Jaimi H. Greenslade

The trial has been prospectively registered with the Australian New Zealand Clinical Trials Registry (ACTRN12625000617460). This work was supported by the Emergency Medicine Foundation (EMF) throug...

Objectives: This study examines the symptoms experienced by patients investigated for Acute Coronary Syndrome (ACS). It aims to determine whether symptom clusters exist, whether these predict acute myocardial infarction (AMI), and whether symptom patterns differ between Aboriginal and Torres Strait Islander people and non‐Indigenous Australians. Methods: This analysis of the LEGEND trial included 2185 patients (22.7% of whom identified as Aboriginal and Torres Strait Islander). Data on presenting symptoms and outcomes were collected from patient medical records. Regression analyses examined whether individual symptoms predicted AMI for Aboriginal and Torres Strait Islander and non‐Indigenous patients. Factor analysis identified symptom clusters. Regression analyses estimated the associations between each symptom cluster and AMI. Results: Six symptom clusters were identified: pleuritic, numbness, anginal, palpitations, epigastric, and infectious. Anginal was most strongly associated with AMI (Risk ratio [RR] = 1.46; 95% CI: 1.31–1.62), while pleuritic was linked to a reduced risk (RR = 0.47; 95% CI: 0.35–0.62). Numbness (RR = 1.29; 95% CI: 1.11–1.49) and infectious (RR = 1.21; 95% CI: 1.05–1.41) were associated with an increased AMI risk. There were individual symptoms that differed for Aboriginal and Torres Strait Islander patients. However, cluster‐level predictive performance was similar across groups. No symptom cluster provided sufficient discriminatory power to rule in or rule out AMI. Conclusions: Symptom presentation in AMI is heterogeneous, and reliance on “classic” symptoms alone may miss at‐risk patients. While some differences in individual symptom associations were observed for Aboriginal and Torres Strait Islander patients, overall cluster patterns were comparable.

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.

Objective: This study aimed to describe healthcare utilisation and costs associated with the assessment of suspected acute coronary syndrome (ACS) under standard care and to compare these outcomes with the Limit of Detection in Emergency Department (LEGEND) strategy, an accelerated diagnostic pathway identifying low‐risk patients using a single highly sensitive troponin (hs‐cTnI). Method: A stepped‐wedge cluster randomised trial was conducted in four Queensland hospitals. Each transitioned from standard care (2016 ACS guidelines) to the LEGEND intervention at randomised intervals. Data were collected for index presentations and 6‐month outcomes. Results: Data were collected from 5347 patients in the standard care phase and 4597 in the LEGEND intervention phase. The intervention reduced mean ED length of stay (−72.0 min, 95% CI: −85.0 to −59.0 min) and inpatient admissions (−2.3%, 95% CI: −4.2% to −0.4%). For low‐risk patients, the intervention further reduced ED length of stay (−97.0 min, 95% CI: −120.5 min to −73.5) and inpatient admissions (−4.2%, 95% CI: −6.9 to −1.6%). Exercise stress testing (EST) utilisation decreased by 3.6% (95% CI: 2.3%–4.9%) overall and 7.7% (95% CI: 5.0%–10.4%) among low‐risk patients during the intervention phase. Total costs decreased from $6849 to $5794 per patient overall, saving $1055 per patient and from $2847 to $2129 per low‐risk patient, saving $718 per patient. Conclusions: The LEGEND strategy demonstrated reduced resource utilisation and costs compared to guideline‐based ACS assessment, particularly for low‐risk patients. Widespread adoption could improve the efficiency and cost‐effectiveness of ACS assessment in the healthcare system.

Aims: High-sensitivity cardiac troponin (hs-cTn) assays are crucial in assessing suspected myocardial infarction (MI). International recommendations recommend evaluating new assays to identify metrics for clinical use. Our primary aim was to identify patients at low risk of index MI using a point of care hs-cTnI (Abbott i-STAT® hs-TnI) assay at presentation. We also sought to examine the diagnostic accuracy of a single value for identifying patients at high risk for acute MI. Methods and results: This prospective multicentre observational trial enrolled patients with suspected acute coronary syndrome. Nine hundred sixty-seven patients had blood drawn on presentation to the emergency department for hs-cTnI measurement. The primary outcome was index MI including type one or two non-ST segment elevation MI. Diagnostic accuracy statistics were calculated at a range of hs-cTnI values. 5.6% of patients met the criteria for MI. A cut-off 99.5%. This threshold had a sensitivity of 94.4% (95% CI: 84.6–98.8%). An hs-cTnI concentration of 60 ng/L (68.3%, 95% CI: 51.9–81.9%). A PPV of 50% (95% CI: 38.0–62.0%) is achieved at a cut-off of >25 ng/L. Conclusion: This study identified two hs-cTnI thresholds (60 ng/L) to identify patients at high risk for MI. Our findings provide promise for improving care in rural and inner-city medical settings.