Percutaneous Embolectomy, Low Dose Thrombolysis or Heparin for Intermediate High Risk Pulmonary Embolism (STRATIFY II)

The STRATIFY II trial investigates the efficacy of three different approaches to reducing thrombus burdon in patients with acute intermediate high-risk pulmonary embolism: percutaneous embolectomy (the AlphaVAC(R), AngioDynamics or the Flow Triever® system, INARI medical), Low intravenous thrombolysis (Alteplase 10 mg) and heparin with the option to perform full-dose thrombolysis. As a co-primary secondary end point the trial assess the incremental efficacy of the embolectomy vs the catheter based low dose thrombolysis approach. Thus the two main hypothesis being tested are: 1. Thrombus burden reduction after 48-96 h is increased with a catheter based (embolectomy or low-dose alteplase) compared to the a heparin with optional high dose thrombolysis approach (1st co-primary outcome) 2. Thrombus burden reduction after 48-96 h is increased with percutaneous embolectomy compared to low-dose alteplase (2nd co-primary outcome)

INCLUSION CRITERIA 1. Age ≥ 18 years 2. Intermediate high-risk PE according to ESC criteria 3. Class II risk assessed by the Pulmonary Embolism Severity Index (1). 4. Thrombus visible in main, lobar or segmental pulmonary arteries on CT angiography 5. 14 days of symptoms or less, with significant worsening of symptoms within 7 days EXCLUSION CRITERIA 1. Altered mental state (GCS \< 14) 2. No qualifying CT angiography performed (\> 24 hour since CT angiography) 3. Women of childbearing potential, unless negative HCG test is present. 4. Thrombolysis for PE within 14 days of randomization 5. Thrombus passing through patent Foramen Ovale (risk of paradoxical embolism) 6. Ongoing oral anticoagulation therapy (heparins, aspirin, antiplatelet therapy and NOAC allowed) 7. Comorbidity making 6 months survival unlikely. 8. Absolute contraindications for thrombolysis: 1. History of haemorrhagic stroke or stroke of unknown origin 2. Ischaemic stroke in previous 6 months 3. Central nervous system neoplasm 4. Major trauma, surgery, or head injury in previous 3 weeks 5. Bleeding diathesis - Active bleeding