Comparison of Three Risk Stratification Rules for Predicting Patients With Acute Coronary Syndrome Presenting to an Australian Emergency Department

Objectives To compare the predictive ability of three risk stratification tools used to assess patients presenting to the ED with potential acute coronary syndrome. Design Pre-planned analysis of an observational study. Setting A single tertiary referral hospital. Participants 1495 patients presented with chest pain. 948 patients were screened and enrolled. Patients with at least 5 min of chest pain suggestive of ACS were eligible. Interventions Subjects were risk categorised using the Heart Foundation of Australia/Cardiac Society of Australia and New Zealand guidelines (HFA/CSANZ), the TIMI score and the GRACE score. Three strata of the TIMI and GRACE score were used to compare to the HFA/CSANZ risk categories. Main outcome measurement 30-Day cardiac event rates including cardiac death, acute myocardial infarction and unstable angina. Results There were 152 events in 91 patients (9.6%). The discriminatory ability of the scores determined by the AUC was 0.83 (95% CI 0.79–0.87) for the GRACE score, 0.79 (95% CI 0.74–0.83) for TIMI score and 0.75 (95% CI 0.70–0.80) for HFA/CSANZ. The AUCs with three strata of the GRACE and TIMI scores were 0.76 (95% CI 0.72–0.81) and 0.68 (95% CI 0.62–0.73) respectively. Conclusions All three scores were similar in performance in quantifying risk in ED patients with possible ACS. The GRACE score identified a sizable low risk cohort with high sensitivity and NPV but complexity of this tool may limit its utility. Improved scores are needed to allow early identification of low- and high-risk patients to support improvements in patient flow and ED overcrowding.