Non-invasive vagus nerve stimulation for acute stroke

In a first-in-human, sham-controlled study, non-invasive vagus nerve stimulation (VNS) was safe and feasible for the acute treatment of ischaemic and haemorrhagic stroke. Infarct growth was relatively small, which may be an indication of efficacy.

Results from preclinical studies have suggested that VNS can be helpful to treat acute stroke and facilitate the benefits of rehabilitation interventions. However, the invasive nature of this treatment clearly limits clinical application [1]. Non-invasive VNS is a recently developed alternative. Safety, feasibility, and potential efficacy of non-invasive VNS was assessed in a randomised, blind, sham-controlled, multicentre study. Prof. Ethem Murat Arsava (Hacettepe University, Turkey) presented the results [2].

A total of 68 participants admitted to 9 clinical sites had acute ischaemic (n=60) or haemorrhagic stroke (n=8) and all received standard care. They were randomised to receive low- or high-dose non-invasive VNS, or sham no later than 6 hours after onset of stroke. Non-invasive VNS was applied to 44 patients, sham to 24 patients. No differences were observed in baseline characteristics between the 2 groups. Low-dose non-invasive VNS consisted of 7 stimulations of 2 minutes each applied to the skin overlying the vagus nerve every 10 minutes for 1 hour; high-dose non-invasive VNS was a double amount of 14 stimulations of 2 minutes every 10 minutes during hour 1 and hour 5. Safety was assessed 2 and 5 minutes after each stimulation and 30 minutes after the final stimulation, and included measures of severe bradycardia (≤50 beats/min) and significant hypotension (≥20 mmHg reduction in arterial blood pressure). Efficacy was evaluated in terms of absolute and relative infarct growth, measured by diffusion-weighted imaging, at baseline and 24 hours post stroke, and the percentage of patients with an NIH Stroke Scale (NIHSS) score of ≤4 points, or with a ≥8-point improvement after 24 hours.

The active treatment showed to be feasible, with all patient receiving all intended stimulation. The results further suggest that non-invasive VNS is safe, as it was not associated with a significantly higher risk of either bradycardia (non-invasive VNS 3.1% vs sham 2.9%; P=0.965) or hypotension (non-invasive VNS 2.5% vs sham 1.1%; P=0.145). No acute coronary syndrome, symptomatic intracerebral haemorrhage, or stimulation site reactions were detected, nor were there any deaths.

Clinical efficacy measures were similar in the sham and non-invasive VNS group. Relative infarct growth was considerably lower in the high-dose non-invasive VNS group than in the sham group (63.3% vs 185.8%; P=0.05), indicating possible efficacy.

1. Li L, et al. Front Neurosci. 2022;16:820665.


2. Arsava EM, et al. Non-invasive vagus nerve stimulation for the acute treatment of stroke. S17.010, AAN 2022, 02–07 April, Seattle, USA.

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Posted on 2 June, 2022