Risk of hemorrhage in patients over age 60 with arteriovenous malformations (AVMs)

Treatment selection for patients 60 years of age and older with intracranial arteriovenous malformations (AVMs), requires careful consideration of the natural history and post-treatment hemorrhagic risk. We aimed to directly compare the natural history of AVMs with post-treatment hemorrhagic risk in this population. We retrospectively reviewed our AVM database of 683 patients. Patients ⩾60 years at diagnosis were included. Treatment modality was divided into four groups: surgery ± embolization (SE), radiosurgery ± embolization (RE), embolization only (Emb), and observation (Obs). The natural history of the AVM was defined as the annual risk of hemorrhage under observation. Risk of hemorrhage after treatment was also calculated. Sixty-one patients with complete data were included. Average age was 68.4 ± 7.5 years, with 55.7% (n = 34) being male. Twenty-seven (44.3%) patients presented with intracerebral hemorrhage (ICH). At last follow-up, modified Rankin Scale was higher in patients with subsequent hemorrhages (p = 0.023). Overall, obliteration was 65.5%, with 100.0% in the SE group and 43.8% in the RE group (p <0.001). During an average follow-up period of 2.8 ± 3.2 years, six patients (9.8%) experienced hemorrhage, with two (12.5%) in the RE group, three (9.4%) in the Obs group and one (9.1%) in the SE group, corresponding to a natural history of 3.5% annual hemorrhage rate and a post-treatment hemorrhagic risk of 3.6%. This post-treatment hemorrhage risk was 2.4% in the SE group and 4.9% in the RE group. Presenting with ICH (p = 0.042) and race (p = 0.014) were associated with a higher risk of follow-up hemorrhage. Definitive treatment for AVM patients ⩾60 years should be cautiously considered. Despite higher post-treatment obliteration rates, the subsequent hemorrhagic risk may exceed that of its natural history. For AVMs with a high risk for hemorrhage, surgery reduces hemorrhagic risk and achieves the highest rate of obliteration.