International stroke genetics consortium - intracranial aneurysm groups - cohorts and phenotypic descriptors

Approximately 3% of the population harbor an unruptured intracranial
aneurysm (IA) and the overall risk of an aneurysmal rupture is about 1%
per year. Rupture of IA causes aneurysmal subarachnoid hemorrhage (aSAH)
and despite recent improvements in risk stratification, imaging, surgical
and intensive care treatment, the functional outcome after aSAH remains
poor. The goal of the present study was
to investigate patient and IA characteristics associated
with IA rupture using a large multicenter collection of well-characterized
cases with IA.  Data were collected in the
context of the genetic studies on IAand were shared
among the International Stroke Genetics Consortium Intracranial Aneurysm
Group (ISGC-IA) (eTable 1). Detailed cohort descriptions
are given in eTable 2. Briefly, all cases had a saccular IA, ruptured or
unruptured confirmed by imaging or surgical exploration. Patients with
conditions known to predispose to IAs, such as autosomal dominant
polycystic kidney disease, Ehlers-Danlos disease, or Marfan’s syndrome,
were excluded. For all participating groups, approval was
received by institutional or regional ethics committee on human
experimentation. Written informed consent was obtained from all patients
(or guardians of patients) participating in the respective
studies.  Initial exploration of the available data allowed
identification of a minimal data set of seven phenotypic patient
characteristics (basis of recruitment, sex, positive family history,
hypertension status, smoking status, age at time of aneurysm rupture, and
multiplicity status), and three aneurysms characteristics (rupture status,
IA maximum diameter at rupture, and IA location) harmonized across
studies (eTable 3).