Background: Systemic thrombolysis was introduced as the sole prehospital treatment option in patients with cardiac arrest in the setting of acute myocardial ischemia or pulmonary embolism; however, it remains the subject of discussion.
Patients and methods: A total of 194 patients with sudden prehospital cardiac arrest were included in this retrospective case control study. Of these patients, 96 in whom circulatory arrest due to cardiac disease (pulmonary artery embolism or myocardial ischemia) was suspected underwent thrombolytic treatment and were compared to the remaining 98 patients that did not undergo thrombolytic therapy. In addition to the circumstances of circulatory arrest, the course and success of resuscitation, as well as in-hospital course (including bleeding complications), overall survival and neurological outcomes were compared.
Results: There were no significant differences between patients with or without thrombolysis in terms of the circumstances of cardiac arrest. Patients that received thrombolytic treatment were significantly younger and were more frequently treated with anticoagulants, platelet aggregation inhibitors and amiodarone. They also received higher doses of epinephrine and arrived at hospital under ongoing resuscitation significantly more frequently. A trend toward more prehospital return of spontaneous circulation (ROSC) following thrombolytic treatment was seen in the entire cohort. However, patients pre-treated with acetylsalicylic acid and heparin did not show better prehospital ROSC rates as a result of additional thrombolytic therapy. Significant differences in terms of bleeding complications or the need for blood transfusion could not be seen due to the small number of patients.
Discussion: The indication for systemic thrombolysis in the context of prehospital resuscitation should remain restricted to patients with clear symptoms of acute pulmonary embolism or recurrent episodes of ventricular fibrillation in the setting of acute myocardial infarction. Due to a lack of evidence, systemic thrombolysis should not be used as a treatment of last resort in younger patients with persistent ventricular fibrillation.
Keywords: Cardiac arrest; Myocardial infarction; Prehospital emergency care; Pulmonary embolism; Thrombolytic therapy.