Bilateral Pulmonary Arteriovenous Fistulas in A Young Patient with Ischemic Stroke: A Case Report

Pulmonary arteriovenous fistulas are uncommon vascular communications between pulmonary arteries and veins that bypass the capillary bed and generate a right-to-left shunt. They may remain clinically silent, but they are relevant in young patients with cryptogenic or apparently paradoxical ischemic stroke. This article reports the case of a 20-year-old male patient with a history of posterior-circulation ischemic stroke secondary to basilar artery thrombosis, residual motor impairment with modified Rankin score 3, and antiphospholipid syndrome under oral anticoagulation. During the diagnostic workup for suspected patent foramen ovale or atrial septal defect, intracardiac echocardiography showed an intact interatrial septum without color-Doppler shunt. Selective pulmonary angiography identified bilateral pulmonary arteriovenous fistulas with drainage to the left atrium. The right lower-lobe fistula was embolized with an Amplatzer Vascular Plug II, whereas the left-sided lesions were treated with Interlock coils. Final angiographic control showed adequate occlusion, without major procedural events. This case emphasizes the need to investigate extracardiac right-to-left shunts when intracardiac defects are not demonstrated in young patients with ischemic stroke, and it supports percutaneous embolization as a feasible therapeutic approach in appropriately selected cases.