International guidelines recommend intravenous thrombolysis (IVT) for high-risk pulmonary embolism (PE). In high-risk PE where IVT is contraindicated or has failed, surgical embolectomy or catheter-directed intervention (CDI) is recommended. CDI is also recommended as an alternative in patients with intermediate-risk PE with haemodynamic deterioration during anticoagulation treatment.

Although there is a lack of randomized studies comparing CDI to anticoagulation or systemic thrombolysis in PE, several studies and recent meta-analyses have shown that CDI is an effective treatment that is associated with fewer complications than IVT, especially bleeding.

The FlowTriever® retrieval/aspiration system is the first mechanical thrombectomy device to receive PE as an indication from the United States Food and Drug administration agency. It combines large-bore aspiration with expanding mesh disks designed to trap and subsequently retract the blood clots from the pulmonary arteries. While Inari Medical, the medical device company that produces the FlowTriever® system, has initiated and published a few prospective trials on FlowTriever® in PE, non-industry sponsored studies are small and mostly retrospective.

In 2021 FlowTriever® became the primary device for CDI in PE at Sahlgrenska University Hospital in Gothenburg, Sweden. Concurrently, several hospitals in Sweden have started using FlowTriever® in high-risk PE. As such, the method needs evaluation and validation on a local and national level.

This retrospective observational study aims to evaluate the outcomes of patients with acute PE treated with the FlowTriever® device in Sweden. A control group consisting of PE patients treated with IVT will be used for comparison.

Inclusion Criteria:

• Age ≥18 years
• Acute PE verified by computed tomography (CT) or angiography
• PE treated with thrombolysis or FlowTriever® during the time period from January 1st of the year when FlowTriever was introduced at each respective participating center to the end of 2023.

Exclusion Criteria:

• None

Adult patients with acute PE