The DOME study is a clinical trial exploring a new treatment approach for patients who suffered a severe brain bleed due to an aneurysm.

To prospectively capture data of patients treated with the guideline-recommended, standard-of-care dome-protection approach. The data will be used to determine:

• (Primary) Incidence of aneurysm re-rupture by 90 days, censored at the time of definitive aneurysm treatment or death, detected on a surveillance head CT or one obtained after a neurological decline.
• (Secondary) Measure functional status of patients around 90 days (+/- 14 days)
• (Secondary) Measure success of dome protection as determined by angiographic criteria and procedural complications

DOME protection is a treatment approach for patients who suffered a severe brain bleed due to an aneurysm. Instead of performing immediate, extensive surgery, this study investigates a minimally invasive procedure called "dome protection", which involves placing tiny coils to patch the most fragile part of the aneurysm. This method aims to prevent re-bleeding and allow the patient to stabilize before undergoing full aneurysm repair. The findings could lead to improved health outcomes in patients with aneurysmal subarachnoid hemorrhage by reducing procedure-related risks.

Inclusion Criteria:

• 18 years or older
• CT confirmed aSAH with an angiographically detected aneurysm
• World Federation of Neurological Sciences (WFNS) aSAH grade 3-5 aneurysm
• LAR available and gives consent within 72 hours after the onset of aSAH (or last known normal

Exclusion Criteria:

• Patients whose aneurysm judged appropriate for balloon-assisted coiling
• Patients whose aneurysm is bleeding from the "neck"
• Patients who are clinically judged to suffer imminent death within 24 hours.
• Pregnancy or positive urine pregnancy test

Patients 18 years or older with CT confirmed aSAH with an angiographically detected aneurysm