Prehospital administration of tenecteplase for ST-segment elevation myocardial infarction in a rural EMS system

Abstract

Introduction: In the setting of ST-segment elevation myocardial infarction (STEMI), early reperfusion yields better patient outcomes. Emergency medical services (EMS) is the first medical contact for half of the afflicted population, and prehospital thrombolysis may result in considerably faster reperfusion compared with percutaneous coronary intervention (PCI) in rural settings. However, there are few reports of prehospital thrombolysis in rural EMS systems.

Objective: To describe a rural EMS system's experience with tenecteplase in STEMI.

Methods: Data were retrospectively abstracted from the medical records of patients receiving tenecteplase using standard chart review guidelines. Primary outcomes included time saved by EMS-initiated thrombolysis, aborted infarctions, serious bleeding events, and in-hospital mortality. Secondary outcomes included reinfarction, rescue angioplasty, and appropriateness of treatment. Time savings was defined as transport time after tenecteplase administration plus 90 minutes, which is the typical door-to-balloon time for PCI laboratories. Aborted infarction was defined as resolution of the cumulative ST-segment elevation to ≤ 50% of that on the initial electrocardiogram (ECG) within two hours after treatment, and peak creatine kinase (CK)/CK-MB levels less than or equal to twice the upper limit of normal.

Results: Seventy-three patients received prehospital tenecteplase; this treatment was determined to be appropriate in 86.4% of cases. The mean patient age was 59 years, and 71.6% of the patients were male. Mean (± standard deviation) scene-arrival-to-drug time was 26.2 (± 11.4) minutes, the mean scene-arrival-to-hospital-arrival time was 73.0 (± 20.6) minutes, and the mean transport time was 46.0 (± 11.1) minutes. Tenecteplase was administered 35.9 (± 25.0) minutes prior to hospital arrival, and the estimated reperfusion time savings over PCI was 125.9 (± 25.0) minutes. Aborted infarctions were observed in 24.1% of patients, whereas 9.6% suffered reinfarction, 47.9% underwent rescue angioplasty, and 16.7% required coronary artery bypass grafting (CABG). Serious bleeding events occurred in 15 patients (20.5%), and four (5.5%) died.

Conclusion: In this retrospective review of rural STEMI patients, tenecteplase was administered 36 minutes prior to hospital arrival, saving approximately two hours over typical PCI strategies and resulting in aborted infarctions in one-fourth of patients. In a rural setting with lengthy transport times to PCI facilities, tenecteplase appears to be a feasible prehospital intervention. Randomized controlled trials are needed to fully evaluate the safety and effectiveness of this intervention prior to widespread adoption.