Inclusion Criteria:  Age >18 years Clinical signs and symptoms consistent with acute PE Echocardiogram, CT pulmonary angiogram (CTPA) or pulmonary angiographic evidence of proximal filling defect in at least one main or lobar pulmonary artery Scheduled for PE treatment with catheter directed therapy and systemic anticoagulation or anticoagulation alone per the investigator's discretion Signs of respiratory failure including a. arterial blood saturation <90%, or b. partial arterial oxygen pressure <60 mmHg, or c. persistent tachypnea with respiratory rates > 20/min  Exclusion Criteria:  Unable to be anticoagulated with heparin or alternative therapy Diagnosis with a minor PE without signs of right ventricular (RV) dysfunction Known sensitivity to radiographic contrast agents that, in the Investigator's opinion, cannot be adequately pre-treated Imaging evidence or other evidence that suggests, in opinion of the Investigator, the patient is not appropriate for mechanical thrombectomy intervention (e.g., inability to navigate to target location or predominately chronic clot) Life expectancy <6 months, as determined by the Investigator