Introduction: Remote ischemic conditioning (RIC) is a phenomenon by which brief periods of sublethal ischemia in one tissue confers protection from ischemic injury to distant tissues. The RIC safety and feasibility must be assessed before applying it in efficacy trials. We report a phase I trial of feasibility and safety of RIC in patients with aneurysmal subarachnoid hemorrhage (aSAH).
Methods: Patients with aSAH received 2-4 RIC sessions on non-consecutive days. A complete session was defined as four rounds of 5 minutes of lower limb ischemia followed by 5 minutes of reperfusion (verified by pedal Doppler). Primary end-points were tolerance to the procedure and any complication attributable to RIC. Secondary end-points included cerebral infarction or hemorrhage.
Results: Twenty patients (70% female, mean age 52, Fisher 3.5, H&H 3.3) were enrolled. Seventeen had evidence of vasospasm during hospitalization. Of 76 RIC sessions performed, 75 were completed and tolerated. One session was incomplete due to poor cooperation secondary to delirium. No patients developed DVTs or other local complications within 2 weeks of their final RIC session. No patients suffered cerebral infarction or hemorrhage throughout the duration of RIC sessions and through 72 hours after their last complete session. Three had infarction confirmed on MRI at 3 and 5 days following the final RIC session.
Conclusions: In aSAH patients, RIC was successfully applied and well tolerated with no procedure-related complications. Moreover, no patient suffered ischemic stroke within 72 hours of a RIC session, consistent with our previous studies showing protective cerebral metabolic changes up to 48 hours after complete RIC sessions. These results suggest that application of RIC as a protective strategy is safe and feasible and may be associated with transient tolerance to ischemia during the treatment period. The efficacy of RIC as neuroprotection should be investigated in larger controlled trials.
Patient Care: This research demonstrates the feasibility of remote ischemic conditioning in patients with aneurysmal subarachnoid hemorrhage and will provide new avenues of investigation in the treatment of acute ischemic stroke.
Learning Objectives: By the conclusion of this session, participants should be able to: 1) Recognize the feasibility of remote ischemic conditioning in subarachnoid hemorrhage patients, 2) Discuss other contexts where remote ischemic conditioning could be feasible.