Highly Sensitive ED Protocol for Identifying Low-Risk Patients with Chest Pain
Implementation of a new accelerated diagnostic protocol could reduce emergency department length of stay and hospitalization rate.
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, 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.
This study demonstrates that the combination of no new ischemic changes on initial ECG, normal point-of-care biomarker panel within 2 hours, and low pretest probability (TIMI score of 0) identifies patients who can safely be discharged from the ED. However, several issues about use of the protocol remain to be addressed, including performance relative to other protocols, whether use of laboratory biomarker testing improves accuracy, effect on patient care costs and hospital stay, and malpractice risk.
John A. Marx, MD, FAAEMPublished in Journal Watch Emergency Medicine March 25, 2011
Citation(s): Than M et al. A 2-h diagnostic protocol to assess patients with chest pain symptoms in the Asia-Pacific region (ASPECT): A prospective observational validation study. Lancet 2011 Mar 26; 377:107.
Patients with chest pain contribute substantially to emergency department attendances, lengthy hospital stay, and inpatient admissions. A reliable, reproducible, and fast process to identify patients presenting with chest pain who have a low short-term risk of a major adverse cardiac event is needed to facilitate early discharge. We aimed to prospectively validate the safety of a predefined 2-h accelerated diagnostic protocol (ADP) to assess patients presenting to the emergency department with chest pain symptoms suggestive of acute coronary syndrome.
This observational study was undertaken in 14 emergency departments in nine countries in the Asia-Pacific region, in patients aged 18 years and older with at least 5 min of chest pain. The ADP included use of a structured pre-test probability scoring method (Thrombolysis in Myocardial Infarction [TIMI] score), electrocardiograph, and point-of-care biomarker panel of troponin, creatine kinase MB, and myoglobin. The primary endpoint was major adverse cardiac events within 30 days after initial presentation (including initial hospital attendance). This trial is registered with the Australia-New Zealand Clinical Trials Registry, number ACTRN12609000283279.
3582 consecutive patients were recruited and completed 30-day follow-up. 421 (11·8%) patients had a major adverse cardiac event. The ADP classified 352 (9·8%) patients as low risk and potentially suitable for early discharge. A major adverse cardiac event occurred in three (0·9%) of these patients, giving the ADP a sensitivity of 99·3% (95% CI 97·9—99·8), a negative predictive value of 99·1% (97·3—99·8), and a specificity of 11·0% (10·0—12·2).
This novel ADP identifies patients at very low risk of a short-term major adverse cardiac event who might be suitable for early discharge. Such an approach could be used to decrease the overall observation periods and admissions for chest pain. The components needed for the implementation of this strategy are widely available. The ADP has the potential to affect health-service delivery worldwide.