Characteristics of intracranial aneurysms associated with extracranial carotid artery disease in South Korea

ObjectiveAlthough it is hypothesized that inflammatory signals and/or hemodynamic stress resulting from carotid disease increase the risk of aneurysm formation and growth, a relationship between intracranial aneurysms and extracranial carotid artery disease (ECAD) has not been explored. Here, we examined the characteristics of intracranial aneurysms associated with ECAD.MethodsA total of 606 consecutive patients with stenosis of 50% or more of the proximal internal carotid artery (pICA) were enrolled. Stenosis was identified by conventional angiography between January 2003 and December 2009. We determined the prevalence of intracranial aneurysms in this population. The characteristics of the aneurysms were analyzed according to the degree and laterality of stenosis. The changes in the aneurysms were tracked for the evaluation of stability.ResultsIn 86 patients (14.2%), 120 aneurysms were detected in association with pICA stenosis. In this group, 97 were associated with unilateral pICA stenosis. The distribution of aneurysms was independent of the laterality of stenosis, but aneurysms were more prevalent in the contralateral side as the stenosis grade increased (P < 0.001). All aneurysms with an imaging follow-up (28.9 ± 14.3 months) were stable, and the course was not affected by treatment of the carotid stenosis. In 23 aneurysms associated with bilateral pICA stenosis, there was only one case that increased in size during a 41-month period.ConclusionIntracranial aneurysms were most likely associated with ECAD, but were evenly distributed irrespective of the laterality of the stenosis. The distribution was related to the severity of the contralateral pICA stenosis. The low incidence of aneurysm growth or rupture in patients with significant ECAD indicates that these aneurysms do not require immediate intervention more than other conditions.