External validation of a rapid algorithm using high-sensitivity troponin assay results for evaluating patients with suspected acute myocardial infarction.

OBJECTIVE: We sought to validate the clinical performance of a rapid assessment pathway incorporating the Siemens Atellica IM high sensitivity cardiac troponin I (hs-cTnI) assay in patients presenting to the emergency department (ED) with suspected acute myocardial infarction (AMI).

METHODS: This was a multicentre prospective observational study of adult ED patients presenting to five Australian hospitals between November 2020 and September 2021. Participants included those with symptoms of suspected AMI (without ST-segment elevation MI on presentation ECG). The Siemen's Atellica IM hs-cTnI laboratory-based assay was used to measure troponin concentrations at admission and after 2-3 hours and cardiologists adjudicated final diagnoses. The HighSTEACS diagnostic algorithm was evaluated, incorporating hs-cTnI concentrations at presentation and absolute changes within the first 2 to 3 hours. The primary outcome was index AMI, including type 1 or 2 non-ST segment elevation MI (NSTEMI) or ST-elevation MI (STEMI) following presentation. 30-day major adverse cardiac outcomes (including AMI, urgent revascularisation or cardiac death) were also reported. The trial was registered with the Australian and New Zealand Clinical Trials Registry.

RESULTS: 1994 patients were included. The average age was 56.2 years (SD = 15.6), and 44.9% were women. 118 (5.9%) patients had confirmed index AMI. The 2-hour algorithm defined 61.3% of patients as low risk. Sensitivity was 99.1% (94.0%-99.9%) and negative predictive value was 99.9% (99.3%-100%). 24.4% of patients were deemed intermediate risk. When applying the parameters for high risk, 252 (14.3%) were identified, with a specificity of 91.5% (88.7%-93.6%) and a PPV of 42.0% (35.6-48.7%).

CONCLUSIONS: A 2-hour algorithm based on the HighSTEACS strategy using the Siemens Atellica IM hs-cTnI laboratory-based assay enables safe and efficient risk assessment of emergency patients with suspected AMI.

TRIAL REGISTRATION NUMBER: ACTRN12621000053820.