Lisa Anne Cannon-Albright
Robert D. Brown JR., John Huston III, Richard Hornung, DR.P.H., Tatiana Foroud, David F. Kallmes, Dawn Kleindorfer, Irene Meissner, Daniel Woo, Laura Sauerbeck, Joseph Broderick and for the Familial Intracranial Aneurysm (FIA) Investigators
Approximately 20% of patients with an intracranial saccular aneurysm report a family history of intracranial aneurysm (IA) or subarachnoid hemorrhage. A better understanding of predictors of aneurysm detection in familial IA may allow more targeted aneurysm screening strategies.
The Familial Intracranial Aneurysm (FIA) study is a multicenter study, in which the primary objective is to define the susceptibility genes related to the formation of IA. First-degree relatives (FDRs) of those affected with IA are offered screening with magnetic resonance (MR) angiography if they were previously unaffected, are ≥ 30 years of age, and have a history of smoking and/or hypertension. Independent predictors of aneurysm detection on MR angiography were determined using the generalized estimating equation version of logistic regression.
Among the first 303 patients screened with MR angiography, 58 (19.1%) had at least 1 IA, including 24% of women and 11.7% of men. Ten (17.2%) of 58 affected patients had multiple aneurysms. Independent predictors of aneurysm detection included female sex (odds ratio [OR] 2.46, p = 0.001), pack-years of cigarette smoking (OR 3.24 for 20 pack-years of cigarette smoking compared with never having smoked, p < 0.001), and duration of hypertension (OR 1.26 comparing those with 10 years of hypertension to those with no hypertension, p = 0.006).
In the FIA study, among the affected patients' FDRs who are > 30 years of age, those who are women or who have a history of smoking or hypertension are at increased risk of suffering an IA and should be strongly considered for screening.
Jason Mackey, Robert D. Brown Jr., Charles J. Moomaw, Laura Sauerbeck, Richard Hornung, Dheeraj Gandhi, Daniel Woo, Dawn Kleindorfer, Matthew L. Flaherty, Irene Meissner, Craig Anderson, E. Sander Connolly, Guy Rouleau, David F. Kallmes, James Torner, John Huston III and Joseph P. Broderick
Familial predisposition is a recognized nonmodifiable risk factor for the formation and rupture of intracranial aneurysms (IAs). However, data regarding the characteristics of familial IAs are limited. The authors sought to describe familial IAs more fully, and to compare their characteristics with a large cohort of nonfamilial IAs.
The Familial Intracranial Aneurysm (FIA) study is a multicenter international study with the goal of identifying genetic and other risk factors for formation and rupture of IAs in a highly enriched population. The authors compared the FIA study cohort with the International Study of Unruptured Intracranial Aneurysms (ISUIA) cohort with regard to patient demographic data, IA location, and IA multiplicity. To improve comparability, all patients in the ISUIA who had a family history of IAs or subarachnoid hemorrhage were excluded, as well as all patients in both cohorts who had a ruptured IA prior to study entry.
Of 983 patients enrolled in the FIA study with definite or probable IAs, 511 met the inclusion criteria for this analysis. Of the 4059 patients in the ISUIA study, 983 had a previous IA rupture and 657 of the remainder had a positive family history, leaving 2419 individuals in the analysis. Multiplicity was more common in the FIA patients (35.6% vs 27.9%, p < 0.001). The FIA patients had a higher proportion of IAs located in the middle cerebral artery (28.6% vs 24.9%), whereas ISUIA patients had a higher proportion of posterior communicating artery IAs (13.7% vs 8.2%, p = 0.016).
Heritable structural vulnerability may account for differences in IA multiplicity and location. Important investigations into the underlying genetic mechanisms of IA formation are ongoing.