Prehospital Fibrinolysis in High-Risk Pulmonary Embolism - Observational Data on Clinical Picture and Outcome

High-risk pulmonary embolism (PE) manifests as obstructive shock or cardiac arrest and requires immediate treatment. Our aim was to explore survival and bleeding complications of prehospital fibrinolysis in the treatment of suspected high-risk PE.

We collected patient data from the emergency medical services (EMS) registry of the Helsinki metropolitan area and the hospital database of Helsinki University Hospital between 2007 and 2019. The inclusion criteria were clinically suspected, high-risk PE treated with intravenous fibrinolysis by EMS. Diagnosis of PE was confirmed in all patients with imaging or by autopsy. Patients who did not receive prehospital fibrinolysis served as comparators.

The study included sixty patients. Twenty-three patients, 44% female, with a mean age of 57 years received prehospital fibrinolysis. Seventeen of those patients (74%) had suffered cardiac arrest and six patients (26%) had obstructive shock as the leading manifestation. Prehospital mortality was 35% (n = 8/23) and in-hospital mortality 27% (n = 4/15), for a total (prehospital + in-hospital) mortality rate of 52% (n = 12/23). All deaths were among patients presenting with cardiac arrest. Two patients had major bleeding complications, but none were fatal. All eleven fibrinolysis patients who were discharged alive from the hospital were still alive at a twelve-month follow-up. In comparison, there were 37 high-risk PE patients who did not receive fibrinolysis. They were older (mean, 72 years) and more likely to present with cardiac arrest (51%), and their 12-month mortality tended to be higher (76%) (p = 0.06).

Out-of-hospital high-risk PE is associated with high mortality. In this case-series, fibrinolysis appears to be safe. The possible survival benefit needs to be confirmed in further trials.