Aneurysms Associated With AVMs

Prevalence/Demographics

Intracranial arteriovenous malformations (iAVMs) are frequently associated with the presence of intracranial aneurysms. The prevalence of AVM-associated aneurysms has been reported in a wide range, from 1.4% to 58% of patients with iAVMs, with the majority of the studies reporting between 10% and 20%. In a 2012 meta-analysis of data from 3923 patients with iAVMs, Gross and Du found that up to 18% of AVMs were associated with aneurysms. Similarly, ARUBA (A Randomised Trial of Unruptured Brain Arteriovenous Malformations) found intracranial aneurysms in 15.5% of patients with unruptured AVMs.

The wide ranges in incidence may be explained by differences related to risk factors associated with the development of aneurysms in patients with iAVMs. Both aneurysm size and the number of aneurysms a patient has have been correlated with increasing age. Arterial aneurysms are rare in the pediatric population and more common in adult patients. In one study of 101 iAVM cases, only 8% of patients who first presented with iAVMs at less than 25 years of age had AVM-associated aneurysms at presentation, but for patients who were older than 50 years at initial presentation, the proportion with AVM-associated aneurysms was 37%.

Aneurysms are often reported to be more frequently seen in association with posterior fossa AVMs, previously reported with a 30% vs 11% prevalence in infratentorial and supratentorial locations, respectively. Aneurysms located in the posterior fossa and associated with infratentorial AVMs have also been found to have larger diameters and a higher rate of hemorrhage than those associated with supratentorial AVMs.

The large discrepancies in the reported prevalence rates for iAVM-associated aneurysms have also been attributed to variations in diagnostic imaging studies and techniques and sampling errors. Nevertheless, despite the wide range of prevalence rates, there is consensus that the prevalence of intracranial aneurysms in patients with iAVMs is greater than the prevalence of intracranial aneurysms in the general population.