Failure of Flow-Diverter Endothelization Visualized with Optic Coherent Tomography Technology.

We report a case of an intracranial aneurysm of the left posterior inferior cerebellar artery, which was treated with a flow-diverting stent. One year later at follow-up, the patient presented with new symptoms due to mass effect in the posterior fossa and a 3-fold enlargement of the aneurysm. Digital subtraction angiography showed an increase in size of the aneurysm with jet flow into the sac. Optic coherent tomography was performed during the procedure, demonstrating a failure of endothelization of the stent with a focal 1-mm opening at the neck of the aneurysm, resulting in jet flow. Parent vessel sacrifice was performed by coiling of the left vertebral artery. The patient had a codominant right vertebral artery and tolerated the procedure well. Two years later, follow-up magnetic resonance angiography showed significant decrease of the size of the aneurysm and symptom regression, with a modified Rankin scale of 1 (functionally independent).