Vagus Nerve Stimulation in Intracerebral and Subarachnoid Haemorrhage: A Systematic Review, Narrative Synthesis and Exploratory Meta-Analysis

The study examined the effectiveness of vagus nerve stimulation (VNS) in hemorrhagic stroke, including intracerebral and subarachnoid hemorrhage. Researchers analyzed 9 studies comprising 4 preclinical experiments on 179 animals and 5 clinical trials with 166 participants. In preclinical studies, VNS reduced inflammatory response, decreased hemorrhage volume, and improved motor recovery. In clinical trials, non-invasive VNS was safe and well tolerated, with signs of reduced inflammatory markers and decreased cerebral vasospasm. Combined analysis showed more favorable functional outcomes with VNS, but the difference was not statistically significant. The authors concluded that VNS is biologically active and feasible, but its effectiveness remains unproven and further large clinical trials are needed.