Flow diverters for direct carotid-cavernous fistulas: A systematic review and meta-analysis

Introduction: Carotid-cavernous fistulae (CCFs) are abnormal connections between the carotid artery and the cavernous sinus, presenting with clinical symptoms such as chemosis, pulsatile proptosis, ocular bruit, and vision loss. Direct fistulae are particularly challenging to treat due to their high flow rate. While transvenous coil embolization is the primary treatment method, this often fails to eradicate the fistula, with the risk of further deterioration. Recently, transarterial embolization with flow diversion (FD) has emerged as a potential therapeutic option. In this meta-analysis, we aimed to evaluate the safety and efficacy of FD for treating CCFs.

Methods: An electronic database search was conducted following Preferred Reporting Items for Systematic Reviews and Meta-Analysis guidelines. Studies of any design including patients treated for CCFs using FDs were included. The primary outcome of interest was the rate of CCF occlusion. We also analyzed the incidence of recurrence with neurologic and non-neurologic complications.

Results: We found 23 studies with a total of 50 direct CCF cases treated with flow diversion. The mean age was 36.36±20.02 years. Trauma (58%) was the most common etiology. Proptosis (46%), cranial nerve palsies (38%), and headache (32%) were the most common presentations. The mean clinical and radiographic follow-up times were 6.32 and 7.15 months, respectively. Overall, the complete CCF occlusion rate was 68% (95% CI 43%–90%), the neurological complication rate was 1% (95% CI 0-13%) and the recurrence rate was 4% (95% CI 0-16%). The meta-regression analysis indicated that from 2010-2022, the obliteration and recurrence rates have increased, but complications have decreased.

Conclusion : Flow diversion provides a safe treatment adjunct to endovascular modalities for the treatment of CCFs, with low complication rates. Its efficacy as a standalone vs. as an adjunct treatment warrants further analysis.