Temporal improvements in prehospital systems-of-care for ST-elevation myocardial infarction patients in Victoria, Australia: a retrospective study

BACKGROUND: Prehospital care is central to outcomes in ST-elevation myocardial infarction (STEMI), yet how systems of care evolve over time remains incompletely described. This study aimed to evaluate the statewide temporal trends in prehospital ST-elevation myocardial infarction (STEMI) care in Victoria, Australia, examining changes in epidemiology, clinical management, time metrics, and adverse events. METHODS: We conducted a retrospective analysis using data from the Victorian Ambulance STEMI Quality Initiative (VASQI). Adults with suspected STEMI treated by paramedics between January 2018 and December 2023 were included. Patient demographics, clinical presentation, and compliance with a prehospital bundle of care (aspirin administration, First Medical Contact [FMC] to ECG ≤ 10 min, hospital notification, and transport to percutaneous coronary intervention [PCI] facility) were analysed and further stratified into patients who received prehospital thrombolysis (PHT) or primary PCI (pPCI) reperfusion pathways. Descriptive statistics and nonparametric tests for trends were used. RESULTS: A total of 18,075 patients were included (median age 67 years, IQR 56-78; 69.7% men). The incidence of suspected STEMI was 58.2 cases per 100,000 person-years (≥ 18 years), increasing from 49.0 in 2018 to 59.5 in 2023 (p = 0.102). Bundle of care compliance was achieved in 69.1% of patients, increasing from 59.5% to 78.2% (+ 18.7% mean difference [MD], 95% CI 16.3-21.1; p for trend < 0.001). Improvements were observed in both PHT (MD, + 22.7%; 95% CI 13.9-31.4; p for trend < 0.001) and non-PHT reperfusion pathways (MD, + 18.4%; 95% CI 15.8-20.9; p for trend < 0.001). All bundle elements showed improvement: aspirin administration by 0.9% (95% CI 0.3-1.4; p for trend = 0.002), FMC to ECG ≤ 10 min by 8.7% (95% CI 6.6-10.8; p for trend < 0.001), hospital notification by 12.6% (95% CI 10.8-14.4; p for trend < 0.001), and direct transport to PCI by 0.9% (95% CI 0.0-1.9; p for trend = 0.046). CONCLUSIONS: Paramedic compliance with the STEMI processes of care improved significantly over the study period. Although key clinical interventions for patients with STEMI have been delivered at high rates, opportunities remain to further optimise care, highlighting the importance of ongoing monitoring of clinical quality performance.