Mechanical valve associated cardioembolic large vessel occlusion in an adolescent successfully treated with endovascular thrombectomy: a case report and focused literature review

Mechanical valve replacement is still used in young patients with severe valvular disease, but lifelong anticoagulation is required because prosthetic valves remain prone to thrombosis and embolization. Mechanical valve related cardioembolic large vessel occlusion has only occasionally been reported in adolescents, and pediatric experience with endovascular thrombectomy in this setting remains limited. A 16-year-old girl with prior mechanical mitral valve replacement and tricuspid valve repair presented with abrupt aphasia and severe left hemiplegia. Her NIHSS score was 16. Computed tomography angiography showed right middle cerebral artery occlusion, and digital subtraction angiography confirmed right M1 occlusion. Urgent endovascular thrombectomy achieved complete reperfusion (mTICI grade 3). Neurological deficits improved rapidly, and she was discharged with an NIHSS score of 0. Admission INR was 1.18, indicating inadequate anticoagulation. Warfarin was subsequently adjusted with regular monitoring, and no recurrent thromboembolic events occurred during follow-up. Mechanical valve associated cardioembolic stroke should be considered in adolescents with acute focal deficits, especially when anticoagulation is subtherapeutic. Early recognition of large vessel occlusion and timely thrombectomy may improve outcomes in selected patients. Continued anticoagulation management is essential to reduce recurrent embolic risk.