In remote preconditioning, ischemia in one organ protects distant organs from ischemic
insults. e.g. brief induced limb ischemia protects the brain from an otherwise more severe
stroke. The investigators propose a study of limb preconditioning in subjects with
subarachnoid hemorrhage who are at high risk of cerebral ischemia in the first 2 weeks after
hemorrhage. The investigators have previously shown that 3x 10min leg conditioning cycles
are tolerated and appear safe. The investigators are now continuing to assess the safety of
the intervention by enrolling an additional 60 patients.
The study will enroll patients with subarachnoid hemorrhage, who generally have a high risk
of ischemic stroke in the 2 weeks following the initial bleed, and patients with clipped or
coiled aneurysm. The study intervention will consist of the application a blood pressure
cuff around the subjects arm or leg and use it to interrupt the circulation to the arm or
leg for 10 minutes. This will be repeated for a total of 3 times every 24 to 48 hours up to
14 days. The cuff will be inflated for 10 minutes and then deflated for 5 minutes. There
will be 3 cycles of this. The cuff will be inflated to 200mmHg.
The primary endpoints are safety in nature and defined as follows:
1. If the prolonged upper or lower extremity application of blood pressure cuff should
induce tissue breakdown, ischemic injury or musculoskeletal injury patient will be
withdrawn from the study.
2. If the subject does not wish to continue with limb preconditioning because of
discomfort or pain.
3. Any unexplained neurological deterioration will be carefully reviewed and the etiology
ascertained. If this should temporally coincide with the preconditioning stimulus on at
least 2 occasions the patient will be withdrawn from the study.
4. Any unexplained cardiovascular event (myocardial ischemia, chest pain, hypotension)
will be carefully monitored and the etiology reviewed. Any temporal association with
the pre-conditioning protocol will be examined.
5. Deep vein thrombosis. Patients with subarachnoid hemorrhage have a high incidence of
deep vein thrombosis. It will be difficult to determine if this is due to the
intervention or not. The investigators will carefully monitor deep vein thrombosis in
the preconditioned leg and compare that to the incidence in the non-preconditioned leg.
The Data Safety Monitoring Board (DSMB) will make final adjudication of the relation of
preconditioning procedure and development of deep vein thrombosis.
- Patients with aneurysmal subarachnoid hemorrhage whose initial angiogram show an
aneurysm and patients with clipped aneurysm will be eligible for enrollment.
- Patients will be enrolled within 96 hours of bleeding onset, if informed consent is
obtained from the participant or health care proxy, as appropriate.
- Hunt Hess Scale > 4
- Inability to undergo limb preconditioning due to local wound or tissue breakdown,
history of peripheral extremity vascular disease or patient discomfort.
- Inability to obtain informed consent from the patient or a health care proxy.
- Ankle-brachial index < 0.7
- Inability to start limb preconditioning within 4 days of bleeding.
- Inability to precondition a leg that is not-plegic (that is preserved anti- gravity
strength) and has not been accessed for catheter angiography
- Age<18 years
- Pregnant women