Impact of Prehospital Administration of Aspirin and Unfractionated Heparin on In-Hospital Outcomes in Patients with Suspected Myocardial Infarction: A Retrospective Cohort Study.

Purpose: In a prehospital setting with limited diagnostic resources, identification of myocardial infarction (MI) can be challenging. However, high diagnostic accuracy of patients with MI is not only necessary to provide early revascularization but also essential to guide prehospital pharmacological therapy. Even though prehospital use of acetylsalicylic acid (ASA) and anticoagulation therapy is widely established, guidelines only recommend these medications in confirmed cases undergoing PCI. This study examines if prehospital treatment with ASA and unfractionated heparin (UFH) influences in-hospital mortality and bleeding rates in patients with suspected MI. Patients and Methods: In this retrospective, single-center cohort study, prehospital treatment with ASA and UFH in 2756 patients with suspected MI was analyzed. Associations between ASA/UFH and death/bleeding until discharge were investigated. To adjust for possible confounders, multiple logistic regression was performed. Furthermore, stepwise logistic regression was carried out in order to investigate factors that influence emergency physicians (EPs) decision to treat with ASA and UFH. Results: Prehospitally administered ASA and UFH was not associated with a significant change in mortality (odds ratio [OR], 0.813; 95% confidence interval [CI] 0.453 to 1.461; Conclusion: Prehospital administration of ASA and UFH did not affect in-hospital mortality and bleeding outcomes in a cohort of patients with suspected MI. These findings suggest that routine prehospital anticoagulation in suspected MI may not improve short-term outcomes and should be reconsidered pending randomized evidence.