Cardiac Remote Ischemic Preconditioning in Coronary Stenting (CRISP Stent) Study: a prospective, randomized control trial

Heart Conditioning as a Healthy Strategy in Management of Cardiac Enlargement

Background

Remote ischemic conditioning (RIC) is widely recognized for its cardioprotective effects in the context of ischemic heart disease. Lately, it has been shown that heart conditioning can be utilized as a healthy strategy in the reversion of disease and aging. In this regard, we examine the impact of RIC on patients with cardiac enlargement.

Methods

Forty-four patients with cardiac enlargement were prospectively enrolled and randomly assigned into RIC group (n = 22) and control group (n = 22). RIC protocol is 3-min inflation/deflation of the blood pressure cuff applied in the upper arm to create transient arm ischemia. RIC treatment was performed once a day for 1 year. Left atrial and ventricular dimensions and left ventricular ejection fraction (LVEF) were all assessed in two groups.

Results

RIC was well-tolerated. After 1 year treatment, left atrial and ventricular dimensions were significantly decreased in the RIC group. Moreover, LVEF showed a significant increase, from 46.24% to 56.45% (P < 0.0001).

Conclusion

The research indicates that a year-long healthy regimen of RIC treatment may effectively reverse cardiac enlargement, thereby endorsing the broader implementation of RIC in the daily routines of these patients.

Effect of perioperative remote ischemic conditioning on myocardial injury in patients with unstable angina undergoing percutaneous coronary intervention: protocol of a multicenter, randomized, double-blind clinical trial

BACKGROUND

Cardiovascular disease is a leading cause of death, with ischemic heart disease being a significant contributor. While percutaneous coronary intervention (PCI) effectively reduces mortality in myocardial infarction patients, its efficacy for unstable angina (UA) patients is controversial. Complications associated with PCI further limit application in UA. RIC is hypothesized to be an effective co-intervention that reduces PCI-related complications and may potentially enhance the efficacy of the PCI procedure itself.

METHODS

This is a pragmatic, prospective, dual-center, double-blind, randomized controlled clinical trial assessing the effect of remote ischemic conditioning (RIC) during percutaneous coronary intervention (PCI) on injury in unstable angina patients aged ≥ 18 years undergoing coronary angiography. Participants will be randomized to receive either RIC or Sham RIC, in addition to standard pharmacotherapy. Primary outcome includes periprocedural myocardial injury measured by hs-cTnT levels, while secondary outcomes encompass major adverse cardiovascular events, coronary artery lesions Gensini Score, arrhythmia, angina incidence, SAQ scores, ECG changes, and cardiac function assessed by two-dimensional echocardiography. The trial aims to recruit 574 participants and is scheduled to be initiated on 15 January 2024. We will conduct the primary statistical analysis using the intention-to-treat principle. Results from the trial will be presented as comparative summary statistics following the Consolidated Standards of Reporting Trials (CONSORT) guidelines.

TRIAL REGISTRATION

ChiCTR2400079855, 15 January 2024.

Paired Remote Ischemic Preconditioning in Recipients and Living Donors Can Mitigate Cardiovascular Stress in Recipients After Living-Donor Kidney Transplantation: A Propensity-Score-Matching Analysis

Background and Objectives: This study explored the effect of paired remote ischemic preconditioning (RIPC), involving both recipients and living donors, on cardiovascular stress in recipients after living-donor kidney transplantation (LDKT). The analysis included an assessment of the impact on cardiovascular biomarkers and post-transplant cardiovascular clinical events. Materials and Methods: A retrospective observational cohort study of 520 adult LDKT patients was conducted, employing propensity score matching (PSM) to analyze perioperative factors. The patients were allocated to no-RIPC (n = 260) and paired-RIPC (n = 260) groups. The two groups were compared with respect to high-sensitivity troponin I (hsTnI) and B-type natriuretic peptide (BNP) levels, corrected QT (QTc) intervals, the occurrence of arrhythmia, and the requirement for cardiovascular interventions. Results: After PSM, there were no significant differences in perioperative parameters between the no-RIPC and paired-RIPC groups. However, on postoperative day (POD) 1, higher hsTnI levels and QTc interval prolongation, as well as higher incidences of arrhythmia and the need for percutaneous coronary intervention (PCI), were determined in the no-RIPC group than in the paired-RIPC group. The associations between paired RIPC and improved cardiovascular outcomes were significant, including reduced odds of elevated hsTnI levels, QTc prolongation, and arrhythmia. The no-RIPC group also had longer intensive care unit (ICU) stays, and higher rates of rescue dialysis. Conclusions: Paired-RIPC involving recipients and donors effectively reduces cardiovascular stress markers and improves postoperative cardiovascular outcomes in LDKT recipients, underscoring its potential as a protective strategy against perioperative cardiovascular risks.

Clinical usage of ischemic tolerance-where are its limits?

Ischemic tolerance is a robust internal defense mechanism of all living organisms. The effectiveness of this mechanism has been repeatedly demonstrated in experiments, but a comprehensive review of the clinical applicability of this phenomenon in practice has not yet been published. The results in clinical practice sound ambiguous and unconvincing in comparison with the results of experimental studies. Also, in many localities, the effect of ischemic tolerance was not clinically proven. For the reasons mentioned, the authors analyze the possible causes of the mentioned discrepancies and provide a comprehensive insight into the possible relevant clinical use of this phenomenon in practice for different groups of patients.

Effect of Delayed Remote Ischemic Preconditioning on Acute Kidney Injury and Outcomes in Patients Undergoing Cardiac Surgery: A Randomized Clinical Trial

BACKGROUND

Remote ischemic preconditioning (RIPC) has 2 time windows for organ protection: acute and delayed. Previous studies have mainly focused on the organoprotective effects of acute RIPC. We aimed to determine whether delayed RIPC can reduce the occurrence of acute kidney injury (AKI) and postoperative complications in patients undergoing cardiac surgery.

METHODS

This prospective, single-center, double-blind, randomized controlled trial involved 509 patients at high risk for AKI who were scheduled for elective cardiac surgery requiring cardiopulmonary bypass. Patients were randomized to receive RIPC (4 cycles of 5-minute inflation and 5-minute deflation on 1 upper arm with a blood pressure cuff) 24 hours before surgery or a sham condition (control group) that was induced by 4 cycles of 5-minute inflation to a pressure of 20 mm Hg followed by 5-minute cuff deflation. The primary end point was the incidence of AKI within the prior 7 days after cardiac surgery. The secondary end points included renal replacement therapy during hospitalization, change in urinary biomarkers of AKI and markers of myocardial injury, duration of intensive care unit stay and mechanical ventilation, and occurrence of nonfatal myocardial infarction, stroke, and all-cause mortality by day 90.

RESULTS

A total of 509 patients (mean age, 65.2±8.2 years; 348 men [68.4%]) were randomly assigned to the RIPC group (n=254) or control group (n=255). AKI was significantly reduced in the RIPC group compared with the control group (69/254 [27.2%] versus 90/255 [35.3%]; odds ratio, 0.68 [95% CI, 0.47-1.00]; P=0.048). There were no significant between-group differences in the secondary end points of perioperative myocardial injury (assessed by the concentrations of cardiac troponin T, creatine kinase myocardial isoenzyme, and NT-proBNP [N-terminal pro-brain natriuretic peptide]), duration of stay in the intensive care unit and hospital, and occurrence of nonfatal myocardial infarction, stroke, and all-cause mortality by day 90.

CONCLUSIONS

Among high-risk patients undergoing cardiac surgery, delayed RIPC significantly reduced the occurrence of AKI.

REGISTRATION

URL: https://www.chictr.org.cn; Unique identifier: ChiCTR2000035568.

Remote Ischemic Conditioning Improves Cardiovascular Function in Heart Failure Patients

Background

Recently, it has been shown that remote ischemic conditioning (RIC) can be used as a healthy regimen to reverse disease and aging. With this in mind, we are studying the consequences of RIC on cardiovascular function in heart failure patients.

Methods

Forty patients with stable heart failure were prospectively enlisted and randomly divided into RIC (n = 20) and control (n = 20) groups. The RIC protocol consists of a 3-min inflation and then deflation of the blood pressure cuff attached to the upper arm to produce transient ischemia of the arm. RIC treatment was performed once daily for 1 year. NYHA class, left ventricular ejection fraction (LVEF), left atrial and ventricular dimensions were all assessed in two groups.

Results

RIC was well tolerated. After 1 year of treatment, New York Heart Association (NYHA) class improved and LVEF showed a significant increase from 37.11% to 52.44% (P < 0.0001). Additionally, the dimensions of the left atrium (from 50.55 to 43.25 mm) and ventricle (from 53.04 to 50.15 mm) were significantly reduced in the RIC group.

Conclusion

This study suggests that 1 year of RIC treatment as a health strategy could improve cardiovascular function in heart failure patients, leading to its widespread use in these patients.

Ticagrelor potentiates cardioprotection by remote ischemic preconditioning: the ticagrelor in remote ischemic preconditioning (TRIP) randomized clinical trial

OBJECTIVE

Remote ischemic preconditioning (RIPC) reduces periprocedural myocardial injury (PMI) after percutaneous coronary intervention (PCI) through various pathways, including an adenosine-triggered pathway. Ticagrelor inhibits adenosine uptake, thus may potentiate the effects of RIPC. This randomized trial tested the hypothesis that ticagrelor potentiates the effect of RIPC and reduces PMI, assessed by post-procedural troponin release.

METHODS

Patients undergoing PCI for non-ST elevation acute coronary syndromes were 1:1 randomized to ticagrelor (TG-Group) or clopidogrel (CL-Group). Within each treatment, patients were 1:1 randomized to a RIPC (RIPC-Group) or a control group (CTRL-Group). The primary endpoint was the difference between post- and pre-procedural troponin at 24 h following PCI, termed deltaTnI.

RESULTS

During a 12-month period, 138 patients were included in the study (34 in the CL-CTRL group, 34 in the TG-CTRL group, 35 in the CL-RIPC group, and 35 in the TG-CTRL group). There was a significant difference in deltaTnI between the study groups [ TG-RIPC:0.04 (0-0.16), CL-CTRL:0.10 (0.03-0.43), CLRIPC:0.11 (0.03-0.89), and TG-CTRL:0.24 (0.06-0.47); p = 0.007]. Eight patients (22.9%) in the TG-RIPC group developed type 4a myocardial infarction (MI), compared to 14 (40%) in the CL-RIPC group, 13 (38.2%) in the CL-CTRL group, and 19 (55.9%) in the TG-CTRL group (p = 0.048). A significant interaction between antiplatelet group allocation and RIPC on deltaTnI was observed [F (1,134) = 7.509; p = 0.007]. In multivariate analysis, the interaction between RIPC and ticagrelor treatment was independently associated with a lower incidence of Type 4a MI.

CONCLUSION

Our results demonstrate an interaction between ticagrelor and RIPC, which may potentiate the cardioprotective effects of RIPC during PCI by reducing PMI.

Periprocedural myocardial infarction and injury

Periprocedural myocardial infarction (PMI) and injury, pertinent to both cardiac and non-cardiac procedures, have gained increasing recognition in clinical practice. Over time, diverse definitions for diagnosing PMI have been developed and validated among patient populations undergoing coronary revascularization. However, this variety in definitions presents considerable challenges in clinical settings and complicates both the design and interpretation of clinical trials. The necessity to accurately diagnose PMI has spurred significant interest in establishing universally accepted and prognostically meaningful thresholds for cardiac biomarkers elevation and supportive ancillary criteria. In fact, elevations in cardiac biomarkers in line with the 4th Universal Definition of Myocardial Infarction, have been extensively confirmed to be associated with increased mortality and cardiovascular events. In the context of non-coronary cardiac procedures, such as Transcatheter Aortic Valve Implantation, there is a growing acknowledgment of both the high incidence rates and the adverse impact of PMI on patient outcomes. Similarly, emerging research underscores the significance of PMI and injury in non-cardiac surgery, highlighting the urgent need for effective prevention and risk management strategies in this domain.

Effects of Remote Ischaemic Conditioning in Stable and Unstable Angina Patients Undergoing Percutaneous Coronary Intervention: A Systematic Review and Meta-Analysis

AIM

Type 4a myocardial infarction (T4aMI), defined as myocardial injury associated with percutaneous coronary intervention (PCI), is associated with a poor prognosis and there is conflicting evidence regarding the effectiveness of remote ischaemic conditioning (RIC) in its prevention. This review aimed to determine the effect of RIC on stable and unstable angina patients.

METHOD

A systematic review was conducted in PubMed and Central database. Outcome measures were: changes in peak troponin, creatine kinase myocardial band (CKMB), C-reactive protein (CRP) level, incidence of T4aMI, and major adverse cardiovascular event (MACE). Data were meta-analysed and reported as standardised mean difference (SMD) and odds ratio (OR). Risk of bias was assessed with the Risk of Bias 2 (RoB2) tool.

RESULTS

Fifteen studies with no significant risk of bias were included. Peak troponin level was reduced in the RIC group, particularly after excluding a study with low statin use, while CKMB and CRP levels resulted in a non-significant SMD between the groups. The incidence of T4aMI was significantly lower in the intervention group (OR 0.714; p=0.026); this finding was also seen in subgroups of elective PCI, pre-conditioning, and high statin use. Incidence of MACE also only reached statistically significant protective effects with OR <1 in similar subgroups. No substantial heterogeneity was found and the funnel plot did not show publication bias.

CONCLUSION

Remote ischaemic conditioning in elective PCI patients has been proven to be potentially beneficial in reducing peak troponin levels and risk of T4aMI and MACE.

Elevated levels of plasma inactive stromal cell derived factor-1α predict poor long-term outcomes in diabetic patients following percutaneous coronary intervention

BACKGROUND

Since the complication of diabetes mellitus (DM) is a risk for adverse cardiovascular outcomes in patients with coronary artery disease (CAD), appropriate risk estimation is needed in diabetic patients following percutaneous coronary intervention (PCI). However, there is no useful biomarker to predict outcomes in this population. Although stromal cell derived factor-1α (SDF-1α), a circulating chemokine, was shown to have cardioprotective roles, the prognostic impact of SDF-1α in diabetic patients with CAD is yet to be fully elucidated. Moreover, roles of SDF-1α isoforms in outcome prediction remain unclear. Therefore, this study aimed to assess the prognostic implication of three forms of SDF-1α including total, active, and inactive forms of SDF-1α in patients with DM and after PCI.

METHODS

This single-center retrospective analysis involved consecutive patients with diabetes who underwent PCI for the first time between 2008 and 2018 (n = 849). Primary and secondary outcome measures were all-cause death and the composite of cardiovascular death, non-fatal myocardial infarction, and ischemic stroke (3P-MACE), respectively. For determining plasma levels of SDF-1α, we measured not only total, but also the active type of SDF-1α by ELISA. Inactive isoform of the SDF-1α was calculated by subtracting the active isoform from total SDF-1α.

RESULTS

Unadjusted Kaplan-Meier analyses revealed increased risk of both all-cause death and 3P-MACE in patients with elevated levels of inactive SDF-1α. However, plasma levels of total and active SDF-1α were not associated with cumulative incidences of outcome measures. Multivariate Cox hazard analyses repeatedly indicated the 1 higher log-transformed inactive SDF-1α was significantly associated with increased risk of all-cause death (hazard ratio (HR): 2.64, 95% confidence interval (CI): 1.28-5.34, p = 0.008) and 3P-MACE (HR: 2.51, 95% CI: 1.12-5.46, p = 0.02). Moreover, the predictive performance of inactive SDF-1α was higher than that of total SDF-1α (C-statistics of inactive and total SDF-1α for all-cause death: 0.631 vs 0.554, for 3P-MACE: 0.623 vs 0.524, respectively).

CONCLUSION

The study results indicate that elevated levels of plasma inactive SDF-1α might be a useful indicator of poor long-term outcomes in diabetic patients following PCI.

TRIAL REGISTRATION

This study describes a retrospective analysis of a prospective registry database of patients who underwent PCI at Juntendo University Hospital, Tokyo, Japan (Juntendo Physicians' Alliance for Clinical Trials, J-PACT), which is publicly registered (University Medical Information Network Japan-Clinical Trials Registry, UMIN-CTR 000035587).

Remote ischemic conditioning reduces adverse events in patients with acute ischemic stroke complicating acute myocardial infarction: a randomized controlled trial

BACKGROUND

Acute ischemic stroke (AIS) complicating an acute myocardial infarction (AMI) is not uncommon, but can severely worsen the clinical prognosis. This study aimed to investigate whether remote ischemic conditioning (RIC) could provide clinical benefits to patients with AIS complicating AMI.

METHODS

Subjects with AIS complicating AMI were recruited in this double-blind, randomized, controlled trial; assigned to the RIC and sham groups; and respectively underwent twice daily RIC and sham RIC for 2 weeks. All subjects received standard medical therapy. The primary endpoint was the rate of major adverse cardiac and cerebrovascular events (MACCEs) within 3 months after enrollment. MACCEs comprise of death from all causes, unstable anginas, AMI, acute ischemic strokes, and transient ischemic attacks.

RESULTS

Eighty subjects were randomly assigned; 37 patients in the RIC group and 40 patients in the sham-RIC group completed the 3-month follow-up and were included in the final analysis. Both RIC and sham RIC procedures were well tolerated. At 3-month follow-up, 11 subjects (29.7%) in the RIC group experienced MACCEs compared to 21 (52.5%) in the sham group (hazard ratio [HR], 0.396; 95% confidence interval, 0.187-0.838; adjusted p < 0.05). Six subjects (16.2%) in the RIC group had died at the 3-month follow up, significantly lower than the 15 (37.5%) deaths in the sham group (adjusted HR 0.333; 95% CI 0.126-0.881; p = 0.027). Seventeen subjects (45.9%) in the RIC group and 6 subjects (15.0%) in the sham group achieved functional independence (mRS score ≤ 2) at 3-month follow-up (adjusted OR 12.75; 95% CI 2.104-77.21; p = 0.006).

CONCLUSIONS

Among patients with acute ischemic stroke complicating acute myocardial infarction, treatment with remote ischemic conditioning decreased the major adverse cardiac and cerebrovascular events and improved functional outcomes at 90 days.

TRIAL REGISTRATION

URL: www.

CLINICALTRIALS

gov . Unique identifier: NCT03868007. Registered 8 March 2019.

Health position paper and redox perspectives on reactive oxygen species as signals and targets of cardioprotection

The present review summarizes the beneficial and detrimental roles of reactive oxygen species in myocardial ischemia/reperfusion injury and cardioprotection. In the first part, the continued need for cardioprotection beyond that by rapid reperfusion of acute myocardial infarction is emphasized. Then, pathomechanisms of myocardial ischemia/reperfusion to the myocardium and the coronary circulation and the different modes of cell death in myocardial infarction are characterized. Different mechanical and pharmacological interventions to protect the ischemic/reperfused myocardium in elective percutaneous coronary interventions and coronary artery bypass grafting, in acute myocardial infarction and in cardiotoxicity from cancer therapy are detailed. The second part keeps the focus on ROS providing a comprehensive overview of molecular and cellular mechanisms involved in ischemia/reperfusion injury. Starting from mitochondria as the main sources and targets of ROS in ischemic/reperfused myocardium, a complex network of cellular and extracellular processes is discussed, including relationships with Ca2+ homeostasis, thiol group redox balance, hydrogen sulfide modulation, cross-talk with NAPDH oxidases, exosomes, cytokines and growth factors. While mechanistic insights are needed to improve our current therapeutic approaches, advancements in knowledge of ROS-mediated processes indicate that detrimental facets of oxidative stress are opposed by ROS requirement for physiological and protective reactions. This inevitable contrast is likely to underlie unsuccessful clinical trials and limits the development of novel cardioprotective interventions simply based upon ROS removal.

Remote ischemic conditioning in necrotizing enterocolitis

Necrotizing enterocolitis (NEC) is a devastating intestinal inflammatory disorder, most prevalent in premature infants, and associated with a high mortality rate that has remained unchanged in the past two decades. NEC is characterized by inflammation, ischemia, and impaired microcirculation in the intestine. Preclinical studies by our group have led to the discovery of remote ischemic conditioning (RIC) as a promising non-invasive intervention in protecting the intestine against ischemia-induced damage during early-stage NEC. RIC involves the administration of brief reversible cycles of ischemia and reperfusion in a limb (similar to taking standard blood pressure measurement) which activate endogenous protective signaling pathways that are conveyed to distant organs such as the intestine. RIC targets the intestinal microcirculation and by improving blood flow to the intestine, reduces the intestinal damage of experimental NEC and prolongs survival. A recent Phase I safety study by our group demonstrated that RIC was safe in preterm infants with NEC. A phase II feasibility randomized controlled trial involving 12 centers in 6 countries is currently underway, to investigate the feasibility of RIC as a treatment for early-stage NEC in preterm neonates. This review provides a brief background on RIC as a therapeutic strategy and summarizes the progression of RIC as a treatment for NEC from preclinical investigation to clinical evaluation.

Anthracyclines and Biomarkers of Myocardial Injury: The Effect of Remote Ischemic Conditioning

Background

Remote ischemic conditioning (RIC) has been beneficial in laboratory studies of anthracycline cardiotoxicity, but its effects in patients is not established.

Objectives

The authors studied the effect of RIC on cardiac biomarkers and function during and after anthracycline chemotherapy.

Methods

The ERIC-Onc study (Effect of Remote Ischaemic Conditioning in Oncology Patients; NCT02471885) was a randomized, single-blind, sham-controlled study of RIC at each chemotherapy cycle. The primary endpoint was troponin T (TnT) during chemotherapy and up to 1 year. Secondary outcomes included cardiac function, major adverse cardiovascular events (MACE), and MACE or cancer death. Cardiac myosin-binding-protein C (cMyC) was investigated in parallel with TnT.

Results

The study was prematurely halted after the evaluation of 55 patients (RIC n = 28, sham n = 27). Biomarkers increased from baseline to cycle 6 of chemotherapy for all patients (median TnT 6 [IQR: 4-9] ng/L to 33 [IQR: 16-36)] ng/L; P ≤ 0.001; cMyC 3 (IQR: 2-5) ng/L to 47 (IQR: 18-49) ng/L; P ≤ 0.001). Mixed-effects regression analysis for repeated measures showed no difference in TnT between the 2 groups (RIC vs sham, mean difference 3.15 ng/L; 95% CI: -0.04 to 6.33; P = 0.053), or cMyC (RIC vs sham, mean difference 4.17 ng/L; 95% CI: -0.12 to 8.45; P = 0.056). There were more MACE and cancer deaths in the RIC group (11 vs 3; HR: 0.25; 95% CI: 0.07-0.90; P = 0.034), with more cancer deaths (8 vs 1; HR: 0.21; 95% CI: 0.04-0.95; P = 0.043) at 1 year.

Conclusions

TnT and cMyC significantly increased during anthracycline chemotherapy with 81% having a TnT ≥14 ng/L at cycle 6. RIC did not affect the rise in biomarkers, but there was a small increase in early cancer deaths, possibly related to the greater proportion of patients with metastatic disease randomized to the RIC group (54%vs 37%). (Effect of Remote Ischaemic Conditioning in Oncology Patients [ERIC-ONC]; NCT02471885).

Tefillin use induces preconditioning associated changes in heart rate variability

Short bouts of occlusion of blood flow can induce a preconditioning response that reduces subsequent damage from longer periods of ischemia. It has been shown that ischemic preconditioning (IPC) can be elicited remotely (RIPC) through limitation of blood flow and as recently described via only pain sensation. Non-obstructive banding (NOB) through the donning of tefillin (a box with sacred texts attached to a leather strap that is traditionally bound to the non-dominant arm of Jewish adults during morning prayers) has been shown to elicit an RIPC response at least partially through pain sensation. This study evaluated the effects of NOB on heart rate variability (HRV) dependent factors that are known to be affected by various RIPC stimuli. We recruited 30 healthy subjects and subjected them to NOB versus control and found various HRV markers associated with RIPC to be changed in the NOB group. This finding provides further evidence that tefillin, likely through NOB induced RIPC changes, may still be a viable clinical pathway to prevent and decrease the morbidity associated with ischemic events.

Safety and Feasibility Assessment of Repetitive Vascular Occlusion Stimulus (RVOS) Application to Multi-Organ Failure Critically Ill Patients: A Pilot Randomised Controlled Trial

Muscle wasting is implicated in the pathogenesis of intensive care unit acquired weakness (ICU-AW), affecting 40% of patients and causing long-term physical disability. A repetitive vascular occlusion stimulus (RVOS) limits muscle atrophy in healthy and orthopaedic subjects, thus, we explored its application to ICU patients. Adult multi-organ failure patients received standard care +/- twice daily RVOS {4 cycles of 5 min tourniquet inflation to 50 mmHg supra-systolic blood pressure, and 5 min complete deflation} for 10 days. Serious adverse events (SAEs), tolerability, feasibility, acceptability, and exploratory outcomes of the rectus femoris cross-sectional area (RFCSA), echogenicity, clinical outcomes, and blood biomarkers were assessed. Only 12 of the intended 32 participants were recruited. RVOS sessions (76.1%) were delivered to five participants and two could not tolerate it. No SAEs occurred; 75% of participants and 82% of clinical staff strongly agreed or agreed that RVOS is an acceptable treatment. RFCSA fell significantly and echogenicity increased in controls (n = 5) and intervention subjects (n = 4). The intervention group was associated with less frequent acute kidney injury (AKI), a greater decrease in the total sequential organ failure assessment score (SOFA) score, and increased insulin-like growth factor-1 (IGF-1), and reduced syndecan-1, interleukin-4 (IL-4) and Tumor necrosis factor receptor type II (TNF-RII) levels. RVOS application appears safe and acceptable, but protocol modifications are required to improve tolerability and recruitment. There were signals of possible clinical benefit relating to RVOS application.

Remote ischemic preconditioning causes transient cell-cycle arrest and renal protection by a NF-kB-dependent Sema5B pathway

Acute kidney injury increases morbidity and mortality, and previous studies have shown that remote ischemic preconditioning (RIPC) reduces the risk of acute kidney injury after cardiac surgery. RIPC increases urinary high mobility group box protein-1 (HMGB1) levels in patients, and this correlates with kidney protection. Here, we show that RIPC reduces renal ischemia-reperfusion injury and improves kidney function in mice. Mechanistically, RIPC increases HMGB1 levels in the plasma and urine, and HMGB1 binds to TLR4 on renal tubular epithelial cells, inducing transcriptomic modulation of renal tubular epithelial cells and providing renal protection, whereas TLR4 activation on nonrenal cells was shown to contribute to renal injury. This protection is mediated by activation of induction of AMPKα and NF-κB; this induction contributes to the upregulation of Sema5b, which triggers a transient, protective G₁ cell cycle arrest. In cardiac surgery patients at high risk for postoperative acute kidney injury, increased HMGB1 and Sema5b levels after RIPC were associated with renal protection after surgery. The results may help to develop future clinical treatment options for acute kidney injury.

Ischemic limb preconditioning-induced anti-arrhythmic effect in reperfusion-induced myocardial injury: is it mediated by the RISK or SAFE pathway?

The mechanism for limb ischemic precondition (RLIPC)-induced suppression of reperfusion arrhythmia remains unknown. The purpose of this study was to examine the roles of the pro-survival reperfusion injury salvage kinase (RISK) and survivor activating factor enhancement (SAFE) pathways in this RLIPC-mediated antiarrhythmic activity. Male Sprague Dawley rats were assigned to sham-operated, control, or RLIPC groups. All rats except for the sham rats had 5 min of left main coronary artery occlusion with another 20 min of reperfusion. RLIPC was initiated by four cycles of limb ischemia (5 min) and reperfusion (5 min) on the bilateral femoral arteries. Hearts in every group were taken for protein phosphorylation analysis. RLIPC ameliorated reperfusion-induced arrhythmogenesis and reduced the incidence of sudden cardiac death during the entire 20-min reperfusion period (66.7% of control rats had SCD vs. only 16.7% of RLIPC-treated rats). RLIPC enhances ventricular ERK1/2 phosphorylation after reperfusion. RLIPC-induced antiarrhythmic action and ERK1/2 phosphorylation are abolished in the presence of the ERK1/2 inhibitor U0126. Limb ischemic preconditioning protects the heart against myocardial reperfusion injury-induced lethal arrhythmia. These beneficial effects may involve the activation of ERK1/2 in the RISK signaling pathway.

Challenges facing the clinical translation of cardioprotection: 35 years after the discovery of ischemic preconditioning

Since coronary reperfusion was introduced into clinical practice in the late 1970s, the further translation of several successful animal experiments on cardioprotection into clinical practice has been disappointing to date. Animal experiments are often performed on young, healthy animals lacking the risk factors, co-morbidities and co-medications characteristic of acute myocardial infarction patients. Many hopes were kindled in 1986 when ischemic preconditioning was discovered. However, it is not yet known how long ischemia can last and what is the best modality for additional cardioprotection through conditioning to obtain benefits. There is a lack of experimental studies on the long-term effects of additional cardioprotection, in addition to the reduction in infarct size; in particular, there is a lack of studies on vessel protection, repair, inflammation, remodeling, and mortality. The reproducibility and robustness of experimental studies are often limited by species differences, the role of co-morbidities, vascular damage, inflammatory processes, and co-medications, which are not adequately considered. In particular, inflammatory processes, including NLRP3 inflammasome, play an important role in the long-term effects. Future studies should focus on interventions/agents with robust preclinical data and should recruit patients who truly have the potential to benefit from further cardioprotection. Here we focus on the main mechanisms and targets of cardioprotection during remote conditioning and their alteration by one of the most common co-morbidities, namely diabetes, in which microvascular lesions and inflammatory processes play extremely important roles.

Effects of Multimodal Bundle with Remote Ischemic Preconditioning and Intrathecal Analgesia on Early Recovery of Estimated Glomerular Filtration Rate after Robot-Assisted Laparoscopic Partial Nephrectomy for Renal Cell Carcinoma

Simple Summary

This study suggested that robot-assisted laparoscopic partial nephrectomy (RALPN) may have benefits with regard to the preservation of renal function and few complications postoperatively in patients with renal cell carcinoma (RCC). However, a reduction in the estimated glomerular filtration rate may be unavoidable. Our results suggested that the preservation of renal function may be enhanced by combining robot-assisted nephron-sparing surgery with an intraoperative bundle strategy consisting of remote ischemic preconditioning (RIPC) and an intrathecal morphine block (ITMB), to protect against ischemia–reperfusion injury and the pain-related stress induced by renal artery clamping and surgical insults. It is important to adjust modifiable variables related to the progression of renal impairment in a timely and appropriate manner for the recovery of renal function after RALPN. Together with surgical and pharmacological methods to minimize irreversible injury, RIPC and ITMB combined bundle therapy may relieve ischemia–reperfusion- and pain-induced stress and serve as a safe and efficient method for improving renal outcomes of RALPN in patients with RCC.

Abstract

We investigated the effects of multimodal combined bundle therapy, consisting of remote ischemic preconditioning (RIPC) and intrathecal morphine block (ITMB), on the early recovery of kidney function after robot-assisted laparoscopic partial nephrectomy (RALPN) in patients with renal cell carcinoma (RCC). In addition, we compared the surgical and analgesic outcomes between patients with and without bundle treatment. This prospective randomized double-blind controlled trial was performed in a cohort of 80 patients with RCC, who were divided into two groups: a bundle group (n = 40) and non-bundle group (n = 40). The primary outcome was postoperative kidney function, defined as the lowest estimated glomerular filtration rate (eGFR) on postoperative day (POD) 2. Surgical complications, pain, and length of hospital stay were assessed as secondary outcomes. The eGFR immediately after surgery was significantly lower in the bundle group compared to the preoperative baseline, but serial levels on PODs 1 and 2 and at three and six months after surgery were comparable to the preoperative baseline. The eGFR level immediately after surgery was lower in the non-bundle than bundle group, and serial levels on PODs 1 and 2 and at three months after surgery remained below the baseline. The eGFR level immediately after surgery was higher in the bundle group than in the non-bundle group. The eGFR changes immediately after surgery, and on POD 1, were smaller in the bundle than in the non-bundle group. The non-bundle group had longer hospital stays and more severe pain than the bundle group, but there were no severe surgical complications in either group. The combined RIPC and ITMB bundle may relieve ischemia–reperfusion- and pain-induced stress, as a safe and efficient means of improving renal outcomes following RALPN in patients with RCC.

Cardioprotective Properties of Humoral Factors Released after Remote Ischemic Preconditioning in CABG Patients with Propofol-Free Anesthesia-A Translational Approach from Bedside to Bench

The cardioprotective effect of remote ischemic preconditioning (RIPC) is well detectable in experimental studies but not in clinical trials. Propofol, a commonly used sedative, is discussed to negatively influence the release of humoral factors after RIPC. Further, results from experimental and clinical trials suggest various comorbidities interact with inducible cardioprotective properties of RIPC. In the present study, we went back from bedside to bench to investigate, in male patients undergoing CABG surgery, whether (1) humoral factors are released after RIPC during propofol-free anesthesia and/or (2) DM interacts with plasma factor release. Blood samples were taken from male patients with and without DM undergoing CABG surgery before (control) and after RIPC (RIPC). To investigate the release of cardioprotective humoral factors into the plasma, isolated perfused hearts of young rats (n = 5 per group) were used as a bioassay. The hearts were perfused with patients’ plasma without (Con) and with RIPC (RIPC) for 10 min (1% of coronary flow) before global ischemia and reperfusion. In additional groups, the plasma of patients with DM was administered (Con DM, RIPC DM). Infarct size was determined by TTC staining. Propofol-free RIPC plasma of male patients without DM showed an infarct size of 59 ± 5% compared to 61 ± 13% with Con plasma (p = 0.973). Infarct sizes from patients with DM showed similar results (RIPC DM: 55 ± 3% vs. Con DM: 56 ± 4%; p = 0.995). The release of humoral factors into the blood after RIPC in patients receiving propofol-free anesthesia undergoing CABG surgery did not show any cardioprotective properties independent of a pre-existing diabetes mellitus.

CoenzymeQ10 and Ischemic Preconditioning Potentially Prevent Tourniquet-Induced Ischemia/Reperfusion in Knee Arthroplasty, but Combined Pretreatment Possibly Neutralizes Their Beneficial Effects

Tourniquet (TQ) use during total knee arthroplasty (TKA) induces ischemia/reperfusion (I/R) injury, resulting in mitochondrial dysfunction. This study aims to determine the effects of coenzyme Q10 (CoQ10) and ischemic preconditioning (IPC), either alone or in combination, on I/R-induced mitochondrial respiration alteration in peripheral blood mononuclear cells (PBMCs) and pain following TKA. Forty-four patients were allocated into four groups: control, CoQ10, IPC, and CoQ10 + IPC. CoQ10 dose was 300 mg/day for 28 days. IPC protocol was three cycles of 5/5-min I/R time. Mitochondrial oxygen consumption rates (OCRs) of PBMCs were measured seven times, at baseline and during ischemic/reperfusion phases, with XFe 96 extracellular flux analyzer. Postoperative pain was assessed for 48 h. CoQ10 improved baseline mitochondrial uncoupling state; however, changes in OCRs during the early phase of I/R were not significantly different from the placebo. Compared to ischemic data, IPC transiently increased basal OCR and ATP production at 2 h after reperfusion. Clinically, CoQ10 significantly decreased pain scores and morphine requirements at 24 h. CoQ10 + IPC abolished analgesic effect of CoQ10 and mitochondrial protection of IPC. In TKA with TQ, IPC enhanced mitochondrial function by a transient increase in basal and ATP-linked respiration, and CoQ10 provides postoperative analgesic effect. Surprisingly, CoQ10 + IPC interferes with beneficial effects of each intervention.

Can Clinical and Functional Outcomes Be Improved with an Intelligent "Internet Plus"-Based Full Disease Cycle Remote Ischemic Conditioning Program in Acute ST-elevation Myocardial Infarction Patients Undergoing Percutaneous Coronary Intervention? Rationale and Design of the i-RIC Trial

BACKGROUND

Acute ST-elevation myocardial infarction (STEMI) is associated with a high incidence of complications as well as a considerable hospitalization rate and economic burden. Preliminary evidence suggests that remote ischemic conditioning (RIC) is a promising non-invasive intervention that may effectively and safely reduce myocardial infarct size, subsequent cardiac events and complications, and mortality. However, RIC's cardio-protective effect remains under debate, especially for single timepoint RIC programs. Adequately powered large-scale randomized controlled trials investigating clinical outcomes are thus needed to clarify the role of full disease cycle RIC programs.

METHODS

The intelligent "Internet Plus"-based full disease cycle remote ischemic conditioning (i-RIC) trial is a pragmatic, multicenter, randomized controlled, parallel group, clinical trial. The term, intelligent "Internet Plus"-based full disease cycle, refers to smart devices aided automatic and real-time monitoring of remote ischemic pre-, per- or post-conditioning intervention for patients with STEMI undergoing percutaneous coronary intervention (PCI). Based on this perspective, 4700 STEMI patients from five hospitals in China will be randomized to a control and an intervention group. The control group will receive PCI and usual care, including pharmacotherapy, before and after PCI. The intervention group will receive pre-, per-, and post-operative RIC combined with long-term i-RIC over a one-month period in addition. A smartphone application, an automated cuff inflation/deflation device and "Internet Plus"-based administration will be used in the long-term phase. The primary outcome is the combined cardiac death or hospitalization for heart failure rate. Secondary outcomes include clinical and functional outcomes: major adverse cardiac and cerebrovascular events rate, all-cause mortality, myocardial reinfarction rate, readmission rate for heart failure and ischemic stroke rate, unplanned revascularization rate, plasma concentration of myocardial infarction-related key biomarkers, infarct size, cardiac function, cardiopulmonary endurance, health-related quality of life, total hospital length of stay, total medical cost, and compliance with treatment regime.

DISCUSSION

The i-RIC trial is designed to test the hypothesis that clinical and functional outcomes can be improved with the i-RIC program in STEMI patients undergoing PCI. The concept of RIC is expected to be enhanced with this intelligent "Internet Plus"-based program focusing on the full disease cycle. If the i-RIC program results in superior improvement in primary and secondary outcomes, it will offer an innovative treatment option for STEMI patients and form the basis of future recommendations.

CLINICAL TRIAL REGISTRATION

Chinese Clinical Trial Registry ( http://www.chictr.org.cn ): ChiCTR2000031550, 04 April 2020.

Prognostically relevant periprocedural myocardial injury and infarction associated with percutaneous coronary interventions: a Consensus Document of the ESC Working Group on Cellular Biology of the Heart and European Association of Percutaneous Cardiovascular Interventions (EAPCI)

A substantial number of chronic coronary syndrome (CCS) patients undergoing percutaneous coronary intervention (PCI) experience periprocedural myocardial injury or infarction. Accurate diagnosis of these PCI-related complications is required to guide further management given that their occurrence may be associated with increased risk of major adverse cardiac events (MACE). Due to lack of scientific data, the cut-off thresholds of post-PCI cardiac troponin (cTn) elevation used for defining periprocedural myocardial injury and infarction, have been selected based on expert consensus opinions, and their prognostic relevance remains unclear. In this Consensus Document from the ESC Working Group on Cellular Biology of the Heart and European Association of Percutaneous Cardiovascular Interventions (EAPCI), we recommend, whenever possible, the measurement of baseline (pre-PCI) cTn and post-PCI cTn values in all CCS patients undergoing PCI. We confirm the prognostic relevance of the post-PCI cTn elevation >5× 99th percentile URL threshold used to define type 4a myocardial infarction (MI). In the absence of periprocedural angiographic flow-limiting complications or electrocardiogram (ECG) and imaging evidence of new myocardial ischaemia, we propose the same post-PCI cTn cut-off threshold (>5× 99th percentile URL) be used to define prognostically relevant ‘major’ periprocedural myocardial injury. As both type 4a MI and major periprocedural myocardial injury are strong independent predictors of all-cause mortality at 1 year post-PCI, they may be used as quality metrics and surrogate endpoints for clinical trials. Further research is needed to evaluate treatment strategies for reducing the risk of major periprocedural myocardial injury, type 4a MI, and MACE in CCS patients undergoing PCI.

The effect of Remote Ischemic Preconditioning (RIPC) on myocardial injury and inflammation in patients with severe aortic valve stenosis undergoing Transcatheter Aortic Valve Replacement (TAVΙ)

BACKGROUND

Remote ischemic preconditioning (RIPC) is being evaluated as a strategy to reduce cardiac injury and inflammation in patients undergoing diverse cardiac invasive and surgical procedures. However, it is unclear whether RIPC has protective effects in patients undergoing the transfemoral- transcatheter aortic valve implantation (TF-TAVΙ) procedure.

METHODS

Between September 2013 and September 2015, 55 random consecutive patients were prospectively assigned to receive SHAM preconditioning (SHAM, 22 patients) or Remote Ischemic Preconditioning (RIPC) (4 cycles of 5 min intermittent leg ischemia and 5 min reperfusion, 33 patients) prior to TF-TAVI. The primary endpoint was to determine the serum levels of: hs-cTn-I (necrosis), CK-18 (apoptosis), and IL-1b (inflammation). Quantification was performed using commercially available ELISA kits. Patients were sampled 1-day pre TF-TAVΙ and 24-hours post TF-TAVΙ. Secondary endpoints included: total mortality, incidence of periprocedural clinical acute myocardial infarction (AMI), acute kidney injury (AKI), and stroke.

RESULTS

22 SHAM patients and 33 RIPC patients were finally analyzed. Our data revealed no significant difference in serum levels of hs-cTn-I and CK-18 among various groups. However, in the RIPC group, the increase in IL1b level was significantly lower for 24-h post TF-TAVΙ, (p < 0.01). There were no significant differences between groups in the secondary endpoints at the follow-up interval of one month. RIPC-related adverse events were not observed.

CONCLUSIONS

Our data suggest that RIPC did not exhibit significant cardiac or kidney protective effects regarding necrosis and apoptosis in patients undergoing TF-TAVΙ. However, an important anti-inflammatory effect was detected in the RIPC group.

Remote ischemic preconditioning reduces the incidence of contrast-induced nephropathy in patients undergoing coronary angiography/intervention: Systematic review and meta-analysis of randomized controlled trials

BACKGROUND

Contrast-induced nephropathy (CIN) is associated with increased mortality and morbidity in patients undergoing coronary angiography (CAG) and percutaneous coronary intervention (PCI). We aimed to assess the latest evidence on the effect of remote ischemic preconditioning (RIPC) on the incidence of CIN in patients undergoing CAG/PCI.

METHODS

We performed a comprehensive search on topics assessing RIPC and CIN in CAG/PCI patients from inception up until July 2019 through several electronic databases.

RESULTS

There were a total of 1,925 subjects from 14 randomized controlled trials. Remote ischemic preconditioning was associated with reduced CIN incidence in patients undergoing CAG/PCI (OR 0.41 [0.30, 0.55], p < .001; I2 : 22%). The nephroprotective effect was also demonstrated in those at moderate-high risk for CIN subgroup (OR 0.41 [0.29, 0.58], p < .001; I2 : 26%) and PCI-only subgroup (OR 0.41 [0.29, 0.58], p < .001; I2 : 0%). Time from RIPC to CAG/PCI has similar effectiveness among ≤45, ≤60, and ≤120 min. Mortality, rehospitalization, hemodialysis, and major adverse events were lower in the RIPC group (OR 0.50 [0.33, 0.76], p = .001; I2 : 0%). Grading of recommendations assessment, development and evaluation (GRADE) assessment showed that RIPC has high evidence certainty for reducing CIN in patients undergoing PCI/CAG, moderate-high risk subgroup, and PCI-only subgroup with absolute reduction of 97 per 1,000, 129 per 1,000, and 121 per 1,000, respectively. Harbord test showed no evidence for the presence of small-study effects (p = .157).

CONCLUSIONS

Remote ischemic preconditioning is an effective procedure to reduce the risk of CIN and should be considered in patients with moderate-high risk at developing CIN.

Cardioprotection for Acute MI in Light of the CONDI2/ERIC-PPCI Trial: New Targets Needed

Protection against ischaemia-reperfusion injury after revascularisation in acute myocardial infarction remains an enigma. Many targets have been identified, but after the failure of the recent Effect of Remote Ischaemic Conditioning on Clinical Outcomes in ST-elevation Myocardial Infarction Patients Undergoing Primary Percutaneous Coronary Intervention (CONDI2/ERIC-PPCI) trial to show translation to clinical benefit, there is still no pharmacological or mechanical strategy that has translated to clinical practice. This article addresses the results of the CONDI2/ERIC-PPCI trial in the context of previous studies of ischaemic conditioning, and then considers the prospects for other potential targets of cardioprotection. Finally, the authors examine the pitfalls and challenges in trial design for future investigation of cardioprotective strategies. In particular, this article highlights the need for careful endpoint and patient selection, as well as the need to pay attention to the biology of cardioprotection during the study.

Remote Ischemic Preconditioning Reduces the Risk of Contrast-Induced Nephropathy in Patients with Moderate Renal Impairment Undergoing Percutaneous Coronary Angiography: A Meta-Analysis

BACKGROUND/AIMS

This meta-analysis evaluated the effects of remote ischemic preconditioning (RIPC) on the risk of contrast-induced nephropathy (CIN) in patients undergoing percutaneous coronary intervention/coronary angiography (PCI/CA).

METHODS

PubMed, Embase, and the Cochrane Central Register of Controlled Trials databases were searched for randomized controlled trials (RCTs) that assessed the effect of RIPC on CIN in patients undergoing PCI/CA. The main outcomes of interest were the incidence of CIN 48-72 h after CA, the levels of serum creatinine, cystatin C, neutrophil gelatinase-associated lipocalin, and estimated glomerular filtration rate (eGFR), mortality, and requirement of hemodialysis and rehospitalization. The analysis was conducted using the random-effect model due to the expected heterogeneity among different studies.

RESULTS

In total, 16 trials covering 2,048 patients were identified. By assessing the methodological quality of the included studies through the Coch-rane risk of bias, we found that of the 16 RCTs, 3 had a low risk of bias, 6 a high, and 7 an unclear risk. The application of RIPC decreased the incidence of CIN (relative risk, RR, 0.50, 95% confidence interval, CI, 0.39-0.65; p < 0.001). Subgroup analyses showed that RIPC decreased the incidence of CIN in patients with eGFR <60 mL/min/1.73 m2 (RR 0.53, 95% CI 0.38-0.75; p < 0.001) but not in patients with eGRF ≥60 mL/min/1.73 m2 (RR 0.82, 95% CI 0.35-1.94; p = 0.66) at baseline. Furthermore, the increase in serum creatinine was significantly lower in patients with RIPC compared to control patients (standardized mean difference -1.41, 95% CI -2.46 to -0.35; p = 0.009).

CONCLUSIONS

Based on 16 RCTs, this meta-analysis shows that RIPC can reduce the risk of CIN in patients with moderate renal impairment undergoing PCI/CA. However, this needs to be confirmed by further high-quality evidence.

The Future of Cardioprotection-Pointing Toward Patients at Elevated Risk as the Target Populations

Translation of the cardioprotective effect by pharmacological and mechanical conditioning therapies into improvement of clinical outcome for the patients has been disappointing. Confounding factors like comorbidity and comedications may explain some of the loss in translation. However, the substantial improvement of outcome in disease states involving ischemia-reperfusion injury, that is, planned cardiac surgery, elective percutaneous coronary intervention, and even primary percutaneous coronary intervention for ST-segment myocardial infarction (STEMI), is the most plausible explanation for the missed demonstration of a clinical benefit. Remote ischemic conditioning has demonstrated consistent cardioprotective effect in experimental and in clinical proof-of-concept studies. As an adjunctive cardioprotective treatment beyond reperfusion, remote ischemic conditioning should address target populations at risk of extensive tissue damage, including patients who experience complications, which may induce profound myocardial ischemia in relation to cardiac surgery or elective percutaneous coronary intervention. Moreover, patients with STEMI and predictable impaired clinical outcome due to delayed hospital admission, high Killip class, cardiogenic shock, and cardiac arrest remain target groups. For high-risk patients, daily remote ischemic conditioning or the corollary of blood flow-restricted exercise may be alternative cardioprotective options during postoperative and post-myocardial infarct rehabilitation.

Periprocedural Myocardial Injury: Pathophysiology, Prognosis, and Prevention

The definition and clinical implications of myocardial infarction occurring in the setting of percutaneous coronary intervention have been the subject of unresolved controversy. The definitions of periprocedural myocardial infarction (PMI) are many and have evolved over recent years. Additionally, the recent advancement of different imaging modalities has provided useful information on a patients' pre-procedural risk of myocardial infarction. Nonetheless, questions on the benefit of different approaches to prevent PMI and their practical implementation remain open. This review aims to address these questions and to provide a current and contemporary perspective.

Effect of Remote Ischemic Conditioning in Patients With Takotsubo Syndrome After Acute Stroke: Study Protocol for a Randomized Controlled Trial

Introduction: Takotsubo syndrome (TTS) is an acute heart failure syndrome which is preceded by a variety of emotional or physical triggers, with central nervous system conditions being an important trigger. Remote ischemic conditioning (RIC) is a promising interventional treatment based on the probability that both TTS and acute coronary syndrome may respond similarly to interventions. The heart protection effect of RIC has been repeatedly confirmed in animal models and observational clinical trials; however, it has never been studied in patients with TTS after acute stroke in randomized clinical trials with a higher level of evidence. The present study will be a proof-of-concept study to determine whether RIC can reduce cardiac injury and eventually improve the heart function and clinical outcomes of TTS patients after acute stroke. Methods and Analysis: A single-center, outcome-assessor-blinded, randomized controlled trial (RCT) will be conducted to evaluate the effect of RIC in TTS patients after acute stroke. Major eligibility criteria include TTS patients diagnosed with acute stroke, which can be confirmed on computed tomography or magnetic resonance imaging; patients aged 18-75 years; patients admitted to a hospital within 48 h after the onset of acute stroke; and patients diagnosed with Takotsubo cardiomyopathy with an InterTAK diagnostic score ≥50. A total of 60 eligible patients will be randomly allocated into either the RIC or the control group. The primary endpoint is a composite of death from any cause and major adverse cardiac and cerebrovascular events during the in-hospital period and at the 1- and 6-month follow-up. Ethics and dissemination: This study has been approved by the Medical Ethics Committee of Xuanwu Hospital, Capital Medical University ([2017] 072). The study findings will be presented at international conferences and published in a peer-reviewed journal. Trial registration: This study has been prospectively registered in the Chinese Clinical Trial Registry on September 10, 2018 (ChiCTR1800018290).

Acute Renal Failure/Acute Kidney Injury (AKI) Associated with Endovascular Procedures

AKI is one of the most common yet underdiagnosed postoperative complications that can occur after any type of surgery. Contrast-induced nephropathy (CIN) is still poorly defined and due to a wide range of confounding individual variables, its risk is difficult to determine. CIN mainly affects patients with underlying chronic kidney disease, diabetes, sepsis, heart failure, acute coronary syndrome and cardiogenic shock. Further research is necessary to better understand pathophysiology of contrast-induced AKI and consequent implementation of effective prevention and therapeutic strategies. Although many therapies have been tested to avoid CIN, the only potent preventative strategy involves aggressive fluid administration and reduction of contrast volume. Regardless of surgical technique—open or endovascular—perioperative AKI is associated with significant morbidity, mortality and cost. Endovascular procedures always require administration of a contrast media, which may cause acute tubular necrosis or renal vascular embolization leading to renal ischemia and as a consequence, contribute to increased number of post-operative AKIs.

Remote ischemic preconditioning inhibits platelet αIIb β3 activation in coronary artery disease patients receiving dual antiplatelet therapy: A randomized trial

OBJECTIVES

We investigated whether remote ischemic preconditioning (RIPC) inhibits agonist-induced conformational activation of platelet αIIb β3 in patients with coronary artery disease already receiving conventional antiplatelet therapy.

PATIENTS/METHODS

Consecutive patients with angiographically confirmed coronary artery disease were randomized to RIPC or sham treatment. Venous blood was collected before and immediately after RIPC/sham. Platelet aggregometry (ADP, arachidonic acid) and whole blood platelet flow cytometry was performed for CD62P, CD63, active αIIb β3 (PAC-1 binding) before and after stimulation with ADP, thrombin ± collagen, or PAR-1 thrombin receptor agonist.

RESULTS

Patients (25 RIPC, 23 sham) were well matched, 83% male, age (mean ± standard deviation) 63.3 ± 13.2 years, 95% aspirin, 81% P2Y12 inhibitor. RIPC did not affect platelet aggregation, nor agonist-induced expression of CD62P, but selectively and significantly decreased αIIb β3 activation after stimulation with either PAR-1 agonist peptide or the combination of thrombin + collagen, but not after ADP nor thrombin alone. The effect of RIPC on platelet αIIb β3 activation was evident in patients receiving both aspirin and P2Y12 inhibitor, and was not associated with an increase in vasodilator-stimulated phosphoprotein phosphorylation.

CONCLUSIONS

Remote ischemic preconditioning inhibits conformational activation of platelet αIIb β3 in response to exposure to thrombin and collagen in patients with coronary artery disease receiving dual antiplatelet therapy. These findings indicate agonist-specific inhibition of platelet activation by RIPC in coronary artery disease that is not obviated by the prior use of P2Y12 inhibitors.

Remote ischemic preconditioning does not influence lectin pathway protein levels in head and neck cancer patients undergoing surgery

BACKGROUND

Cancer patients who undergo tumor removal, and reconstructive surgery by transfer of a free tissue flap, are at high risk of surgical site infection and ischemia-reperfusion injury. Complement activation through the lectin pathway (LP) may contribute to ischemia-reperfusion injury. Remote ischemic preconditioning (RIPC) is a recent experimental treatment targeting ischemia-reperfusion injury. The study aims were to investigate LP protein plasma levels in head and neck cancer patients compared with healthy individuals, to explore whether RIPC affects LP protein levels in head and neck cancer surgery, and finally to examine the association between postoperative LP protein levels and the risk of surgical site infection.

METHODS

Head and neck cancer patients (n = 60) undergoing tumor resection and reconstructive surgery were randomized 1:1 to RIPC or sham intervention administered intraoperatively. Blood samples were obtained preoperatively, 6 hours after RIPC/sham, and on the first postoperative day. LP protein plasma levels were measured utilizing time-resolved immunofluorometric assays.

RESULTS

H-ficolin and M-ficolin levels were significantly increased in cancer patients compared with healthy individuals (both P ≤ 0.02). Conversely, mannan-binding lectin (MBL)-associated serine protease (MASP)-1, MASP-3, collectin liver-1 (CL-L1), and MBL-associated protein of 44 kilodalton (MAp44) levels were decreased in cancer patients compared with healthy individuals (all P ≤ 0.04). A significant reduction in all LP protein levels was observed after surgery (all P < 0.001); however, RIPC did not affect LP protein levels. No difference was demonstrated in postoperative LP protein levels between patients who developed surgical site infection and patients who did not (all P > 0.13).

CONCLUSIONS

The LP was altered in head and neck cancer patients. LP protein levels were reduced after surgery, but intraoperative RIPC did not influence the LP. Postoperative LP protein levels were not associated with surgical site infection.

Evaluating the Therapeutic Efficacy and Safety of Landiolol Hydrochloride for Management of Arrhythmia in Critical Settings: Review of the Literature

Background

Landiolol hydrochloride, a highly cardio-selective beta-1 blocker with an ultra-short-acting half-life of 4 minutes, was originally approved by Japan for treatment of intraoperative tachyarrhythmias. This review aims to provide an integrated overview of the current state of knowledge of landiolol hydrochloride in the management of arrhythmia in critical settings.

Methods

We searched MEDLINE, EMBASE, and the Cochrane Library to retrieve relevant articles with a total of 65 records identified.

Results

The high β1 selectivity (β1/β2 ratio of 255:1) of landiolol causes a more rapid heart rate (HR) decrease compared to esmolol while avoiding decreases in mean arterial blood pressure. Recently, it has been found useful in left ventricular dysfunction patients and fatal arrhythmia requiring emergency treatment. Recent random clinical trials (RCT) have revealed therapeutic and prophylactic effects on arrhythmia, and very low-dose landiolol might be effective for preventing postoperative atrial fibrillation (POAF) and sinus tachycardia. Likewise, landiolol is an optimal choice for perioperative tachycardia treatment during cardiac surgery. The high β1 selectivity of landiolol is useful in heart failure patients as a first-line therapy for tachycardia and arrhythmia as it avoids the typical depression of cardiac function seen in other β-blockers. Application in cardiac injury after percutaneous coronary intervention (PCI), protection for vital organs (lung, kidney, etc.) during sepsis, and stabilizing hemodynamics in pediatric patients are becoming the new frontier of landiolol use.

Conclusion

Landiolol is useful as a first-line therapy for the prevention of POAF after cardiac/non-cardiac surgery, fatal arrhythmias in heart failure patients and during PCI. Moreover, the potential therapeutic effect of landiolol for sepsis in pediatric patients is currently being explored. As positive RCT results continue to be published, new clinical uses and further clinical studies in various settings by cardiologists, intensivists and pediatric cardiologists are being conducted.

Irisin and troponin I expression in dialysis patients submitted to remote ischemic preconditioning: a pilot study

Background:

Renal replacement therapy continues to be related to high hospitalization rates and poor quality of life. All-cause morbidity and mortality in renal replacement therapy in greater than 20% per year, being 44 times greater when diabetes is present, and over 10 times that of the general population. Regardless of treatment, the 5-year survival is 40%, surpassing many types of cancers. Irisin is a hormone that converts white adipose tissue into beige adipose tissue, aggregating positive effects like fat mass control, glucose tolerance, insulin resistance, prevention of muscle loss, and reduction in systemic inflammation.

Objectives:

To determine the serum levels of troponin I in hemodialysis patients submitted to remote ischemic preconditioning (RIPC) associated with irisin expression.

Methods:

This was a prospective, randomized, double-blind clinical trial with patients with chronic kidney disease submitted to hemodialysis for a 6-month period. Troponin I, IL-6, urea, TNF-α, and creatinine levels were determined from blood samples. The expressions of irisin, thioredoxin, Nf-kb, GPX4, selenoprotein and GADPH were also evaluated by RT-PCR.

Results:

Samples from 14 hypertensive patients were analyzed, 9 (64.3%) of whom were type 2 diabetics, aged 44-64 years, and 50% of each sex. The difference between pre- and post-intervention levels of troponin I was not significant. No differences were verified between the RIPC and control groups, except for IL-6, although a significant correlation was observed between irisin and troponin I.

Conclusion:

Remote ischemic preconditioning did not modify irisin or troponin I expression, independent of the time of collection.

The efficacy of remote ischemic conditioning in preventing contrast-induced nephropathy among patients undergoing coronary angiography or intervention: An updated systematic review and meta-analysis

Background

Numerous trials have investigated the effect of remote ischemic conditioning (RIC) in preventing contrast‐induced nephropathy (CIN) in patients receiving contrast medium (CM). This meta analysis aims to validate the role of RIC in preventing CIN.

Methods

We searched the PubMed, EMBASE, and Web of Science databases for eligible randomized controlled trials (RCTs) published before April 27, 2019. Two investigators independently extracted basic characteristics from each study. Odds ratios (ORs) with corresponding 95% confidence intervals (CIs) were used to examine the treatment effect.

Results

A total of 18 studies comprising 2,503 patients were included in our meta‐analysis. Compared with conventional therapy, RIC significantly reduced the risk of CIN (OR = 0.43, 95% CI: 0.33, 0.56, p < .05). Subgroup analyses showed that the protective effect of RIC was stronger in the low‐osmolar contrast media group (OR = 0.32; 95% CI: 0.23, 0.45, p < .05) and the nondiabetic group (OR = 0.39; 95% CI: 0.29, 0.53 p < .05). RIC also significantly reduced major adverse cardiovascular events within the first 6 months (OR = 0.39; p < .05), but the influence was not present after long‐term follow‐up.

Conclusions

Our meta‐analysis showed that RIC could effectively reduce CIN risk and decrease the short‐term incidence of relevant adverse events. Furthermore, the effects of CIN are more pronounced in nondiabetic patients and with the use of low‐osmolar contrast medium. This meta‐analysis of small trials suggests a possible protective effect of RIC on contrast‐induced nephropathy and favors the performance of a large randomized trial to further investigate this strategy.

Egr-1 functions as a master switch regulator of remote ischemic preconditioning-induced cardioprotection

Despite improved treatment options myocardial infarction (MI) is still a leading cause of mortality and morbidity worldwide. Remote ischemic preconditioning (RIPC) is a mechanistic process that reduces myocardial infarction size and protects against ischemia reperfusion (I/R) injury. The zinc finger transcription factor early growth response-1 (Egr-1) is integral to the biological response to I/R, as its upregulation mediates the increased expression of inflammatory and prothrombotic processes. We aimed to determine the association and/or role of Egr-1 expression with the molecular mechanisms controlling the cardioprotective effects of RIPC. This study used H9C2 cells in vitro and a rat model of cardiac ischemia reperfusion (I/R) injury. We silenced Egr-1 with DNAzyme (ED5) in vitro and in vivo, before three cycles of RIPC consisting of alternating 5 min hypoxia and normoxia in cells or hind-limb ligation and release in the rat, followed by hypoxic challenge in vitro and I/R injury in vivo. Post-procedure, ED5 administration led to a significant increase in infarct size compared to controls (65.90 ± 2.38% vs. 41.00 ± 2.83%, p < 0.0001) following administration prior to RIPC in vivo, concurrent with decreased plasma IL-6 levels (118.30 ± 4.30 pg/ml vs. 130.50 ± 1.29 pg/ml, p < 0.05), downregulation of the cardioprotective JAK-STAT pathway, and elevated myocardial endothelial dysfunction. In vitro, ED5 administration abrogated IL-6 mRNA expression in H9C2 cells subjected to RIPC (0.95 ± 0.20 vs. 6.08 ± 1.40-fold relative to the control group, p < 0.05), resulting in increase in apoptosis (4.76 ± 0.70% vs. 2.23 ± 0.34%, p < 0.05) and loss of mitochondrial membrane potential (0.57 ± 0.11% vs. 1.0 ± 0.14%-fold relative to control, p < 0.05) in recipient cells receiving preconditioned media from the DNAzyme treated donor cells. This study suggests that Egr-1 functions as a master regulator of remote preconditioning inducing a protective effect against myocardial I/R injury through IL-6-dependent JAK-STAT signaling.

Remote Ischemic Preconditioning Acutely Improves Coronary Microcirculatory Function

Background Remote ischemic preconditioning (RIPC) attenuates myocardial damage during elective and primary percutaneous coronary intervention. Recent studies suggest that coronary microcirculatory function is an important determinant of clinical outcome. The aim of this study was to assess the effect of RIPC on markers of microcirculatory function. Methods and Results Patients referred for cardiac catheterization and fractional flow reserve measurement were randomized to RIPC or sham. Operators and patients were blinded to treatment allocation. Comprehensive physiological assessments were performed before and after RIPC/sham including the index of microcirculatory resistance and coronary flow reserve after intracoronary glyceryl trinitrate and during the infusion of intravenous adenosine. Thirty patients were included (87% male; mean age: 63.1±10.0 years). RIPC and sham groups were similar with respect to baseline characteristics. RIPC decreased the calculated index of microcirculatory resistance (median, before RIPC: 22.6 [interquartile range [IQR]: 17.9-25.6]; after RIPC: 17.5 [IQR: 14.5-21.3]; P=0.007) and increased coronary flow reserve (2.6±0.9 versus 3.8±1.7, P=0.001). These RIPC-mediated changes were associated with a reduction in hyperemic transit time (median: 0.33 [IQR: 0.26-0.40] versus 0.25 [IQR: 0.20-0.30]; P=0.010). RIPC resulted in a significant decrease in the calculated index of microcirculatory resistance compared with sham (relative change with treatment [mean±SD] was -18.1±24.8% versus +6.1±37.5; P=0.047) and a significant increase in coronary flow reserve (+41.2% [IQR: 20.0-61.7] versus -7.8% [IQR: -19.1 to 10.3]; P<0.001). Conclusions The index of microcirculatory resistance and coronary flow reserve are acutely improved by remote ischemic preconditioning. This raises the possibility that RIPC confers cardioprotection during percutaneous coronary intervention as a result of an improvement in coronary microcirculatory function. Clinical Trial Registration URL: www.anzctr.org.au/ . Unique identifier: CTRN12616000486426.

Neuro-autonomic changes induced by remote ischemic preconditioning (RIPC) in healthy young adults: Implications for stress

The mechanisms underlying the protective effects of remote ischemic preconditioning (RIPC) are not presently clear. Recent studies in experimental models suggest the involvement of the autonomic nervous system (ANS) in cardioprotection. The aim of this study was to investigate the changes in ANS in healthy young volunteers divided into RIPC (n = 22) or SHAM (n = 18) groups. RIPC was induced by 1 cycle of 4 min inflation/5 min deflation followed by 2 cycles of 5 min inflation/5 min deflation of a cuff placed on the upper left limb. The study included analysis of heart rate (HR), blood pressure (BP), heart rate variability (HRV), measurements of microcirculation and porphyrin fluorescence in the limb before and after the RIPC. RIPC caused reactive hyperemia in the limb and reduced blood porphyrin level. A mental load (serial sevens test) and mild motor stress (hyperventilation) were performed on all subjects before and after RIPC or corresponding rest in the SHAM group. Reduction of HR occurred during the experiments in both RIPC and SHAM groups reflecting RIPC-independent adaptation of the subjects to the experimental procedure. However, in contrast to the SHAM group, RIPC altered several of the spectral indices of HRV during the serial sevens test and hyperventilation. This was expressed predominantly as an increase in power of the very low-frequency band of the spectrum, increased values of detrended fluctuation analysis and weakening of correlation between the HRV parameters and HR. In conclusion, RIPC induces changes in the activity of ANS that are linked to stress resistance.

The role of Glucagon-Like Peptide 1 Loading on periprocedural myocardial infarction During elective PCI (GOLD-PCI study): A randomized, placebo-controlled trial

BACKGROUND

The incretin hormone glucagon-like peptide 1 (GLP-1) has been shown to protect against lethal ischemia-reperfusion injury in animal models and against nonlethal ischemia reperfusion injury in humans. Furthermore, GLP-1 receptor agonists have been shown to reduce major adverse cardiovascular and cerebrovascular events (MACCE) in large-scale studies. We sought to investigate whether GLP-1 reduced percutaneous coronary intervention (PCI)-associated myocardial infarction (PMI) during elective PCI.

METHODS

The study was a randomized, double-blind controlled trial in which patients undergoing elective PCI received an intravenous infusion of either GLP-1 at 1.2 pmol/kg/min or matched 0.9% saline placebo before and during the procedure. Randomization was performed in 1:1 fashion, with stratification for diabetes mellitus. Six-hour cardiac troponin I (cTnI) was measured with a primary end point of PMI defined as rise ≫×5 upper limit of normal (280 ng/L). Secondary end points included cTnI rise and MACCE at 12 months.

RESULTS

A total of 192 patients were randomized with 152 (79%) male and a mean age of 68.1 ± 8.9 years. No significant differences in patient demographics were noted between the groups. There was no difference in the rate of PMI between GLP-1 and placebo (9 [9.8%] vs 8 [8.3%], P = 1.0) or in the secondary end points of difference in median cTnI between groups (9.5 [0-88.5] vs 20 [0-58.5] ng/L, P = .25) and MACCE at 12 months (7 [7.3%] vs 9 [9.4%], P = .61).

CONCLUSIONS

In this randomized, placebo-controlled trial, GLP-1 did not reduce the low incidence of PMI or abrogate biomarker rise during elective PCI, nor did it influence the 12-month MACCE rate which also remained low.

CLINICAL TRIAL REGISTRATION

Clinicaltrials.gov Number: NCT02127996https://clinicaltrials.gov/ct2/show/NCT02127996.

Effect of remote ischemic preconditioning on electrophysiological parameters in nonvalvular paroxysmal atrial fibrillation: The RIPPAF Randomized Clinical Trial

BACKGROUND

Atrial fibrillation (AF) remains the most relevant arrhythmia with a prevalence of 2%. The treatment options are either highly invasive and cost-intensive or limited by potential side effects or insufficient efficacy. However, no direct means of prevention that could reduce the burden of AF have been tested.

OBJECTIVE

The purpose of this study was to determine whether remote ischemic preconditioning (RIPC) has an impact on inducibility and sustainability of AF.

METHODS

A total of 146 patients with paroxysmal AF undergoing electrophysiology study were randomized to receive either RIPC, performed by short episodes of forearm ischemia, or sham intervention (clinicaltrials.gov identifier: NCT02779660). Effective refractory periods, conduction times, velocities, and conduction delays measured were analyzed by pacing from the coronary sinus (CS). End points of the study were the inducibility and sustainability of AF after prespecified rapid pacing sequences.

RESULTS

RIPC significantly reduces the inducibility (odds ratio 0.35; 95% confidence interval 0.17-0.71; P = .003) and sustainability (odds ratio 0.36; 95% confidence interval 0.16-0.81; P = .01) of AF. Furthermore, it decreased dispersion of atrial refractory periods (16.0 ± 14.0 ms vs 22.7 ± 19.0 ms; P = .021) as well as atrial conduction delays (49.2 ± 19.6 ms vs 56.2 ± 22.5 ms; P = .049 for proximal CS and 42.4 ± 16.6 ms vs 49.8 ± 22.2 ms; P = .029 for distal CS). In the whole cohort, longer atrial conduction delay (57.6 ± 22.2 ms vs 50.0 ± 20.5 ms; P = .044) and slower conduction velocity (1.74 ± 0.3 mm/ms vs 1.93 ± 0.5 mm/ms; P = .006) were associated with inducibility of AF whereas a wider dispersion of effective refractory periods (25.9 ± 18.3 ms vs 15.7 ± 11.6 ms; P = .028) maintained AF episodes.

CONCLUSION

RIPC reduces the inducibility and sustainability of AF, which is possibly mediated by changes in electrophysiological properties of the atria. It may be used as a simple noninvasive procedure to reduce AF burden.

Repetitive vascular occlusion stimulus (RVOS) versus standard care to prevent muscle wasting in critically ill patients (ROSProx):a study protocol for a pilot randomised controlled trial

BACKGROUND

Forty per cent of critically ill patients are affected by intensive care unit-acquired weakness (ICU-AW), to which skeletal muscle wasting makes a substantial contribution. This can impair outcomes in hospital, and can cause long-term physical disability after hospital discharge. No effective mitigating strategies have yet been identified. Application of a repetitive vascular occlusion stimulus (RVOS) a limb pressure cuff inducing brief repeated cycles of ischaemia and reperfusion, can limit disuse muscle atrophy in both healthy controls and bed-bound patients recovering from knee surgery. We wish to determine whether RVOS might be effective in mitigating against muscle wasting in the ICU. Given that RVOS can also improve vascular function in healthy controls, we also wish to assess such effects in the critically ill. We here describe a pilot study to assess whether RVOS application is safe, tolerable, feasible and acceptable for ICU patients.

METHODS

This is a randomised interventional feasibility trial. Thirty-two ventilated adult ICU patients with multiorgan failure will be recruited within 48 h of admission and randomised to either the intervention arm or the control arm. Intervention participants will receive RVOS twice daily (except only once on day 1) for up to 10 days or until ICU discharge. Serious adverse events and tolerability (pain score) will be recorded; feasibility of trial procedures will be assessed against pre-specified criteria and acceptability by semi-structured interview. Together with vascular function, muscle mass and quality will be assessed using ultrasound and measures of physical function at baseline, on days 6 and 11 of study enrolment, and at ICU and hospital discharge. Blood and urine biomarkers of muscle metabolism, vascular function, inflammation and DNA damage/repair mechanism will also be analysed. The Health questionnaire will be completed 3 months after hospital discharge.

DISCUSSION

If this study demonstrates feasibility, the derived data will be used to inform the design (and sample size) of an appropriately-powered prospective trial to clarify whether RVOS can help preserve muscle mass/improve vascular function in critically ill patients.

TRIAL REGISTRATION

ISRCTN Registry, ISRCTN44340629. Registered on 26 October 2017.

Effect of long-term remote ischemic conditioning on inflammation and cardiac remodeling

Background. Remote ischemic conditioning (RIC) protects against acute ischemia-reperfusion injury and may have beneficial effects in patients with stable cardiovascular disease. We investigated the effect of long-term RIC treatment in patients with chronic ischemic heart failure (CIHF). Methods. Prespecified post-hoc analysis of a prospective, exploratory and outcome-assessor blinded study. Twenty-one patients with compensated CIHF and 21 matched controls without heart failure or ischemic heart disease were treated with RIC once daily for 28 ± 4 days. RIC was conducted as 4 cycles of 5 minutes upper arm ischemia followed by 5 minutes of reperfusion. We evaluated circulating markers of inflammation and cardiac remodeling at baseline and following long-term RIC. Results. RIC reduced C-reactive protein from 1.5 (0.6-2.5) to 1.3 (0.6-2.1) mg/l following long-term RIC treatment (p = .02) and calprotectin from 477 (95% CI 380 to 600) to 434 (95% CI 354 to 533) ng/ml (p = .03) in patients with CIHF, but not in matched controls. Overall, RIC did not affect circulating markers related to adaptive or innate immunology or cardiac remodeling in patients with CIHF. Among patients with CIHF and N-terminal pro-brain natriuretic peptide (NT-proBNP) plasma levels above the geometric mean of 372 ng/l, long-term RIC treatment reduced soluble ST2 (n = 9) from 22.0 ± 3.7 to 20.3 ± 3.9 ng/ml following long-term RIC treatment (p = .01). Conclusion. Our findings suggest that long-term RIC treatment has mild anti-inflammatory effects in patients with compensated CIHF and anti-remodeling effects in those with increased NT-proBNP levels. This should be further investigated in a randomized sham-controlled trial.

Effects of ischaemic conditioning on tissue oxygen saturation and heart rate variability: an observational study

Objective

Ischaemic conditioning (IC) has organ-protective effects, but its clinical results have been inconsistent. Tissue oxygen saturation (StO₂) and heart rate variability (HRV) reflect peripheral microcirculation and autonomic nervous system activity, but their changes during IC have not been well documented. We assessed StO₂ and HRV during IC in patients undergoing cardiac surgery and healthy volunteers.

Methods

Ten patients undergoing cardiac surgery and 10 healthy male volunteers underwent remote IC (four 5-minute cycles of ischaemia/reperfusion) applied to the upper arm. Changes in StO₂ at the thenar eminence and HRV according to the R-R intervals were recorded during IC.

Results

The lowest StO₂ during ischaemia significantly decreased in patients and significantly increased in volunteers. Among the HRV parameters, the low-frequency domain, which corresponds to sympathetic activity, significantly increased after IC in volunteers but not in patients. Other variables were similar between the groups.

Conclusions

These results suggest that the minimum tissue oxygen content is depleted during ischaemia in patients and preserved in healthy volunteers. Sympathetic nervous activity seems to increase after IC in healthy volunteers but remains unaffected in patients. Thus, IC may act differently between patients undergoing cardiac surgery and healthy subjects.

Protective effect of remote ischemic pre-conditioning on patients undergoing cardiac bypass valve replacement surgery: A randomized controlled trial

Remote ischemic pre-conditioning (RIPC) may have a protective effect on myocardial injury associated with cardiac bypass surgery (CPB). The objective of the present study was to investigate the effect of RIPC on ischemia/reperfusion (I/R) injury and to assess the underlying mechanisms. A total of 241 patients who underwent valve replacement were randomly assigned to receive either RIPC (n=121) or control group (n=120). The primary endpoint was peri-operative myocardial injury (PMI), which was determined by serum Highly sensitive cardiac troponin T (hsTnT). The secondary endpoint was the blood gas indexes, acute lung injury and length of intensive care unit stay, length of hospital stay and major adverse cardiovascular events. The results indicated that in comparison with control group, RIPC treatment reduced the levels of hsTnT at 6 and 24 h post-CPB (P<0.001), as well as the alveolar-arterial oxygen pressure difference and respiratory index after CPB. Furthermore, RIPC reduced the incidence of acute lung injury by 15.3% (54.1% in the control group vs. 41.3% in the RIPC group, P=0.053). It was indicated that RIPC provided myocardial and pulmonary protection during CPB. In addition, the length of the intensive care unit and hospital stay was reduced by RIPC. Mechanistic investigation revealed a reduced content of soluble intercellular adhesion molecule-1, endothelin-1 and malondialdehyde, as well as elevated levels of nitric oxide in the RIPC group compared with those in the control group. This indicated that RIPC protected against I/R injury associated with CPB through reducing the inflammatory response and oxidative damage, as well as improving pulmonary vascular tension. In conclusion, RIPC reduced myocardial and pulmonary injury associated with CPB. This protective effect may be associated with the inhibition of the inflammatory response and oxidative injury. The present study proved the efficiency of this approach in reducing ischemia/reperfusion injury associated with cardiac surgery. Clinical trial registry no. ChiCTR1800015393.

Short-term remote ischemic conditioning may protect monkeys after ischemic stroke

Objective

We aimed to evaluate the safety and effectiveness of short-term remote ischemic postconditioning (RIPC) in acute stroke monkey models.

Methods

Acute stroke monkeys were allocated to four groups based on the number of limbs exposed to RIPC. RIPC was initiated by 5-min cuff inflation/deflation cycles of the target limb(s) for 5-10 bouts. Vital signs, skin integrity, brain MRI, and serum levels of cardiac enzymes (myoglobin, creatine kinase [CK], CK-muscle/brain [CK-MB]), one inflammatory marker (high-sensitivity C-reactive protein [hsCRP], and one endothelial injury marker (von Willebrand factor [vWF]) were assessed. Spetzler scores were used to assess neurological function.

Results

No significant differences in vital signs or local skin integrity were found. Short-term RIPC did not reduce infarct volume under any condition at the 24th hour after stroke. However, neurological function improved in multi-limb RIPC compared with sham and single-limb RIPC at the 30th day follow-up after stroke. Myoglobin, CK, and CK-MB levels were reduced after multi-limb RIPC, regardless of the number of bouts. Moreover, multi-limb RIPC produced a greater diminution in CK-MB levels, whereas two-limb RIPC was more effective in reducing serum CK levels at the 24th hour after stroke. hsCRP increased after 5 bouts of multi-limb RIPC before decreasing below baseline and single-limb RIPC levels. Serum vWF was decreased at later time points after RIPC in all RIPC groups.

Conclusions

Stroke monkeys in hyperacute stage may benefit from short-term RIPC; however, whether this intervention can be translated into clinical use in patients with acute ischemic stroke warrants further study.

Sevoflurane, Propofol and Carvedilol Block Myocardial Protection by Limb Remote Ischemic Preconditioning

The effects of remote ischemic preconditioning (RIPC) in cardiac surgery have been inconsistent. We investigated whether anesthesia or beta-blockers interfere with RIPC cardioprotection. Fifty patients undergoing cardiac surgery were randomized to receive limb RIPC (four cycles of 5-min of upper arm cuff inflation/deflation) in the awake state (no-anesthesia; n = 17), or under sevoflurane (n = 17) or propofol (n = 16) anesthesia. In a separate crossover study, 11 healthy volunteers received either carvedilol or no medication prior to RIPC. Plasma dialysates were obtained and perfused through an isolated male Sprague⁻Dawley rat heart subjected to 30-min ischemia/60-min reperfusion, following which myocardial infarct (MI) size was determined. In the cardiac surgery study, pre-RIPC MI sizes were similar among the groups (39.7 ± 4.5% no-anesthesia, 38.9 ± 5.3% sevoflurane, and 38.6 ± 3.6% propofol). However, post-RIPC MI size was reduced in the no-anesthesia group (27.5 ± 8.0%; p < 0.001), but not in the anesthesia groups (35.7 ± 6.9% sevoflurane and 35.8 ± 5.8% propofol). In the healthy volunteer study, there was a reduction in MI size with RIPC in the no-carvedilol group (41.7 ± 4.3% to 30.6 ± 8.5%; p < 0.0001), but not in the carvedilol group (41.0 ± 4.0% to 39.6 ± 5.6%; p = 0.452). We found that the cardioprotective effects of limb RIPC were abolished under propofol or sevoflurane anesthesia and in the presence of carvedilol therapy.