Objective: To evaluate the effectiveness of the treatment of patients with cranial dural arteriovenous fistulas [dAVFs] on long-term follow-up and determine factors that affect the post-treatment clinical outcome.

Materials and Methods: After being certified by the Siriraj Institutional Review Board, Faculty of Medicine Siriraj Hospital, Mahidol University, 180 patients with cranial dAVFs were retrospectively reviewed at the Interventional Neuroradiology Unit, Siriraj Hospital, Bangkok, Thailand. There were 118 females and 62 males, age ranged from 15 to 85 years with mean age of 52.64 years. The dAVFs were classified angiographically according to Davies’ criteria and Cognard classification into benign and aggressive shunts. Endovascular procedure was the first treatment option. Therapeutic outcomes were measured by angiographic appearances to complete (no residual shunt or retrograde leptomeningeal venous drainage [RLVD]), partial treatment (residual RLVD), and procedural complications. The clinical outcomes were defined into favorable (cure or improved without new symptoms or disability) and unfavorable (unchanged or worsening symptoms). Thirty-one patients (17.22%) lost to follow-up were excluded. The possible factors that may associate with patient’s outcome were compared between favorable and unfavorable groups. Relationship between therapeutic results and clinical outcome were analyzed.

Results: Of the 180 patients, there were 231 shunts. Multiple shunts were found at 26.11%. Thirty-nine patients (21.67%) had aggressive symptoms (e.g., neurological deficit, cognitive impairment, or seizure). The most common location of dAVF was the cavernous (55.84%), followed by transverse sigmoid sinus (27.27%) and superior sagittal sinus (7.79%) respectively. Aggressive shunts were found at 48.33%. The abnormal image findings were white matter changes at 16.81%, hemorrhage at 12.39%, hydrocephalus at 6.19%, and parenchymal calcification in one patient. One hundred forty-nine patients (82.78%) who had follow-up (ranging from 1 month to 12 years with average at 9.61 months), 136 (91.26%) had favorable outcome. For unfavorable outcome, significant related factors were hydrocephalus (p = 0.002) and calcification (p = 0.002). For favorable outcome, significant related factors were benign symptoms (p<0.01) and no associated sinus thrombosis (p<0.01). For therapeutic results, complete treatment achieved high favorable outcome (93.15%). Endovascular complication rate was 4.7%.

Conclusion: High favorable clinical outcome of cranial dAVF was achieved with low complication rate. Aggressive clinical and angiographic presentations as well as intracranial venous congestion were reversible following an effective treatment. The favorable clinical outcome is predictable in benign symptoms (p<0.01) and no associated sinus thrombosis (p<0.01). Excluding complication, unfavorable outcome is related with ventricular dilatation (p = 0.002) and subcortical calcification (p = 0.002) caused by prolong increased intracranial pressure or chronic venous congestion. When treatment result is unresponsive, offering treatment in patients with these factors should be reconsidered.

Keywords: Dural arteriovenous fistula, Dural arteriovenous shunt, Symptom, Clinical outcome