Remote Ischemic PreConditioning (RIPC)

Inclusion Criteria:

1. A diagnosis of an unruptured brain aneurysm deemed suitable for repair by neuroendovascular techniques involving intraluminal occlusion by detachable platinum coils, stent-assisted coiling, pipeline stent, balloon-assisted coiling, covered stent only, neck-bridge device, re-coiling, or re-treatment of a previously coiled/treated aneurysm. There are no restrictions on adjunctive devices.
2. Absence of ongoing ischemic symptoms such as transient ischemic attacks, minor strokes, stroke-in-evolution, or clinical evidence of cerebral vasospasm within 2 weeks prior to randomization. (If a CT scan, cerebral angiogram, or other imaging performed during the 2 weeks prior to randomization shows radiological vasospasm deemed by the treating physician to be potentially clinically significant, the subject is excluded).
3. Male or female with a minimum age of 18 years on the day of enrollment.
4. Informed consent and availability of the subject for the entire study period and willingness of the subject to adhere to protocol requirements, as evidenced by a signed Informed Consent Form.

Exclusion Criteria:

1. Dissecting or mycotic brain aneurysm. Fusiform or atherosclerotic intracerebral aneurysms may be eligible for the trial if endovascular treatment is planned with a goal of exclusion of the aneurysm from the circulation.
2. Planned endovascular vessel sacrifice as the primary modality for aneurysm treatment.
3. Known history of life-threatening allergic reaction to any medication.
4. Soft tissue, orthopedic, or vascular injury which, in the judgment of the investigator, would preclude arm ischemic conditioning (e.g. superficial wounds, venous, arterial ulcers, gangrene).
5. History of peripheral vascular disease or deep vein thrombosis in either arm.
6. Women who are pregnant, or have a positive urine or blood (β-hCG) pregnancy test.
7. Women who are breastfeeding.
8. Any clinically significant psychiatric or psychological disease, which would preclude the patient from completing the protocol.
9. Pre-morbid (estimated) modified Rankin scale score of greater than 2. A subject is not excluded if they have a pre-morbid modified Rankin scale of greater than 2 but the disability does not interfere with the subject's ability to complete an MRI and the cognitive evaluations.
10. Previous serious traumatic brain injury that would preclude the patient from completing the protocol or preclude MRI analysis of small strokes.
11. Patients with peripherally inserted central catheters, hemodialysis shunts, arteriovenous fistulae or grafts in the treatment limb, or lymphedema.
12. Patients with known Human Immunodeficiency Virus (HIV) infection.
13. Patients who are unable to have an MRI scan for any reason.
14. Participation in a clinical trial with an investigational drug within 30 days preceding this study. Previous participation in any clinical trial investigating ischemia following endovascular aneurysm treatment, participation in another trial involving RIPC, or prior receipt of RIPC.
15. Severe or unstable concomitant condition disease or chronic condition, which, in the opinion of the investigator, could affect assessment of the safety or efficacy of study intervention.
16. Any other medical condition that the site investigator deems would put the patient at excessive risk of participation in the study or an expected life expectancy less than 1 year or that would result in inability to collect clinical outcomes at 30 days.
17. Systolic blood pressure above 200mm Hg.
18. Cannot tolerate inflation of the tourniquet on their arm consistent with blood pressure cuff.