Highly Sensitive ED Protocol for Identifying Low-Risk Patients with Chest Pain

Protocols to facilitate safe early discharge from the emergency department (ED) for low-risk patients with chest pain have limitations, including lack of validation and variable sensitivity. The prospective, observational, multinational Asia-Pacific Evaluation of Chest Pain Trial assessed a new, accelerated diagnostic protocol in consecutive adult ED patients who had at least 5 minutes of chest, neck, jaw, or arm pain or discomfort without obvious noncardiac cause and who did not have ST-segment-elevation myocardial infarction (STEMI).

The protocol included Thrombolysis In Myocardial Infarction (TIMI) score (see the table), electrocardiogram (ECG), and point-of-care biomarker testing (within 2 hours after arrival) for troponin I, creatine kinase MB, and myoglobin. Patients with TIMI scores of 0, no new ischemic changes on initial ECG, and normal biomarker panels were classified as low risk.

Among 3582 patients who completed 30-day follow-up, 421 (11.8%) had major adverse cardiac events within 30 days, most often non-STEMI (10.1%). Of 352 patients (9.8%) who were classified as low risk, 3 (0.9%) had major adverse cardiac events. The protocol had a sensitivity of 99.3% for identifying low-risk patients, a specificity of 11.0%, and a negative predictive value (NPV) of 99.1%. Had TIMI score not been included, NPV would have been 96.7%, and an additional 44 patients with major adverse cardiac events would have been missed.