As per results from the RESIST study, remote ischaemic conditioning (RIC)—while not being associated with any major safety issues—has failed to improve functional outcomes in patients with acute ischaemic stroke.
These findings were presented today at the European Stroke Organisation Conference (ESOC; 24–26 May, Munich, Germany) by Rolf Blauenfeldt (Aarhus University Hospital, Aarhus, Denmark), who noted that, nevertheless, subgroup analyses of the study are “warranted” to explore possible subsets of patients who could benefit from RIC, and to inform the design of more individualised trials in the future.
The multicentre, prospective, randomised, patient assessor-blinded, sham-controlled RESIST trial was designed to assess the efficacy of RIC in improving 90-day functional outcomes in acute stroke patients.
A total of 1,500 patients suspected of having an acute stroke were enrolled in the study. They were randomly assigned to RIC or a sham treatment that was started in the ambulance, and continued during hospital admission. Notably, half of these patients were included in the first hour after symptom onset.
Some 149 patients (10%) had transient ischaemic attack and 382 (27%) had a ‘stroke mimic’, and did not fulfill the inclusion criteria. The target population was represented by 902 patients with a confirmed diagnosis of ischaemic or haemorrhagic stroke—436 of whom were treated with RIC and 466 treated with sham.
Treatment with RIC was not associated with a shift towards better functional outcomes on the modified Rankin scale (mRS) at 90 days, as per the trial’s primary endpoint. RIC was also not found to be superior to sham treatments in other key secondary endpoints. There were no safety issues related to the intervention.
While, overall, results from the RESIST trial failed to demonstrate the efficacy of early conditioning in acute stroke, Blauenfeldt did state that these findings “do not exclude the possibility” that RIC may be effective if used bilaterally (in two extremities); for a longer duration; or in certain stroke sub-populations like intracranial arterial stenosis or small vessel disease.
In a later ESOC session, on Friday 26 May, a detailed subgroup analysis from RESIST was also presented by Blauenfeldt. In patients with a stroke due to small vessel disease and who had at least 80% treatment adherence, RIC “significantly increased” the chances of an improved functional outcome at 90 days. Blauenfeldt noted that, despite this being a predefined subgroup analysis, the overall trial was neutral and no corrections for multiple comparisons had been made. As such, he stated that the results “should be interpreted with caution”, but may serve as a base for planning future trials on RIC and stroke due to small vessel disease.