A new 0 and 2 hour risk assessment for acute myocardial infarction in emergency department patients using a high sensitivity point of care troponin assay

AIMS: A 0 and 2 h strategy using novel point-of-care high-sensitivity troponin I (POC hs-cTnI) measurements may provide rapid and accurate risk stratification for acute myocardial infarction (AMI) in the emergency department (ED) by reducing time to troponin results and improving clinical decision-making. METHODS AND RESULTS: A prospective multicentre diagnostic accuracy study enrolled 1021 patients presenting to EDs with symptoms suggestive of AMI. POC hs-cTnI measurements were obtained from stored plasma samples at presentation (0 h) and 2 h later using the Abbott i-STAT® hs-TnI assay and compared with central laboratory assay results. A risk stratification algorithm was derived. The primary endpoint was AMI (type 1 and 2) or cardiac death during the index presentation. The primary safety endpoint was 30 day major adverse cardiac events (MACE), incorporating AMI and cardiac death. AMI was diagnosed in 80 patients (7.8%). When identifying low-risk patients, the 0/2 h strategy using the POC hs-cTnI assay demonstrated 98.8% sensitivity (95% CI: 93.2-100%) with an NPV of 99.9% (95% CI: 99.2-100%) for the primary endpoint. For high-risk patients, specificity was 97.7% (95% CI: 96.5-98.5) and PPV 74.7% (95% CI: 64.3-83.4%) for the primary endpoint. The protocol safely identified 66.7% of patients as low-risk within 2 h, with 6 low risk patients (0.9%) having a MACE diagnosis at 30 day follow-up. CONCLUSION: A 0/2 h protocol using the Abbott i-STAT® hs-TnI assay safely risk stratified emergency patients with suspected ACS and had comparable performance to two central laboratory-based assays. The use of POC testing supports timely results and may improve the time to clinical decision-making.