Limb Remote Ischemic Preconditioning Applied During Sevoflurane Anesthesia Does Not Protect the Lungs in Patients Undergoing Adult Heart Valve Surgery.

BACKGROUND: Two consistent overall cell protective preconditioning treatments should provide more protection. We hypothesized that limb remote ischemic preconditioning (RIPC, second preconditioning stimulus) applied during sevoflurane inhalation (first preconditioning stimulus) would provide more protection to the lungs of patients undergoing adult heart valve surgery. METHODS: In this randomized, placebo-controlled, double-blind trial, 50 patients were assigned to the RIPC group or the placebo group (1:1). Patients in the RIPC group received three 5-min cycles of 300 mmHg cuff inflation/deflation of the left-side lower limb before aortic cross-clamping. Anesthesia consisted of opioids and propofol for induction and sevoflurane for maintenance. The primary end point was comparison of the postoperative arterial-alveolar oxygen tension ratio (a/A ratio) between groups. Secondary end points included comparisons of pulmonary variables, postoperative morbidity and mortality and regional and systemic inflammatory cytokines between groups. RESULTS: In the RIPC group, the a/A ratio and other pulmonary variables exhibited no significant differences throughout the study period compared with the placebo group. No significant differences in either plasma or bronchoalveolar lavage levels of TNF- α were noted between the groups at 10 min after anesthetic induction and 1 h after cross-clamp release. The percentage of neutrophils at 12 h postoperation was significantly increased in the RIPC group compared with the placebo group (91.34±0.00 vs. 89.42±0.10, P = 0.023). CONCLUSIONS: Limb RIPC applied during sevoflurane anesthesia did not provide additional significant pulmonary protection following adult valvular cardiac surgery.

Effect of remote ischemic preconditioning in patients with STEMI during primary percutaneous coronary intervention: a meta-analysis of randomized controlled trials.

Remote ischemic conditioning is usually associated with cardioprotective intervention against ischemia-reperfusion. However, the effect of remote ischemic preconditioning (RIC-pre) completed before myocardial reperfusion with intermittent limb ischemia-reperfusion in patients with STEMI undergoing primary percutaneous coronary intervention (PPCI) is unclear. PubMed, EMBASE, and the Cochrane Library were fully searched from the beginning of each database up to September 2019 to find seven RCTs, a total of 2796 patients with STEMI undergoing PPCI with RIC-pre and 2818 patients with STEMI undergoing PPCI alone. No significant discrepancy in cardiac death was observed between RIC-pre and control groups (RR 1.03, 95% CI [0.76-1.41], P = 0.83, I2 = 40%). The incidences of hospitalization for heart failure (RR 1.03, 95% CI [0.85-1.25], P = 0.77, I2 = 0%), myocardial infarction (RR 0.86, 95% CI [0.59-1.26], P = 0.44, I2 = 0%), and stroke (RR 1.04, 95% CI [0.62-1.77], P = 0.87, I2 = 0%) were not decreased in RIC-pre group when compared with control group. Subgroup analysis revealed similar risk in clinical adverse events at long- and short-term follow-up between two groups. However, peak of creatine kinase-myocardial band (CK-MB) was reduced in RIC-pre group (SWD -0.42, 95% CI [-0.77, -0.07], P = 0.02, I2 = 34%). RIC-pre tended to a low peak of CK-MB in patients with STEMI undergoing PPCI, but lacked significant beneficial effects on improving clinical outcomes at long- and short-term follow-up.

A systematic review and meta-analysis of remote ischemic preconditioning for vascular surgery.

BACKGROUND: Remote ischemic preconditioning (RIPC) is a method of preparing the body for a later prolonged ischemic episode to protect against subsequent detrimental effects. This study aimed to identify the effects of RIPC in vascular surgery. METHODS: A standard Preferred Reporting Items for Systematic Reviews and Meta-Analyses search was conducted of randomized controlled trials of RIPC in patients undergoing open or endovascular aneurysm repair, carotid endarterectomy, or lower limb bypass reporting on mortality and renal or cardiac outcomes. Random-effects meta-analysis was performed using Review Manager 5.3 (The Nordic Cochrane Center, Copenhagen, Denmark). RESULTS: A total of 13 randomized controlled trials in the meta-analysis included 548 patients in the RIPC cohort and 549 controls. There was no significant difference in mortality, renal dysfunction, myocardial infarction, myocardial injury, or length of stay between the groups, with subgroup and sensitivity analysis showing no significant difference. CONCLUSIONS: Current evidence demonstrates no benefit of RIPC in vascular surgery. Further large multicenter trials of RIPC in major vascular surgery should be considered.

Effect of Remote Ischemic Preconditioning on Outcomes in Adult Cardiac Surgery: A Systematic Review and Meta-analysis of Randomized Controlled Studies.

BACKGROUND: Remote ischemic preconditioning (RIPC) has been demonstrated to prevent organ dysfunction in cardiac surgery patients. However, recent large, prospective, multicenter, randomized controlled trials (RCTs) had controversial results. Thus, a meta-analysis of RCTs was performed to investigate whether RIPC can reduce the incidence of acute myocardial infarction (AMI), acute kidney injury (AKI), and mortality in adult cardiac surgery patients. METHODS: Study data were collected from Medline, Elsevier, Cochrane Central Register of Controlled Trials and Web of Science databases. RCTs involving the effect of RIPC on organ protection in cardiac surgery patients, which reported the concentration or total release of creatine kinase-myocardial band, troponin I/troponin T (TNI/TNT) after operation, or the incidence of AMI, AKI, or mortality, were selected. Two reviewers independently extracted data using a standardized data extraction protocol where TNI or TNT concentrations; total TNI released after cardiac surgery; and the incidence of AKI, AMI, and mortality were recorded. Review Manager 5.3 software was used to analyze the data. RESULTS: Thirty trials, including 7036 patients were included in the analyses. RIPC significantly decreased the concentration of TNI/TNT (standard mean difference [SMD], -0.25 ng/mL; 95% confidence interval [CI], -0.41 to -0.048 ng/mL; P = .004), creatine kinase-myocardial band (SMD, -0.22; 95% CI, -0.07-0.35 ng/mL; P = .46), and the total TNI/TNT release (SMD, -0.49 ng/mL; 95% CI, -0.93 to -0.55 ng/mL; P = .03) in cardiac surgery patients after a procedure. However, RIPC could not reduce the incidence of AMI (relative risk, 0.89; 95% CI, 0.70-1.13; P = .34) and AKI (relative risk, 0.88; 95% CI, 0.72-1.06; P = .18), and there was also no effect of RIPC on mortality in adult cardiac surgery patients. Interestingly, subgroup analysis showed that RIPC reduced incidence of AKI and mortality of cardiac surgery patients who received volatile agent anesthesia. CONCLUSIONS: Our meta-analysis demonstrated that RIPC reduced TNI/TNT release after cardiac surgery. RIPC did not significantly reduce the incidence of AKI, AMI, and mortality. However, RIPC could reduce mortality in patients receiving volatile inhalational agent anesthesia.

Remote ischaemic conditioning for preventing and treating ischaemic stroke.

BACKGROUND: Remote ischaemic conditioning (RIC) has been developed as a neuroprotective strategy to prevent and treat ischaemic stroke. It usually involves restricting blood flow to limbs and then releasing the ischaemic blood to promote a neuroprotective effect. Preclinical studies have suggested that RIC may have beneficial effects in ischaemic stroke patients and those at risk of ischaemic stroke. However, existing evidence is insufficient to demonstrate the efficacy and safety of RIC in preventing and treating ischaemic stroke. OBJECTIVES: To assess the benefits and harms of RIC for preventing ischaemic stroke and for treating people with ischaemic stroke and those at risk for ischaemic stroke. SEARCH METHODS: We searched the Cochrane Stroke Group Trials Register (16 January 2018), the Cochrane Central Register of Controlled Trials (CENTRAL; 2017, Issue 12) in the Cochrane Library (January 2018), MEDLINE Ovid (1946 to January 2018), Embase Ovid (1974 to January 2018), Web of Science Core Collection (1950 to January 2018) and three Chinese databases (January 2018). We also searched four ongoing trials registers, reference lists, and conference proceedings. SELECTION CRITERIA: We included randomised controlled trials (RCTs) comparing RIC with sham RIC or medical management in people with ischaemic stroke or at risk of ischaemic stroke. DATA COLLECTION AND ANALYSIS: Two review authors independently selected studies, assessed trial quality and risk of bias, and extracted data. We used the GRADE approach to assess the quality of the evidence. MAIN RESULTS: We included seven trials, involving 735 participants, in this review. We analysed the effects of RIC on preventing and treating ischaemic stroke respectively.We evaluated risk of bias and judged it to be low for generation of allocation sequence in six studies and unclear in one study; unclear for allocation concealment in four studies and low in three studies; high for incomplete outcome data (attrition bias) in five studies and low in two studies; high for blinding in three studies and low in four studies; low for selective reporting; and high for other sources of bias in six studies and low in one study.We included three trials (involving 371 participants) in the analysis of the effects of RIC on ischaemic stroke prevention. In people with symptomatic intracerebral artery stenosis, recurrent stroke was significantly reduced by RIC (risk ratio (RR) 0.32, 95% confidence interval (CI) 0.12 to 0.83; 2 trials, 182 participants, low-quality evidence). In people with carotid stenosis undergoing carotid stenting, there was no significant difference in the incidence of ischaemic stroke between participants treated with RIC and non-RIC (RR 0.22, 95% CI 0.01 to 4.03; 1 trial, 189 participants, low-quality evidence); however the stroke severity (assessed by infarct volume) was significantly lower in participants treated with RIC (mean difference (MD) -0.17 mL, 95% CI -0.23 to -0.11; 1 trial, 189 participants, low-quality evidence). Adverse events associated with RIC were significantly higher in participants treated with RIC (RR 10.91; 95% CI 2.01 to 59.28; 3 trials, 371 participants, low-quality evidence), but no severe adverse event was attributable to RIC treatment. No participants experienced death or cardiovascular events during the period of the studies; and no trial reported haemorrhagic stroke or improvement in neurological, phycological or cognitive impairment.We included four trials (involving 364 participants) in the analysis of the effects of RIC on ischaemic stroke treatment. In acute ischaemic stroke, for people receiving intravenous thrombolysis, the rate of death or dependency was significantly increased by RIC treatment compared with non-RIC treatment (RR 2.34; 95% 1.19 to 4.61; 1 trial, 285 participants, low-quality evidence). In people with acute ischaemic stroke, there was no significant difference between RIC and non-RIC for reducing stroke severity as assessed by the National Institutes of Health Stroke Scale score and the final infarct volume (standardised mean difference (SMD) -0.24 mL, 95% CI -1.02 to 0.54; 2 trials, 175 participants, very low quality evidence). There was no significant difference between RIC and non-RIC for improving the psychological impairment (SMD -0.37 points, 95% CI -1.15 to 0.41; 1 trial, 26 participants, very low quality evidence) and the cognitive impairment (SMD -0.26 points; 95% CI -0.72 to 0.21; 3 trials, 79 participants, low-quality evidence) in people with acute ischaemic stroke and cerebral small vessel disease. No trial reported ischaemic stroke, recurrent ischaemic stroke, improvement in neurological impairment, hemorrhagic stroke, cardiovascular events, and RIC associated adverse events. AUTHORS' CONCLUSIONS: We found low-quality evidence that RIC may reduce the risk of recurrent stroke in participants with intracerebral artery stenosis and reduce stroke severity in participants undergoing carotid stenting, but it may increase death or dependence in participants with acute ischaemic stroke who are undergoing intravenous thrombolysis. However, there is considerable uncertainty about these conclusions because of the small number of studies and low quality of the evidence.

Ischaemic preconditioning for the reduction of renal ischaemia reperfusion injury.

BACKGROUND: Ischaemia reperfusion injury can lead to kidney dysfunction or failure. Ischaemic preconditioning is a short period of deprivation of blood supply to particular organs or tissue, followed by a period of reperfusion. It has the potential to protect kidneys from ischaemia reperfusion injury. OBJECTIVES: This review aimed to look at the benefits and harms of local and remote ischaemic preconditioning to reduce ischaemia and reperfusion injury among people with renal ischaemia reperfusion injury. SEARCH METHODS: We searched Cochrane Kidney and Transplant's Specialised Register to 5 August 2016 through contact with the Information Specialist using search terms relevant to this review. SELECTION CRITERIA: We included all randomised controlled trials measuring kidney function and the role of ischaemic preconditioning in patients undergoing a surgical intervention that induces kidney injury. Kidney transplantation studies were excluded. DATA COLLECTION AND ANALYSIS: Studies were assessed for eligibility and quality; data were extracted by two independent authors. We collected basic study characteristics: type of surgery, remote ischaemic preconditioning protocol, type of anaesthesia. We collected primary outcome measurements: serum creatinine and adverse effects to remote ischaemic preconditioning and secondary outcome measurements: acute kidney injury, need for dialysis, neutrophil gelatinase-associated lipocalin, hospital stay and mortality. Summary estimates of effect were obtained using a random-effects model, and results were expressed as risk ratios (RR) and their 95% confidence intervals (CI) for dichotomous outcomes, and mean difference (MD) and 95% CI for continuous outcomes. MAIN RESULTS: We included 28 studies which randomised a total of 6851 patients. Risk of bias assessment indicated unclear to low risk of bias for most studies. For consistency regarding the direction of effects, continuous outcomes with negative values, and dichotomous outcomes with values less than one favour remote ischaemic preconditioning. Based on high quality evidence, remote ischaemic preconditioning made little or no difference to the reduction of serum creatinine levels at postoperative days one (14 studies, 1022 participants: MD -0.02 mg/dL, 95% CI -0.05 to 0.02; I2 = 21%), two (9 studies, 770 participants: MD -0.04 mg/dL, 95% CI -0.09 to 0.02; I2 = 31%), and three (6 studies, 417 participants: MD -0.05 mg/dL, 95% CI -0.19 to 0.10; I2 = 68%) compared to control.Serious adverse events occurred in four patients receiving remote ischaemic preconditioning by iliac clamping. It is uncertain whether remote ischaemic preconditioning by cuff inflation leads to increased adverse effects compared to control because the certainty of the evidence is low (15 studies, 3993 participants: RR 3.47, 95% CI 0.55 to 21.76; I2 = 0%); only two of 15 studies reported any adverse effects (6/1999 in the remote ischaemic preconditioning group and 1/1994 in the control group), the remaining 13 studies stated no adverse effects were observed in either group.Compared to control, remote ischaemic preconditioning made little or no difference to the need for dialysis (13 studies, 2417 participants: RR 0.85, 95% CI 0.37 to 1.94; I2 = 60%; moderate quality evidence), length of hospital stay (8 studies, 920 participants: MD 0.17 days, 95% CI -0.46 to 0.80; I2 = 49%, high quality evidence), or all-cause mortality (24 studies, 4931 participants: RR 0.86, 95% CI 0.54 to 1.37; I2 = 0%, high quality evidence).Remote ischaemic preconditioning may have slightly improved the incidence of acute kidney injury using either the AKIN (8 studies, 2364 participants: RR 0.76, 95% CI 0.57 to 1.00; I2 = 61%, high quality evidence) or RIFLE criteria (3 studies, 1586 participants: RR 0.91, 95% CI 0.75 to 1.12; I2 = 0%, moderate quality evidence). AUTHORS' CONCLUSIONS: Remote ischaemic preconditioning by cuff inflation appears to be a safe method, and probably leads to little or no difference in serum creatinine, adverse effects, need for dialysis, length of hospital stay, death and in the incidence of acute kidney injury. Overall we had moderate-high certainty evidence however the available data does not confirm the efficacy of remote ischaemic preconditioning in reducing renal ischaemia reperfusion injury in patients undergoing major cardiac and vascular surgery in which renal ischaemia reperfusion injury may occur.

Remote ischaemic preconditioning for coronary artery bypass grafting (with or without valve surgery).

BACKGROUND: Despite substantial improvements in myocardial preservation strategies, coronary artery bypass grafting (CABG) is still associated with severe complications. It has been reported that remote ischaemic preconditioning (RIPC) reduces reperfusion injury in people undergoing cardiac surgery and improves clinical outcome. However, there is a lack of synthesised information and a need to review the current evidence from randomised controlled trials (RCTs). OBJECTIVES: To assess the benefits and harms of remote ischaemic preconditioning in people undergoing coronary artery bypass grafting, with or without valve surgery. SEARCH METHODS: In May 2016 we searched CENTRAL, MEDLINE, Embase and Web of Science. We also conducted a search of ClinicalTrials.gov and the International Clinical Trials Registry Platform (ICTRP). We also checked reference lists of included studies. We did not apply any language restrictions. SELECTION CRITERIA: We included RCTs in which people scheduled for CABG (with or without valve surgery) were randomly assigned to receive RIPC or sham intervention before surgery. DATA COLLECTION AND ANALYSIS: Two review authors independently assessed trials for inclusion, extracted data and checked them for accuracy. We calculated mean differences (MDs), standardised mean differences (SMDs) and risk ratios (RR) using a random-effects model. We assessed quality of the trial evidence for all primary outcomes using the GRADE methodology. We completed a 'Risk of bias' assessment for all studies and performed sensitivity analysis by excluding studies judged at high or unclear risk of bias for sequence generation, allocation concealment and incomplete outcome data. We contacted authors for missing data. Our primary endpoints were 1) composite endpoint (including all-cause mortality, non-fatal myocardial infarction or any new stroke, or both) assessed at 30 days after surgery, 2) cardiac troponin T (cTnT, ng/L) at 48 hours and 72 hours, and as area under the curve (AUC) 72 hours (µg/L) after surgery, and 3) cardiac troponin I (cTnI, ng/L) at 48 hours, 72 hours, and as area under the curve (AUC) 72 hours (µg/L) after surgery. MAIN RESULTS: We included 29 studies involving 5392 participants (mean age = 64 years, age range 23 to 86 years, 82% male). However, few studies contributed data to meta-analyses due to inconsistency in outcome definition and reporting. In general, risk of bias varied from low to high risk of bias across included studies, and insufficient detail was provided to inform judgement in several cases. The quality of the evidence of key outcomes ranged from moderate to low quality due to the presence of moderate or high statistical heterogeneity, imprecision of results or due to limitations in the design of individual studies.Compared with no RIPC, we found that RIPC has no treatment effect on the rate of the composite endpoint with RR 0.99 (95% confidence interval (CI) 0.78 to 1.25); 2 studies; 2463 participants; moderate-quality evidence. Participants randomised to RIPC showed an equivalent or better effect regarding the amount of cTnT release measured at 72 hours after surgery with SMD -0.32 (95% CI -0.65 to 0.00); 3 studies; 1120 participants; moderate-quality evidence; and expressed as AUC 72 hours with SMD -0.49 (95% CI -0.96 to -0.02); 3 studies; 830 participants; moderate-quality evidence. We found the same result in favour of RIPC for the cTnI release measured at 48 hours with SMD -0.21 (95% CI -0.40 to -0.02); 5 studies; 745 participants; moderate-quality evidence; and measured at 72 hours after surgery with SMD -0.37 (95% CI -0.59 to -0.15); 2 studies; 459 participants; moderate-quality evidence. All other primary outcomes showed no differences between groups (cTnT release measured at 48 hours with SMD -0.14, 95% CI -0.33 to 0.06; 4 studies; 1792 participants; low-quality evidence and cTnI release measured as AUC 72 hours with SMD -0.17, 95% CI -0.48 to 0.14; 2 studies; 159 participants; moderate-quality evidence).We also found no differences between groups for all-cause mortality after 30 days, non-fatal myocardial infarction after 30 days, any new stroke after 30 days, acute renal failure after 30 days, length of stay on the intensive care unit (days), any complications and adverse effects related to ischaemic preconditioning. We did not assess many patient-centred/salutogenic-focused outcomes. AUTHORS' CONCLUSIONS: We found no evidence that RIPC has a treatment effect on clinical outcomes (measured as a composite endpoint including all-cause mortality, non-fatal myocardial infarction or any new stroke, or both, assessed at 30 days after surgery). There is moderate-quality evidence that RIPC has no treatment effect on the rate of the composite endpoint including all-cause mortality, non-fatal myocardial infarction or any new stroke assessed at 30 days after surgery, or both. We found moderate-quality evidence that RIPC reduces the cTnT release measured at 72 hours after surgery and expressed as AUC (72 hours). There is moderate-quality evidence that RIPC reduces the amount of cTnI release measured at 48 hours, and measured 72 hours after surgery. Adequately-designed studies, especially focusing on influencing factors, e.g. with regard to anaesthetic management, are encouraged and should systematically analyse the commonly used medications of people with cardiovascular diseases.

Remote Ischemic Preconditioning and Clinical Outcomes in On-Pump Coronary Artery Bypass Grafting: A Meta-Analysis of 14 Randomized Controlled Trials.

The purpose of this article is to perform the first pooled analysis on remote ischemic preconditioning (RIPC) used for the improvement of clinical outcomes of patients only undergoing on-pump coronary artery bypass grafting (CABG) in randomized controlled trials (RCTs). A systematic search was performed using PubMed, the Cochrane Library, and the Web of Science to identify studies that described the effect of RIPC on postoperative mortality in patients only undergoing on-pump CABG. The outcomes included postoperative mortality, postoperative morbidity (including incidence of myocardial infarction, atrial fibrillation, stroke, acute kidney injury, and renal replacement therapy), mechanical ventilation (MV), intensive care unit length of stay (ICU LOS), and hospital length of stay (HLOS). A total of 14 RCTs (2830 participants) were included. Our meta-analysis found that RIPC failed to reduce the postoperative mortality in patients only undergoing on-pump CABG compared with control individuals (odds ratio, 0.81; 95% confidence interval, [0.40, 1.64]; P = 0.55; I2 = 25%). Moreover, there were no differences in postoperative morbidity, ICU LOS, and HLOS between the two groups. However, MV in the RIPC group was shorter than that in control individuals (standard mean difference, -0.41; 95% confidence interval, [-0.80, -0.01]; P = 0.04; I2 = 73%). The present meta-analysis found that RIPC failed to improve most of clinical outcomes in patients only undergoing on-pump CABG; however, MV was reduced. Adequately powered trials are warranted to provide more evidence in the future.

Remote ischaemic preconditioning in orthotopic liver transplantation (RIPCOLT trial): a pilot randomized controlled feasibility study.

BACKGROUND: Ischaemia Reperfusion (IR) injury is a major cause of morbidity, mortality and graft loss following Orthotopic Liver Transplantation (OLT). Utilising marginal grafts, which are more susceptible to IR injury, makes this a key research goal. Remote Ischaemic Preconditioning (RIPC) has been shown to ameliorate hepatic IR injury in experimental models. Whether RIPC can reduce IR injury in human liver transplant recipients is unknown. METHODS: Forty patients undergoing liver transplantation were randomized to RIPC or a sham. RIPC was induced through three 5 min cycles of alternate ischaemia and reperfusion of the left leg prior to surgery. Data on clinical outcomes was collected prospectively. Per-operative cytokine levels were measured. RESULTS: Fourty five of 51 patients approached (88%) were willing to enroll in the study. Five patients were excluded and 40 randomized, of which 20 underwent RIPC which was successfully completed in all patients. There were no complications following RIPC. Median day 3 AST levels were slightly higher in the RIPC group (221 IU vs 149 IU, p = 1.00). CONCLUSIONS: RIPC is acceptable and safe in liver transplant recipients. This study has not demonstrated evidence of a reduction in short-term measures of IR injury. Longer follow up will be required and consideration of an altered protocol.

High osteoprotegerin levels predict MACCE in STEMI patients, but are not associated with myocardial salvage.

OBJECTIVES: High circulating levels of osteoprotegerin (OPG) carry prognostic impact in cohorts with various cardiovascular diagnoses. With the present study, we aim to investigate the role of OPG within the scale of myocardial damage. DESIGN: This study includes 219 consecutive patients with acute ST-elevation myocardial infarction randomized to primary percutaneous coronary intervention (pPCI) or pPCI and remote ischemic per-conditioning. Salvage index via myocardial single-photon emission CT assessment (data available in 61% of the patients) was performed, and derived from Day 1 (myocardial area at risk) and Day 30 (final infarct size). Plasma OPG levels were measured using an in-house immunoassay. A combined end-point of all-mortality, myocardial infarction, stroke, readmission for heart failure and ischemic stroke/transient ischemic attack (Major Adverse Cardiac and Cerebrovascular Events [MACCE]) was used for follow-up; 45 (38-48 months). RESULTS: High OPG levels were associated with the severity of cardiovascular disease. During follow-up, OPG was a predictor of MACCE (unadjusted, HR: 2.1, 95% CI: 1.14-3.85, P = 0.017). Adjustments for age, gender, and body mass index preserved the independent predictive power of OPG. However, OPG levels were neither associated with salvage index nor with the final infarct size. Remote ischemic per-conditioning had no effect on OPG levels. CONCLUSION: Despite absent association between OPG levels and the scale of myocardial damage, high OPG levels predict a significantly increased risk of MACCE.

Meta-analysis of ischaemic preconditioning for liver resections.

BACKGROUND: Vascular clamping reduces blood loss during liver resection but leads to ischaemia-reperfusion injury. Ischaemic preconditioning (IP) may reduce this. This study aimed to evaluate IP in liver resection under clamping. METHODS: This was a systematic review and meta-analysis of randomized clinical trials (RCTs) evaluating IP in adults undergoing liver resection under either continuous clamping (CC) or intermittent clamping (IC). Primary outcomes were mortality, liver failure and morbidity. Secondary outcomes included duration of operation, blood loss, length of hospital stay, length of intensive therapy unit stay, transfusion requirements, prothrombin time, and bilirubin and aminotransferase levels. Weighted mean differences were calculated for continuous data, and pooled odds ratios (ORs) for dichotomous data. Results were produced with a random-effects model with 95 per cent confidence intervals (c.i.). RESULTS: A total of 2960 records were identified and 11 RCTs included 669 patients (IP 331, control 338). No significant difference in mortality (6 RCTs; IP 186, control 190; OR 1·36, 95 per cent c.i. 0·13 to 13·68; P = 0·80) or morbidity (6 RCTs; IP 186, control 190; OR 0·58, 0·31 to 1·07; P = 0·08) was found for IP plus CC versus CC. Nor was there a significant difference in mortality (4 RCTs; IP 122, control 121; OR 1·33, 0·24 to 7·32; P = 0·74) or morbidity (4 RCTs; IP 122, control 121; OR 0·87, 0·52 to 1·47; P = 0·61) for IP plus (CC or IC) versus IC. No significant differences were found for secondary outcome measures. CONCLUSION: This meta-analysis failed to find a significant benefit of IP in liver resection.

Remote Ischemic Conditioning in Acute Myocardial Infarction and Shock States.

Remote ischemic conditioning is the phenomenon whereby brief, nonlethal episodes of ischemia in one organ (such as a limb) protect a remote organ from ischemic necrosis induced by a longer duration of severe ischemia followed by reperfusion. This phenomenon has been reproduced by dozens of experimental laboratories and was shown to reduce the size of myocardial infarction in many but not all clinical studies. In one recent large clinical trial, remote ischemic conditioning induced by repetitive blood pressure cuff inflations on the arm did not reduce infarct size or improve clinical outcomes. This negative result may have been related in part to the overall success of early reperfusion and current adjunctive therapies, such as antiplatelet therapy, antiremodeling therapies, and low-risk patients, that may make it difficult to show any advantage of newer adjunctive therapies on top of existing therapies. One relevant area in which current outcomes are not as positive as in the treatment of heart attack is the treatment of shock, where mortality rates remain high. Recent experimental studies show that remote ischemic conditioning may improve survival and organ function in shock states, especially hemorrhagic shock and septic shock. In this study, we review the preclinical studies that have explored the potential benefit of this therapy for shock states and describe an ongoing clinical study.

Effect of ischemic preconditioning on cardiovascular outcomes in patients with symptomatic coronary artery disease: a cohort study.

BACKGROUND: Despite the powerful myocardial protection of ischemic preconditioning (IP) observed in experimental studies, it remains a challenge to observe such protection in humans. Thus, the aim of this study was to evaluate the possible effects of IP on clinical outcomes in patients with coronary artery disease (CAD). PATIENTS AND METHODS: In this cohort study, patients with multivessel CAD, preserved systolic ventricular function, and stable angina were prospectively selected. They underwent two sequential exercise stress tests (EST) to evaluate IP presence. IP was considered present if patients had an improvement in the time to the onset of 1.0-mm STsegment deviation in the second EST. The primary end point was the composite rate of cardiac death, nonfatal myocardial infarction, or revascularization during 1-year follow-up. Patients with (IP+) and without (IP-) the cardioprotective mechanism were compared regarding clinical end points. RESULTS: A total of 229 patients completed EST and had IP evaluated: 165 (72%) were IP+ and 64 (28%) were IP - patients. Of these, 218 patients had complete follow-up. At 1-year, event-free survival regarding the primary end point was 95.5 versus 83.6% (P = 0.0024) and event-free survival regarding cardiac death or myocardial infarction was 99.4 versus 91.7% (P=0.0020), respectively, in IP + and IP - groups. The unadjusted hazard ratio (IP + /IP-) for the primary end point was 4.63 (1.52-14.08). After multivariate analysis, IP was still significantly associated with better clinical outcomes (P = 0.0025). CONCLUSION: This data suggest that IP may contribute to better clinical outcomes in patients with ischemic heart disease.

Remote Ischemic Preconditioning in High-risk Cardiovascular Surgery Patients: A Randomized-controlled Trial.

Remote ischemic preconditioning (RIPC) may reduce biomarkers of ischemic injury after cardiovascular surgery. However, it is unclear whether RIPC has a positive impact on clinical outcomes. We performed a blinded, randomized controlled trial to determine if RIPC resulted in fewer adverse clinical outcomes after cardiac or vascular surgery. The intervention consisted of 3 cycles of RIPC on the upper limb for 5 minutes alternated with 5 minutes of rest. A sham intervention was performed on the control group. Patients were recruited who were undergoing (1) high-risk cardiac or vascular surgery or (2) cardiac or vascular surgery and were at high risk of ischemic complications. The primary end point was a composite outcome of mortality, myocardial infarction, stroke, renal failure, respiratory failure, and low cardiac output syndrome, and the secondary end points included the individual outcome parameters that made up this score, as well as troponin-I values. A total of 436 patients were randomized and analysis was performed on 215 patients in the control group and on 213 patients in the RIPC group. There were no differences in the composite outcome between the 2 groups (RIPC: 67 [32%] and control: 72 [34%], relative risk [0.94 {0.72-1.24}]) or in any of the individual components that made up the composite outcome. Additionally, we did not observe any differences between the groups in troponin-I values, the length of intensive care unit stay, or the total hospital stay. RIPC did not have a beneficial effect on clinical outcomes in patients who had cardiovascular surgery.

Long-term outcome following remote ischemic postconditioning during percutaneous coronary interventions-the RIP-PCI trial long-term follow-up.

The clinical value of ischemic conditioning during percutaneous coronary intervention (PCI) and mode of administration is controversial. Our aim was to assess the long-term effect of remote ischemic postconditioning among patients undergoing PCI. We randomized 360 patients undergoing PCI who presented with a negative troponin T at baseline into 3 groups: 2 groups received remote ischemic postconditioning (with ischemia applied to the arm in 1 group and to the thigh in the other group), and the third group acted as a control group. Remote ischemic postconditioning was applied during PCI immediately following stent deployment, by 3, 5-minute cycles of blood pressure cuff inflation to >200 mm Hg on the arm or thigh (20 mm Hg to the arm in the control), with 5-minute breaks between each cycle. There were no differences in baseline characteristics among the 3 groups. Periprocedural myocardial injury occurred in 33% (P = 0.64). After 1 year, there was no difference between groups in death (P = 0.91), myocardial infarction (P = 0.78), or repeat revascularization (P = 0.86). During 3 years of follow-up, there was no difference in death, myocardial infarction, and revascularization among the groups (P = 0.45). Remote ischemic postconditioning during PCI did not affect long-term cardiovascular outcome. A similar effect was obtained when remote ischemia was induced to the upper or lower limb. ClinicalTrials.gov Identifier: NCT00970827.

Remote Ischemic Perconditioning to Reduce Reperfusion Injury During Acute ST-Segment-Elevation Myocardial Infarction: A Systematic Review and Meta-Analysis.

BACKGROUND: Remote ischemic conditioning (RIC) is a noninvasive therapeutic strategy that uses brief cycles of blood pressure cuff inflation and deflation to protect the myocardium against ischemia-reperfusion injury. The objective of this systematic review was to determine the impact of RIC on myocardial salvage index, infarct size, and major adverse cardiovascular events when initiated before catheterization. METHODS AND RESULTS: Electronic searches of Medline, Embase, and Cochrane Central Register of Controlled Trials were conducted and reference lists were hand searched. Randomized controlled trials comparing percutaneous coronary intervention (PCI) with and without RIC for patients with ST-segment-elevation myocardial infarction were included. Two reviewers independently screened abstracts, assessed quality of the studies, and extracted data. Data were pooled using random-effects models and reported as mean differences and relative risk with 95% confidence intervals. Eleven articles (9 randomized controlled trials) were included with a total of 1220 patients (RIC+PCI=643, PCI=577). Studies with no events were excluded from meta-analysis. The myocardial salvage index was higher in the RIC+PCI group compared with the PCI group (mean difference: 0.08; 95% confidence interval, 0.02-0.14). Infarct size was reduced in the RIC+PCI group compared with the PCI group (mean difference: -2.46; 95% confidence interval, -4.66 to -0.26). Major adverse cardiovascular events were lower in the RIC+PCI group (9.5%) compared with the PCI group (17.0%; relative risk: 0.57; 95% confidence interval, 0.40-0.82). CONCLUSIONS: RIC appears to be a promising adjunctive treatment to PCI for the prevention of reperfusion injury in patients with ST-segment-elevation myocardial infarction; however, additional high-quality research is required before a change in practice can be considered.

Ischemic preconditioning as a possible explanation for the age decline relative mortality in sleep apnea.

Breathing disorders in sleep are prevalent phenomena profoundly affecting the cardiovascular system. Mortality studies of sleep apnea patients revealed maximum risk of dying in younger patients and a pronounced age-decline in relative mortality reaching non significant levels in patients older than 50 years. We hypothesize that the age decline mortality risk in sleep apnea can be explained by cardiovascular and cerebrovascular protection conferred by ischemic preconditioning resulting from the nocturnal cycles of hypoxia-reoxygenation. The association of ischemic preconditioning with increase levels of vascular endothelial growth factor, increased production of oxygen reactive species, heat shock proteins, adenosine, and TNF-alpha, all demonstrated in sleep apnea, provide preliminary support to our hypothesis.

Ischemic preconditioning modifies mortality and inflammatory response.

PURPOSE: To evaluate the effect of ischemic preconditioning on mortality, inflammatory mediators and oxidative stress after intestinal ischemia and reperfusion. METHODS: Male Wistar rats were allocated according to the period of ischemia with or without ischemic preconditioning which consist on clamping the superior mesenteric artery for 10 minutes followed by reperfusion for 10 minutes before the sustained ischemia period. Mortality was assessed in Phase 1 study, and the CINC-1, CINC-2 and MDA levels in the lungs were analyzed in Phase 2. RESULTS: Mortality was lower in the ischemic preconditioning group subjected to 90 minutes of ischemia compared to the group without ischemic preconditioning (I-90: 50% and IPC-90: 15%, p=0.018), and it was lower in the ischemic preconditioning group as a whole compared to the groups without ischemic preconditioning (IPC-14% and I=30%, p=0.006). Lower levels of MDA, CINC-1, and CINC-2 were observed in the animals that were subjected to ischemic preconditioning compared to the animals that were not (MDA: I-45=1.23 nmol/mg protein, and IPC-45=0.62 nmol/mg protein, p=0.0333; CINC-1: I-45=0.82 ng/mL and IPC-45=0.67 ng/mL, p=0.041; CINC-2: I-45=0.52 ng/mL and IPC-45=0.35 ng/mL, p=0.032). CONCLUSION: Ischemic preconditioning reduces mortality, inflammatory process and oxidative stress in rats subjected to intestinal ischemia and reperfusion.

Remote ischemic conditioning in ST-elevation myocardial infarction as adjuvant to primary angioplasty (RIC-STEMI): study protocol for a randomized controlled trial.

BACKGROUND: ST-elevation myocardial infarction (STEMI) accounts for nearly one third of acute coronary syndromes. Despite improved STEMI patient care, mortality remains high, contributing significantly to the ischemic heart disease burden. This may partly be related to ischemia-reperfusion injury (IRI). Remote ischemic conditioning (RIC), through short cycles of ischemia-reperfusion applied to a limb, has been shown to reduce IRI in various clinical settings. Our primary hypothesis is that RIC will reduce adverse events related to STEMI when applied as adjunctive therapy to primary percutaneous coronary intervention (PCI). METHODS/DESIGN: "Remote ischemic conditioning in ST-elevation myocardial infarction as adjuvant to primary angioplasty" (RIC-STEMI) is an ongoing prospective, single-center, open-label, randomized controlled trial to assess whether RIC as an adjunctive therapy during primary PCI in patients presenting with STEMI can improve clinical outcomes. After enrollment, participants are randomized according to a computer-generated randomization schedule, in a ratio of 1:1 to RIC or no intervention, in blocks of four individuals. RIC is begun at least 10 min before the estimated time of the first balloon inflation and its duration is 30 min. Ischemia is induced by three cycles of inflation of a blood pressure cuff placed on the left lower limb to 200 mmHg and then deflation to 0 mmHg for another 5 min. Primary endpoint is a combined endpoint of death from cardiac cause or hospitalization for heart failure (HF) on follow-up (including device implantation: implantable cardioverter defibrillator, cardiac resynchronization and left ventricular assist device). Secondary endpoints are myocardial infarction (MI) size (estimated by the 48 h area under the curve of serum troponin I levels), development of Q-wave MI, left ventricular function (assessed by echocardiography within the first 3 days after admission), contrast-induced nephropathy, in-hospital mortality, all-cause mortality and, finally, major adverse cardiovascular events. Patients will have a minimum follow-up period of 12 months. From 11 March 2013 to 31 December 2014, 324 patients have been enrolled and randomized. We expect to complete enrollment of the 494 patients deemed necessary within 3 years. TRIAL REGISTRATION: ClinicalTrials.gov identifier: NCT02313961; registered on 8 December 2014.

A MultiCenter Pilot Randomized Controlled Trial of Remote Ischemic Preconditioning in Major Vascular Surgery.

A pilot randomized controlled trial that evaluated the effect of remote ischemic preconditioning (RIPC) on clinical outcomes following major vascular surgery was performed. Eligible patients were those scheduled to undergo open abdominal aortic aneurysm repair, endovascular aortic aneurysm repair, carotid endarterectomy, and lower limb revascularization procedures. Patients were randomized to RIPC or to control groups. The primary outcome was a composite clinical end point comprising any of cardiovascular death, myocardial infarction, new-onset arrhythmia, cardiac arrest, congestive cardiac failure, cerebrovascular accident, renal failure requiring renal replacement therapy, mesenteric ischemia, and urgent cardiac revascularization. Secondary outcomes were components of the primary outcome and myocardial injury as assessed by serum troponin values. The primary outcome occurred in 19 (19.2%) of 99 controls and 14 (14.1%) of 99 RIPC group patients (P = .446). There were no significant differences in secondary outcomes. Our trial generated data that will guide future trials. Further trials are urgently needed.