Rational: The main danger with intracranial aneurism is its rupture conjugated with subarachnoid hemorrhage (SAH) occurrence. SAH is a severe pathology leading not only to neurological but also extra cerebral disorders. The major cause of morbidity and mortality when developing a SAH is the secondary development of a delayed cerebral ischemia consecutive to a prolonged vasospasm of cerebral arteries. The understanding of the pathophysiological mechanisms of SAH complication, such as vasospasm which is the more frequent, is essential.

Vasospasm is defined as a reversible shrinking of an artery lumen diameter in the subarachnoid space, beginning generally between 4 and 12 days after the hemorrhage. Such a vasospasm could have a huge clinical impact leading to delayed neurological ischemic deficiency in 17 to 40 % of cases. Up to day, mechanisms involved in vasospasm occurrence are not well described.

Disposing of well-established genetics and transcriptomics databases along with cerebral ischemia and inflammation is essential to unravel the mechanisms leading to vasospasm occurrence on SAH patients. It will enable researchers to better comprehend SAH pathology and elaborate an efficient and individualized therapeutic strategy to SAH acute phase in order to reduce the risk of vasospasm occurrence.

Aims: 1) Constitute DNA and RNA Biobank via blood proofing oh SAH patients 2) Constitute a database grouping clinical and biological data 3) Look for genetic and transcriptomic early markers via genomic approaches 4) Correlate these different markers with vasospasm occurrence and clinical evolution of the patients

Study: Patients inclusion will be done following their admission (D1) in the " unité de réanimation neurochirurgicale" of Pitié-Salpètrière Hospital. After obtaining of the informed consent, blood proofing will be realized daily during 12 days: one daily 2.5ml tube for the transcriptomic study and a single 10ml EDTA tube for genetic analyses. Clinical and biological follow-up will be performed as usual.

200 patients will be initially included during 2 to 3 years for the transcriptomic study of which 1/3 will develop vasospastic complication. The transcriptomic study will thus be performed by comparing patients developing or not developing this complication

Expected Results: Unravel vasospasm early genetic markers.

Inclusion Criteria:

• Patient entering the neurosurgical unit in the 48 hours following an aneurismal sub-arachnoid hemorrhage and treated in the 96 first hours (embolization or surgery)
• Aged more than 18
• Caucasian origin
• Affiliated to a social care service
• Having (or one of is related if he is comatose) given its informed consent

Exclusion Criteria:

• Subjects which do not have a social care protection
• Subjects (or one of is related if he is comatose) refusing to sign the consent
• Subjects being under a protective juridical system for adults

Caucasian subjects, aged more than 18, suffering of sub-arachnoid hemorrhage