Long-term stability of Onyx: is there any indication for repeated angiography after dural arteriovenous fistula embolization?

Indications for alternative endovascular techniques in carotid-cavernous fistulas: A 20-year single-center experience

BACKGROUND

While coiling is considered the standard treatment for carotid-cavernous fistulas (CCFs), studies demonstrating excellent results using new materials, especially flow diverter (FD) stents and liquid embolisates, are becoming more frequent. The indications and effectiveness of these alternative endovascular techniques remain unclear.

METHODS

A total of 22 direct and 20 indirect CCFs were included in the study. These were further subdivided based on the embolic material used: coils versus FD stents for direct and coils versus liquid embolisates for indirect CCFs. The subgroups were subjected to statistical analysis.

RESULTS

An angiographic cure was achieved in 88% of all CCFs, 93% of patients' experienced clinical improvement or remained stable. Direct CCFs were treated with coiling (41%) or with both coils and FD stents (55%). One (4%) patient with a direct CCF was treated with FD stent alone. Statistical analysis comparing these subgroups revealed a significantly higher complete occlusion rate immediately after treatment in the coiling subgroup (67% vs. 23%, p = 0.0409). The occlusion rates at the last follow-up were similar (89% vs. 85%). Indirect CCFs were treated with coiling (35%) or liquid embolisates (65%). All three periprocedural ischemic complications were recorded within the liquid subgroup, resulting in a significantly higher clinical deterioration rate (p = 0.0333).

CONCLUSION

FD stents in direct and liquid embolisates in indirect fistulas did not demonstrate better angiographic or clinical outcomes compared to convetional coiling. Liquid agents carried a higher risk of ischemic complications. Alternative embolization materials should be reserved for CCFs that cannot be treated with simple coiling.

Copolymer liquid embolization of dural arteriovenous fistulas: A 20-year single-center experience

BACKGROUND AND PURPOSE

Dural arteriovenous fistulas (DAVFs) with cortical venous drainage (CVD) carry significant risks of cerebral ischemia and intracranial hemorrhage. Endovascular treatment (EVT) using Onyx, a copolymer-based liquid embolic material, has become the preferred approach. However, the optimal treatment strategy for anterior cranial fossa DAVFs remains debated.

METHODS

This retrospective study analyzed outcomes of EVT for DAVFs in a single center from 2002 to 2023. Patient data including demographics, clinical status, angiographic findings, embolization techniques, and outcomes were recorded. The results of the anterior fossa malformations were analyzed separately afterward.

RESULTS

A total of 195 DAVFs were included in the study. The most common presenting symptom was hemorrhage (41%), most fistulas were located in the transverse and sigmoid sinus region (48%), and the majority of DAVFs had direct CVD (78%). Transarterial embolization with Onyx was the preferred treatment strategy in majority of cases (92%). Overall, 94% of patients showed improvement or stability on the modified Rankin Scale. Two patients died due to rebleeding after partial DAVF embolization. Onyx demonstrated higher immediate complete occlusion rate compared to other embolic materials (88% vs. 35%). Overall, 91% of fistulas were closed at the last follow-up. Ten anterior fossa DAVFs were treated, resulting in clinical improvement and complete occlusion in all cases.

CONCLUSION

Based on the results of our study, we believe that a cure of DAVFs, including those in the anterior fossa, can be achieved in more than 90% of cases through transarterial Onyx embolization, given long-term clinical experience.