Remote Ischemic Pre-Conditioning in Subarachnoid Hemorrhage: A Prospective Randomized Pilot Trial

Abstract

Background: Remote ischemic preconditioning (RIPC) is an innate mechanism of organ protection in response to transient ischemia in a distant organ. This pilot trial looks to apply RIPC in patients with aneurysmal subarachnoid hemorrhage (aSAH) to gauge its effect on clinical outcomes. Methods: Patients were randomized to the high pressure occlusion group (HPO) or the low pressure occlusion group (LPO). Retrospectively matched controls were also analyzed. The HPO under went lower extremity RIPC treatments on non-consecutive days. Each treatment was 4 five-minute cycles of manual blood pressure cuff inflation with loss of a distal pulse. LPO received cuff inflation but with pulses present, all other procedures were same as HPO. Primary outcome of vasospasm was measured with neurological change and confirmed with radiological study. Findings: The final analysis was done on 33 patients with 11 in each group. Patient demographics, aneurysm location, admission intubation, GCS, mRankin score, Hunt and Hess score, Fisher Grade and aneurysm management were not significantly different between groups. Vasospasm was not different between groups. Secondary outcome of hospital length of stay (LOS) was shorter in LPO compared to the control (p=0·0400). ICU LOS was also shorter in LPO compared to the control (p= 0·0354). DCI, one and six month mRankin score, and mortality were not significantly different between the groups. Interpretation: A difference in vasospasm was not noted between groups but there was decreased hospital and ICU LOS in the LPO compared to the control group. It has been previously noted that vasospasm do not correlate well with DCI or outcomes. Although DCI was not statistically significant between groups there was increased DCI in the control group compared to LPO. This may be the reason for the LOS improvement. Future studies should focus on DCI and outcome measures to evaluate efficacy of RIPC. Clinical Trial Registration Number: Registered on Clinicaltrials.gov, number NCT02381522. Funding Statement: This study was departmentally funded. No external funding source. Declaration of Interests: All authors have no conflicts of interest. Ethics Approval Statement: Approval was obtained from our University’s Institutional Review Board (#5150015).