Comparison of early biomarker strategies with the Heart Foundation of Australia/Cardiac Society of Australia and New Zealand guidelines for risk stratification of emergency department patients with chest pain.

Objectives: To compare cardiac risk stratification using a 0 and 2 h point-of-care (POC) cardiac troponin (cTn), 0 and 2 h POC multi-biomarkers against the 0 and 6 h laboratory cTn reference standard.

Methods: A prospective observational study of ED patients presenting with chest pain was performed. Patients were risk stratified and treated as per the Heart Foundation of Australia/Cardiac Society of Australia and New Zealand (HF-A/CS-ANZ) guidelines using the 0 and 6 h laboratory cTn (T6). Patients were further stratified using a 0 and 2 h POC cTn (T2) plus 0 and 2 h POC multi-biomarkers (cTn, creatine kinase-MB, myoglobin) (M2). The T6, T2 and M2 strategies were compared using the 30-day major adverse cardiac events as the primary outcome.

Results: Seven hundred and four patients (median age 54 years, male 62.1%) were enrolled. Using the T6 reference standard, 2%, 61% and 37% were stratified as low, intermediate and high risk, respectively. The 30-day event rates were 0%, 3.5% and 28.6%, respectively. The T2 strategy stratified 1.5%, 57% and 41% as low, intermediate and high risk, respectively, with 30-day event rates of 0%, 4.2% and 24.8%, respectively. The M2 strategy resulted in significantly different risk distribution with 1%, 40% and 59% stratified as low, intermediate and high risk, respectively, with 30-day event rates of 0%, 3.9% and 18.8%, respectively.

Conclusion: Using a 2 h POC cTn-only biomarker strategy with the HF-A/CS-ANZ guidelines accurately identified a population at intermediate risk of 30-day events in whom further objective testing might be accelerated, allowing subsequent early discharge of the majority of this cohort. Within 2 h of presentation a high risk population could be identified in whom early management, including admission, was required.