The PERSEVERE Study

Inclusion Criteria:

1. Age at enrollment ≥18 years

2. Objective evidence of a proximal filling defect in at least one main or lobarpulmonary artery

3. High-risk class of acute PE

4. RV dysfunction, as defined RV/LV ratio ≥1.0

5. Willing and able to provide informed consent, or if unable, through a LegalAuthorized Representative, with permitting research without prior consent as a thirdoption (for Europe and UK sites only), provided compliance with IRB/EC approvals andadherence to regulatory, ethical and national standards

Exclusion Criteria:

1. Prolonged cardiac arrest with loss of consciousness associated with neurologicaldeficit.

2. Imaging evidence or other evidence that suggests, in the opinion of theInvestigator, the patient is not appropriate for catheter-based intervention

3. Known pre-existing CTEPH, or CT signs of chronic PE that may point to pre-existingCTEPH

4. Recent stroke (<14 days)

5. Recent cranial or spinal surgery (<14 days)

6. Life-threatening active bleeding or hemorrhage into a critical area

7. Known intracranial tumor

8. End-stage medical condition with life expectancy <3 months (irrespective of theseverity of acute PE), as determined by the Investigator

9. Known sensitivity to radiographic contrast agents that, in the Investigator'sopinion, cannot be adequately pre-treated

10. Inability to anticoagulate the patient, or known to have heparin-inducedthrombocytopenia (HIT)

11. Current participation in another drug or device study that may interfere with theconduct of this trial

12. Ventricular arrhythmias refractory to treatment at the time of enrollment

13. Subject has any condition for which, in the opinion of the investigator,participation would not be in the best interest of the subject (e.g., compromise thewell-being or that could prevent, limit, or confound the protocol-specifiedassessments), including a contraindication to use of FlowTriever System per localapproved labeling

14. Subject is part of a vulnerable population (e.g., currently pregnant, breastfeedingor incarcerated) per local definitions

15. Subject was previously enrolled in this study

16. Subject has received prior thrombolytic (systemic or catheter-directed) therapy forany reason or thrombectomy (surgical or catheter-based) therapy for index PE, within 30 days prior to randomization