Remote Ischemic Conditioning on Infarct Growth in Patients With Acute Ischemic Stroke: Subgroup Analysis From the RESIST Trial

BACKGROUND: Remote ischemic conditioning (RIC) is a promising cerebroprotective strategy, but its effects on early infarct dynamics are unclear. We assessed whether RIC reduces acute-to-24-hour infarct growth on magnetic resonance imaging in this predefined RESIST substudy (Remote Ischemic Conditioning in Patients With Acute Stroke). METHODS: We included consecutive patients with acute ischemic stroke from a single RESIST center where acute and 24-hour magnetic resonance imaging were acquired. Infarcts were automatically segmented on diffusion-weighted images using a combined deep learning algorithm. For the primary analysis, brain infarct volume (mL) was analyzed using a linear mixed-effects model with group (RIC versus sham), scan time (baseline/24 hours), their interaction (group×scan), age, and prehospital stroke severity as predictors. Secondary analyses comprised stratified subgroup analyses by age, sex, smoking, diabetes, hypertension, arterial fibrillation, previous acute ischemic stroke, National Institutes of Health Stroke Scale scores, reperfusion treatment, and change from baseline. RESULTS: Of 384 screened patients with acute ischemic stroke, 346 were analyzed (RIC=162; sham=184) with similar baseline characteristics (age, 71 [interquartile range, 62–80] versus 73 [interquartile range, 64–78] years; female 34% versus 36%). Median infarct growth was similar (RIC, 0.45 [interquartile range, −0.54 to 2.86] versus sham, 0.40 mL [interquartile range, −0.50 to 4.74]). The mean infarct growth from acute to 24-hour magnetic resonance imaging was comparable between the RIC group (6.19 [range, −44.94 to 277.01] mL) and the sham group (5.80 [range, −66.18 to 182.13] mL). No significant differences in infarct growth were found between groups, and subgroup analyses likewise showed no significant differences across National Institutes of Health Stroke Scale score or reperfusion categories. CONCLUSIONS: In this RESIST substudy, combined prehospital and early in-hospital RIC was not associated with differences in early diffusion-weighted imaging–based infarct growth compared with sham.