Fatal Thrombosis of the Internal Carotid Artery Following Surpass Evolve Flow Diverter Treatment of an Intracranial Aneurysm

Flow diverters (FDs) are widely used in the treatment of intracranial aneurysms, offering a minimally invasive option for anatomically complex lesions. Although generally effective, early thrombotic occlusion of the parent artery remains a rare but devastating complication. The authors report a case of fatal internal carotid artery thrombosis following technically successful deployment of the surpass evolve flow diverter (SEFD) in a 62-year-old woman with an unruptured C6 segment aneurysm. The patient had demonstrated adequate preoperative platelet inhibition, and intravenous tirofiban was administered intraoperatively. However, on postoperative day 2, she developed acute neurological deterioration. Emergent angiography revealed complete occlusion of the internal carotid artery (ICA). Despite prompt mechanical thrombectomy and decompressive craniectomy, the patient died from brainstem failure. Retrospective review revealed that the patient had discontinued clopidogrel during a temporary discharge before the procedure-a fact not disclosed to the medical team. This unrecognized lapse in dual antiplatelet therapy likely contributed to the early thrombotic occlusion of the ICA. This case underscores the importance of medication reconciliation, patient education on antiplatelet adherence, and the potential value of platelet function testing in optimizing perioperative management. As the use of next-generation flow diverters expands, such lessons are critical for preventing avoidable complications.