Transarterial Embolization of Brain Arteriovenous Malformations: Single Center Experience

Geometrical Characteristics of Grade III Arteriovenous Malformations That Contribute to Better Outcomes in Endovascular Treatment

BACKGROUND

Grade III brain arteriovenous malformation (AVM) is a distinct subgroup of AVMs that encompasses multiple subtypes according to the Spetzler-Martin classification.

METHODS

This retrospective study included 61 patients with grade III AVM who underwent embolization between 2010 and 2022. The study analyzed the angioarchitecture of the AVM nidus and evaluated the outcomes of the embolization procedures.

RESULTS

There were 29 patients (47.5%) with subtype S1E1V1, 20 patients (32.8%) with subtype S2E1V0, and 12 patients (19.7%) with subtype S2E0V1. The rate of complete occlusion in all patients was 47.5% (29 patients). The rate of complete occlusion was higher in cases with a compact nidus (P < 0.001). Several parameters were associated with occlusion of the AVM nidus, including ≤3 arterial feeders (P = 0.017) and presentation with hemorrhage (P = 0.007), with the majority of patients with a compact nidus presenting with hemorrhage. Other factors associated with compact geometry were the presence of a single deep vein, ≤3 arterial feeders, ≤2 superficial draining veins, and an AVM nidus size ≤3 cm.

CONCLUSIONS

The compact nature of grade III AVM is a crucial predictor for the success of embolization. Several characteristics associated with a compact nidus, such as presentation with hemorrhage and a lower number of arterial feeders, have a significantly higher closure rate. Other factors, such as a single deep draining vein, reduced superficial venous drainage, and small size, show a strong association with complete obliteration.

Angiographic predictors of spontaneous obliteration of transarterial partially embolized brain arteriovenous malformations

BACKGROUND

Spontaneous obliteration of cerebral arteriovenous malformations is uncommon but could occur after partial embolization.

METHODS

A retrospective study of 140 patients that underwent embolization for cerebral AVMs from 2005 to August 2019 using liquid embolic agents. The angiographic outcome of patients was classified as regard complete embolization, partial embolization, and complete obliteration after partial embolization. The parameters studied included size, location, number of arterial feeders, number of draining veins, rupture status, embolic agent, and patient factors as well.

RESULTS

The study patients included 74 (53%) females and 66 (47%) males. Their age ranged from 7 to 43 years old. One hundred and eight patients (77%) presented with hemorrhage. The AVM grades were grade II in 57 (40.7%) patients and grade III in 56 (39.3%) patients. Sixty-one (43.57%) patients were treated by n-Butyl Cyanoacrylate and 71 (50.71%) patients were treated with Onyx, and both materials were used together in 8 cases. Follow-up angiography was done from 6 to 36 months after embolization. The rate of complete occlusion in all patients was 61.43% (86 patients). There were three groups of patients, the first group had complete occlusion of the nidus at the time of embolization and included 68 (48.57%) patients. The second group had partial embolization with partial occlusion of the nidus 54 patients (38.57%). The 3rd group included 18 patients (12.85%) with complete nidal occlusion on follow up after partial embolization. The delay in the venous drainage of the AVM to the late arterial phase or early venous phase with flow stasis was a significant predictor of future obliteration on follow up after partial embolization. Other significant parameters that were associated with the progressive disappearance of the AVM nidus on follow up after partial embolization are presentation with hemorrhage, AVMs size less than 3 cm, the presence of single draining or double draining veins, superficial venous drainage, and one or 2 arterial feeders.

CONCLUSION

Spontaneous closure of intracranial arteriovenous malformations after partial embolization may be encountered in cases of stasis of flow during embolization procedure with a delay of the venous drainage. A long-term follow-up of more cases over many years is required to confirm the validity of this conclusion.

The value of preoperative embolization in large and giant solid cerebellar hemangioblastomas

BACKGROUND

Solid cerebellar hemangioblastomas are highly vascular lesions and may cause catastrophic hemorrhage during excision.

METHODS

This retrospective study enrolled 10 patients (7 men and 3 women, with a mean age of 38.2 ± 12.5 years) with solid cerebellar hemangioblastomas. All patients had a solitary tumor and underwent surgical resection of the lesion through a suboccipital approach. The basic features, serial radiographic examinations, and operative records were analyzed.

RESULTS

The most common presenting symptoms were headache (100%), ataxia (100%), and long tract manifestations (60%). Three patients had experienced failed surgery previously due to massive intraoperative bleeding. Three patients were confirmed as having Von Hippel-Lindau disease. The average size of the tumor was 40.7 ± 8.7 mm in its maximal diameter (range 25-58 mm). Total endovascular occlusion obtained in six patients, near total occlusion in three patients, and incomplete occlusion in one patient. Nine (90.0%) patients underwent gross total resection and one (10.0%) underwent partial resection. After the primary surgery, eight (80.0%) patients experienced improvement in their symptoms, two (20.0%) maintained their pre-treatment status, and none showed neurological deterioration following tumor resection. Blood loss during surgery after embolization was minimal and controllable.

CONCLUSION

Preoperative embolization improves safety and efficacy of the microsurgical excision of such tightly located very vascular tumors. Embolization changes the concept of this lesion surgery into piecemeal removal rather than a total mass extraction technique. Liquid agents are superior to particles in obliteration of such lesions.

Endovascular Modalities for the Treatment of Cavernous Sinus Arteriovenous Fistulas: A Single-Center Experience

BACKGROUND

Cavernous sinus (CS) fistulas are classified into traumatic and spontaneous. Traumatic carotid-cavernous fistulas (CCFs) are usually direct internal carotid artery (ICA) high-flow fistulas; whereas spontaneous CCFs are usually dural, low-flow fistulas and generally possess less severe symptoms than direct carotid-cavernous fistulas.

METHODS

This study involved 34 patients who were classified into 2 groups: Group A included 26 patients with direct carotid-cavernous fistula; and Group B included 8 patients with indirect dural cavernous fistula. All patients had ocular manifestations. One patient had subarachnoid hemorrhage. Coils were used alone in 19 cases of direct fistula and in 1 case of dural fistulas. Coils and Onyx (Covidien, Mansfield, MA, USA) were used in 7 cases of direct fistula and in 2 cases of dural fistulas. Onyx alone was used to treat 5 cases with dural fistulas but none of the cases with direct fistulas. Covered stents and coils were used in 2 cases of direct fistulas.

RESULTS

All patients in both groups showed full recovery of their clinical signs and symptoms. Only 1 procedure-related complication was observed (3%) in which a patient had an embolic event and trigeminal dysesthesia as a result of Onyx reflux through external carotid artery-ICA anastomosis.

CONCLUSION

Coils are superior solid embolic agents used for the treatment of direct high-flow fistulas, while Onyx is more valuable in dural low-flow CCF. Onyx shortens the procedure time and decreases procedure cost. Onyx injection inside the CS proper through the transarterial or transvenous route may be safer than Onyx injected inside dural arteries supplying the CS. However, more cases are needed to determine this.