This trial is testing a device called FlowTriever to treat patients with certain types of blood clots in their lungs. These patients have clots that are not immediately life-threatening but still need treatment. The device works by physically removing the clots through a small, minimally invasive procedure. The FlowTriever System is the first FDA-approved mechanical thrombectomy device for treating pulmonary embolism, enabling nonsurgical removal of clots without thrombolytic medication.