Endovascular Treatment for Dural Arteriovenous Fistula with Symptomatic Venous Outflow Impairment

Dural arteriovenous fistula (DAVF) with sinus occlusion and cortical reflux often presents with neurological symptoms. These symptoms are due to venous congestion and hypertension that often result in intracranial hemorrhage and venous infarction. We investigate 25 patients (9% of all our DAVF cases) including 19 males and 6 females aged from 46 to 79 years old with brain dysfunction due to marked venous reflux from DAVF. The lesions were located in the lateral sinus in 17 patients, the superior sagittal sinus in 2, the tentorial sinus in 3, and other locations in 3 cases. Clinical manifestations included hemorrhage with various neurological deficits in 10 patients and brain dysfunction due to venous congestion in 15 patients, including 7 with visual disturbances, 5 with cognitive dysfunction or dementia, 4 with convulsions, and 3 with other symptoms. Twelve patients were treated with transarterial embolization (TAE), 10 with transvenous embolization and 3 with surgical sinus packing. Sinoplasty with balloon catheter was performed in 3 patients. Angiographically, the fistula was totally occluded in 16 patients, almost completely occluded in 7 and only partially occluded in 2. TAE with glue showed a high cure rate (70%). Symptoms improved or recovered in 18 patients. However, symptoms did not change in 3 patients, including 1 with pre-operatively severe neurological deficits and 2 with visual disturbance untreated for a prolonged time or treated palliatively. We found that there were 2 venous reflux patterns to the cortical vein in cases of DAVF. They include reflux to the cortical vein as the only drainage route from the isolated sinus, and retrograde flow through the sagittal sinus due to the bilateral occlusion of lateral sinus resulting in pancerebral vascular congestion. The former represented the aggressive type and showed focal venous congestion and required early occlusion of shunt flow. The latter showed more chronic progression with cognitive or psychological dysfunction requiring reconstruction of the drainage pathway as well as shunt occlusion. These treatments should be performed as early as possible to avoid irreversible damage to the brain. Although treatment strategy should be selected according to the location of each DAVF and its possible approach, transarterial target embolization using liquid embolic materials is promising due to its high cure rate.