Effect of remote ischemic conditioning on cerebral blood flow regulation in patients with ischemic stroke: a randomized, controlled trial

Acute ischemic stroke (AIS) is a major contributor to long-term disability despite current therapies. Although remote ischemic conditioning (RIC) has potential benefits in patients with AIS, its underlying mechanisms remain poorly understood. We aimed to explore the effects of RIC on the regulation of cerebral blood flow (CBF) among patients with AIS. This was a randomized controlled trial with participant-and-blinded endpoints that included 120 patients with AIS from June 2023 to May 2024. RIC/sham RIC treatment was performed at a pressure of 200 mmHg or 60 mmHg twice a day for seven consecutive days. The primary efficacy outcome was the difference in CBF regulation 7 days after randomization between the two groups. Patients were followed up for 90 days after randomization to assess modified Rankin Scale (mRS) scores. One hundred and twenty (120) patients with AIS were included in the intention-to-treat population (60 in each group). The results showed that the phase difference, which is a key parameter of CBF regulation, in the RIC group was significantly higher than that in the sham RIC group [affected side: RIC group: 36.84° (interquartile range [IQR], 21.49° to 51.36°), sham RIC group: 28.57° (17.17°, 38.52°), adjusted β coefficient = 11.336, 95% confidence interval (CI) = 4.523–18.149, P = 0.001; unaffected side: RIC group: 35.13° (20.77°, 56.51°), sham RIC group: 30.37° (15.65°, 40.11°), adjusted β coefficient = 11.780, 95% CI = 4.260–19.300, P = 0.002]. Additionally, there were no statistically significant differences in the secondary outcomes including blood pressure, heart rate, cerebral blood flow velocity in the middle cerebral artery, and 90-day mRS scores between the two groups ( P > 0.05). RIC treatment did not increase adverse events during hospitalization. RIC can significantly improve CBF regulation in patients with AIS, which may be an intermediate mechanism by which it benefits this patient population. Clinical Trial Number: NCT05915832, Clinical Trial Registry: ClinicalTrials.gov, Registration Date: 2023-06-23.