Identifying low-risk chest pain in the emergency department without troponin testing: a validation study of the HE-MACS and HEAR risk scores

INTRODUCTION: Patients presenting to EDs with chest pain of possible cardiac origin represent a substantial and challenging cohort to risk stratify. Scores such as HE-MACS (History and Electrocardiogram-only Manchester Acute Coronary Syndromes decision aid) and HEAR (History, ECG, Age, Risk factors) have been developed to stratify risk without the need for troponin testing. Validation of these scores remains limited. METHODS: We performed a post hoc analysis of the Limit of Detection and ECG discharge strategy randomised-controlled trial dataset (n=629; June 2018 to March 2019; 8 UK hospitals) to calculate HEAR and HE-MACS scores. A <4% risk of major adverse cardiac events (MACE) at 30 days using HE-MACS and a score of <2 calculated using HEAR defined 'very low risk' patients suitable for discharge. The primary outcome of MACE at 30 days was used to assess diagnostic accuracy. RESULTS: MACE within 30 days occurred in 42/629 (7%) of the cohort. HE-MACS and HEAR scores identified 85/629 and 181/629 patients as 'very low risk', with MACE occurring in 0/85 and 1/181 patients, respectively. The sensitivities of each score for ruling out MACE were 100% (95% CI: 91.6% to 100%) for HE-MACS and 97.6% (95% CI: 87.7% to 99.9%) for HEAR. Presenting symptoms within these scores were poorly predictive, with only diaphoresis reaching statistical significance (OR: 4.99 (2.33 to 10.67)). Conventional cardiovascular risk factors and clinician suspicion were related to the presence of MACE at 30 days. CONCLUSION: HEAR and HE-MACS show potential as rule out tools for acute myocardial infarction without the need for troponin testing. However, prospective studies are required to further validate these scores.