STUDY PROTOCOL published: 25 September 2020 doi: 10.3389/fneur.2020.569696 REMOTE Ischemic Perconditioning Among Acute Ischemic Stroke Patients in Catalonia: REMOTE-CAT Edited by: PROJECT Bruno Meloni, University of Western Francisco Purroy 1,2*† , Gloria Arque 2† , Gerard Mauri 1,2 , Cristina García-Vázquez 2 , Australia, Australia Mikel Vicente-Pascual 1,2 , Cristina Pereira 2 , Daniel Vazquez-Justes 1,2 , Reviewed by: Coral Torres-Querol 2 , Ana Vena 1,2 , Sònia Abilleira 3 , Pere Cardona 4 , Carles Forné 5† , Craig S. Anderson, Xavier Jiménez-Fàbrega 6 , Jorge Pagola 7 , Manuel Portero-Otin 8 , University of New South Ana Rodríguez-Campello 9 , Àlex Rovira 10 and Joan Martí-Fàbregas 11 Wales, Australia Vasileios-Arsenios Lioutas, 1 Stroke Unit, Department of Neurology, Hospital Universitari Arnau de Vilanova de Lleida, Lleida, Spain, 2 Clinical Beth Israel Deaconess Medical Center Neurosciences Group, Institut de Recerca Biomèdica de Lleida (IRBLleida), Universitat de Lleida, Lleida, Spain, 3 Stroke and Harvard Medical School, Programme, Agency for Health Quality and Assessment of Catalonia, CIBER Epidemiología y Salud Pública (CIBERESP), United States Barcelona, Spain, 4 Stroke Unit, Hospital de Bellvitge, Hospitalet de Llobregat, Spain, 5 Department of Basic Medical *Correspondence: Sciences, Universitat de Lleida, Lleida, Spain, 6 Servei d’Emergències Mèdiques, Hospitalet de Llobregat, Spain, 7 Stroke Francisco Purroy Unit, Neurology Department, Vall d’Hebron Hospital, Barcelona, Spain, 8 Department of Experimental Medicine, fpurroygarcia@gmail.com NUTREN-Nutrigenomics, Biomedical Institut de Recerca Biomèdica de Lleida (IRBLleida), Universitat de Lleida, Lleida, Spain, 9 Neurovascular Research Group, Neurology Department, Institut Hospital del Mar d’Investigacions Mèdiques-Hospital del † ORCID: Mar, Departament de Medicina, Universitat Autònoma de Barcelona, Barcelona, Spain, 10 Section of Neuroradiology and MRI Francisco Purroy Unit, Department of Radiology, Hospital Universitari Vall d’Hebron, Universitat Autònoma de Barcelona, Barcelona, Spain, orcid.org/0000-0002-1808-5968 11 Stroke Unit, Hospital de Sant Pau, Barcelona, Spain Gloria Arque orcid.org/0000-0002-8039-3726 Carles Forné Rationale: Remote ischemic perconditioning during cerebral ischemia (RIPerC) refers orcid.org/0000-0002-8133-3274 to the application of brief episodes of transient limb ischemia commonly to a limb, it represents a new safe, simple and low-cost paradigm in neuroprotection. Specialty section: This article was submitted to Aim and/or Hypothesis: To evaluate the effects of RIPerC on acute ischemic stroke Stroke, a section of the journal (AIS) patients, applied in the ambulance, to improve functional outcomes compared with Frontiers in Neurology standard of care. Received: 04 June 2020 Sample Size Estimates: A sample size of 286 patients in each arm achieves 80% power Accepted: 27 August 2020 Published: 25 September 2020 to detect treatment differences of 14% in the outcome, using a two-sided binomial test Citation: at significance level of 0.05, assuming that 40% of the control patients will experience Purroy F, Arque G, Mauri G, good outcome and an initial misdiagnosis rate of 29%. García-Vázquez C, Vicente-Pascual M, Pereira C, Methods and Design: We aim to conduct a multicentre study of pre-hospital RIPerC Vazquez-Justes D, Torres-Querol C, application in AIS patients. A total of 572 adult patients diagnosed of suspected Vena A, Abilleira S, Cardona P, Forné C, Jiménez-Fàbrega X, clinical stroke within 8 h of symptom onset and clinical deficit >0 according to Pagola J, Portero-Otin M, prehospital rapid arterial occlusion evaluation (RACE) scale score will be randomized, Rodríguez-Campello A, Rovira À and in blocks of size 4, to RIPerC or sham. Patients will be stratified by RACE score Martí-Fàbregas J (2020) REMOTE Ischemic Perconditioning Among scale. RIPerC will be started in the ambulance before hospital admission and Acute Ischemic Stroke Patients in continued in the hospital if necessary. It will consist of five cycles of electronic Catalonia: REMOTE-CAT PROJECT. Front. Neurol. 11:569696. tourniquet inflation and deflation (5 min each). The cuff pressure for RIPerC will doi: 10.3389/fneur.2020.569696 be 200 mmHg during inflation. Sham will only simulate vibration of the device. Frontiers in Neurology | www.frontiersin.org 1 September 2020 | Volume 11 | Article 569696 Purroy et al. Remote-Cat Project Study Outcome(s): The primary outcome will be the difference in the proportion of patients with good outcomes as defined by a mRS score of 2 or less at 90 days. Secondary outcomes to be monitored will include early neurological improvement rate, treatment related serious adverse event rates, size of the infarct volume, symptomatic intracranial hemorrhage, metabolomic and lipidomic response to RIPerC and Neuropsychological evaluation at 90 days. Discussion: Neuroprotective therapies could not only increase the benefits of available reperfusion therapies among AIS patients but also provide an option for patients who are not candidates for these treatments. REMOTE-CAT will investigate the clinical benefit of RIC as a new neuroprotective strategy in AIS. Clinical Trial Registration: www.ClinicalTrials.gov, identifier: NCT03375762. Keywords: ischemic stroke, remote ischemic perconditioning (rPerC), neuroprotection, infarct size (IS), metabolomics (OMICS) INTRODUCTION AND RATIONALE METHODS Stroke is one of the leading causes of death worldwide and Design the main cause of disability (1). Currently, the only therapies REMOTE-CAT is a prospective randomized controlled for acute ischemic stroke (AIS) patients are the administration multicentre clinical trial that follows CONSORT statement of rt-PA (2) and/or endovascular treatment (3). Unfortunately, (12). The study will be performed in accordance with the many patients cannot benefit from these therapies due to standards of good clinical practice (International committee on their contraindications or evolution time. Neuroprotective Harmonization of E6 Guideline for Good Clinical Practice) and therapies could not only increase the benefits of available the latest revision of the Declaration of Helsinki. The study has reperfusion therapies but also provide an option for patients been approved by the Ethics Committee on Clinical Research who are not candidates for these treatments (4). However, of the Hospital Universitari Arnau de Vilanova of Lleida most neuroprotection trials have so far failed to demonstrate (approval code 1744). All patients will provide written informed their efficacy in AIS patients, despite promising results in consent. The protocol is registered in ClinicalTrials.gov identifier animal studies (4). Remote ischemic perconditioning (RIPerC) is NCT03375762. represents a new paradigm in neuroprotection (5). It potential upregulates endogenous defense systems to achieve ischemic Patient Population tolerance in brain ischemia (6). It consists of brief episodes Inclusion and exclusion criteria are detailed in Table 1. of transient limb ischemia. According to studies in coronary Summarizing, REMOTE-CAT focuses on patients with suspected ischemia, RIPerC during the ischemic event is safe, feasible, and acute stroke identified in the pre-hospital setting by emergency related to a decrease in myocardial injury (7). However, there is medical services (EMS). The EMS is a public company limited data about the clinical utility of RIPerC in AIS patients. responsible for urgent prehospital care including Code Stroke Only four randomized clinical trials (RCTs) have been completed (CS) patients. We will include consecutive adult subjects (age and published (8–11). All of them demonstrated that RIC is safe ≥18 years old) with CS activation will be included. CS activation and feasible in AIS. One has been conducted to test RIPerC in criteria include neurologic impairment suggestive of acute stroke a prehospital setting in AIS patients and as an adjunct treatment according to FAST criteria (13), time from symptom onset of with intravenous alteplase (11). Two other small-size studies were <8 h and previous functional independence (modified Rankin only designed to evaluate the safety and feasibility of RIC in Scale, mRS≤2). Patients should have at least motor impairment AIS patients recruited within 24 h of onset of symptoms (8) and (Figure 1). Baseline assessments and study procedures are in alteplase treated patients (9). The last and the largest study reported in Table 2. included 188 patients with confirmed carotid ischemic stroke within 6 h of symptoms onset (10). None of them demonstrated a Randomization significant clinical effect or a significant effect on brain infarction First, patients will be stratified using the rapid arterial occlusion volume growth. evaluation (RACE) scale score (14) and then, they will be We aim to conduct a multicentre study of pre-hospital RIPerC randomly allocated in blocks of size four, to either receive in AIS patients applied within 8 h of stroke onset. Our hypothesis remote ischemic conditioning (RIPerC group) or sham in the is that RIPerC would be safe and would induce endogenous ambulance. An on-call physician not involved in the study will neuroprotective phenomena associated with good outcomes in perform the randomization using a computer program located in AIS patients treated with revascularization therapies or not. a web server. Frontiers in Neurology | www.frontiersin.org 2 September 2020 | Volume 11 | Article 569696 Purroy et al. Remote-Cat Project TABLE 1 | Inclusion and exclusion criteria. In all eligible patients, a brain MRI will be performed within 3–4 days of the onset of symptoms, including the following Inclusion criteria sequences: (1) transverse T2-FLAIR; (2) transverse T2∗ -weighted • Age above 18 years old gradient-echo; (3) transverse diffusion-weighted (DWI) single- • Suspected clinical stroke within 8 h of onset of neurological symptoms shot echo-planar spin-echo; and, (4) axial 3D time-of-flight • Stroke code (SC) activation MR angiography (through the circle of Willis). All participating • Independent in daily living before the acute onset of symptoms (mRs ≤ 2) centers will follow the same protocol. A neuroradiologist blinded • RACE score>0 and RACE motor score>0 • Written informed consent (patient or legal representative) to clinical features and intervention will review the MRI images. Infarct volume will be defined as the hyperintense area on the Exclusion criteria initial isotropic DWI acquired with a b value of 1,000 sec/mm2. In addition, we will use metabolomic and lipidomic analyses • Unknown onset of symptoms to define a panel of serum biomarkers accurately related to • Coma (GCS< 8) RIC phenomenon. For these purposes, in 100 patients (50 sham • Malignancy or significant comorbidity thought to limit life expectancy to <6 months and 50 RIPerC), blood samples for further determination of • Pregnancy metabolomics and lipidomics will be drawn at arrival to hospital, • Participation in other clinical trial related with a research at days 3 and 5 as previously performed (16, 17). As we did not medical product/device have preliminary data and no metabolites have yet been defined RACE, The rapid arterial occlusion evaluation scale; mRs, Modified Rankin scale; GCS, we will performed a non-targeted metabolomics and lipidomic Glasgow Coma Scale. profiling in order to identify differential molecules found in the intervention group. The neuropsychological evaluation will include Montreal Intervention cognitive assessment, trail making test part a and b, the Wechsler RIPerC will consist of automatically delivered five cycles of adult intelligence scale, the free and cued selective reminding electronic tourniquet inflation to the upper non-paretic limb, test, the apathy evaluation scale and the Rey complex figure test. each lasting 5 min and separated by 5 min of cuff deflation. We also performed the Health-related quality of life assessment The cuff will be inflated to 200 mmHg and it will be applied questionnaire (EQ-5D) at 90 days. to the opposite arm to the one experiencing motor and/or sensory deficit in order to reduce the risk of phlebitis and to Data Monitoring Body maintain the somatosensory stimuli. RIPerC will be initiated An independent data safety monitoring board (DSMB) will look by the ambulance staff during transportation and it will be after the safety of the study. It will ensure that the rate of finished for all patients in the ambulance or during Hospital SICH and serious adverse events is similar in the two groups. admission. All patients in both groups will be treated according to An interim analysis will be performed after the inclusion of conventional care procedures following international guidelines. the first 100 patients for early stopping due to safety reasons. Thus, mechanical thrombectomy and intravenous fibrinolysis Moreover, the DSMB could recommend stopping the study for will be allowed. Revascularization therapies will not be delayed safety reasons at any moment and make recommendations to the due to the study. The non-interventionist group will use a sham Executive Committee regarding efficacy, quality and feasibility of device. It will simulate vibration of the device but no inflation will the study. be performed. Discomfort and complications related to RIPerC will be recorded. Sample Size Estimates A sample size of 280 subjects in each arm achieves 80% power to Primary Outcome detect treatment differences of 14% between the intervention and The primary outcome will be the difference in the proportion of the control groups, using a two-sided binomial test at significance patients with good outcomes as defined by a mRS score of 2 or level of 0.05, assuming that 40% of the control patients will less at 90 days. experience good outcome defined by a mRS score of 2 or less at 90 days, and allowing a misdiagnosis rate of 29% (15% of Secondary Outcomes haemorrhagic strokes and 14% of mimic stroke conditions). The secondary outcomes will be: (1) a decrease in the National Two extra interim analyses will be performed at 33 and 67% of Institutes of Health Stroke Scale (NIHSS) score greater or equal recruitment on the primary outcome. Early stopping is planned than 4 between baseline and day one, 5 ± 1 days and 90 if large differences between the study groups are observed in ± 7 days; (2) a mRS score of 2 or less at 5 ± 1 days; (3) order to reduce study participants’ exposure to the inferior study the rate of serious adverse events related to the intervention; arm and saving time and resources. Since repeated significance (4) the rate of symptomatic intracerebral hemorrhage (SICH) testing on accumulating data will be performed, adjustment of defined by the Safe Implementation of Thrombolysis in Stroke the usual hypothesis testing procedure to maintain the overall Monitoring Study protocol at 24–36 hours (15); (5) acute significance level of 0.05 will be done by using the flexible type infarct volume; (6) metabolomic and lipidomic response to I error spending function (18, 19). Due to the interim analyses, RIC; and, (7) neuropsychological evaluation of cognitive and the sample size must be increased by an inflation factor of 1.02, affective domains. resulting in 572 patients (286 per group). Frontiers in Neurology | www.frontiersin.org 3 September 2020 | Volume 11 | Article 569696 Purroy et al. Remote-Cat Project FIGURE 1 | Graphical representation of REMOTE-CAT clinical trial procedures. After Stroke Code activation in the ambulance, remote ischemic perconditioning (RIPerC) is applied by an automatic device during transportion to the nearest Stroke care center. Usual medical care will be performed in the stroke center. Statistical Analyses Handling Missing Data Included patients will be described with respect to demographic If there are missing data, they will be reported for each variable and clinical characteristics, according to the study arm. and missingness mechanism will be explored. Missing values Continuous variables will be summarized using means and could depend on other observed data. We will consider these standard deviations for normally distributed data; or median and missing values as missing at random (MAR). If there is no 25–75% percentiles for non-normally distributed data. Normal correlation between the missing values and other observed data distribution will be assessed by means of the Shapiro–Wilks (i.e., the Little’s test is not statistically significant, p > 0.05) test, rejecting normality when p < 0.05. Categorical data will missing values will be considered missing completely at random be summarized using counts and percentages. Comparisons will (MCAR) (20). If missing values are MAR, a series of multiple be performed by means of the Pearson’s chi-squared test for imputations by chained equations will be performed and the categorical variables; the t-test for normally distributed data; and Rubin’s rules will be used to combine variable estimates and the Mann–Whitney U-test for non-normally distributed data. standard errors (21). If missing values are MCAR, complete case Primary analysis will be performed by means of the binomial analysis will be performed. test. If the study groups are unbalanced, the primary outcome will be compared using a logistic regression model that will include Current Status of the Trial the variables exhibiting baseline differences as covariates. The study started recruitment in August 2019 in one Hospital, Secondary outcomes will be compared using the most and the estimated completion date is August 2022. At 1st August appropriate test according to the distribution of the data. As with 2020: 76 patients have been recruited. the primary analysis, secondary outcomes and safety outcome analyses will be conducted using multivariable generalized linear Study Organization and Funding models with suitable links. FP is the coordinating investigator of the study, which is funded The analysis will be performed on the intention-to-treat by a grant from the Spanish National Ministry of Heath— set and will be repeated on the per-protocol set as a PI17/01725. sensitivity analysis. DISCUSSION RIPerC emerges as an interesting neuroprotective strategy (5). Stratified Analysis Our study improves the previous limited experience in humans All objectives will be assessed in the following stratified (8, 11). It includes all AIS with symptom onset within 8 h and analyses: (i) by sex; (ii) depending on whether patients have not only intravenous alteplase treated patients (11). According undergone thrombectomy; (iii) depending on whether patients to the animal model, it is effective when applied both alone have undergone thrombectomy and treated with rtPA; (iv) and in combination with revascularization therapies (22, 23). whether patients have undergone thrombectomy or treated with Although few studies have been published about the effect of rtPA; and (v) number of cycles of inflation and deflation finished RIC in AIS, some important issues have been learned (8–11). to evaluate a possible dose-response effect. As in Hougaard’s trial (11) and in most of the trials involving Frontiers in Neurology | www.frontiersin.org 4 September 2020 | Volume 11 | Article 569696 Purroy et al. Remote-Cat Project TABLE 2 | Study procedures for eligible patients with AIS. Time points Prehospital Admission 24 h 3 days 5 days 3 months Enrollment Eligibility screen X Patient/family information X X Acute waiver of consent X Randomization X RACE scale X Blood pressure X X‡ Informed consent X AIS confirmation X* X* Demographics and medical history X Reperfusion therapies X Intervention RIC/Sham application X Complications related to RIC X X X X Assessment NIHSS X X X X Modified Rankin scale X X X Neuroimaging X X# MRI X Blood biomarkers X X X Stroke etiology X Quality of life X Neuropsychological evaluation X Safety measurement Intrahospital complications X X SICH X X RACE, rapid arterial occlusion evaluation; AIS, acute ischemic stroke; RIC, remote ischemic conditioning; MRI, magnetic resonance imaging; NIHSS, National Institutes of Health Stroke Scale. ‡ Blood pressure will be reported at the end of RIC/Sham application and 1 h after. *Patients with intracranial hemorrhage will complete the 90 days follow-up. Patients without evidence of brain ischemia will be followed until discharge and through registries. # Patients treated with intravenous rtPA and/or EVT will undergo neuroimaging at 24 h. patients with myocardial infarction (7, 24) it is applied it in patients have silent peripheral arterial disease defined by a low the ambulance, as soon as possible, in order to induce the ankle-brachial index (30). One of the main shortcomings of maximum effect. This action seems to be safe although the the previously mentioned Hougaard’s trial (11) was that fewer definitive diagnosis will not be established until the arrival at the than one out of three patients complete the four cycles of hospital. To date, no serious adverse effects have been reported limb ischemia. We will therefore use an automatic device. To in RIC studies (5, 7–11, 25). The recent RCT published by Pico avoid misdiagnosis only subjects with RACE score of >0 and et al. failed to demonstrate an effect of RIC in the final infarction RACE motor items >0 will be included. Finally, according size in AIS. One explanation of their neutral results was that to the stroke treatment academic industry roundtable (STAIR) the treatment with RIC was performed too late during or after recommendations a clinical endpoint would clearly evaluate the the receipt of reperfusion therapies (10). In addition, we will utility of applying RIPerC in AIS patients. increase the number of cycles to five. Most RIC trials use the four- cycle protocol (7, 11) due to tradition. The ischemic conditioning SUMMARY AND CONCLUSIONS phenomena was first demonstrated using this protocol in an animal model of myocardial infarction (26). Recent studies in RIPerC represents a new paradigm in neuroprotection animal models address the need to increase the number of with limited data in AIS patients. According to previous cycles in order to optimize the efficacy of RIPerC (27). Some preclinical and clinical studies of acute ischemia, a clinical other recent successes in remote ischemic preconditioning (28) RIPerC trial should include both candidates and non- and chronic postconditioning (29) in AIS patients have used candidates for reperfusion therapies. As the RIPerC effect the 5-cycle protocol. Increasing the duration of the cycle to decreases with time, RIPerC should be started during 10 min does not offer any further protection (27). Although the the transfer of stroke code patients. The size of the trial quantity of muscle mass affects the efficacy of the intervention, should be large enough to detect differences in clinical we decided to perform the RIPerC on an upper arm rather outcomes and not only neuroimaging endpoints. Finally, than on a leg for safety reasons as up to one in four AIS the RIC device should be automatic to not only ensure that Frontiers in Neurology | www.frontiersin.org 5 September 2020 | Volume 11 | Article 569696 Purroy et al. Remote-Cat Project patients finish all of the programmed cycles but also to and study conduct. GA, CF, and SA substantively revised the interfere as little as possible with the work of paramedics manuscript. All authors read and approved the final manuscript. during the transfer and of nurses and physicians during the admission. FUNDING ETHICS STATEMENT This study was supported by the Government of Catalonia- Agència de Gestió d’Ajuts Universitaris i de Recerca (FP: 2017 The studies involving human participants were reviewed and SGR 1628), Instituto de Salud Carlos III and co-funded by approved by the Ethics Committee on Clinical Research of European Union (ERDF A way to make Europe) (FP: Project the Hospital Universitari Arnau de Vilanova de Lleida. The PI17-01725) and the INVICTUS plus Research Network (Carlos patients/participants provided their written informed consent to III Health Institute). participate in this study. ACKNOWLEDGMENTS AUTHOR CONTRIBUTIONS The content of this manuscript has been presented in part at FP conceived the study and wrote the paper. FP, GM, CG-V, the European Stroke Organization Conference in 2018, European MV-P, DV-J, and GA were involved in protocol development Stroke Journal 2018, Vol. 3(1S) 160. REFERENCES in patients with acute ischemic stroke: a randomized trial. Stroke. (2014) 45:159–67. doi: 10.1161/STROKEAHA.113.001346 1. Mozaffarian D, Benjamin EJ, Go AS, Arnett DK, Blaha MJ, Cushman M, et al. 12. Schulz KF, Altman DG, Moher D, Group C. CONSORT 2010 statement: American heart association statistics and stroke statistics, heart disease and updated guidelines for reporting parallel group randomised trials. BMJ. (2010) stroke statistics-2016 update: a report from the American heart association. 340:c332. doi: 10.1136/bmj.c332 Circulation. (2016) 133:e38–360. doi: 10.1161/CIR.0000000000000350 13. Harbison J, Hossain O, Jenkinson D, Davis J, Louw SJ, Ford GA. Diagnostic 2. Demaerschalk BM, Kleindorfer DO, Adeoye OM, Demchuk AM, Fugate JE, accuracy of stroke referrals from primary care, emergency room physicians, Grotta JC, et al. American heart association stroke, council on and prevention, and ambulance staff using the face arm speech test. Stroke. (2003) 34:71– scientific rationale for the inclusion and exclusion criteria for intravenous 6. doi: 10.1161/01.STR.0000044170.46643.5E alteplase in acute ischemic stroke: a statement for healthcare professionals 14. Perez de la Ossa N, Carrera D, Gorchs M, Querol M, Millan M, Gomis M, from the American heart association/American stroke association. Stroke. et al. Design and validation of a prehospital stroke scale to predict large (2016) 47:581–641. doi: 10.1161/STR.0000000000000086 arterial occlusion: the rapid arterial occlusion evaluation scale. Stroke. (2014) 3. Saver JL, Goyal M, van der Lugt A, Menon BK, Majoie CB, Dippel 45:87–91. doi: 10.1161/STROKEAHA.113.003071 DW, et al. Time to treatment with endovascular thrombectomy and 15. Wahlgren N, Ahmed N, Davalos A, Ford GA, Grond M, Hacke outcomes from ischemic stroke: a meta-analysis. JAMA. (2016) 316:1279– W, et al. Thrombolysis with alteplase for acute ischaemic stroke 88. doi: 10.1001/jama.2016.13647 in the safe implementation of thrombolysis in stroke-monitoring 4. Chamorro A, Dirnagl U, Urra X, Planas AM. Neuroprotection in study (SITS-MOST): an observational study. Lancet. (2007) acute stroke: targeting excitotoxicity, oxidative and nitrosative stress, and 369:275–82. doi: 10.1016/S0140-6736(07)60149-4 inflammation. Lancet Neurol. (2016) 15:869–81. doi: 10.1016/S1474-4422(16) 16. Purroy F, Cambray S, Mauri-Capdevila G, Jove M, Sanahuja J, 00114-9 Farre J, et al. Metabolomics predicts neuroimaging characteristics 5. Hess DC, Blauenfeldt RA, Andersen G, Hougaard KD, Hoda MN, Ding Y, of transient ischemic attack patients. EBioMed. (2016) 3964:30514– et al. Remote ischaemic conditioning-a new paradigm of self-protection in the X. doi: 10.1016/j.ebiom.2016.11.010 brain. Nat Rev Neurol. (2015) 11:698–710. doi: 10.1038/nrneurol.2015.223 17. Jove M, Mauri-Capdevila G, Suarez I, Cambray S, Sanahuja J, Quilez A, 6. Purroy F, Garcia C, Mauri G, Pereira C, Torres C, Vazquez-Justes D, et al. et al. Metabolomics predicts stroke recurrence after transient ischemic attack. Induced neuroprotection by remote ischemic perconditioning as a new Neurology. (2015) 84:36–45. doi: 10.1212/WNL.0000000000001093 paradigm in ischemic stroke at the acute phase, a systematic review. BMC 18. Kim K, DeMets DL. Confidence intervals following group sequential tests in Neurol. (2020) 20:266. doi: 10.1186/s12883-020-01836-8 clinical trials. Biometrics. (1987) 43:857–64. doi: 10.2307/2531539 7. Man C, Gong D, Zhou Y, Fan Y. Meta-analysis of remote ischemic 19. Lan KKG, DeMets DL. Discrete sequential boundaries for clinical trials. conditioning in patients with acute myocardial infarction. Sci Rep. (2017) Biometrika. (1983) 70:659–63. doi: 10.1093/biomet/70.3.659 7:43529. doi: 10.1038/srep43529 20. Jakobsen JC, Gluud C, Wetterslev J, Winkel P. When and how should 8. England TJ, Hedstrom A, O’Sullivan S, Donnelly R, Barrett DA, Sarmad multiple imputation be used for handling missing data in randomised clinical S, et al. RECAST (Remote ischemic conditioning after stroke trial): a pilot trials - a practical guide with flowcharts. BMC Med Res Methodol. (2017) randomized placebo controlled phase II trial in acute ischemic stroke. Stroke. 17:162. doi: 10.1186/s12874-017-0442-1 (2017) 48:1412–15. doi: 10.1161/STROKEAHA.116.016429 21. White IR, Royston P, Wood AM. Multiple imputation using chained 9. Che R, Zhao W, Ma Q, Jiang F, Wu L, Yu Z, et al. rt-PA with remote ischemic equations: issues and guidance for practice. Stat Med. (2011) 30:377– postconditioning for acute ischemic stroke. Ann Clin Transl Neurol. (2019) 99. doi: 10.1002/sim.4067 6:364–72. doi: 10.1002/acn3.713 22. Hoda MN, Siddiqui S, Herberg S, Periyasamy-Thandavan S, Bhatia 10. Pico F, Lapergue B, Ferrigno M, Rosso C, Meseguer E, Chadenat ML, et al. K, Hafez SS, et al. Remote ischemic perconditioning is effective Effect of in-hospital remote ischemic perconditioning on brain infarction alone and in combination with intravenous tissue-type plasminogen growth and clinical outcomes in patients with acute ischemic stroke: the activator in murine model of embolic stroke. Stroke. (2012) RESCUE BRAIN randomized clinical trial. JAMA Neurol. (2020) 77:1– 43:2794–9. doi: 10.1161/STROKEAHA.112.660373 11. doi: 10.1001/jamaneurol.2020.0326 23. Hahn CD, Manlhiot C, Schmidt MR, Nielsen TT, Redington AN. Remote 11. Hougaard KD, Hjort N, Zeidler D, Sørensen L, Nørgaard A, Hansen TM, ischemic per-conditioning: a novel therapy for acute stroke? Stroke. (2011) et al. Remote ischemic perconditioning as an adjunct therapy to thrombolysis 42:2960–2. doi: 10.1161/STROKEAHA.111.622340 Frontiers in Neurology | www.frontiersin.org 6 September 2020 | Volume 11 | Article 569696 Purroy et al. Remote-Cat Project 24. McLeod SL, Iansavichene A, Cheskes S. Remote ischemic perconditioning 29. Meng R, Asmaro K, Meng L, Liu Y, Ma C, Xi C, et al. Upper limb ischemic to reduce reperfusion injury during acute st-segment-elevation preconditioning prevents recurrent stroke in intracranial arterial stenosis. myocardial infarction: a systematic review and meta-analysis. Neurology. (2012) 79:1853–61. doi: 10.1212/WNL.0b013e318271f76a J Am Heart Assoc. (2017) 6:e005522. doi: 10.1161/JAHA.117. 30. Purroy F, Coll B, Oró M, Setó E, Piñol-Ripoll G, Plana A, et al. Predictive value 005522 of ankle brachial index in patients with acute ischaemic stroke. Eur J Neurol. 25. Zhao W, Che R, Li S, Ren C, Li C, Wu C, et al. Remote ischemic conditioning (2010) 17:602–6. doi: 10.1111/j.1468-1331.2009.02874.x for acute stroke patients treated with thrombectomy. Ann Clin Transl Neurol. (2018) 5:850–6. doi: 10.1002/acn3.588 Conflict of Interest: The authors declare that the research was conducted in the 26. Murry CE, Jennings RB, Reimer KA. Preconditioning with ischemia: a delay absence of any commercial or financial relationships that could be construed as a of lethal cell injury in ischemic myocardium. Circulation. (1986) 74:1124– potential conflict of interest. 36. doi: 10.1161/01.CIR.74.5.1124 27. Johnsen J, Pryds K, Salman R, Lofgren B, Kristiansen SB, Botker HE. The Copyright © 2020 Purroy, Arque, Mauri, García-Vázquez, Vicente-Pascual, Pereira, remote ischemic preconditioning algorithm: effect of number of cycles, cycle Vazquez-Justes, Torres-Querol, Vena, Abilleira, Cardona, Forné, Jiménez-Fàbrega, duration and effector organ mass on efficacy of protection. Basic Res Cardiol. Pagola, Portero-Otin, Rodríguez-Campello, Rovira and Martí-Fàbregas. This is an (2016) 111:10. doi: 10.1007/s00395-016-0529-6 open-access article distributed under the terms of the Creative Commons Attribution 28. Zhao W, Meng R, Ma C, Hou B, Jiao L, Zhu F, et al. Safety License (CC BY). The use, distribution or reproduction in other forums is permitted, and efficacy of remote ischemic preconditioning in patients with provided the original author(s) and the copyright owner(s) are credited and that the severe carotid artery stenosis before carotid artery stenting: a original publication in this journal is cited, in accordance with accepted academic proof-of-concept, randomized controlled trial. Circulation. (2017) practice. No use, distribution or reproduction is permitted which does not comply 135:1325–35. doi: 10.1161/CIRCULATIONAHA.116.024807 with these terms. Frontiers in Neurology | www.frontiersin.org 7 September 2020 | Volume 11 | Article 569696