Monitoring of Remote Ischemic Conditioning with a Tissue Reflectance Sensor: A Randomized Control Trial.

INTRODUCTION

Remote ischemic conditioning (RIC) is delivered by a transient (5 min) pressure increase in the arm BP cuff by a variable 30-50 mmHg above systolic BP to a maximum of 200 mmHg. This inconsistency in pressure application may affect the fidelity of intervention delivery. We tested the hypothesis that monitoring remote ischemic conditioning (RIC) with an adjunct forearm skin tissue reflectance sensor (STRS) device may be feasible in patients with acute ischemic stroke (AIS) and cerebral small vessel disease (cSVD).

METHODS

We screened patients with AIS within 7 days of symptom onset for moderate-to-severe cSVD. Eligible patients were randomized 2:1 to receive intervention RIC or sham RIC. The primary outcome measure was a composite feasibility of the forearm STRS (patient-level comfort and technical aspects measured by IOx1 and IOx2). The secondary outcome was changes in forearm STRS-derived tissue reflectance responses during the pressure-on phase (5 min) and the early pressure-off phase (1 min) of RIC. Multivariable linear regression analysis assessed the relationship between IOx1 and intervention allocation. We also used receiver operating characteristic curve analysis to propose candidate thresholds for classifying the magnitude of the tissue oxygenation response to RIC.

RESULTS

Fifty-one [34 intervention (68 RIC sessions), 17 sham (29 RIC sessions)] patients with mean ± SD age of 69±12.8 years, 24(47.1%) were females, were enrolled at a median (IQR) 42(26-78) hours after symptom onset, and median baseline National Institute of Health stroke Scale of 5(3-7). STRS-derived median relative IOx1(β = 0.33, p = 0.002) and median relative IOx2 (β = 0.23, p = 0.04) slopes during the pressure-on phase were different in the intervention arm compared to the sham arm. A percent IOx1 change of 4- 13.7% can be considered a threshold to differentiate between intervention and sham treatment. The median Likert scale score was similar: 3.5 (3-4) in the intervention group and 4 (4-5) in the sham group.

CONCLUSION

RIC monitoring with forearm STRS is feasible in patients with AIS. Clinical trials evaluating the efficacy of RIC interventions can use STRS to assess fidelity.

CLINICAL TRIAL REGISTRATION NUMBER: ClinicalTrials.gov ID: NCT05408130 (https://clinicaltrials.gov/study/NCT05408130).