0%; odds ratio, 1.92; 95% confidence interval, 1.18-3.13; p = 0.008). Of 542 patients randomized in this study, one had a MACE on 30-day follow-up; this patient was in the experimental group. The authors reported that the event occurred following clinician error and could have happened in either the control or experimental group.


The authors concluded that an accelerated diagnostic protocol for patients presenting with possibly cardiac chest pain is an effective mechanism for improving early discharge rates in appropriately low-risk patients.


The limitations of this single-center experience aside, the authors provided compelling evidence about the effectiveness and practicality of an accelerated diagnostic pathway applied to patients presenting with possibly cardiac chest pain. In this trial, nearly twice as many patients were discharged early when clinicians used the experimental pathway. Other centers could replicate and easily apply the accelerated diagnostic algorithm used in this study without allocation of additional resources. Implementation of such a pathway has implications for reducing costs and improving outcomes.

Clinical Topics: Acute Coronary Syndromes, ACS and Cardiac Biomarkers

Keywords: Myocardial Infarction, Acute Coronary Syndrome, Biological Markers, Chest Pain, Electrocardiography, Troponin

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