Reperfusion Treatment in Acute Pulmonary Embolism

Reperfusion Treatment in Acute Pulmonary Embolism: A Multicenter Observational Study in the Nordic Countries

International guidelines recommend immediate reperfusion with systemic thrombolysis (ST) as first-line treatment in high-risk pulmonary embolism (PE). The therapy improves hemodynamics and overall survival but is also associated with a significant risk of severe bleeding. Catheter-directed intervention (CDI) is recommended as an alternative reperfusion therapy in high-risk PE when ST is contraindicated or has failed, as well as in patients who deteriorate or fail to improve during anticoagulation (AC) treatment. Despite lack of high-quality evidence and randomized studies between CDI and standard care, the use of CDI is spreading rapidly in high-risk PE and in less severe PE not fulfilling current treatment criteria.

Several CDI methods are available, including mechanical thrombectomy (MT) and catheter-directed thrombolysis (CDT), but no method is currently recommended over the other. In Sweden, the MT device FlowTriever® (FT) was introduced in 2021 and has since then been the predominant method. Industry sponsored trials have investigated FT in uncontrolled observational trials and primarily in intermediate-risk PE. The investigator-initiated research on FT is limited to relatively small, descriptive, single-arm studies, or trials focusing on intermediate-risk PE.

There are several ongoing trials comparing different CDI methods to anticoagulation. However, in clinical practice, patients with acute PE may be subjected to different reperfusion strategies depending on severity and available resources. The PE-NORDIC observational study will compare the outcomes of different patient groups treated with current CDI methods used in the Nordic countries to patients treated with ST.

Inclusion Criteria:

• All adult patients (≥18 years), including pregnant women, with verified (CTPA, angiography or scintigraphy) acute pulmonary embolism who are planned for, or have received, treatment with catheter directed intervention or systemic thrombolysis
• Informed consent (for patients who do not survive before informed consent can be obtained, a waiver of consent applies)

Exclusion Criteria:

• Ongoing enrolment in interventional catheter directed intervention trial
• Surgical embolectomy as primary reperfusion treatment