Remote ischaemic conditioning for neurological disorders-a systematic review and narrative synthesis

INTRODUCTION

Remote ischaemic conditioning (RIC) refers to the use of controlled transient ischemic and reperfusion cycles, commonly of the upper or lower limb, to mitigate cellular damage from ischaemic injury. Preclinical studies demonstrate that RIC may have a neuroprotective effect and therefore could represent a novel therapeutic option in the management of neurological disorders. The aim of this review is to comprehensively describe the current clinical evidence of RIC in neurological disorders.

METHODS

A computerised search of EMBASE and OVID MEDLINE was conducted from 2002 to October 2023 for randomised controlled trials (RCTs) investigating RIC in neurological diseases.

RESULTS

A total of 46 different RCTs in 12 different neurological disorders (n = 7544) were included in the analysis. Conditions included acute ischaemic stroke, symptomatic intracranial stenosis and vascular cognitive impairment. The most commonly used RIC protocol parameters in the selected studies were as follows: cuff pressure at 200 mmHg (27 trials), 5-min cycle length (42 trials), 5 cycles of ischaemia and reperfusion (24 trials) and the application to the upper limb unilaterally (23 trials).

CONCLUSIONS

The comprehensive analysis of the included studies reveals promising results regarding the safety and therapeutic effect of RIC as an option for managing neurological diseases. Particularly, the strongest evidence supports its potential use in chronic stroke patients and vascular cognitive impairment. The neuroprotective effects of RIC, as demonstrated in preclinical studies, suggest that this therapeutic approach could extend its benefits to various other diseases affecting the nervous system. However, to establish the efficacy of RIC across different neurological disorders, further trials with larger sample sizes and more diverse patient populations are warranted. Upcoming trials are expected to provide valuable evidence that will not only confirm the efficacy of RIC in neurological disease management but also help identify the most optimal RIC regimen for specific conditions.

Remote ischaemic conditioning for fatigue after stroke (RICFAST): A pilot randomised controlled trial

BACKGROUND

Post stroke fatigue (PSF) affects 50 % of stroke survivors, and can be disabling. Remote ischaemic conditioning (RIC), can preserve mitochondrial function, improve tissue perfusion and may mitigate PSF. This pilot randomised controlled trial evaluates the safety and feasibility of using RIC for PSF and evaluated measures of cellular bioenergetics.

METHODS

24 people with debilitating PSF (7 item Fatigue Severity Score, FSS-7 > 4) were randomised (1:1) in this single-centre phase 2 study to RIC (blood pressure cuff inflation around the upper arm 200 mmHg for 5 min followed by 5 min of deflation), or sham (inflation pressure 20 mmHg), repeated 4 cycles, 3 times per week for 6 weeks. Primary outcomes were safety, acceptability, and compliance. Secondary outcomes included FSS-7, 6 min walking test (6MWT), peak oxygen consumption (V̇O2peak), ventilatory anaerobic threshold (VAT), and muscle adenosine triphosphate (ATP) content measured using 31-phosphorous magnetic resonance spectroscopy of tibialis anterior.

RESULTS

RIC was safe (no serious adverse events, adverse events mild) and adherence excellent (91 % sessions completed). Exploratory analysis revealed lower FSS-7 scores in the RIC group compared to sham at 6 weeks (between group difference FSS-7 -0.7, 95 %CI -2.0 to 0.6), 3 months (-1.0, 95 %CI -2.2 to 0.2) and 6 months (-0.9, 95 %CI -2.0 to 0.2). There were trends towards increased VAT, increased muscle ATP content and improved 6MWT in the RIC group.

DISCUSSION

RIC is safe and acceptable for people with PSF and may result in clinically meaningful improvements in fatigue and muscle bioenergetics that require further investigation in larger studies.

Secondary prevention with a structured semi-interactive stroke prevention package in INDIA (SPRINT INDIA): a multicentre, randomised controlled trial

BACKGROUND

There is a high burden of stroke, including recurrent stroke, in India. We aimed to assess the effect of a structured semi-interactive stroke prevention package in patients with subacute stroke to reduce recurrent strokes, myocardial infarction, and death.

METHODS

This was a multicentre, randomised, clinical trial conducted in 31 centres of the Indian Stroke Clinical Trial Network (INSTRuCT). Adult patients with first stroke and access to a mobile cellular device were randomly allocated (1:1) to intervention and control groups by the research coordinators at each centre using a central, in-house, web-based randomisation system. The participants and research coordinators at each centre were not masked to group assignment. The intervention group received regular short SMS messages and videos that promoted risk factor control and medication adherence and an educational workbook, in one of 12 languages, and the control group received standard care. The primary outcome was a composite of recurrent stroke, high-risk transient ischaemic attack, acute coronary syndrome, and death at 1 year. The outcome and safety analyses were done in the intention-to-treat population. The trial is registered with ClinicalTrials.gov, NCT03228979 and Clinical Trials Registry-India (CTRI/2017/09/009600) and was stopped for futility after interim analysis.

FINDINGS

Between April 28, 2018, and Nov 30, 2021, 5640 patients were assessed for eligibility. 4298 patients were randomised to the intervention group (n=2148) or control group (n=2150). 620 patients were not followed up at 6 months and a further 595 patients were not followed up at 1 year because the trial was stopped for futility after interim analysis. 45 patients were lost to follow-up before 1 year. Acknowledgment of receipt of the SMS messages and videos by the intervention group patients was low (17%). The primary outcome occurred in 119 (5·5%) of 2148 patients in the intervention group and 106 (4·9%) of 2150 patients in the control group (adjusted odds ratio 1·12; 95% CI 0·85-1·47; p=0·370). Among the secondary outcome measures, alcohol cessation and smoking cessation were higher in the intervention group than in the control group (alcohol cessation 231 [85%] of 272 in the intervention group vs 255 [78%] of 326 in the control group; p=0·036; smoking cessation 202 [83%] vs 206 [75%]; p=0·035). Medication compliance was better in the intervention group than in the control group (1406 [93·6%] of 1502 vs 1379 [89·8%] of 1536; p<0·001). There was no significant difference between the two groups in other secondary outcome measures at 1 year: blood pressure, fasting blood sugar (mg/dL), low-density lipoprotein cholesterol (mg/dL), and triglycerides (mg/dL), BMI, modified Rankin Scale, and physical activity.

INTERPRETATION

A structured semi-interactive stroke prevention package did not reduce vascular events when compared with standard care. However, there was an improvement in some lifestyle behavioural factors, including adherence to medication, which might have long-term benefits. There was a possibility of type 2 error owing to reduced power since there were fewer events and a high number of patients could not be followed up.

FUNDING

Indian Council of Medical Research.

Assessment of remote ischemic conditioning delivery with optical sensor in acute ischemic stroke: Randomised clinical trial protocol

BACKGROUND

Remote ischemic conditioning (RIC) is delivered by a blood pressure cuff over the limb, raising pressure 50 mmHg above the systolic blood pressure, to a maximum of 200 mmHg. The cuff is inflated for five minutes and then deflated for five minutes in a sequential ischemia-reperfusion cycle 4-5 times per session. Elevated pressure in the limb may be associated with discomfort and consequently reduced compliance. Continuous assessment of relative blood concentration and oxygenation with a tissue reflectance spectroscopy (a type of optical sensor device) placed over the forearm during the RIC sessions of the arm will allow us to observe the effect of inflation and deflation of the pressure cuff. We hypothesize, in patients with acute ischemic stroke (AIS) and small vessel disease, RIC delivered together with a tissue reflectance sensor will be feasible.

METHODS

The study is a prospective, single-center, randomized control trial testing the feasibility of the device. Patients with AIS within 7 days from symptoms onset; who also have small vessel disease will be randomized 2:1 to intervention or sham control arms. All patients randomized to the intervention arm will receive 5 cycles of ischemia/reperfusion in the non-paralyzed upper limb with a tissue reflectance sensor and patients in the sham control arm will receive pressure by keeping the cuff pressure at 30 mmHg for 5 minutes. A total of 51 patients will be randomized, 17 in the sham control arm and 34 in the intervention arm. The primary outcome measure will be the feasibility of RIC delivered for 7 days or at the time of discharge. The secondary device-related outcome measures are fidelity of RIC delivery and the completion rate of intervention. The secondary clinical outcome includes a modified Rankin scale, recurrent stroke and cognitive assessment at 90 days.

DISCUSSION

RIC delivery together with a tissue reflectance sensor will allow insight into the blood concentration and blood oxygenation changes in the skin. This will allow individualized delivery of the RIC and improve compliance.

CLINICAL TRIAL REGISTRATION

ClinicalTrials.gov Identifier: NCT05408130, June 7, 2022.

Induced neuroprotection by remote ischemic perconditioning as a new paradigm in ischemic stroke at the acute phase, a systematic review

BACKGROUND

Remote ischemic conditioning during cerebral ischemia (remote ischemic perconditioning, RIPerC) refers to the application of several cycles of brief ischemia and reperfusion (I/R) commonly to a limb, and it represents a new paradigm in neuroprotection with multiple mechanisms of action in ischemic stroke (IS) patients during acute phase. Some clinical trials just finished, and a few others are still ongoing; gather the current knowledge and pull it down to influence the present and future studies was the goal of this paper.

METHODS

A systematic review of published research papers and/or registered clinical trials since 2000 was performed.

RESULTS

Nineteen studies were identified and only four studies were completed. All of them have demonstrated that RIPerC is safe, feasible and well tolerated in IS patients. However, a high heterogeneity of clinical trial characteristics was observed: five (26.3%) randomized clinical trials (RCTs) included only thrombolytic-treated patients, three (15.8%) RCTs only thrombectomy-treated patients, and five (26.3%) RCTs required radiological confirmation of IS. Temporal inclusion criteria vary from 4 h to 48 h. Most of the clinical trials used 4 cycles of RIPerC in the upper non-affected limb. Interestingly, only three (16.7%) RCTs applied RIPerC during the transportation in the ambulance. Neuroimaging outputs were the main endpoints when endovascular therapy was applied; functional outcome is also the main endpoint in large-medium size studies.

CONCLUSIONS

This review summarizes the completed and ongoing clinical trials on RIPerC in IS patients, where RIPerC has been used alone or in combination with recanalization therapies. Ongoing clinical trials will provide new information on the best RIPerC intervention strategy and potentially improve the functional outcome of IS patients; definition of new RIPerC strategies would ideally aim at enhancing tissue preservation, promoting neurological recovery, and stratify patients to improve treatment feasibility.