Unruptured Epileptogenic Brain Arteriovenous Malformations.

AIM To determine whether specific clinical and radiographic factors predispose arteriovenous malformations (AVMs) presenting with seizure and to predict the seizure risk for individual AVM patients. MATERIAL AND METHODS Clinical features and cerebral angiograms of consecutive 45 unruptured AVM patients who were diagnosed in our center in a 2-year period were reviewed. Patient data (analysis cohort) was used to determine risk factors for seizure and to construct epileptogenic AVM groups. These risk groups were tested with the second half of the patient data (test cohort). RESULTS Among 45 unruptured AVMs (47.9%), initial seizures occurred in 20 unruptured AVMs (44.4%). Two of these 20 patients had a bleed in 117 patient-years for an annual bleed rate of 1.7%. There was no significant difference in hemorrhagic risk between epileptogenic AVM and asymptomatic AVM (P=0.918). Multivariate analysis revealed 2 factors associated with seizure: frontal and temporal AVM locations (P < 0.001) and a compact AVM morphology (P=0.003). CONCLUSION Analysis of a group of unruptured AVMs demonstrated that epileptogenic AVMs have an annual hemorrhage risk similar to that of the asymptomatic AVMs. Frontal and temporal AVM locations and a compact AVM morphology were significantly associated with epileptogenic AVMs.