Review question

What are the benefits of using remote ischaemic conditioning (a noninvasive physical therapy that involves inflating blood pressure cuffs to reduce blood flow in arms and legs, and then releasing the affected blood around the body) in people with stroke or those at risk of stroke caused by low blood flow?

Background

Stroke is the leading cause of adult disability globally, and ischaemic stroke (caused by reduced blood flow) accounts for most strokes. Nearly a quarter of individuals with ischaemic stroke will experience further events (recurrent stroke). Remote ischaemic conditioning (RIC) is a strategy to protect and prevent damage to brain tissue by improving its ability to tolerate reduced blood flow. Studies have suggested that RIC may have beneficial effects for preventing and treating ischaemic stroke.

Study characteristics

This review included seven studies (specifically randomised controlled trials), involving 735 people. The studies compared RIC with sham RIC or medical management in people with ischaemic stroke or at risk of ischaemic stroke. Three trials (involving 371 people) were eligible for our analysis of RIC for preventing ischaemic stroke, and another four trials (involving 364 people) were eligible for our analysis of RIC for treating ischaemic stroke. The included trials were carried out in China, Denmark, and the UK.

Key results

The results of this review are current up to January 2018. In people with narrowing of arteries in the brain, RIC may reduce the risk of recurrent stroke. In people being treated with stenting (the insertion of a metal or plastic tube) for narrowed arteries in the neck, RIC may reduce the size of new brain injuries caused by reduced blood flow. However, its effect on clinical outcomes (stroke and death) was unclear. Adverse events were significantly more common in the RIC group but were not reported to be severe.

Among people with acute ischaemic stroke (where it had only been several hours from symptom onset) who received clot-dissolving medicines, we found that RIC may increase the risk of death or dependency (needing help from others). We found no significant differences in the size of the final stroke. In people with acute ischaemic stroke and chronic blood vessel disease of the brain, RIC did not affect measures of nerve function, mood, or thinking ability.

Quality of evidence

There is low-quality evidence which suggests that RIC may help prevent recurrent stroke in people with narrowed arteries in the brain, and may increase death or dependency in people with acute ischaemic stroke who received clot dissolving medication. The evidence is less clear for reducing the volume of the stroke (size of brain lesion caused by low blood flow). Further research is likely to have an important impact on our confidence in these findings.