Seizure risk should not influence AVM treatment decisions

By Eleanor McDermid

Choosing to treat patients with arteriovenous malformations (AVMs) surgically rather than conservatively has no bearing on their risk for seizures, suggest findings from the Scottish Audit of Intracranial Vascular Malformations (SAIVMs).

"These findings blunt the common assertion that interventional AVM therapy reduces seizure recurrence, thus justifying the treatment of otherwise asymptomatic, unruptured brain AVMs," says Christian Stapf (Hôpital Lariboisière, Paris, France), author of an editorial that accompanies the paper in Neurology.

The observational multicenter SAIVMS included 229 patients in total. Of these patients, 155 presented with intracranial hemorrhage, with 91 undergoing surgery. During up to 5 years of follow up, 35% of patients who underwent surgery had a first-ever seizure, compared with 26% of those treated conservatively; this difference was not statistically significant.

In multivariate analysis of this patient group (the only group in which it was possible), the only factor that predicted seizure risk was the size of hematoma at presentation.

Treatment also had no significant effect on seizure risk in the 44 patients whose AVMs were discovered incidentally, with rates of 21% and 10% in those treated surgically and conservatively, respectively.

The overall risk for seizure during follow up was elevated in the 60 patients who presented with seizure, but again did not differ between the 39 who underwent surgery and the 21 treated conservatively, at 67% and 72%, respectively.

Rustam Al-Shahi Salman (Western General Hospital, Edinburgh, UK) and colleagues had hypothesized that early seizure risk after AVM discovery would be highest in patients who underwent surgical management, because of the impact of craniotomy on the surrounding brain tissue. However, 2-year seizure rates among patients who presented with seizures were almost identical among those treated surgically and those managed conservatively, at 52% and 57%, respectively.

Stapf comments that the findings "may remind treatment teams that the primary goal of interventional AVM therapy remains the prevention of future AVM hemorrhage, and that its benefit for the prevention of epileptic seizures remains as yet unproven, at least over a 5-year period."

He says that the study "also emphasizes that the neurologist's role should be more than as a silent bystander in the multidisciplinary management of symptomatic AVM patients."

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