Paramedic-Administered Fibrinolysis in Older Patients with Prehospital ST-Segment Elevation Myocardial Infarction

Emergency ambulance services are an essential component of rapid treatment of prehospital ST-segment elevation myocardial infarction (STEMI). The effectiveness and safety of prehospital fibrinolysis in older STEMI patients is unknown. This study investigated the effectiveness and safety of paramedic-administered prehospital fibrinolysis in STEMI patients ≥75 years of age who were identified by paramedics in Queensland, Australia.

Included were STEMI patients ≥75 years of age who were identified by paramedics in Queensland (Australia), and received prehospital fibrinolysis with tenecteplase or did not receive this treatment due to age being the sole contraindication, between 2010 and 2023. Patient characteristics, outcomes, and safety profiles were compared between the two groups, as well as between patients receiving full-dose and half-dose of tenecteplase.

In total, 86 patients received prehospital fibrinolysis and 83 did not. Patients receiving prehospital fibrinolysis were slightly younger (median 77 vs 81 years, p < 0.001). There was no statistically significant difference in mortality rates at 24 h (risk difference [RD] prehospital fibrinolysis vs no prehospital fibrinolysis 2.1%, 95% confidence interval [CI] - 5.6 to 9.8%, p = 0.41), 30 days (RD -0.3%, 95% CI -9.6 to 9.0%, p = 0.58), and one year (RD -1.7%, 95% CI -12.1 to 8.7%, p = 0.46) between the two groups. There was no statistically significant difference in functional outcomes on discharge (RD for favorable functional outcome 8.8%, 95% CI -6.0 to 23.6%, p = 0.25). No intracranial or major non-intracranial hemorrhage was observed in the entire study sample. Patients receiving full-dose tenecteplase were younger, closer to a hospital capable of percutaneous coronary intervention, in metropolitan areas, and had shorter time from symptom onset to tenecteplase than those receiving half-dose.

This study was the first that investigated the effectiveness and safety of paramedic-administered fibrinolysis in older patients with STEMI. No intracranial or major non-intracranial hemorrhage was recorded for the study sample. There was no association between prehospital fibrinolysis and mortality or functional outcomes.