Ischemic Stroke Due to Paradoxical Embolism in a Patient with Patent Foramen Ovale, Bilateral Distal Deep Vein Thrombosis and Platypnea-Orthodeoxia Syndrome: A Case Report

Patent foramen ovale (PFO) is a common congenital cardiac defect. It is usually asymptomatic, but it can be associated with relevant clinical manifestations such as cryptogenic stroke and platypnea-orthodeoxia syndrome. We present the case of a patient with hemodynamically significant carotid artery stenosis who underwent endarterectomy for a transient ischemic attack (TIA). After surgery, the patient presented an ischemic stroke due to M2 occlusion treated with mechanical thrombectomy. During hospitalization, a distal bilateral deep vein thrombosis was found. The patient developed respiratory failure due to a massive right-to-left shunt through a large PFO (platypnea-orthodeoxia syndrome). These findings are consistent with the hypothesis that the TIA and the subsequential ischemic stroke were related to paradoxical embolism rather than atherothromboembolism. The aim of our case report is to raise awareness of the possible complications of such a common finding as PFO.