Subarachnoid Hemorrhage of Unknown Cause after Transvenous Embolization of Transverse Sigmoid Sinus Dural Arteriovenous Fistula Followed by Transarterial Embolization: A Case Report.

Objective: Dural arteriovenous fistula (dAVF) is generally treated by endovascular therapy, but transarterial embolization (TAE) carries the risk of potential complications, including distal migration of embolic material, brain infarction, and venous congestion. Intracranial hemorrhage is infrequent but remains a considerable concern.

Case Presentation: A man in the seventh decade presented with left hemiparesis. Brain MRI revealed right corona radiata infarction and incidentally identified a left transverse sigmoid sinus dAVF. Under a diagnosis of Borden type III and Cognard type IIb, an endovascular treatment plan was initiated. After an unsuccessful attempt at transvenous embolization, TAE with Onyx (Medtronic, Minneapolis, MN, USA) successfully resolved the dAVF. However, immediate post-treatment CT revealed subarachnoid hemorrhage, leading to decompressive craniotomy. Follow-up DSA showed no residual shunts, and the cause of the bleeding remained unknown.

Conclusion: Despite the unknown cause of bleeding, a thorough evaluation of preoperative hemodynamics and diligent postoperative examination is crucial in managing dAVF cases. Further pathological investigations are needed to gain a comprehensive understanding of such occurrences.