Unexpected paradoxical embolization following catheter-directed thrombectomy with the FlowTriever™ system in a patient with pulmonary embolism: a case report

Background The optimal therapy for patients suffering from acute pulmonary embolism (PE) classified as intermediate-high risk still needs to be identified. Catheter-directed thrombectomy (CDTE) is a safe procedure to reduce thrombus burden immediately. The lack of randomized trials is one reason: catheter-directed thrombolysis (CDT) has not yet received a clear recommendation in our guidelines. Herein, we report an unexpected event in the course of a patient with PE treated with CDTE using the FlowTriever (TM) system, the only FDA-approved catheter system for percutaneous mechanical thrombectomy regarding this indication. Case Summary A 57-year-old male presented with dyspnoea at the emergency department of our university hospital. The computed tomography (CT) scan showed bilateral PE, and ultrasound of the left lower limb revealed deep venous thrombosis. According to the current ESC guidelines, he was classified intermediate-high risk. We performed bilateral CDTE. On the first and third day post-intervention, our patient presented neurological deficits. Whereas the first CT scan of the cerebrum remained normal, the CT scan at Day 3 showed demarcated embolic stroke. Further imaging diagnostic gave evidence to an ischemic lesion in the left kidney. Transesophageal echocardiography revealed a patent foramen ovale (PFO) as the origin of paradoxical embolism and thus mechanism of both ischemic lesions. Compliant to the current recommendations, percutaneous PFO closure was performed. Our patient recovered properly without any sequelae. Discussion Whether the deep venous thrombosis is the source of embolization or the catheter-directed retrieval of clots may have transported clot material to the right atrium which further on embolized systemically will remain unclear. Yet, we have to consider it as a potential complication in catheter-directed treatment of PE in patients with a PFO.