Seizure risk with AVM treatment or conservative management

Abstract

Methods:We used annual general practitioner follow-up, patient questionnaires, and medical records surveillance to quantify the 5-year risk of seizures and the chances of achieving 2-year seizure freedom for adults undergoing AVM treatment compared to adults managed conservatively in a prospective, population-based observational study of adults in Scotland, newly diagnosed with an AVM in 1999-2003. Results:We identified 229 adults with a new diagnosis of an AVM, of whom two-thirds received AVM treatment (154/229; 67%) during 1,862 person-years of follow-up (median completeness of follow-up 97%). There was no significant difference in the proportions with a first or recurrent seizure over 5 years following AVM treatment, compared to the first 5 years following clinical presentation in conservatively managed adults, in analyses stratified by mode of presentation (intracerebral hemorrhage, 35% vs 26%, p ϭ 0.5; seizure, 67% vs 72%, p ϭ 0.6; incidental, 21% vs 10%, p ϭ 0.4). For patients with epilepsy, the chances of achieving 2-year seizure freedom during 5-year follow-up were similar following AVM treatment (n ϭ 39; 52%, 95% confidence interval [CI] 36% to 68%) or conservative management (n ϭ 21; 57%, 95% CI 35% to 79%; p ϭ 0.7). Conclusions:In this observational study, there was no difference in the 5-year risk of seizures with AVM treatment or conservative management, irrespective of whether the AVM had presented with hemorrhage or epileptic seizures. Neurology Adults with a brain arteriovenous malformation (AVM) are at risk of epileptic seizures, especially when the AVM is supratentorial (in the temporal lobe in particular) and after intracerebral hemorrhage (ICH) has occurred.1 The main aim of AVM treatment is to reduce the risk of AVM-related ICH, but invasive procedures might also reduce the risk of seizures by obliterating epileptogenic foci. Conversely, surgical excision, endovascular embolization, and stereotactic radiosurgery could also raise the risk of seizures.Case series have reported conflicting results about seizure control following AVM treatment: surgery has been associated with better, 2-7 unchanged, or worse seizure control 8 -10 ; the effect of stereotactic radiosurgery has been promising, 11-21 although a delayed increase in seizure fre-

Seizure outcomes following radiosurgery for cerebral arteriovenous malformations

“…In a recent prospective, populationbased observational study comparing seizure outcomes between AVM treatment and conservative management, Josephson et al observed no significant difference in the 5-year risk of a recurrent unprovoked seizure between conservative management and AVM treatment (72% vs 67%, respectively; p = 0.6). 36 The same study also found that the 2-year seizure-free rates did not differ significantly between the conservative and treatment groups (57% vs 52%, respectively; p = 0.7). Although the differences were not significant, patients who underwent AVM treatment may have had a higher baseline propensity for seizures, and their seizures may have been refractory to conservative management, thus resulting in AVM treatment.…”

Medical vs invasive therapy in AVM-related epilepsy

“…10,11 Both studies had similar sample sizes, population demographics, and AVM characteristics (table 1). Similar rates of invasive treatment-related AVM obliteration were obtained in each study (75% 11 vs 72% 10 ).…”

“…The follow-up periods ranged from 4.6 years to 13 years. There was a substantial gap in the time of data collection between the 2 studies; one 11 was a retrospective review of tertiary care cases from 1966 to 1979, while the second 10 was a prospective, population-based study reporting on data from 1999 to 2011.…”

“…The differences in study quality were related to representativeness of the exposed cohort, comparability of the cohorts, and evaluation of seizure freedom (table 2). The more recent publication 10 was given a higher quality rating in each of these areas because the data were population-based (rather than derived from a single center); the authors reported potential confounding variables such as age, sex, and size of AVM; and the assessment of the seizure freedom was clearly outlined and explained. None of these above factors was addressed in the earlier study.…”

“…11 The interventional and medical management arms were otherwise comparable apart from the invasive group being slightly younger in one study. 10 Meta-analysis of seizure freedom. The 2 controlled studies comprised a total of 106 patients (interventional treatment n 5 47; conservative medical management n 5 59).…”