Mechanical Thrombectomy for Large-Vessel Occlusion after Fontan Procedure in an Adult.

Objective: Patients with adult congenital heart disease (ACHD) are at increased risk of thromboembolic events. However, case reports describing the use of mechanical thrombectomy (MT) for acute large-vessel occlusion (LVO) in this population remain limited. This case report describes an LVO caused by cardiogenic embolism in an adult patient who underwent the Fontan procedure for tricuspid atresia. Case Presentation: A 31-year-old woman with a history of an extracardiac Fontan procedure for tricuspid atresia presented with right-sided paralysis and leftward conjugate deviation. CTA revealed occlusion of the left internal carotid artery with a large ischemic penumbra. MT was performed using a direct aspiration first-pass technique, resulting in complete reperfusion. The patient was discharged with mild residual impairment of dexterity in the right upper hand. At 24 years of age, she had previously developed a large vessel occlusion in the M1 segment of the middle cerebral artery, which was successfully treated with MT, leaving only mild deficits. Despite a comprehensive evaluation for an embolic source, no source was identified. She was therefore diagnosed with embolic stroke of undetermined source and was treated with direct oral anticoagulants. Cardiac CT and delayed-enhancement MRI at the current presentation revealed a thrombus in the rudimentary right ventricle that had not been detected by echocardiography. Anticoagulation therapy was initiated, and no recurrence of thromboembolic events was observed. Conclusion: Although rare, LVO can occur at a young age in patients with ACHD. A thorough understanding of the unique anatomical characteristics of this population is essential for identifying the source of embolism and optimizing management strategies.