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).