Endovascular Patch Embolization for Blood Blister-Like Aneurysms in Dorsal Segment of Internal Carotid Artery

OBJECTIVE: Blood blister-like aneurysms (BBAs) in the dorsal segment of the internal carotid artery are fragile and difficult to treat, and the optimal treatment for BBAs is still controversial. We report clinical and angiographic results with procedural details for the treatment of BBA by using the endovascular patch embolization method. METHODS: We retrospectively reviewed patients who presented with subarachnoid hemorrhage caused by internal carotid artery-BBAs and were treated with the endovascular patch embolization method in our center from October 2011 to March 2015. Clinical records, angiographic findings, procedural details, and follow-up results are reported in this study. RESULTS: Eight patients were enrolled in this study. All patients were treated with the endovascular patch embolization method. The key points of this method are step-bystep stent deployment and swaying of the microcatheter to coil the aneurysm sac and the wedge-shaped space between the stent and parent artery and, thereby, in the aneurysm sac and parent artery around the aneurysm neck When the stent is completely deployed, an endovascular patch is formed and anchored around the neck of the BBA. The procedure was successful in all cases. No acute complications developed in any case. No rerupture or recurrence of the BBA occurred during follow-up. One patient with Hunt-Hess V subarachnoid hemorrhage died of multiple organ failure 4 months post treatment. Another patient died of intracranial infection related to the ventricle-peritoneal shunt. The remaining 6 patients had good clinical outcomes (modified Rankin Scale score of zero). CONCLUSION: Endovascular patch embolization is an improvement on stent-assisted coil embolization, which could be successfully performed only with extensive skill and patience. Endovascular patch embolization could be an effective method in BBA treatment. However, its efficacy and safety should be verified in a larger patient cohort and long-term follow-up study.