Identifying patients for early discharge: performance of decision rules among patients with acute chest pain

Abstract

Background: The HEART score and North American Chest Pain Rule (NACPR) are decision rules designed to identify acute chest pain patients for early discharge without stress testing or cardiac imaging. This study compares the clinical utility of these decision rules combined with serial troponin determinations.

Methods and results: A secondary analysis was conducted of 1005 participants in the Myeloperoxidase In the Diagnosis of Acute coronary syndromes Study (MIDAS). MIDAS is a prospective observational cohort of Emergency Department (ED) patients enrolled from 18 US sites with symptoms suggestive of acute coronary syndrome (ACS). The ability to identify participants for early discharge and the sensitivity for ACS at 30 days were compared among an unstructured assessment, NACPR, and HEART score, each combined with troponin measures at 0 and 3h. ACS, defined as cardiac death, acute myocardial infarction, or unstable angina, occurred in 22% of the cohort. The unstructured assessment identified 13.5% (95% CI 11.5-16%) of participants for early discharge with 98% (95% CI 95-99%) sensitivity for ACS. The NACPR identified 4.4% (95% CI 3-6%) for early discharge with 100% (95% CI 98-100%) sensitivity for ACS. The HEART score identified 20% (95% CI 18-23%) for early discharge with 99% (95% CI 97-100%) sensitivity for ACS. The HEART score had a net reclassification improvement of 10% (95% CI 8-12%) versus unstructured assessment and 19% (95% CI 17-21%) versus NACPR.

Conclusions: The HEART score with 0 and 3 hour serial troponin measures identifies a substantial number of patients for early discharge while maintaining high sensitivity for ACS.

Keywords: Acute coronary syndrome; Chest pain; Clinical decision rules; Risk stratification.

Copyright © 2012 Elsevier Ireland Ltd. All rights reserved.

Figures

Figure 1

The North American Chest Pain Rule (NACPR) and the HEART score. NACPR: a patient is considered low-risk if they have none of the high risk criteria. The HEART score: Low-risk= 0-3, High risk= 4 or greater. Risk factors include currently treated diabetes mellitus, current or recent (30), or a history of significant atherosclerosis (coronary revascularization, myocardial infarction, stroke, or peripheral arterial disease). ECG = electrocardiogram, ACS = acute coronary syndrome.

Figure 2

Study flow diagram: numbers of patients enrolled, excluded, and with complete data. MIDAS= Myeloperoxidase In the Diagnosis of Acute coronary syndromes Study, NACPR=North American Chest Pain Rule.

Figure 3

Number of ACS events at 30 days. AMI, unstable angina, and cardiac deaths, missed by each risk stratification strategy. ACS = acute coronary syndrome, AMI= acute myocardial infarction.