Transvenous Coil Embolization for the Treatment of Carotid Cavernous Fistula after Pipeline Placement: A Case Report

The Pipeline embolization device (PED), a type of flow diverter, has become an appealing alternative treatment option for large or giant and wide-necked intracranial aneurysms. Carotid cavernous fistula (CCF) resulting from delayed aneurysmal rupture is a rare complication of PED placement with unknown pathophysiology. Here, we describe a case of CCF resulting from aneurysmal rupture following PED placement, and present the details of treatment by transvenous coil embolization. An 81-year-old woman was referred to our hospital for treatment of an 18.0 × 10.3 mm intracranial aneurysm located in the cavernous segment of the left internal carotid artery, noted during an examination of her diplopia. Endovascular treatment was conducted by positioning a single PED (4.75 × 25 mm) across the neck of the aneurysm. The postoperative course was uneventful, and the patient was discharged 8 days post procedure. On post-procedure day 10, her left oculomotor nerve palsy had worsened and she had developed left abducens nerve palsy, left exophthalmos, and left chemosis. Angiography demonstrated left direct CCF because of rupture of the aneurysm that had been treated with PED. Transvenous coil embolization was performed on post-procedure day 11 to treat the CCF, and complete resolution of the CCF and significant thrombus formation within the aneurysm sac were confirmed 11 days after the second procedure. Our angiographic results suggest that the aneurysmal rupture was caused by aneurysmal volume expansion associated with PED-induced thrombosis. Transvenous coil embolization for the treatment of CCF following PED placement constitutes a new challenge.