Cardiac remote ischaemic preconditioning reduces periprocedural myocardial infarction for patients undergoing percutaneous coronary interventions: a meta-analysis of randomised clinical trials

Association between Ranolazine, Ischemic Preconditioning, and Cardioprotection in Patients Undergoing Scheduled Percutaneous Coronary Intervention

Background and Objectives: Remote ischemic preconditioning (RIPC) has demonstrated efficacy in protecting against myocardial ischemia-reperfusion injury when applied before percutaneous coronary revascularization. Ranolazine, an anti-ischemic drug, has been utilized to minimize ischemic events in chronic angina patients. However, there is a lack of trials exploring the combined effects of ranolazine pretreatment and RIPC in patients undergoing percutaneous coronary interventions (PCIs). Materials and Methods: The present study is a prospective study which enrolled 150 patients scheduled for nonemergent percutaneous coronary revascularization. Three groups were formed: a control group undergoing only PCIs, an RIPC group with RIPC applied to either upper limb before the PCI (preconditioning group), and a group with RIPC before the PCI along with prior ranolazine treatment for stable angina (ranolazine group). Statistical analyses, including ANOVAs and Kruskal-Wallis tests, were conducted, with the Bonferroni correction for type I errors. A repeated-measures ANOVA assessed the changes in serum enzyme levels (SGOT, LDH, CRP, CPK, CK-MB, troponin I) over the follow-up. Statistical significance was set at p < 0.05. Results: The ranolazine group showed (A) significantly lower troponin I level increases compared to the control group for up to 24 h, (B) significantly lower CPK levels after 4, 10, and 24 h compared to the preconditioning group (p = 0.020, p = 0.020, and p = 0.019, respectively) and significantly lower CPK levels compared to the control group after 10 h (p = 0.050), and (C) significantly lower CK-MB levels after 10 h compared to the control group (p = 0.050). Conclusions: This study suggests that combining RIPC before scheduled coronary procedures with ranolazine pretreatment may be linked to reduced ischemia induction, as evidenced by lower myocardial enzyme levels.

Elevated platelet-leukocyte complexes are associated with, but dispensable for myocardial ischemia-reperfusion injury

AIMS

P-selectin is an activatable adhesion molecule on platelets promoting platelet aggregation, and platelet-leukocyte complex (PLC) formation. Increased numbers of PLC are circulating in the blood of patients shortly after acute myocardial infarction and predict adverse outcomes. These correlations led to speculations about whether PLC may represent novel therapeutic targets. We therefore set out to elucidate the pathomechanistic relevance of PLC in myocardial ischemia and reperfusion injury.

METHODS AND RESULTS

By generating P-selectin deficient bone marrow chimeric mice, the post-myocardial infarction surge in PLC numbers in blood was prevented. Yet, intravital microscopy, flow cytometry and immunohistochemical staining, echocardiography, and gene expression profiling showed unequivocally that leukocyte adhesion to the vessel wall, leukocyte infiltration, and myocardial damage post-infarction were not altered in response to the lack in PLC.

CONCLUSION

We conclude that myocardial infarction associated sterile inflammation triggers PLC formation, reminiscent of conserved immunothrombotic responses, but without PLC influencing myocardial ischemia and reperfusion injury in return. Our experimental data do not support a therapeutic concept of selectively targeting PLC formation in myocardial infarction.

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.

The effect of remote ischaemic preconditioning on myocardial injury in emergency hip fracture surgery (PIXIE trial): phase II randomised clinical trial

OBJECTIVE

To investigate whether remote ischaemic preconditioning (RIPC) prevents myocardial injury in patients undergoing hip fracture surgery.

DESIGN

Phase II, multicentre, randomised, observer blinded, clinical trial.

SETTING

Three Danish university hospitals, 2015-17.

PARTICIPANTS

648 patients with cardiovascular risk factors undergoing hip fracture surgery. 286 patients were assigned to RIPC and 287 were assigned to standard practice (control group).

INTERVENTION

The RIPC procedure was initiated before surgery with a tourniquet applied to the upper arm and consisted of four cycles of forearm ischaemia for five minutes followed by reperfusion for five minutes.

MAIN OUTCOME MEASURES

The original primary outcome was myocardial injury within four days of surgery, defined as a peak plasma cardiac troponin I concentration of 45 ng/L or more caused by ischaemia. The revised primary outcome was myocardial injury within four days of surgery, defined as a peak plasma cardiac troponin I concentration of 45 ng/L or more or high sensitive troponin I greater than 24 ng/L (the primary outcome was changed owing to availability of testing). Secondary outcomes were peak plasma troponin I and total troponin I release during the first four days after surgery (cardiac and high sensitive troponin I), perioperative myocardial infarction, major adverse cardiovascular events, and all cause mortality within 30 days of surgery, length of postoperative stay, and length of stay in the intensive care unit. Several planned secondary outcomes will be reported elsewhere.

RESULTS

573 of the 648 randomised patients were included in the intention-to-treat analysis (mean age 79 (SD 10) years; 399 (70%) women). The primary outcome occurred in 25 of 168 (15%) patients in the RIPC group and 45 of 158 (28%) in the control group (odds ratio 0.44, 95% confidence interval 0.25 to 0.76; P=0.003). The revised primary outcome occurred in 57 of 286 patients (20%) in the RIPC group and 90 of 287 (31%) in the control group (0.55, 0.37 to 0.80; P=0.002). Myocardial infarction occurred in 10 patients (3%) in the RIPC group and 21 patients (7%) in the control group (0.46, 0.21 to 0.99; P=0.04). Statistical power was insufficient to draw firm conclusions on differences between groups for the other clinical secondary outcomes (major adverse cardiovascular events, 30 day all cause mortality, length of postoperative stay, and length of stay in the intensive care unit).

CONCLUSIONS

RIPC reduced the risk of myocardial injury and infarction after emergency hip fracture surgery. It cannot be concluded that RIPC overall prevents major adverse cardiovascular events after surgery. The findings support larger scale clinical trials to assess longer term clinical outcomes and mortality.

TRIAL REGISTRATION

ClinicalTrials.gov NCT02344797.

Remote Ischemic Preconditioning With the Use of Lower Limb Before Coronary Artery Bypass Surgery With Cardiopulmonary Bypass and Anesthesia With Propofol

OBJECTIVE

to study potantial of remote ischemic preconditioning (RIP) as method of cardioprotection during coronary artery bypass surgery with cardiopulmonary bypass (CPB) and anesthesia with propofol.

MATERIALS AND METHODS

We included in this study 87 patients (7 were excluded) with ischemic heart disease, hospitalized in the clinic of aortic and cardiovascular surgery of the I. M. Sechenov First Moscow State Medical University clinical hospital № 1. All patients had indications for direct myocardial revascularization by coronary artery bypass surgery. One day before operation patients were randomly assigned to 2 groups depending on preparation scheme: main group of RIP and the control group. The frequency of complications during surgery and in the postoperative period was assessed. Troponin I level was measured before, and in 2 and 24 hours after surgery. The level of lactate in the venous blood was measured before and after surgery.

RESULTS

Numbers of intraoperative and early postoperative complications in the main and control groups were similar. There were no differences between groups in troponin I and lactate levels after surgery.

CONCLUSIONS

Remote ischemic preconditioning has no effect on the outcome of coronary artery bypass surgery with cardiopulmonary bypass and anesthesia with propofol.

Impact of increasing dose of intracoronary adenosine on peak hyperemia duration during fractional flow reserve assessment

BACKGROUND

Fractional Flow Reserve (FFR) is currently indicated as a first line strategy for the functional assessment of intermediate coronary stenoses. However, the protocol for inducing hyperemia still lacks standardization. Intracoronary adenosine boli, with a progressive increase to high-dosage, have been proposed as a sensitive and accurate strategy for the classification of coronary stenoses, although being potentially affected by the achievement of plateau of the effect and by a less prolonged and stable hyperemia as compared to intravenous administration. Therefore, the aim of the present study was to define the conditioning parameters and assess the impact of increasing-dose intracoronary adenosine on peak hyperemia duration in patients undergoing FFR for intermediate coronary stenoses.

METHODS

FFR was assessed in patients with intermediate (40 to 70%) lesions by pressure-recording guidewire (Prime Wire, Volcano), after induction of hyperemia with intracoronary boli of adenosine (from 60 to 1440 μg, with dose doubling at each step). Hyperemic duration was defined as the time for the variation form minimum FFR ± 0.02 and time to recovery till baseline values.

RESULTS

We included 87 patients, undergoing FFR evaluation of 101 lesions. Mean peak hyperemia duration and time to recovery significantly increased with adenosine doses escalation (p = 0.02 and p < 0.001). Peak hyperemia duration and time to recovery with 1440 μg adenosine were 14.5 ± 12.6 s and 45.2 ± 30.7 s, respectively. Hyperemia duration was not related to Quantitative Coronary Angiography (QCA) parameters or FFR values. In fact, a similar increase in the time of hyperemic peak was noted when comparing patients with positive or negative FFR (p_between = 0.87) or patients with lesions < or ≥20 mm (p_between = 0.92) and lesions involving left main coronary or proximal left anterior descending artery (LAD) (p_between = 0.07). A linear relationship was observed between time to recovery and FFR variations, with a greater time to baseline required in patients with FFR ≤ 0.80 (p = 0.003) and in lesions ≥ 20 mm (p = 0.006), but not in LAD/LM lesions (p = 0.55).

CONCLUSIONS

The present study shows a progressive raise in the duration of peak hyperemia and time to recovery, after the administration of increasing doses of intracoronary adenosine for the assessment of FFR. Therefore, considering the potential advantages of a high-dose adenosine protocol, allowing a more prolonged hyperemia and a more precise and reliable measurement of FFR, further larger studies with such FFR strategy should certainly be advocated to confirm its safety and benefits, before its routinely use recommendation.

Mitochondrial and Contractile Function of Human Right Atrial Tissue in Response to Remote Ischemic Conditioning

Background Remote ischemic preconditioning ( RIPC ) by repeated brief cycles of limb ischemia/reperfusion attenuates myocardial ischemia/reperfusion injury. We aimed to identify a functional parameter reflecting the RIPC -induced protection in human. Therefore, we measured mitochondrial function in right atrial tissue and contractile function of isolated right atrial trabeculae before and during hypoxia/reoxygenation from patients undergoing coronary artery bypass grafting with RIPC or placebo, respectively. Methods and Results One hundred thirty-seven patients under isoflurane anesthesia underwent RIPC (3×5 minutes blood pressure cuff inflation on the left upper arm/5 minutes deflation, n=67) or placebo (cuff uninflated, n=70), and right atrial appendages were harvested before ischemic cardioplegic arrest. Myocardial protection by RIPC was assessed from serum troponin I/T concentrations over 72 hours after surgery. Atrial tissue was obtained for isolation of mitochondria ( RIPC /placebo: n=10/10). Trabeculae were dissected for contractile function measurements at baseline and after hypoxia/reoxygenation (60 min/30 min) and for western blot analysis after hypoxia/reoxygenation ( RIPC /placebo, n=57/60). Associated with cardioprotection by RIPC (26% decrease in the area under the curve of troponin I/T), mitochondrial adenosine diphosphate-stimulated complex I respiration (+10%), adenosine triphosphate production (+46%), and calcium retention capacity (+37%) were greater, whereas reactive oxygen species production (-24%) was less with RIPC than placebo. Contractile function was improved by RIPC (baseline, +7%; reoxygenation, +24%). Expression and phosphorylation of proteins, which have previously been associated with cardioprotection, were not different between RIPC and placebo. Conclusions Cardioprotection by RIPC goes along with improved mitochondrial and contractile function of human right atrial tissue. Clinical Trial Registration URL: https://www.clinicaltrials.gov . Unique identifier: NCT 01406678.

The effects of remote ischaemic preconditioning on coronary artery function in patients with stable coronary artery disease

Background

Remote ischaemic preconditioning (RIPC) is a cardioprotective intervention invoking intermittent periods of ischaemia in a tissue or organ remote from the heart. The mechanisms of this effect are incompletely understood. We hypothesised that RIPC might enhance coronary vasodilatation by an endothelium-dependent mechanism.

Methods

We performed a prospective, randomised, sham-controlled, blinded clinical trial. Patients with stable coronary artery disease (CAD) undergoing elective invasive management were prospectively enrolled, and randomised to RIPC or sham (1:1) prior to angiography. Endothelial-dependent vasodilator function was assessed in a non-target coronary artery with intracoronary infusion of incremental acetylcholine doses (10^− 6, 10^− 5, 10^− 4 mol/l). Venous blood was sampled pre- and post-RIPC or sham, and analysed for circulating markers of endothelial function. Coronary luminal diameter was assessed by quantitative coronary angiography. The primary outcome was the between-group difference in the mean percentage change in coronary luminal diameter following the maximal acetylcholine dose (Clinicaltrials.gov identifier: NCT02666235).

Results

75 patients were enrolled. Following angiography, 60 patients (mean ± SD age 57.5 ± 8.5 years; 80% male) were eligible and completed the protocol (n = 30 RIPC, n = 30 sham). The mean percentage change in coronary luminal diameter was − 13.3 ± 22.3% and − 2.0 ± 17.2% in the sham and RIPC groups respectively (difference 11.32%, 95%CI: 1.2– 21.4, p = 0.032). This remained significant when age and sex were included as covariates (difference 11.01%, 95%CI: 1.01– 21.0, p = 0.035). There were no between-group differences in endothelial-independent vasodilation, ECG parameters or circulating markers of endothelial function.

Conclusions

RIPC attenuates the extent of vasoconstriction induced by intracoronary acetylcholine infusion. This endothelium-dependent mechanism may contribute to the cardioprotective effects of RIPC.

Effect of Remote Ischemic Preconditioning on Perioperative Cardiac Events in Patients Undergoing Elective Percutaneous Coronary Intervention: A Meta-Analysis of 16 Randomized Trials

Background

The main objective of this meta-analysis was to investigate whether remote ischemic preconditioning (RIPC) reduces cardiac and renal events in patients undergoing elective cardiovascular interventions.

Methods and Results

We systematically searched articles published from 2006 to 2016 in PubMed, EMBASE, Web of Science, Cochrane Library, and Google Scholar. Odds ratios (ORs) with 95% confidence intervals (CIs) were used as the effect index for dichotomous variables. The standardized mean differences (SMDs) with 95% CIs were calculated as the pooled continuous effect. Sixteen RCTs of 2435 patients undergoing elective PCI were selected. Compared with control group, RIPC could significantly reduce the incidence of perioperative myocardial infarction (OR = 0.64; 95% CI: 0.48–0.86; P = 0.003) and acute kidney injury (OR = 0.56; 95% CI: 0.322–0.99; P = 0.049). Metaregression analysis showed that the reduction of PMI by RIPC was enhanced for CAD patients with multivessel disease (coef.: −0.05 [−0.09; −0.01], P = 0.022). There were no differences in the changes of cTnI (P = 0.934) and CRP (P = 0.075) in two groups.

Conclusion

Our meta-analysis of RCTs demonstrated that RIPC can provide cardiac and renal protection for patients undergoing elective PCI, while no beneficial effect on reducing the levels of cTnI and CRP after PCI was reported.

Acute coronary syndrome and acute kidney injury: role of inflammation in worsening renal function

Background

Acute Kidney Injury (AKI), a common complication of acute coronary syndromes (ACS), is associated with higher mortality and longer hospital stays. The role of cytokines and other mediators is unknown in AKI induced by an ACS (ACS-AKI), leading to several unanswered questions. The worsening of renal function is usually seen as a dichotomous phenomenon instead of a dynamic change, so evaluating changes of the renal function in time may provide valuable information in the ACS-AKI setting. The aim of this study was to explore inflammatory factors associated to de novo kidney injury induced by de novo cardiac injury secondary to ACS.

Methods

One hundred four consecutive patients with ACS were initially included on the time of admission to the Coronary Unit of the Instituto Nacional de Cardiología in Mexico City, from February to May 2016, before any invasive procedure, imaging study, diuretic or anti-platelet therapy. White blood count, hemoglobin, NT-ProBNP, troponin I, C-reactive protein, albumin, glucose, Na⁺, K⁺, blood urea nitrogen (BUN), total cholesterol, HDL, LDL, triglycerides, creatinine (Cr), endothelin-1 (ET-1), leukotriene-B4, matrix metalloproteinase-2 and -9, tissue inhibitor of metalloproteinases-1, resolvin-D1 (RvD1), lipoxin-A4 (LXA4), interleukin-1β, −6, −8, and −10 were measured. We finally enrolled 78 patients, and subsequently we identified 15 patients with ACS-AKI. Correlations were obtained by a Spearman rank test. Low-rank regression, splines regressions, and also protein–protein/chemical interactions and pathways analyses networks were performed.

Results

Positive correlations of ΔCr were found with BUN, admission Cr, GRACE score, IL-1β, IL-6, NT-ProBNP and age, and negative correlations with systolic blood pressure, mean-BP, diastolic-BP and LxA4. In the regression analyses IL-10 and RvD1 had positive non-linear associations with ΔCr. ET-1 had also a positive association. Significant non-linear associations were seen with NT-proBNP, admission Cr, BUN, Na⁺, K⁺, WBC, age, body mass index, GRACE, SBP, mean-BP and Hb.

Conclusion

Inflammation and its components play an important role in the worsening of renal function in ACS. IL-10, ET-1, IL-1β, TnI, RvD1 and LxA4 represent mediators that might be associated with ACS-AKI. IL-6, ET-1, NT-ProBNP might represent crossroads for several physiopathological pathways involved in “de novo cardiac injury leading to de novo kidney injury”.

Electronic supplementary material

The online version of this article (doi:10.1186/s12872-017-0640-0) contains supplementary material, which is available to authorized users.

Relation of subclinical serum creatinine elevation to adverse in-hospital outcomes among myocardial infarction patients

BACKGROUND:

Acute kidney injury is associated with adverse outcomes after acute ST elevation myocardial infarction (STEMI). It remains unclear, however, whether subclinical increase in serum creatinine that does not reach the consensus criteria for acute kidney injury is also related to adverse outcomes in STEMI patients undergoing primary percutaneous coronary intervention.

METHODS:

We conducted a retrospective study of 1897 consecutive STEMI patients between January 2008 and May 2016 who underwent primary percutaneous coronary intervention, and in whom acute kidney injury was not diagnosed throughout hospitalization. We investigated the incidence of subclinical acute kidney injury (defined as serum creatinine increase of ≥ 0.1 and < 0.3 mg/dl) and its relation to a composite end point of adverse in hospital outcomes.

RESULTS:

Subclinical acute kidney injury was detected in 321 patients (17%). Patients with subclinical acute kidney injury had increased rate of the composite end point of adverse in-hospital events (20.3% vs. 9.7%, p<0.001), a finding which was independent of baseline renal function. Individual components of this end point (occurrence of heart failure, atrial fibrillation, need for mechanical ventilation and in-hospital mortality) were all significantly higher among patients with subclinical acute kidney injury ( p< 0.05 for all). In a multivariable regression model subclinical acute kidney injury was independently associated with higher risk for adverse in-hospital events (odds ratio 1.92.6, 95% confidence interval: 1.23-2.97, p=0.004).

CONCLUSIONS:

Among STEMI patients treated with primary percutaneous coronary intervention, small, subclinical elevations of serum creatinine, while not fulfilling the consensus criteria for acute kidney injury, may serve as a significant biomarker for adverse outcomes.

The impact of a single episode of remote ischemic preconditioning on myocardial injury after elective percutaneous coronary intervention

Introduction

Myocardial injury after percutaneous coronary intervention (PCI) occurs in approximately 30% of procedures, and is related to worse prognosis. Effects of remote ischemic preconditioning (RIPC) on reperfusion injury have been investigated before, yielding conflicting results.

Aim

To assess the impact of a single episode of RIPC on myocardial injury after elective PCI.

Material and methods

One hundred and four patients undergoing elective PCI, with normal baseline cardiac troponin-I (cTn-I) values, were randomized to two groups. Two patients were excluded due to data loss, and 102 patients were analyzed. Five minutes of ischemic preconditioning was delivered just before the intervention to the preconditioning group, by inflating the blood pressure cuff up to 200 mm Hg on the non-dominant arm. Postprocedural 16^th hour cTn-I, ΔcTn-I (difference between the 16^th h and baseline cTn-I values) and the prevalence of type 4a myocardial infarction were compared between the two groups.

Results

Median cTn-I values after the procedure were compared. 16^th hour cTn-I was insignificantly lower in the preconditioning arm (0.026 μg/l vs. 0.045 μg/l, p = 0.186). The incidence of cTn-I elevation 5-fold above the upper reference limit (URL) (> 0.115 μg/l) was lower in the preconditioning group, but it was also not significant (21.6% vs. 11.8%, p = 0.184).

Conclusions

A single episode of RIPC before elective PCI demonstrated less troponin elevation but failed to show a significant effect.

miR-21 enhances cardiac fibrotic remodeling and fibroblast proliferation via CADM1/STAT3 pathway

Background

Cardiac fibrosis play a key role in the atrial fibrillation pathogenesis but the underlying potential molecular mechanism is still understood. However, potential mechanisms for miR-21 upregulation and its role in cardiac fibrosis remain unclear. The controls cell proliferation and processes fundamental to disease progression.

Methods

In this study, immunohistochemistry, real-time RT-PCR, cell transfection, cell cycle, cell proliferation and Western blot were used, respectively.

Results

Here we have been demonstrated that the tumor suppressor cell adhesion molecule 1 (CADM1) is the potential target of miR-21. Our study revealed that miR-21 regulation of CADM1 expression, which was decreased in cardiac fibroblasts and fibrosis tissue. The cardiac fibroblasts transfected with miR-21 mimic promoted miR-21 overexpression enhanced STAT3 expression and decreased CADM1 expression. Nevertheless, the cardiac fibroblasts transfected with miR-21 inhibitor obtained the opposite expression result. Furthermore, downexpression of miR-21 suppressed cardiac fibroblast proliferation.

Conclusions

These results suggested that miR-21 overexpression promotes cardiac fibrosis via STAT3 signaling pathway by decrease CADM1 expression, indicating miR-21 as an important signaling molecule for cardiac fibrotic remodeling and AF.

Meta-Analysis of Randomized Trials on Remote Ischemic Conditioning During Primary Percutaneous Coronary Intervention in Patients With ST-Segment Elevation Myocardial Infarction

Ischemia/reperfusion injury adversely affects the final infarct size (IS) after primary percutaneous coronary intervention (PCI) in patients with ST-segment elevation myocardial infarction (STEMI). Few studies have evaluated the role of remote ischemic conditioning (RIC) in reducing ischemia/reperfusion injury. However, the results of these studies were not consistent, and an overview of overall effectiveness of this technique in patients with STEMI is lacking. We conducted this meta-analysis to evaluate the available evidence in literature regarding the application of RIC in patients with STEMI who underwent primary PCI. The authors included randomized trials that studied RIC in patients with STEMI who underwent primary PCI versus no conditioning (standard of care). Final analysis included 8 trials with a total of 1,083 patients. Compared with standard of care alone, RIC was associated with reduced IS assessed by biomarker release (standardized mean difference = -0.23, 95% confidence interval [CI] -0.37 to -0.09; p = 0.001), better rates of ST-segment resolution (54% vs 30%; relative risk [RR] 1.78; 95% CI 1.35 to 2.34; p <0.001), reduced major adverse cardiac and cerebrovascular events (11% vs 20%; RR 0.57; 95% CI 0.39 to 0.83; p = 0.003), and nonsignificant reduction in IS assessed by cardiac imaging (standardized mean difference = -0.15; 95% CI -1.03 to -0.14; p = 0.36). There was no difference in postprocedural Thrombolysis In Myocardial Infarction-III flow between RIC and standard of care groups (86% vs 87%; RR 0.99; 95% CI 0.94 to 1.05; p = 0.81). In conclusion, remote ischemic conditioning may improve cardiovascular outcomes in patients with STEMI who underwent primary PCI evidenced by reduced biomarkers release, major adverse cardiac and cerebrovascular events, and better ST-segment resolution.

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.

Cyclophilin A mediates the ox-LDL-induced activation and apoptosis of macrophages via autophagy

BACKGROUND

Oxidized low-density lipoprotein (ox-LDL) is the most common inflammatory factor that mediates the activation and apoptosis of macrophages. Cyclophilin A (CyPA) is expressed following oxidative stress, hypoxia, and infection. However, the role of CyPA in the activation and apoptosis of macrophages is unclear. The aims of the study were to determine whether CyPA mediates the ox-LDL-induced activation and apoptosis in RAW264.7 cells and to analyze potential mechanisms.

METHODS AND RESULTS

Through Western blot and ELISA test, the expression of CyPA induced by ox-LDL is time-dependent in RAW264.7 cells. Gene silencing of CyPA reduced the generation of lipid droplets in the cytoplasm and downregulated the expression of the surface markers of macrophage activation, namely, CD80, CD86, and major histocompatibility complex class 2 antigen. Cell apoptosis is significantly decreased and the level of anti-apoptosis protein bcl-2 is increased in CyPA silent cells compared with the control group. Finally, autophagy-related protein LC3-II/LC3-I ratio level significantly decreased in CyPA silent cells with less autophagosome formation while the blocked autophagy flux was recovered. The differences in the activation and apoptosis between CyPA silent cells and the control cells were inhibited by pre-treatment with class III PI 3-kinase inhibitor 3-MA.

CONCLUSIONS

These results indicate that CyPA mediates the ox-LDL-induced activation and apoptosis in RAW264.7 cells by regulating autophagy.

Remote ischemic preconditioning attenuates EGR-1 expression following myocardial ischemia reperfusion injury through activation of the JAK-STAT pathway

BACKGROUND/OBJECTIVES

Remote ischemic preconditioning (RIPC) protects the myocardium from ischemia/reperfusion (I/R) injury however the molecular pathways involved in cardioprotection are yet to be fully delineated. Transcription factor Early growth response-1 (Egr-1) is a key upstream activator in a variety of cardiovascular diseases. In this study, we elucidated the role of RIPC in modulating the regulation of Egr-1.

METHODS

This study subjected rats to transient blockade of the left anterior descending (LAD) coronary artery with or without prior RIPC of the hind-limb muscle and thereafter excised the heart 24h following surgical intervention. In vitro, rat cardiac myoblast H9c2 cells were exposed to ischemic preconditioning by subjecting them to 3cycles of alternating nitrogen-flushed hypoxia and normoxia. These preconditioned media were added to recipient H9c2 cells which were then subjected to 30min of hypoxia followed by 30min of normoxia to simulate myocardial I/R injury. Thereafter, the effects of RIPC on cell viability, apoptosis and inflammatory markers were assessed.

RESULTS

We showed reduced infarct size and suppressed Egr-1 in the heart of rats when RIPC was administered to the hind leg. In vitro, we showed that RIPC improved cell viability, reduced apoptosis and attenuated Egr-1 in recipient cells.

CONCLUSIONS

Selective inhibition of intracellular signaling pathways confirmed that RIPC increased production of intracellular nitric oxide (NO) and reactive oxygen species (ROS) via activation of the JAK-STAT pathway which then inactivated I/R-induced ERK 1/2 signaling pathways, ultimately leading to the suppression of Egr-1.

Novel cardioprotective and regenerative therapies in acute myocardial infarction: a review of recent and ongoing clinical trials

Following the original large-scale randomized trials of aspirin and β-blockade, there have been a number of major advances in pharmacological and mechanical treatments for acute myocardial infarction. Despite this progress, myocardial infarction remains a major global cause of mortality and morbidity, driving a quest for novel treatments in this area. As the understanding of mitochondrial dynamics and the pathophysiology of reperfusion injury has evolved, the last three decades have seen advances in ischemic conditioning, pharmacological and metabolic cardioprotection, as well as biological and stem-cell therapies. The aim of this review is to provide a synopsis of adjunctive cardioprotective and regenerative therapies currently undergoing or entering early clinical trials in the treatment of patients with acute myocardial infarction.

Cardiac Remote Ischemic Preconditioning Prior to Elective Vascular Surgery (CRIPES): A Prospective, Randomized, Sham-Controlled Phase II Clinical Trial

BACKGROUND

Remote ischemic preconditioning (RIPC) has been shown to reduce infarct size in animal models. We hypothesized that RIPC before an elective vascular operation would reduce the incidence and amount of a postoperative rise of the cardiac troponin level.

METHODS AND RESULTS

Cardiac Remote Ischemic Preconditioning Prior to Elective Vascular Surgery (CRIPES) was a prospective, randomized, sham-controlled phase 2 trial using RIPC before elective vascular procedures. The RIPC protocol consisted of 3 cycles of 5-minute forearm ischemia followed by 5 minutes of reperfusion. The primary endpoint was the proportion of subjects with a detectable increase in cardiac troponin I (cTnI) and the distribution of such increases. From June 2011 to September 2015, 201 male patients (69±7, years) were randomized to either RIPC (n=100) or a sham procedure (n=101). Indications for vascular surgery included an expanding abdominal aortic aneurysm (n=115), occlusive peripheral arterial disease of the lower extremities (n=37), or internal carotid artery stenosis (n=49). Of the 201 patients, 47 (23.5%) had an increase in cTnI above the upper reference limit within 72 hours of the vascular operation, with no statistically significant difference between those patients assigned to RIPC (n=22; 22.2%) versus sham procedure (n=25; 24.7%; P=0.67). Among the cohort with increased cTnI, the median peak values (interquartile range) in the RIPC and control group were 0.048 (0.004-0.174) and 0.017 (0.003-0.105), respectively (P=0.54).

CONCLUSIONS

In this randomized, controlled trial of men with increased perioperative cardiac risks, elevation in cardiac troponins was common following vascular surgery, but was not reduced by a strategy of RIPC.

CLINICAL TRIAL REGISTRATION

URL: https://www.clinicaltrials.gov. Unique identifier: NCT01558596.

Transplantation of EPCs overexpressing PDGFR-β promotes vascular repair in the early phase after vascular injury

BACKGROUND

Endothelial progenitor cells (EPCs) play important roles in the regeneration of the vascular endothelial cells (ECs). Platelet-derived growth factor receptor (PDGFR)-β is known to contribute to proliferation, migration, and angiogenesis of EPCs, this study aims to investigate effects of transplantation of EPCs overexpressing PDGFR-β on vascular regeneration.

METHODS

We transplanted genetically modified EPCs overexpressing PDGFR-β into a mouse model with carotid artery injury. After 3 days of EPCs transplantation, the enhanced green fluorescent protein (EGFP)-expressing cells were found at the injury site and the lining of the lumen by laser scanning confocal microscope (LSCM). At 4, 7, and 14 days of the carotid artery injury, reendothelialization was evaluated by Evans Blue staining. Neointima formation was evaluated at day 14 with hematoxylin and eosin (HE) staining by calculating the neointimal area, medial area, and neointimal/media (NI/M) ratio. Intimal cell apoptosis was evaluated using TUNEL assay. Then we tested whether PDGF-BB-induced VSMC migration and PDGF-BB's function in reducing VSMC apoptosis can be attenuated by EPCs overexpressing PDGFR-β in a transwell co-culture system.

RESULTS

Our results showed that EPCs overexpressing PDGFR-β accelerates reendothelialization and mitigates neointimal formation at 14 days after injury. Moreover, we found that there is great possibility that EPCs overexpressing PDGFR-β enhanc VSMC apoptosis and suppress VSMC migration by competitive consumption of PDGF-BB in the early phase after carotid artery injury in mice.

CONCLUSIONS

We report the first in vivo and in vitro evidence that transplantation of genetically modified EPC can have a combined effect of both amplifying the reendothelialization capacity of EPCs and inhibiting neointima formation so as to facilitate better inhibition of adverse remodeling after vascular injury.

Remote ischaemic conditioning in the context of type 2 diabetes and neuropathy: the case for repeat application as a novel therapy for lower extremity ulceration

An emerging treatment modality for reducing damage caused by ischaemia–reperfusion injury is ischaemic conditioning. This technique induces short periods of ischaemia that have been found to protect against a more significant ischaemic insult. Remote ischaemic conditioning (RIC) can be administered more conveniently and safely, by inflation of a pneumatic blood pressure cuff to a suprasystolic pressure on a limb. Protection is then transferred to a remote organ via humoral and neural pathways. The diabetic state is particularly vulnerable to ischaemia–reperfusion injury, and ischaemia is a significant cause of many diabetic complications, including the diabetic foot. Despite this, studies utilising ischaemic conditioning and RIC in type 2 diabetes have often been disappointing. A newer strategy, repeat RIC, involves the repeated application of short periods of limb ischaemia over days or weeks. It has been demonstrated that this improves endothelial function, skin microcirculation, and modulates the systemic inflammatory response. Repeat RIC was recently shown to be beneficial for healing in lower extremity diabetic ulcers. This article summarises the mechanisms of RIC, and the impact that type 2 diabetes may have upon these, with the role of neural mechanisms in the context of diabetic neuropathy a focus. Repeat RIC may show more promise than RIC in type 2 diabetes, and its potential mechanisms and applications will also be explored. Considering the high costs, rates of chronicity and serious complications resulting from diabetic lower extremity ulceration, repeat RIC has the potential to be an effective novel advanced therapy for this condition.

Relationship between fasting glucose levels and in-hospital mortality in Chinese patients with acute myocardial infarction and diabetes mellitus: a retrospective cohort study

BACKGROUND

Previous studies have demonstrated that elevated admission and fasting glucose (FG) is associated with worse outcomes in patients with acute myocardial infarction (AMI). However, the quantitative relationship between FG levels and in-hospital mortality in patients with AMI remains unknown. The aim of the study is to assess the prevalence of elevated FG levels in hospitalized Chinese patients with AMI and diabetes mellitus and to determine the quantitative relationship between FG levels and the in-hospital mortality as well as the optimal level of FG in patients with AMI and diabetes mellitus.

METHODS

A retrospective study was carried out in 1856 consecutive patients admitted for AMI and diabetes mellitus from 2002 to 2013. Clinical variables of baseline characteristics, in-hospital management and in-hospital adverse outcomes were recorded and compared among patients with different FG levels.

RESULTS

Among all patients recruited, 993 patients (53.5 %) were found to have FG ≥100 mg/dL who exhibited a higher in-hospital mortality than those with FG < 100 mg/dL (P < 0.001). Although there was a high correlation between FG levels and in-hospital mortality in all patients (r = 0.830, P < 0.001), the relationship showed a J-curve configuration with an elevated mortality when FG was less than 80 mg/dL. Using multivariate logistic regression models, we identified that age, FG levels and Killip class of cardiac function were independent predictors of in-hospital mortality in AMI patients with diabetes mellitus.

CONCLUSIONS

More than half of patients with AMI and diabetes mellitus have FG ≥100 mg/dL and the relationship between in-hospital mortality and FG level was a J-curve configuration. Both FG ≥ 100 mg/dL and FG <80 mg/dL were identified to be independent predictors of in-hospital mortality and thus the optimal FG level in AMI patients with diabetes mellitus appears to be 80-100 mg/dL.

Cardioprotective effect of atorvastatin alone or in combination with remote ischemic preconditioning on the biochemical changes induced by ischemic/reperfusion injury in a mutual prospective study with a clinical and experimental animal arm

BACKGROUND

Atorvastatin and remote ischemic preconditioning (RIPC) have beneficial cardiovascular protective effects. The aim of the study was to investigate possible effect of this drug alone and in combination with RIPC on the biochemical changes induced by ischemic/reperfusion injury (I/R) in a combined study with a clinical and experimental animal arm.

METHODS

Thirty consecutive patients undergoing elective percutaneous coronary intervention (PCI) were divided into three groups (10 each): group I (control group without any preconditioning), group II (patients who were maintained on atorvastatin (80mg/day) for one month before PCI), and group III (similar to group II but PCI was preceded by RIPC). On the other hand, sixty adult male New Zealand white rabbits were divided into 6 groups (10 each): group I (control), group II (sham), group III (I/R as 30min ischemia followed by 120min reperfusion), group IV (regular atorvastatin 10mg/kg for 40days orally followed by I/R), group V (I/R preceded by RIPC) and group VI (similar to group IV but I/R was preceded by RIPC). Tumor necrosis factor-α (TNF-α), interleukin-6 (IL-6), nitric oxide (NO), troponin I (cTnI), creatine kinase MB (CK-MB) and C-reactive protein (CRP) were measured in blood for all study groups.

RESULTS

Clinical and experimental parts showed that groups with RIPC combined with atorvastatin pre-treatment showed a synergistic protective effect against I/R injury as evidenced by significant reduction (P<0.001) in the levels of TNF-α, cTnI (in patients) and IL-6, CK-MB and CRP (in rabbits) while the level of NO was significantly (P<0.001) increased compared with other groups.

CONCLUSIONS

Pretreatment with atorvastatin combined with RIPC can exert a synergistic cardioprotective effects by reducing the possible biochemical changes related to ischemic reperfusion injury.

Opioids in Remote Ischemic Preconditioning-Induced Cardioprotection

Remote ischemic preconditioning (RIPC) is an intriguing process whereby transient regional ischemia and reperfusion episodes to remote tissues including skeletal, renal, mesenteric provide protection to the heart against sustained ischemia-reperfusion-induced injury. Clinically, this technique has been used in patients undergoing various surgical interventions including coronary artery bypass graft surgery, abdominal aortic aneurysm repair, percutaneous coronary intervention, and heart valve surgery. The endogenous opioid system is extensively expressed in the brain to modulate pain sensation. Besides the role of opioids in relieving pain, numerous researchers have found their critical involvement in evoking cardioprotective effects. Endogenous opioids including endorphins, enkephalins, and dynorphins are released during RIPC and are critically involved in mediating RIPC-induced cardioprotective effects. It has been suggested that during RIPC, the endogenous opioids may be released into the systemic circulation and may travel via bloodstream that act on the myocardial opioid receptors to induce cardioprotection. The present review describes the potential role of opioids in mediating RIPC-induced cardioprotection.

The Impact of Remote Ischemic Preconditioning on Arterial Stiffness and Heart Rate Variability in Patients with Angina Pectoris

Remote ischemic preconditioning (RIPC) is the set of ischemia episodes that protects against subsequent periods of prolonged ischemia through the cascade of adaptive responses; however, the mechanisms of RIPC are not entirely clear. Here, we aimed to study the impact of RIPC in patients with stable angina pectoris and compare it with healthy individuals with respect to arterial stiffness and heart rate variability. In the randomized, sham-controlled, crossover blind design study, a group of 30 coronary heart disease (CHD) patients (63.9 ± 1.6 years) with stable angina pectoris NYHA II-III and a control group of 20 healthy individuals (58.2 ± 2.49) were both randomly allocated for remote RIPC or sham RIPC. Arterial stiffness, pulse wave velocity (Spygmacor, Australia), and heart rate variability (HRV) were recorded before and after the procedure followed by the crossover examination. In the group of healthy individuals, RIPC showed virtually no impact on the cardiovascular parameters, while, in the CHD group, the systolic and central systolic blood pressure, central pulse pressure, and augmentation decreased, and total power of HRV improved. We conclude that ischemic preconditioning reduces not only systolic blood pressure, but also reduces central systolic blood pressure and improves arterial compliance and heart rate modulation reserve, which may be associated with the antianginal effect of preconditioning.

Clinical Profile and Long-Term Prognostic Factors of a Young Chinese Han Population (≤ 40 Years) Having ST-Segment Elevation Myocardial Infarction

BACKGROUND

The proportion of the mainland Chinese population with premature ST-segment elevation myocardial infarction is significantly elevated. Young patients with ST-segment elevation myocardial infarction have a different risk factor profile and clinical outcome compared with elder patients, and may also differ as compared to young patients in Western populations.

METHODS

We analyzed a total of 9462 consecutive ST-segment elevation myocardial infarction patients, and recruited 341 consecutive cases who had survived their first ST-segment elevation myocardial infarction at the age less than 40 years, and followed-up these patients for 5 years.

RESULTS

The most prevalent risk factor in young Chinese ST-segment elevation myocardial infarction patients was smoking (307/341, 90.03%) and male gender (328/341, 96.19%), although young patients had fewer traditional risk factors of acute myocardial infarction than the control group [(1.63 ± 1.03) vs. (2.38 ± 1.15), p < 0.01]. The number of affected vessels in cases was significantly less than in the elder control group (p < 0.01). During the follow-up, blood lipids and blood pressure of most patients reached the target level, while 42.10% of patients reported continuation of smoking. Multivariable data analysis showed that persistence of smoking (OR: 3.784, 95% CI: 1.636-8.751, p < 0.01) was the most significant prognostic factor of cardiac events after adjusting for various confounding factors.

CONCLUSIONS

We demonstrated that cigarette smoking is the most prevalent factor among the avoidable cardiovascular risk factors for young ST-segment elevation myocardial infarctions in China. Accordingly, continued smoking is the most powerful predictor for the recurrence of cardiac events in young Chinese patients with ST-segment elevation myocardial infarction.

KEY WORDS

Premature myocardial infarction; Prognosis; Risk factor.

Rotational atherectomy in very long lesions: Results for the ROTATE registry

BACKGROUND

Rotational atherectomy (RA) is relatively contraindicated in patients with lesions ≥25 mm of length. Aim of this study was to evaluate RA safety and efficacy in this subset of patients with new technology and devices.

METHODS AND RESULTS

From April 2002 to August 2013, the ROTATE registry included all consecutive patients undergoing RA in 8 centres. They were divided into shorter lesion group (SLG, lesions < 25 mm) and longer lesion group (LLG, lesions ≥ 25 mm). The angiographic success (AS) was the primary end point. Procedural complications (PC), a composite end point of procedural perforation, slow flow/no flow, and in-hospital major acute cardiovascular events (MACE), were secondary end points, along with death, nonfatal MI, target lesion revascularization, and MACE during follow-up. Sensitivity analysis was performed according to generation of DES. 1186 patients were included: 51.5% in SLG and 48.4% in LLG. Mean age was 70.4 ± 9.3 years, 64.5% were male. AS and PC did not differ between the two groups (93% vs 91%, p = 0.24 and 9.8 vs 9.4%, p = 0.84). During follow-up (27.6 ± 22.9 months), MACE did not differ between the two groups (28% vs 29.1%, p = 0.95). At multivariate analysis chronic kidney disease, male gender increased risk of MACE (HR 1.94, IQR 1.29-2.0, p = 0.01, HR 0.52, IQR 0.34-0.79, p = 0.01) while second-generation DES seemed protective (HR 0.53, IQR 0.31-0.88, p = 0.02). Data were confirmed at sensitivity analysis for second-generation DES (759 pts, 63.9%). No differences were found in this subpopulation between the two groups in term of AS, PC, and long-term MACE (93.6% vs 93.5%, p = 0.28, 11.9% vs 9.4%, p = 0.32 and 25.5% vs 23.9%, p = 0.72, respectively).

CONCLUSIONS

Treating coronary lesions ≥ 25 mm length with RA does not impact short- and long-term outcome, in particular, in patients with second-generation DES. © 2016 Wiley Periodicals, Inc.

Remote Ischemic Conditioning: Its Benefits and Limitations

This editorial describes benefits and limitations of remote ischemic conditioning. Remote ischemic conditioning was shown to reduce myocardial intact size in at least 4 sizeable clinical trials of acute myocardial infarction. It was not effective in recent studies of cardiac surgery. Reasons for these differences are discussed.

Atorvastatin treatment improves effects of implanted mesenchymal stem cells: meta-analysis of animal models with acute myocardial infarction

BACKGROUND

Previous studies reported that Atorvastatin (ATOR) can improve the efficacy of Mesenchymal stem cells (MSCs) transplantation after acute myocardial infarction (AMI). However, the results of those studies were inconsistent. To clarify the beneficial effects of atorvastatin added to the cell therapy with MSCs in animal model of acute myocardial infarction (AMI), we performed a systematic review and meta-analysis of case-control studies.

METHODS

Searches were performed using the PubMed database, the Excerpta Medica Database (Embase), the Science Citation Index, the China National Knowledge Information database, the Wanfang database, and the Chinese Scientific and Technological Journal Database (VIP database). The search term included "Atorvastatin (or Ator)", "Mesenchymal Stem Cells (or Mesenchymal Stem Cell or MSC or MSCs)" and "Acute Myocardial Infarction (or Myocardial Infarction or AMI or MI)". The endpoints were the left ventricular ejection fraction (LVEF) in animal model with AMI.

RESULTS

In total, 5 studies were included in the meta-analysis. Pooled analysis indicated a significant LVEF difference at 4 weeks follow-up between MSCs + ATOR combine group and MSCs alone group (95 % CI, 9.09-13.62 %; P < 0.01) with heterogeneity (P = 0.28; P >0.05) and inconsistency (I(2): 22 %).

CONCLUSIONS

Atorvastatin can enhance the existing effects of MSCs transplantation, and this combinational therapy is a superior cell/pharmacological therapeutic approach that merits future preclinical and clinical studies.

From Protecting the Heart to Improving Athletic Performance - the Benefits of Local and Remote Ischaemic Preconditioning

Remote Ischemic Preconditioning (RIPC) is a non-invasive cardioprotective intervention that involves brief cycles of limb ischemia and reperfusion. This is typically delivered by inflating and deflating a blood pressure cuff on one or more limb(s) for several cycles, each inflation-deflation being 3-5 min in duration. RIPC has shown potential for protecting the heart and other organs from injury due to lethal ischemia and reperfusion injury, in a variety of clinical settings. The mechanisms underlying RIPC are under intense investigation but are just beginning to be deciphered. Emerging evidence suggests that RIPC has the potential to improve exercise performance, via both local and remote mechanisms. This review discusses the clinical studies that have investigated the role of RIPC in cardioprotection as well as those studying its applicability in improving athletic performance, while examining the potential mechanisms involved.

Confounders of Cardioprotection by Remote Ischemic Preconditioning in Patients Undergoing Coronary Artery Bypass Grafting

OBJECTIVES

Remote ischemic conditioning (RIC) by repetitive blood pressure cuff inflation/deflation around a limb provides cardioprotection in patients undergoing coronary artery bypass grafting (CABG). Cardioprotection is confounded by risk factors, comorbidities and comedications. We aimed to identify confounders that possibly attenuate the protection provided by RIC.

METHODS

In a retrospective analysis of our single-center, randomized, double-blind trial of patients undergoing elective CABG with/without RIC prior to ischemic cardioplegic arrest, we analyzed demographics, medications and intraoperative variables. The primary end point was myocardial injury, as reflected by the area under the curve for serum troponin I (TnI) from baseline to 72 h after surgery.

RESULTS

In models with 2 independent variables and in the multivariate analysis, age and aortic cross-clamp time impacted on TnI release. Subgroup analyses confirmed RIC-induced protection in all age tertiles. There was no protection with an aortic cross-clamp time ≤56 min (RIC/control = 1.026 not significant), but there was protection with 57-75 min (RIC/control = 0.757; p = 0.0348) and ≥76 min (RIC/control = 0.735; p = 0.0277). Gender, β-blockers, statins, angiotensin-converting enzyme (ACE) inhibitors or angiotensin receptor blockers (ARBs) and intraoperative nitroglycerine did not impact on TnI release.

CONCLUSION

Age, gender, β-blockers, statins, ACE inhibitors, ARBs and intraoperative nitroglycerine have no significant impact on RIC-induced cardioprotection during CABG. However, greater myocardial ischemia/reperfusion injury at longer cross-clamp time facilitates the detection of protection by RIC.

Cardioprotection by remote ischemic conditioning: Mechanisms and clinical evidences

In remote ischemic conditioning (RIC), several cycles of ischemia and reperfusion render distant organ and tissues more resistant to the ischemia-reperfusion injury. The intermittent ischemia can be applied before the ischemic insult in the target site (remote ischemic preconditioning), during the ischemic insult (remote ischemic perconditioning) or at the onset of reperfusion (remote ischemic postconditioning). The mechanisms of RIC have not been completely defined yet; however, these mechanisms must be represented by the release of humoral mediators and/or the activation of a neural reflex. RIC has been discovered in the heart, and has been arising great enthusiasm in the cardiovascular field. Its efficacy has been evaluated in many clinical trials, which provided controversial results. Our incomplete comprehension of the mechanisms underlying the RIC could be impairing the design of clinical trials and the interpretation of their results. In the present review we summarize current knowledge about RIC pathophysiology and the data about its cardioprotective efficacy.

Remote Ischemic Preconditioning and Outcomes of Cardiac Surgery

BACKGROUND

Whether remote ischemic preconditioning (transient ischemia and reperfusion of the arm) can improve clinical outcomes in patients undergoing coronary-artery bypass graft (CABG) surgery is not known. We investigated this question in a randomized trial.

METHODS

We conducted a multicenter, sham-controlled trial involving adults at increased surgical risk who were undergoing on-pump CABG (with or without valve surgery) with blood cardioplegia. After anesthesia induction and before surgical incision, patients were randomly assigned to remote ischemic preconditioning (four 5-minute inflations and deflations of a standard blood-pressure cuff on the upper arm) or sham conditioning (control group). Anesthetic management and perioperative care were not standardized. The combined primary end point was death from cardiovascular causes, nonfatal myocardial infarction, coronary revascularization, or stroke, assessed 12 months after randomization.

RESULTS

We enrolled a total of 1612 patients (811 in the control group and 801 in the ischemic-preconditioning group) at 30 cardiac surgery centers in the United Kingdom. There was no significant difference in the cumulative incidence of the primary end point at 12 months between the patients in the remote ischemic preconditioning group and those in the control group (212 patients [26.5%] and 225 patients [27.7%], respectively; hazard ratio with ischemic preconditioning, 0.95; 95% confidence interval, 0.79 to 1.15; P=0.58). Furthermore, there were no significant between-group differences in either adverse events or the secondary end points of perioperative myocardial injury (assessed on the basis of the area under the curve for the high-sensitivity assay of serum troponin T at 72 hours), inotrope score (calculated from the maximum dose of the individual inotropic agents administered in the first 3 days after surgery), acute kidney injury, duration of stay in the intensive care unit and hospital, distance on the 6-minute walk test, and quality of life.

CONCLUSIONS

Remote ischemic preconditioning did not improve clinical outcomes in patients undergoing elective on-pump CABG with or without valve surgery. (Funded by the Efficacy and Mechanism Evaluation Program [a Medical Research Council and National Institute of Health Research partnership] and the British Heart Foundation; ERICCA ClinicalTrials.gov number, NCT01247545.).

Effect of Trimetazidine in Patients Undergoing Percutaneous Coronary Intervention: A Meta-Analysis

Optimizing the metabolism of the myocardium is a new strategy for patients with ischemic heart disease. Many studies have reported beneficial effects of trimetazidine (TMZ) on the clinical prognosis of patients with ischemic heart disease, but whether these beneficial effects are extended to patients undergoing percutaneous coronary intervention (PCI) remains uncertain. A meta-analysis was performed to evaluate the effect of TMZ on patients undergoing PCI. We conducted an electronic search of PubMed, Cochrane databases, the China National Knowledge Infrastructure, and Chinese Biological Medicine Database to identify randomized controlled trials. Methodological quality was assessed according to the Jadad scale score, and the meta-analysis was performed using Cochrane Collaboration RevMan 5.2 and Comprehensive Meta-Analysis. Dichotomous data were analyzed using relative risk (RR) or odds ratio (OR) with effect size indicated by the 95% confidence interval (CI), and continuous variables were analyzed using weighted mean differences (WMD) with effect size indicated by the 95% CI. Sensitivity analysis was performed by changing the statistical methods and effect model. Nine studies involving a total of 778 patients were included in this meta-analysis. Additional use of TMZ significantly improved the left ventricular ejection fraction (WMD: 3.11, 95% CI: [2.26, 3.96]) and reduced elevated cardiac troponin Ic level (RR: 0.69, 95% CI: [0.48, 0.99]), angina attacks during PCI (OR: 0.16, 95% CI: [0.07, 0.38]), and ischemic ST-T changes on the echocardiogram during PCI (RR: 0.76, 95% CI: [0.59, 0.98]). However, no significant difference was observed in serum BNP level 30 days after PCI between the experimental and control group. Additional use of TMZ for patients undergoing PCI may reduce myocardial injury during the procedure and improve cardiac function.

Chronic Losartan Treatment Up-Regulates AT1R and Increases the Heart Vulnerability to Acute Onset of Ischemia and Reperfusion Injury in Male Rats

Inhibition of angiotensin II type 1 receptor (AT1R) is an important therapy in the management of hypertension, particularly in the immediate post-myocardial infarction period. Yet, the role of AT1R in the acute onset of myocardial ischemia and reperfusion injury still remains controversial. Thus, the present study determined the effects of chronic losartan treatment on heart ischemia and reperfusion injury in rats. Losartan (10 mg/kg/day) was administered to six-month-old male rats via an osmotic pump for 14 days and hearts were then isolated and were subjected to ischemia and reperfusion injury in a Langendorff preparation. Losartan significantly decreased mean arterial blood pressure. However, heart weight, left ventricle to body weight ratio and baseline cardiac function were not significantly altered by the losartan treatment. Of interest, chronic in vivo losartan treatment significantly increased ischemia-induced myocardial injury and decreased post-ischemic recovery of left ventricular function. This was associated with significant increases in AT1R and PKCδ expression in the left ventricle. In contrast, AT2R and PKCε were not altered. Furthermore, losartan treatment significantly increased microRNA (miR)-1, -15b, -92a, -133a, -133b, -210, and -499 expression but decreased miR-21 in the left ventricle. Of importance, addition of losartan to isolated heart preparations blocked the effect of increased ischemic-injury induced by in vivo chronic losartan treatment. The results demonstrate that chronic losartan treatment up-regulates AT1R/PKCδ and alters miR expression patterns in the heart, leading to increased cardiac vulnerability to ischemia and reperfusion injury.

Impact of cardiovascular risk factors and medication use on the efficacy of remote ischaemic conditioning: post hoc subgroup analysis of a randomised controlled trial

OBJECTIVES

Remote ischaemic conditioning (RIC) promotes cardioprotection in patients undergoing primary percutaneous coronary intervention (pPCI) for ST-elevation myocardial infarction (STEMI). The effect of RIC may be modified by cardiovascular risk factors and their medications. We examined whether cardiovascular risk factors, lipid and glucose levels, and medication use influenced the efficacy of RIC in patients with STEMI treated with pPCI.

DESIGN

Post hoc subgroup analysis of a single-centre randomised controlled trial.

PARTICIPANTS

A total of 139 patients with STEMI, randomised during ambulance transport to hospital for pPCI with (n=71) or without (n=68) RIC, met the trial criteria and achieved data for a myocardial salvage index (MSI).

INTERVENTIONS

RIC was administered through intermittent arm ischaemia with four cycles of 5 min inflation and 5 min deflation of a blood pressure cuff.

PRIMARY OUTCOME MEASURES

MSI, estimated by single-photon emission CT. We evaluated the efficacy of RIC on the MSI in patient subgroups of cardiovascular risk factors, lipid and glucose levels, and medication use.

RESULTS

We found no significant difference in the efficacy of RIC in subgroups of cardiovascular risk factors, lipid and glucose levels, and medication use. However, point estimates indicated a reduced effect of RIC among smokers (median difference in MSI between RIC and control groups: -0.02 (95% CI -0.32 to 0.28) in smokers vs 0.25 (95% CI 0.08 to 0.42) in non-smokers, p value for interaction=0.13) and an increased effect of RIC in statin users (median difference in MSI between RIC and control groups: 0.34 (95% CI 0.03 to 0.65) in statin users vs 0.09 (95% CI -0.11 to 0.29) in non-statin users, p value for interaction=0.19).

CONCLUSIONS

RIC as an adjunct to pPCI seems to improve MSI in our trial population of patients with STEMI regardless of most cardiovascular risk factors and their medications. Our post hoc finding on a limited sample size calls for further investigation in large-scale multicentre trials.

TRIAL REGISTRATION NUMBER

NCT00435266.

Cardiovascular disease in HIV patients: from bench to bedside and backwards

HIV patients are exposed to a higher risk of adverse cardiovascular events, due to complex interactions between traditional risk factors and HIV infection itself in terms of ongoing endothelial dysfunctional immune activation/inflammation and increased risk of thrombosis. On the other hand, long-span antiretroviral therapy administration still raises questions on its long-term safety in an era in which life expectancy is becoming longer and longer while treatment of non-HIV-related serious events is increasingly raising concern. In this article, we will critically analyse the current knowledge of pathological and clinical aspects pertaining to the increased risk of cardiovascular events associated with HIV.

Ischaemic conditioning: pitfalls on the path to clinical translation

The development of novel adjuvant strategies capable of attenuating myocardial ischaemia-reperfusion injury and reducing infarct size remains a major, unmet clinical need. A wealth of preclinical evidence has established that ischaemic 'conditioning' is profoundly cardioprotective, and has positioned the phenomenon (in particular, the paradigms of postconditioning and remote conditioning) as the most promising and potent candidate for clinical translation identified to date. However, despite this preclinical consensus, current phase II trials have been plagued by heterogeneity, and the outcomes of recent meta-analyses have largely failed to confirm significant benefit. As a result, the path to clinical application has been perceived as 'disappointing' and 'frustrating'. The goal of the current review is to discuss the pitfalls that may be stalling the successful clinical translation of ischaemic conditioning, with an emphasis on concerns regarding: (i) appropriate clinical study design and (ii) the choice of the 'right' preclinical models to facilitate clinical translation.

Remote ischaemic conditioning in percutaneous coronary intervention: a meta-analysis of randomised trials

Introduction

It remains uncertain whether remote ischaemic conditioning (RIC) using cycles of limb ischaemia-reperfusion as a conditioning stimulus benefits patients undergoing percutaneous coronary intervention (PCI).

Aim

We performed a meta-analysis toassessthe effect of RIC in PCI.

Material and methods

The PubMed, EMBASE, Web of Science, and CENTRAL databases were searched for randomised controlled trials (RCTs) comparing RIC with controls. The treatment effects were measured as a pooled odds ratio (OR), standardised mean difference (SMD), and corresponding 95% confidence intervals (95% CIs) using random-effects models.

Results

Fourteen RCTs, including 2,301 patients, were analysed. Compared to the controls, RIC significantly reduced the cardiac enzyme levels (SMD = –0.21; 95% CI: –0.39 to –0.04; p = 0.015; heterogeneity test, I² = 75%), and incidence of PCI-related myocardial infarction (OR = 0.70; 95% CI, 0.51–0.98; p = 0.037). There was a trend toward an improvement in the complete ST-segment resolution rate with RIC (OR = 1.83; 95% CI: 0.99–3.40; p = 0.054). No significant difference could be detected between the two groups regarding the risk for acute kidney injury after PCI. Univariate meta-regression analysis suggested that the major source of significant heterogeneity was the PCI type (primary or non-emergent) for the myocardial enzyme levels (adjusted R² = 0.44). Subsequent subgroup analysis confirmed the results.

Conclusions

The present meta-analysis showed that RIC could confer cardioprotection for patients undergoing coronary stent implantation. Moreover, the decrease in the myocardial enzyme levels was more pronounced in the patients treated with primary PCI.

Remote ischemic conditioning: from experimental observation to clinical application: report from the 8th Biennial Hatter Cardiovascular Institute Workshop

In 1993, Przyklenk and colleagues made the intriguing experimental observation that ‘brief ischemia in one vascular bed also protects remote, virgin myocardium from subsequent sustained coronary artery occlusion’ and that this effect ‘…. may be mediated by factor(s) activated, produced, or transported throughout the heart during brief ischemia/reperfusion’. This seminal study laid the foundation for the discovery of ‘remote ischemic conditioning’ (RIC), a phenomenon in which the heart is protected from the detrimental effects of acute ischemia/reperfusion injury (IRI), by applying cycles of brief ischemia and reperfusion to an organ or tissue remote from the heart. The concept of RIC quickly evolved to extend beyond the heart, encompassing inter-organ protection against acute IRI. The crucial discovery that the protective RIC stimulus could be applied non-invasively, by simply inflating and deflating a blood pressure cuff placed on the upper arm to induce cycles of brief ischemia and reperfusion, has facilitated the translation of RIC into the clinical setting. Despite intensive investigation over the last 20 years, the underlying mechanisms continue to elude researchers. In the 8th Biennial Hatter Cardiovascular Institute Workshop, recent developments in the field of RIC were discussed with a focus on new insights into the underlying mechanisms, the diversity of non-cardiac protection, new clinical applications, and large outcome studies. The scientific advances made in this field of research highlight the journey that RIC has made from being an intriguing experimental observation to a clinical application with patient benefit.