Nomogram for predicting live birth in ovulatory women undergoing frozen-thawed embryo transfer

BACKGROUND

Study objectives included the development of a practical nomogram for predicting live birth following frozen-thawed embryo transfers in ovulatory women.

METHODS

Totally, 2884 patients with regular menstrual cycles in our center were retrospectively enrolled. In an 8:2 ratio, we randomly assigned patients to training and validation cohorts. Then we identified risk factors by multivariate logistic regression and constructed nomogram. Finally, receiver operating characteristic curve analysis, calibration curve and decision curve analysis were performed to assess the calibration and discriminative ability of the nomogram.

RESULTS

We identified five variables which were related to live birth, including age, anti-Müllerian hormone (AMH), protocol of frozen-thawed embryo transfer (FET), stage of embryos and amount of high-quality embryos. We then constructed nomograms that predict the probabilities of live birth by using those five parameters. Receiver operating characteristic curve analysis (ROC) showed that the area under the curve (AUC) for live birth was 0.666 (95% CI: 0.644-0.688) in the training cohort. The AUC in the subsequent validation cohorts was 0.669 (95% CI, 0.625-0.713). The clinical practicability of this nomogram was demonstrated through calibration curve analysis and decision curve analysis.

CONCLUSIONS

Our nomogram provides a visual and simple tool in predicting live birth in ovulatory women who received FET. It could also provide advice and guidance for physicians and patients on decision-making during the FET procedure.

Coronary microvascular obstruction and dysfunction in patients with acute myocardial infarction

Despite prompt epicardial recanalization in patients presenting with ST-segment elevation myocardial infarction (STEMI), coronary microvascular obstruction and dysfunction (CMVO) is still fairly common and is associated with poor prognosis. Various pharmacological and mechanical strategies to treat CMVO have been proposed, but the positive results reported in preclinical and small proof-of-concept studies have not translated into benefits in large clinical trials conducted in the modern treatment setting of patients with STEMI. Therefore, the optimal management of these patients remains a topic of debate. In this Review, we appraise the pathophysiological mechanisms of CMVO, explore the evidence and provide future perspectives on strategies to be implemented to reduce the incidence of CMVO and improve prognosis in patients with STEMI.

Effect of ischaemic postconditioning on markers of myocardial injury in ST-elevation myocardial infarction: a meta-analysis

OBJECTIVES

This study aimed to perform a meta-analysis of the short-term impact of ischaemic postconditioning (IPoC) on myocardial injury in ST elevation myocardial infarction (STEMI) using surrogate cardiac biomarkers.

METHODS

Eligible studies were identified using several article databases. Randomised controlled trials published between 1 January 2000 and 1 December 2021 comparing IPoC to standard of therapy in STEMI patients were included in the search. Outcomes included surrogates of myocardial injury, specifically peak troponin, creatine-kinase (CK) and CK myoglobin binding (CK-MB) enzyme levels.

RESULTS

11 articles involving 1273 patients reported on CK-MB and 8 studies involving 505 patients reported on CK. Few studies used troponin as an outcome, thus, a subanalysis of troponin dynamics was not performed. Meta-regression analysis demonstrated no significant effect of IPoC on peak CK-MB (effect size -0.41, 95% CI -1.15 to 0.34) or peak CK (effect size -0.42, 95% CI -1.20 to 0.36). Linear regression analysis demonstrated a significant correlation between a history of smoking and CK-MB in the IPoC group (p=0.038).

CONCLUSIONS

IPoC does not seem to protect against myocardial injury in STEMI, except possibly in smokers. These results resonate with some studies using imaging techniques to ascertain myocardial damage. More research using troponin and cardiac imaging should be pursued to better assess the effects of IPoC on cardiovascular outcomes in STEMI.

Ischemic Postconditioning Confers No Benefit to Left Ventricular Systolic Function: A Meta-Analysis of Cardiac Magnetic Resonance Imaging Results

Ischemic postconditioning (IPoC) is a technique suggested to reduce reperfusion injury in patients suffering acute ST-elevation myocardial infarction (STEMI), although its use is highly controversial. This meta-analysis aimed to evaluate the effect of IPoC with percutaneous coronary intervention in patients with acute STEMI, as measured by follow-up left ventricular ejection fraction (LVEF) on cardiac magnetic resonance imaging. The investigators searched PubMed, Embase, and Web of Science for all randomized controlled trials published during the last 2 decades. After the removal of duplicates, 2,021 articles from online databases had been identified using relevant search criteria. The included randomized controlled trials had studied patients with acute STEMI and Thrombolysis in Myocardial Infarction flow 0 to 1 at presentation and had measured follow-up LVEF using cardiac magnetic resonance imaging. Overall, 11 studies (n = 1,339 patients) qualified for inclusion. In each study, the control group did not differ significantly from the experimental group. The pooled data from included studies were analyzed using standardized mean difference between IPoC and control groups, and the 95% confidence interval for LVEF; the results were visualized using a forest plot. Bivariate regression analyses and 1-way analyses of LVEF coefficient ratios were done to isolate for various clinical and procedural parameters. An analysis of pooled data of the IPoC (n = 674) and control (n = 665) groups showed that IPoC did not significantly impact follow-up LVEF (using standardized mean difference 0.10, 95% confidence interval 0.00 to 0.21). Further analysis showed that IPoC did not improve follow-up LVEF when isolating for relevant clinical and procedural parameters. In conclusion, the use of IPoC as an adjunctive therapy to percutaneous coronary intervention seemingly provides no benefit to left ventricular systolic function, as quantified with cardiac magnetic resonance imaging, in patients with acute STEMI with Thrombolysis in Myocardial Infarction flow 0 to 1.

Effects of ischaemic postconditioning in aortic valve replacement: a multicenter randomized controlled trial

OBJECTIVES

The effect of ischaemic postconditioning (IPost) on postcardioplegic cardiac function is not known. We hypothesized that IPost was cardioprotective in adult patients undergoing elective aortic valve replacement.

METHODS

In a multicentre, prospective, randomized trial, patients (n = 209) were randomized to either a standard operation (controls) or postconditioning. Immediately before the cross-clamp was released, patients in the postconditioning group underwent 3 cycles of flow/non-flow (2 min each) of normothermic blood via the antegrade cardioplegia line. The primary end point was cardiac index. Secondary end points included additional haemodynamic measurements, biomarkers of cardiomyocyte injury, renal function parameters, intra- and postoperative arrhythmias and use of inotropic agents.

RESULTS

There was no significant difference between the groups regarding cardiac index [mean between-group difference, 95% confidence interval (CI), 0.11 (-0.1 to 0.3), P = 0.27]. Postconditioning had no effect on other haemodynamic parametres. There was no between-group difference regarding troponin T or creatine kinase MB. Postconditioning reduced the relative risk for arrhythmias by 45% (P = 0.03) when postoperative atrial fibrillation and intraoperative ventricular fibrillation were combined. There were no differences in patients with/without diabetes, patients above/below 70 years of age or between the centres. However, after postconditioning, the cardiac index [95% CI, 0.46 (0.2-0.7), P = 0.001], cardiac output (P < 0.001), mean arterial pressure (P < 0.001) and left ventricular stroke work index (P < 0.001) were higher in males compared to females.

CONCLUSIONS

IPost had no overall cardioprotective effects in patients undergoing aortic valve replacement but improved postoperative cardiac performance in men compared to women.

New Interventional Therapies beyond Stenting to Treat ST-Segment Elevation Acute Myocardial Infarction

Myocardial infarction remains the principal cause of death in Europe. In patients with ST-segment-elevation myocardial infarction (STEMI), a promptly revascularization with primary percutaneous intervention (PCI) has transformed prognosis in the last decades. However, despite increasing successful PCI procedures, mortality has remained unchanged in recent years. Also, due to an unsatisfactory reperfusion, some patients have significant myocardial damage and suffer left ventricular adverse remodeling with reduced function—all that resulting in the onset of heart failure with all its inherent clinical and socioeconomic burden. As a consequence of longer ischemic times, distal thrombotic embolization, ischemia-reperfusion injury and microvascular dysfunction, the resultant myocardial infarct size is the major prognostic determinant in STEMI patients. The improved understanding of all the pathophysiology underlying these events has derived to the development of several novel therapies aiming to reduce infarct size and to improve clinical outcomes in these patients. In this article, based on the mechanisms involved in myocardial infarction prognosis, we review the new interventional strategies beyond stenting that may solve the suboptimal results that STEMI patients still experience.

Long-term outcomes of ischemic post-conditioning primary PCI and conventional primary PCI in acute STEMI: a meta-analysis of randomized trials

BACKGROUND

Data regarding ischemic postconditioning during percutaneous coronary intervention (PCI) as compared conventional PCI alone has yielded conflicting results.

METHODS

Online databases comparing use of ischemic postconditioning percutaneous coronary intervention (ICP-PPCI) in STEMI patients with conventional PPCI were selected. Mortality, heart failure (HF), myocardial infarction (MI), and major adverse cardiac events (MACE) were evaluated. The primary outcome was composite of HF, MI, and mortality. Pooled risk ratio (RR) with 95% confidence interval (CI) were computed using random-effects model.

RESULTS

Eight studies consisting of 2,566 patients (ICP-PPCI n = 1,228; PPCI n = 1,278) were included. The mean age for PPCI group was 61.38 ± 7.86 years (51% men) and for PCI 59.83 ± 8.94 years (47% men). There were no differences in outcome between ICP-PPCI and PPCI in terms of HF (RR 0.87 95% CI0.51-1.48; p = 0.29), MI (RR 1.28, 95%CI0.74-2.20; p = 0.20), mortality (RR 0.93, 95%CI0.64-1.34; p = 0.58), and MACE (RR 0.89, 95%CI0.74-1.07; p = 0.22). The results for composite event for the ICP-PPCI and PPIC procedures, at ≥1 year follow-up duration, were comparable (RR 1.00 95%CI0.82-1.22; p = 1).

CONCLUSION

Ischemic postconditioning post percutaneous coronary intervention in STEMI patients has no long-term benefits over conventional PCI.

Co-morbidities and co-medications as confounders of cardioprotection-Does it matter in the clinical setting?

The translation of cardioprotection from robust experimental evidence to beneficial clinical outcome for patients suffering acute myocardial infarction or undergoing cardiovascular surgery has been largely disappointing. The present review attempts to critically analyse the evidence for confounders of cardioprotection in patients with acute myocardial infarction and in patients undergoing cardiovascular surgery. One reason that has been proposed to be responsible for such lack of translation is the confounding of cardioprotection by co-morbidities and co-medications. Whereas there is solid experimental evidence for such confounding of cardioprotection by single co-morbidities and co-medications, the clinical evidence from retrospective analyses of the limited number of clinical data is less robust. The best evidence for interference of co-medications is that for platelet inhibitors to recruit cardioprotection per se and thus limit the potential for further protection from myocardial infarction and for propofol anaesthesia to negate the protection from remote ischaemic conditioning in cardiovascular surgery. LINKED ARTICLES: This article is part of a themed issue on Risk factors, comorbidities, and comedications in cardioprotection. To view the other articles in this section visit http://onlinelibrary.wiley.com/doi/10.1111/bph.v177.23/issuetoc.

Role of HSP90 in suppressing TLR4-mediated inflammation in ischemic postconditioning

BACKGROUND

Myocardial inflammation mediated by toll-like receptor 4 (TLR4) plays an active role in myocardial ischemia/reperfusion (I/R) injury. Studies show that heat shock protein 90 (HSP90) is involved in ischemic postconditioning (IPostC) cardioprotection. This study investigates the roles of TLR4 and HSP90 in IPostC.

METHODS

Rats were subjected to 30 min ischemia, then 2 h reperfusion. IPostC was applied by three cycles of 30 s reperfusion, then 30 s reocclusion at reperfusion onset. Sixty rats were randomly divided into four groups: sham, I/R, IPostC, and geldanamycin (GA, HSP90 inhibitor, 1 mg/kg) plus IPostC (IPostC + GA).

RESULTS

IPostC significantly reduced I/R-induced infarct size (40.2±2.1% versus 28.4±2.4%; P < 0.05); the release of cardiac Troponin T, creatine kinase-MB, and lactate dehydrogenase (191.5±3.1 versus 140.6±3.3 pg/ml, 3394.6±132.7 versus 2880.7±125.5 pg/ml, 2686.2±98.6 versus 1848.8±90.1 pg/ml, respectively; P < 0.05); and cardiomyocyte apoptosis (40.3±2.2% versus 27.0±1.6%; P < 0.05). Further, local and circulating IL-1β, IL-6, TNF-α, and ICAM-1 levels decreased; TLR4 expression and nuclear factor-KB (NF-κB) signaling decreased; and cardiac HSP90 expression increased. Blocking HSP90 function with GA inhibited IPostC protection and anti-inflammation, suggesting that IPostC has a HSP90-dependent anti-inflammatory effect.

CONCLUSION

HSP90 may play a role in IPostC-mediated cardioprotection by inhibiting TLR4 activation, local and systemic inflammation, and NF-kB signaling.

Combined Intrahospital Remote Ischemic Perconditioning and Postconditioning Improves Clinical Outcome in ST-Elevation Myocardial Infarction

RATIONALE

Remote ischemic conditioning (RIC) or ischemic postconditioning (PostC) may protect the myocardium from ischemia-reperfusion injury in patients with ST-segment-elevation myocardial infarction.

OBJECTIVE

To determine whether combined intrahospital RIC and PostC or PostC alone in addition to primary percutaneous coronary intervention (PCI) reduce long-term clinical events after ST-segment-elevation myocardial infarction.

METHODS AND RESULTS

The present study is a post hoc analysis of a prospective trial which randomized 696 ST-segment-elevation myocardial infarction patients with symptoms <12 hours 1:1:1 to either combined RIC and PostC in addition to primary PCI, PostC alone in addition to primary PCI, or conventional PCI (control). Three cycles of RIC were performed by inflation of an upper arm blood pressure cuff for 5 minutes followed by deflation for 5 minutes. PostC was performed after primary PCI via 4 cycles of 30 seconds balloon occlusions followed by 30 seconds of reperfusion. Major adverse cardiac events consisting of cardiac death, reinfarction, and new congestive heart failure were assessed during long-term follow-up. Follow-up data were obtained in 97% of patients in median 3.6 years after the index event (interquartile range, 2.9-4.2 years). Major adverse cardiac events occurred in 10.2% of patients in the combined RIC and PostC group and in 16.9% in the control group (odds ratio, 0.56; 95% CI, 0.32-0.97; P=0.04). The difference was driven by a significantly reduced rate of new congestive heart failure in the RIC and PostC group (2.7% versus 7.8%; odds ratio, 0.32; 95% CI, 0.13-0.84; P=0.02). In contrast, PostC alone did not reduce major adverse cardiac events compared with controls (14.1% versus 16.9%; odds ratio, 0.81; 95% CI, 0.48-1.35; P=0.41), and the reduction of new congestive heart failure was not statistically significant (3.5% versus 7.8%; odds ratio, 0.43; 95% CI, 0.18-1.03; P=0.05).

CONCLUSIONS

Cardioprotection by combined intrahospital RIC and PostC in addition to primary PCI significantly reduced the rate of major adverse cardiac events and new congestive heart failure after ST-segment-elevation myocardial infarction.

CLINICAL TRIAL REGISTRATION

URL: http://www.clinicaltrials.gov . Unique identifier: NCT02158468.

Effect of Ischemic Postconditioning During Primary Percutaneous Coronary Intervention for Patients With ST-Segment Elevation Myocardial Infarction: A Randomized Clinical Trial

Importance

Ischemic postconditioning of the heart during primary percutaneous coronary intervention (PCI) induced by repetitive interruptions of blood flow to the ischemic myocardial region immediately after reopening of the infarct-related artery may limit myocardial damage.

Objective

To determine whether ischemic postconditioning can improve the clinical outcomes in patients with ST-segment elevation myocardial infarction (STEMI).

Design, Setting, And Participants

In this multicenter, randomized clinical trial, patients with onset of symptoms within 12 hours, STEMI, and thrombolysis in myocardial infarction (TIMI) grade 0-1 flow in the infarct-related artery at arrival were randomized to conventional PCI or postconditioning. Inclusion began on March 21, 2011, through February 2, 2014, and follow-up was completed on February 2, 2016. Analysis was based on intention to treat.

Interventions

Patients were randomly allocated 1:1 to conventional primary PCI, including stent implantation, or postconditioning performed as 4 repeated 30-second balloon occlusions followed by 30 seconds of reperfusion immediately after opening of the infarct-related artery and before stent implantation.

Main Outcome and Measures

A combination of all-cause death and hospitalization for heart failure.

Results

During the inclusion period, 1234 patients (975 men [79.0%] and 259 women [21.0%]; mean [SD] age, 62 [11] years) underwent randomization in the trial. Median follow-up was 38 months (interquartile range, 24-58 months). The primary outcome occurred in 69 patients (11.2%) who underwent conventional primary PCI and in 65 (10.5%) who underwent postconditioning (hazard ratio, 0.93; 95% CI, 0.66-1.30; P = .66). The hazard ratios were 0.75 (95% CI, 0.49-1.14; P = .18) for all-cause death and 0.99 (95% CI, 0.60-1.64; P = .96) for heart failure.

Conclusions and Relevance

Routine ischemic postconditioning during primary PCI failed to reduce the composite outcome of death from any cause and hospitalization for heart failure in patients with STEMI and TIMI grade 0-1 flow at arrival.

Trial Registration

clinicaltrials.gov Identifier: NCT01435408.

Effects of ischaemic postconditioning on outcomes of patients with ST-segment elevation myocardial infarction who underwent primary percutaneous coronary intervention: a meta-analysis

OBJECTIVE

The aim of this meta-analysis was to evaluate the effects of ischaemic postconditioning (IPC) therapy on hard clinical endpoints in ST-segment elevation myocardial infarction (STEMI) patients who underwent primary percutaneous coronary intervention (PPCI).

DESIGN

Systematic review and meta-analysis to evaluate the effects of IPC on the outcomes of patients with STEMI.

DATA SOURCES

PubMed, Embase and the Cochrane Library were systematically searched for relevant articles published prior to May 1, 2018.

ELIGIBILITY CRITERIA FOR SELECTING STUDIES

Randomised trials comparing conventional PPCI to PPCI combined with IPC in STEMI patients were included. The primary endpoint was heart failure. Secondary endpoints were all-cause mortality and major adverse cardiac events (MACE), including cardiac death, heart failure and MI. The Cochrane Reviewer's Handbook 4.2 was used to assess the risk of bias.

DATA EXTRACTION AND SYNTHESIS

Relevant data were extracted by two independent investigators. We derived pooled risk ratios (RRs) with random effects models. Sensitivity and subgroup analyses were performed.

RESULTS

Ten studies that had enrolled 3137 patients were included. PPCI combined with IPC failed to reduce heart failure (RR: 0.88, 95% CI: 0.61 to 1.26, p=0.47; absolute risk: 3.64% in the IPC group and 4.11% in the PPCI only group), all-cause mortality (RR: 0.94, 95% CI: 0.69 to 1.27, p=0.68; absolute risk: 5.07% in the IPC group and 5.27% in the PPCI onlygroup), MACE (RR: 1.05, 95% CI: 0.83 to 1.32, p=0.69; absolute risk: 9.37% in the IPC group and 8.93% in the PPCI only group), cardiac death (RR: 1.28, 95% CI: 0.85 to 1.93, p=0.24; absolute risk: 4.28% in the IPC group and 3.25% in the PPCI only group) and MI (RR: 1.08, 95% CI: 0.38 to 3.12, p=0.88; absolute risk: 3.61% in the IPC group and 3.44% in the PPCI only group).

CONCLUSIONS

IPC combined with PPCI does not reduce heart failure, MACE and all-cause mortality compared with traditional PPCI in patients with STEMI.

TRIAL REGISTRATION NUMBER

CRD42017063959.

Remote ischemic conditioning during primary percutaneous coronary intervention in patients with ST-segment elevation myocardial infarction: a systematic review and meta-analysis

Objective

This systematic review was designed to evaluate the efficacy of remote ischemic conditioning (RIC) with primary percutaneous coronary intervention (PCI) versus primary PCI alone for ST-segment elevation myocardial infarction (STEMI).

Search strategy

Computerized search for trials from PubMed, EMBASE, CENTRAL and Cochrane Database of Systematic Reviews databases.

Selection criteria

Trials investigating RIC plus primary PCI (group A) versus primary PCI alone (group B).

Outcome measures

Myocardial enzyme levels; left ventricular ejection fraction (LVEF); major adverse cardiac and cerebrovascular events (MACCEs); TIMI flow grade III; myocardial salvage index or infarct size per patients.

Results

In all, 14 studies involving 3165 subjects were included. There was a significant association of myocardial edema levels, myocardial salvage index and incidence of MACCEs in group A compared with group B (myocardial edema levels: SMD = − 0.36, 95% CI (− 0.59, − 0.13); myocardial salvage index: MD = 0.06, 95% CI (0.02, 0.10); MACCE: OR = 0.70, 95% CI (0.57, 0.85)). With regard to infarct size, TIMI flow grade III and LVEF, group A appeared to be equivalent with group B (infarct size: MD = − 1.67, 95% CI (− 3.46, 0.11); TIMI flow grade III: OR = 1.04, 95% CI (0.71, 1.52); LVEF: MD = 0.74, 95% CI (− 0.80, 2.28)).

Conclusion

RIC was associated with lower myocardial edema levels, myocardial salvage index and incidence of MACCE, while non-significant beneficial effect on infarct size, TIMI flow grade III or LVEF. These findings suggest that RIC is a promising adjunctive treatment to PCI for the prevention of reperfusion injury in STEMI patients.

Remote ischemic conditioning improves myocardial parameters and clinical outcomes during primary percutaneous coronary intervention: a meta-analysis of randomized controlled trials

We conducted a systematic review and meta-analysis to evaluate the effects of remote ischemic conditioning on myocardial parameters and clinical outcomes in ST segment elevation acute myocardial infarction (STEMI) patients undergoing primary percutaneous coronary intervention. Ten eligible randomized controlled trials with 1006 STEMI patients were identified. Compared with controls, remote ischemic conditioning reduced the myocardial enzyme levels (standardized mean difference =-0.86; 95% CI: -1.44 to -0.28; P = 0.004; I2 = 94.5%), and increased the incidence of complete ST-segment resolution [odds ratio (OR) = 1.74; 95% CI: 1.09 to 2.77; P = 0.02; I2 = 47.9%]. Remote ischemic conditioning patients had a lower risk of all-cause mortality (OR = 0.27; 95% CI: 0.12 to 0.62; P = 0.002; I2 = 0.0%) and lower major adverse cardiovascular and cerebrovascular events rate (OR=0.45; 95% CI: 0.27 to 0.75; P = 0.002; I2 = 0.0%). Meta-analysis suggested that remote ischemic conditioning conferred cardioprotection by reducing myocardial enzymes and increasing the incidence of complete ST-segment resolution in patients after STEMI. As a result, clinical outcomes were improved in terms of mortality and incidence of major adverse cardiovascular and cerebrovascular events.

Meta-analysis of the effects of ischemic postconditioning on structural pathology in ST-segment elevation acute myocardial infarction

In this meta-analysis, we assessed cardiac magnetic resonance imaging data to determine the effects of local and remote ischemic postconditioning (LPoC and RPoC, respectively) on structural pathology in ST-segmentel elevation acute myocardial infarction (STEMI). We searched the Pubmed, Embase and Cochrane Library databases up to May 2017 and included 12 randomized controlled trials (10 LPoC and 2 RPoC)containing 1069 study subjects with thrombolysis in myocardial infarction flow grade 0~1. Weighed mean difference (WMD), standardized mean difference (SMD), and odds ratio (OR) were used for the pooled analysis. Random-effect model was used for the potential clinical inconsistency. LPoC and RPoC increased the myocardial salvage index (n = 5; weighted mean difference (WMD) = 5.52; P = 0.005; I2 = 76.0%), and decreased myocardial edema (n = 7; WMD = -3.35; P = 0.0009; I2 = 18.0%). However, LPoC and RPoC did not reduce the final infarct size (n = 10; WMD = -1.01; P > 0.05; I2 = 68.0%), left ventricular volume (n = 10; standardized mean difference = 0.23; P > 0.05; I2 = 93.0%), the incidence of microvascular obstruction (n = 6; OR = 0.99; P > 0.05; I2 = 0.0%) or the extent of microvascular obstruction (n = 3; WMD = -0.09; P > 0.05; I2 = 6.0%). This meta-analysis shows that LPoC and/or RPoC improves myocardial salvage and decreases myocardial edema in STEMI patients without affecting final infarct size, left ventricular volume or microvascular obstruction.

Myocyte membrane and microdomain modifications in diabetes: determinants of ischemic tolerance and cardioprotection

Cardiovascular disease, predominantly ischemic heart disease (IHD), is the leading cause of death in diabetes mellitus (DM). In addition to eliciting cardiomyopathy, DM induces a ‘wicked triumvirate’: (i) increasing the risk and incidence of IHD and myocardial ischemia; (ii) decreasing myocardial tolerance to ischemia–reperfusion (I–R) injury; and (iii) inhibiting or eliminating responses to cardioprotective stimuli. Changes in ischemic tolerance and cardioprotective signaling may contribute to substantially higher mortality and morbidity following ischemic insult in DM patients. Among the diverse mechanisms implicated in diabetic impairment of ischemic tolerance and cardioprotection, changes in sarcolemmal makeup may play an overarching role and are considered in detail in the current review. Observations predominantly in animal models reveal DM-dependent changes in membrane lipid composition (cholesterol and triglyceride accumulation, fatty acid saturation vs. reduced desaturation, phospholipid remodeling) that contribute to modulation of caveolar domains, gap junctions and T-tubules. These modifications influence sarcolemmal biophysical properties, receptor and phospholipid signaling, ion channel and transporter functions, contributing to contractile and electrophysiological dysfunction, cardiomyopathy, ischemic intolerance and suppression of protective signaling. A better understanding of these sarcolemmal abnormalities in types I and II DM (T1DM, T2DM) can inform approaches to limiting cardiomyopathy, associated IHD and their consequences. Key knowledge gaps include details of sarcolemmal changes in models of T2DM, temporal patterns of lipid, microdomain and T-tubule changes during disease development, and the precise impacts of these diverse sarcolemmal modifications. Importantly, exercise, dietary, pharmacological and gene approaches have potential for improving sarcolemmal makeup, and thus myocyte function and stress-resistance in this ubiquitous metabolic disorder.

Downregulation of Na+/Ca2+ Exchanger Isoform 1 Protects Isolated Hearts by Sevoflurane Postconditioning but Not by Delayed Remote Ischemic Preconditioning in Rats

Background:

Calcium regulatory proteins-L-type Ca²⁺ channels (LTCCs), ryanodine receptor 2 (RyR2), and Na⁺/Ca²⁺ exchanger isoform 1 (NCX1) have been recognized as important protective mechanisms during myocardial ischemia-reperfusion injury (I/RI). Both sevoflurane postconditioning (SevoPoC) and delayed remote ischemic preconditioning (DRIPC) have been shown to protect the heart against I/RI. In this study, we aimed to compare the effects of SevoPoC and DRIPC on the expression of the three calcium regulatory proteins in an isolated rat heart model.

Methods:

After 30-min balanced perfusion, isolated hearts from rats were subjected to 30-min ischemia followed by 60-min reperfusion. Totally 40 isolated hearts were randomly assigned to four groups (n = 10/group): time control group, I/RI group, SevoPoC group, and DRIPC group. The effect of SevoPoC (3% v/v) and DRIPC were observed. Myocardial infarct size (IS), cardiac troponin I level, and heart function were measured. The protein and messenger RNA levels of LTCCs, RyR2, and NCX1 were determined.

Results:

Both SevoPoC and DRIPC improved the recovery of myocardial function, and reduced cardiac troponin I release after I/RI. The decrease in IS was more significant in the SevoPoC group than that in the DRIPC group (16.50% ± 4.54% in the SevoPoC group [P = 0.0006], and 22.34% ± 4.02% in the DRIPC group [P = 0.0007] vs. 35.00% ± 5.24% in the I/RI group, respectively). SevoPoC, but not DRIPC significantly inhibited the activity of NCX1 (0.59 ± 0.09 in the I/RI group vs. 0.32 ± 0.16 in the SevoPoC group, P = 0.006; vs. 0.57 ± 0.14 in the DRIPC group, P = 0.072). No statistical significant differences were observed in the expression of LTCCs and RyR2 between SevoPoC and DRIPC. In addition, subsequent correlation analysis showed a significantly positive relationship between the cardiac troponin I level and the protein expression of NCX1 (r = 0.505, P = 0.023).

Conclusion:

SevoPoC may be more effective in the cardioprotection than DRIPC partly due to the deactivation of NCX1.

Age and Surgical Complexity impact on Renoprotection by Remote Ischemic Preconditioning during Adult Cardiac Surgery: A Meta analysis

We aimed to conduct an up-to-date meta-analysis to comprehensively assess the renoprotective effect of remote ischemic preconditioning (RIPC) in patients undergoing adult cardiac surgery. 21 randomized controlled trials (RCTs) with a total of 6302 patients were selected and identified. Compared with controls, RIPC significantly reduced the incidence of acute kidney injury (AKI) [odds ratio (OR) = 0.79; P = 0.02; I² = 38%], and in particular, AKI stage I (OR = 0.65; P = 0.01; I² = 55%). RIPC significantly shortened mechanical ventilation (MV) duration [weighted mean difference (WMD) = −0.79 hours; P = 0.002; I² = 53%), and reduced intensive care unit (ICU) stay (WMD = −0.23 days; P = 0.07; I² = 96%). Univariate meta-regression analyses showed that the major sources of heterogeneity for AKI stage I were age (coefficient = 0.06; P = 0.01; adjusted R2 = 0.86) and proportion of complex surgery (coefficient = 0.02; P = 0.03; adjusted R2 = 0.81). Subsequent multivariate regression and subgroup analyses also confirmed these results. The present meta-analysis suggests that RIPC reduces the incidence of AKI in adults undergoing cardiac surgery and this benefit was more pronounced in younger patients undergoing non-complex cardiac surgery. RIPC may also shorten MV duration and ICU stay. Future RCTs tailored for those most likely to benefit from RIPC warrants further investigation.

Ischemic postconditioning during primary percutaneous coronary intervention

BACKGROUND

Although some studies have shown potential benefit for ischemic postconditioning (IPoC) during primary percutaneous coronary intervention (PCI) in improving surrogate markers of reperfusion and infarction size, the benefit of this approach on clinical outcomes remains unknown.

METHODS AND RESULTS

Electronic databases were searched for randomized clinical trials that compared IPoC versus conventional treatment during primary PCI. Random effects DerSimonian-Laird risk ratios (RR) were calculated for different clinical and surrogate outcomes. The main outcome of this analysis was all-cause mortality. A total of 25 trials involving 3,619 patients were included in the analysis. At a mean follow up of 14 months (95% confidence interval (CI) 8.6-19.4 months), the incidence of all-cause mortality was 4.9% [95% CI 3.8-6.0%] in the IPoC group versus 3.8% [95% CI 1.9-5.7%] in the control group (RR 0.92, 95% CI 0.68-1.24, P = 0.74). The risk of reinfarction (2.7% [95% CI 1.1-4.3%] vs. 2.3% [0.6-4.0%]; RR 1.29, 95% CI 0.62-2.68, P = 0.72), heart failure (3.6% [95% CI 2.0-5.1%] vs. 5.7% [95% CI 3.3-8.2%]; RR 0.77, 95% CI 0.58-1.06, P = 0.24), target vessel revascularization (3.2% [95% CI 1.7-4.7%] vs. 2.4% [95% CI 1.4-3.3%]; RR 1.40, 95% CI 0.90-2.20, P = 0.20), and stent thrombosis (2.4% [95% CI 1.1-3.8%] vs. 1.8% [95% CI 0.5-3.2%]); RR 1.50, 95% CI 0.60-3.70, P = 0.40) was similar in both groups.

CONCLUSIONS

IPoC does not appear to reduce the risk of clinical adverse events in patients with ST-elevation myocardial infarction undergoing primary PCI. © 2017 Wiley Periodicals, Inc.

Remote ischaemic pre-conditioning for the prevention of acute kidney injury

Acute kidney injury (AKI) is a common complication associated with high morbidity and mortality in hospitalized patients. One potential mechanism underlying renal injury is ischaemia/reperfusion injury (IRI), which attributed the organ damage to the inflammatory and oxidative stress responses induced by a period of renal ischaemia and subsequent reperfusion. Therapeutic strategies that aim at minimizing the effect of IRI on the kidneys may prevent AKI and improve clinical outcomes significantly. In this review, we examine the technique of remote ischaemic preconditioning (rIPC), which has been shown by several trials to confer organ protection by applying transient, brief episodes of ischaemia at a distant site before a larger ischaemic insult. We provide an overview of the current clinical evidence regarding the renoprotective effect of rIPC in the key clinical settings of cardiac or vascular surgery, contrast-induced AKI, pre-existing chronic kidney disease (CKD) and renal transplantation, and discuss key areas for future research.

Translational failure of anti-inflammatory compounds for myocardial infarction: a meta-analysis of large animal models

AIMS

Numerous anti-inflammatory drugs have been tested in large animal studies of myocardial infarction (MI). Despite positive results, translation of anti-inflammatory strategies into clinical practice has proved to be difficult. Critical disparities between preclinical and clinical study design that influence efficacy may partly be responsible for this translational failure. The aim of the present systematic review was to better understand which factors underlie the failure of transition towards the clinic.

METHODS AND RESULTS

Meta-analysis and regression of large animal studies were performed to identify sources that influenced effect size of anti-inflammatory compounds in large animal models of MI. We included 183 studies, containing 3331 large animals. Infarct size (IS) as a ratio of the area at risk (12.7%; 95% confidence interval, CI 11.1-14.4%, P < 0.001) and IS as a ratio of the left ventricle (3.9%; 95% CI 3.1-4.7%, P < 0.001) were reduced in treatment compared with control groups. Effect size was higher when outcome was assessed early after MI (P = 0.013) and where studies included only male animals (P < 0.001). Mortality in treated animals was higher in studies that blinded the investigator during the experiment (P = 0.041) and depended on the type of drug used (P < 0.001).

CONCLUSIONS

As expected, treatment with anti-inflammatory drugs leads to smaller infarct size in large animal MI models. Timing of outcome assessment, sex, and study quality are significantly associated with outcome and may explain part of the translational failure in clinical settings. Effect size depends on the type of drug used, enabling identification of compounds for future clinical testing.

Interaction of risk factors, comorbidities, and comedications with ischemia/reperfusion injury and cardioprotection by preconditioning, postconditioning, and remote conditioning

Pre-, post-, and remote conditioning of the myocardium are well described adaptive responses that markedly enhance the ability of the heart to withstand a prolonged ischemia/reperfusion insult and provide therapeutic paradigms for cardioprotection. Nevertheless, more than 25 years after the discovery of ischemic preconditioning, we still do not have established cardioprotective drugs on the market. Most experimental studies on cardioprotection are still undertaken in animal models, in which ischemia/reperfusion is imposed in the absence of cardiovascular risk factors. However, ischemic heart disease in humans is a complex disorder caused by, or associated with, cardiovascular risk factors and comorbidities, including hypertension, hyperlipidemia, diabetes, insulin resistance, heart failure, altered coronary circulation, and aging. These risk factors induce fundamental alterations in cellular signaling cascades that affect the development of ischemia/reperfusion injury per se and responses to cardioprotective interventions. Moreover, some of the medications used to treat these risk factors, including statins, nitrates, and antidiabetic drugs, may impact cardioprotection by modifying cellular signaling. The aim of this article is to review the recent evidence that cardiovascular risk factors and their medication may modify the response to cardioprotective interventions. We emphasize the critical need to take into account the presence of cardiovascular risk factors and concomitant medications when designing preclinical studies for the identification and validation of cardioprotective drug targets and clinical studies. This will hopefully maximize the success rate of developing rational approaches to effective cardioprotective therapies for the majority of patients with multiple risk factors.

Cardioprotection by combined intrahospital remote ischaemic perconditioning and postconditioning in ST-elevation myocardial infarction: the randomized LIPSIA CONDITIONING trial

AIMS

Remote ischaemic conditioning (RIC) and postconditioning (PostC) are both potent activators of innate protection against ischaemia-reperfusion injury and have demonstrated cardioprotection in experimental and clinical ST-elevation myocardial infarction (STEMI) trials. However, their combined effects have not been studied in detail. The aim of this study was to evaluate if the co-application of intrahospital RIC and PostC has a more powerful effect on myocardial salvage compared with either PostC alone or control.

METHODS AND RESULTS

This prospective, controlled, single-centre study randomized 696 STEMI patients to one of the following three groups: (i) combined intrahospital RIC + PostC in addition to primary percutaneous coronary intervention (PCI); (ii) PostC in addition to PCI; and (iii) conventional PCI (control). The primary endpoint myocardial salvage index was assessed by cardiac magnetic resonance (CMR) imaging within 3 days after infarction. Secondary endpoints included infarct size and microvascular obstruction (MVO) assessed by CMR. The combined clinical endpoint consisted of death, reinfarction, and new congestive heart failure within 6 months. The primary endpoint myocardial salvage index was significantly greater in the combined RIC + PostC group when compared with the control group (49 [interquartile range 30-72] vs. 40 [interquartile range 16-68], P = 0.02). Postconditioning alone failed to improve myocardial salvage when compared with conventional PCI (P = 0.39). The secondary endpoints, including infarct size and MVO, showed no significant differences between groups. Clinical follow-up at 6 months revealed no differences in the combined clinical endpoint between groups (P = 0.44).

CONCLUSION

Combined intrahospital RIC + PostC in conjunction with PCI in STEMI significantly improves myocardial salvage in comparison with control and PostC.

CLINICALTRIALSGOV

NCT02158468.

The challenge of translating ischemic conditioning from animal models to humans: the role of comorbidities

Following a period of ischemia (local restriction of blood supply to a tissue), the restoration of blood supply to the affected area causes significant tissue damage. This is known as ischemia-reperfusion injury (IRI) and is a central pathological mechanism contributing to many common disease states. The medical complications caused by IRI in individuals with cerebrovascular or heart disease are a leading cause of death in developed countries. IRI is also of crucial importance in fields as diverse as solid organ transplantation, acute kidney injury and following major surgery, where post-operative organ dysfunction is a major cause of morbidity and mortality. Given its clinical impact, novel interventions are urgently needed to minimize the effects of IRI, not least to save lives but also to reduce healthcare costs. In this Review, we examine the experimental technique of ischemic conditioning, which entails exposing organs or tissues to brief sub-lethal episodes of ischemia and reperfusion, before, during or after a lethal ischemic insult. This approach has been found to confer profound tissue protection against IRI. We discuss the translation of ischemic conditioning strategies from bench to bedside, and highlight where transition into human clinical studies has been less successful than in animal models, reviewing potential reasons for this. We explore the challenges that preclude more extensive clinical translation of these strategies and emphasize the role that underlying comorbidities have in altering the efficacy of these strategies in improving patient outcomes.

Influence of cardiovascular risk factors on infarct size and interaction with mechanical ischaemic postconditioning in ST-elevation myocardial infarction

Objective

Previous studies have shown that mechanical postconditioning (PostC) significantly reduces infarct size (IS) in patients with acute myocardial infarction. Our objective was to assess the influence of traditional cardiovascular (CV) risk factors on IS and their interaction with ischaemic PostC in patients with acute ST-elevation myocardial infarction (STEMI).

Methods

The study population was constituted from the clinical database pooling of four previously published PostC prospective, multicentre, randomised, open-label controlled trials with identical inclusion criteria. Patients with STEMI, presenting within 12 h of symptoms onset referred for percutaneous coronary intervention, were included. Mechanical ischaemic PostC was performed by four repeated cycles of inflation–deflation of the angioplasty balloon within 1 min of reflow, while the control group underwent no intervention. IS was assessed by measuring total creatine kinase release over 72 h.

Results

173 patients, aged 58±12 years, 76% males, 48% anterior infarct were included (82 in the PostC group, 91 in the control group). IS was significantly reduced in the PostC compared to the control group (71.7±41.6 vs 88.2±54.5×10³ arbitrary units; p=0.027). After adjustment for abnormally contracting segments, older patients had smaller IS and smokers had larger IS. Gender, diabetes, hypertension, dyslipidemia and obesity did not have any significant effect on IS. Multivariate regression analysis showed that none of the traditional risk factors had a significant impact on the cardioprotective effect of mechanical ischaemic PostC.

Conclusions

The present analysis suggests that the cardioprotective effect of mechanical PostC is not influenced by traditional CV risk factors that are prevalent in patients with STEMI.

Targeting reperfusion injury in the era of primary percutaneous coronary intervention: hope or hype?

Introduction of reperfusion therapy by primary percutaneous coronary intervention (PCI) has resulted in improved outcomes for patients presenting with ST-segment elevation myocardial infarction. Despite the obvious advantages of primary PCI, acute restoration of blood flow paradoxically also jeopardises the myocardium in the first minutes of reperfusion-a phenomenon known as reperfusion injury. Prevention of reperfusion injury may help to improve outcome following primary PCI. This review focuses on the clinical evidence of potential therapeutic cardioprotective methods as adjuvant to primary PCI. Despite overall disappointing, there exists some promising strategies, including ischaemic postconditioning, remote ischaemic conditioning, pharmacological conditioning with focus on adenosine, cyclosporine A, glucose-insulin-potassium, exenatide, atrial natriuretic peptide and metoprolol and cooling. But hitherto no large randomised study has demonstrated any effect on outcome, and ongoing studies that address this issue are underway. Moreover, this review will discuss important clinical predictors associated with reperfusion injury during primary PCI that may interfere with a potential protective effect (pre-PCI thrombolysis in myocardial infarction flow, preinfarction angina, collateral flow, duration of ischaemia and hyperglycaemia). This paper will also provide a short overview of the technical issues related to surrogate endpoints in phase II trials. Based upon these discussions, the paper will provide factors that should be taken into account when designing future clinical studies.

Ischemic postconditioning of the isolated human myocardium: Role of the applied protocol

Background

Ischemic postconditioning (IPostC), has been proposed as a useful approach to reduce infarct size in all species, but its clinical utility remains unclear.

Objective

To investigate the role played by the protocol used on the efficacy of IPostC in protecting the diseased human myocardium.

Methods

Myocardial atrial samples from patients were subjected to a 90 min ischemia/120 min reoxygenation followed by different IPostC protocols to investigate the role of the time of ischemia (30, 60, 90 and 120 s) and the number of cycles (1, 2, 3 and 4) with 60 and 120 s of total ischemic time. Muscles were also subjected to ischemic preconditioning (IPreC). The release of lactate dehydrogenase (LDH) and the measurement of tetrazolium bromide (MTT) were determined.

Results

IPostC increased the LDH and decreased the MTT values from those of control, independently of the duration of the conditioning ischemia. LDH and MTT values also worsened by augmenting the number of IPostC cycles whereas they were significantly improved by IPreC. However, analysis of individual results indicated that in approximately 1/3 of the cases IPostC exhibited some degree of protection especially in the presence of increased ischemic injury.

Conclusions

The present findings show that IPostC of the human myocardium may be influenced by the protocol used and also by the degree of the preceding ischemic injury. IPostC was beneficial in approximately 1/3 of the cases; however in the remaining cases it increased ischemic damage and, therefore, these results raise a word of caution on its broad clinical use.

Long-term effects of ischemic postconditioning on clinical outcomes: 1-year follow-up of the POST randomized trial

BACKGROUND

In the Effects of Postconditioning on Myocardial Reperfusion in Patients with ST-segment Elevation Myocardial Infarction (POST) trial, ischemic postconditioning failed to improve myocardial reperfusion. However, long-term effects of ischemic postconditioning on clinical outcomes are not known in patients with ST-segment elevation myocardial infarction.

METHODS

A total of 700 patients undergoing primary percutaneous coronary intervention (PCI) were randomly assigned to the postconditioning group or the conventional primary PCI group in a 1:1 ratio. Postconditioning was performed immediately after restoration of coronary flow by balloon occlusion 4 times for 1 minute. Complete follow-up data for major clinical events at 1 year were available in 695 patients (99.3%), and analyses were done by the intention to treat principle. The primary outcome was a composite of death, myocardial infarction, severe heart failure, or stent thrombosis at 1 year.

RESULTS

At 1 year, a composite of death, myocardial infarction, severe heart failure, or stent thrombosis occurred in 21 patients (6.1%) in the postconditioning group and 16 patients (4.6%) in the conventional PCI group (hazard ratio [HR] 1.32, 95% CI 0.69-2.53, P = .40). The risk of death (4.9% vs 3.7%, HR 1.32, 95% CI 0.64-2.71, P = .46), heart failure (2.6% vs 2.3%, HR 1.13, 95% CI 0.44-2.94, P = .80), and stent thrombosis (2.3% vs 1.7%, HR 1.34, 95% CI 0.46-3.85, P = .59) did not differ significantly between the 2 groups.

CONCLUSIONS

Ischemic postconditioning does not seem to improve the 1-year clinical outcomes in patients with ST-segment elevation myocardial infarction undergoing primary PCI.

Cardiac function in a long-term follow-up study of moderate and severe porcine model of chronic myocardial infarction

BACKGROUND

Novel therapies need to be evaluated in a relevant large animal model that mimics the clinical course and treatment in a reasonable time frame. To reliably assess therapeutic efficacy, knowledge regarding the translational model and the course of disease is needed.

METHODS

Landrace pigs were subjected to a transient occlusion of the proximal left circumflex artery (LCx) (n = 6) or mid-left anterior descending artery (LAD) (n = 6) for 150 min. Cardiac function was evaluated before by 2D echocardiography or 3D echocardiography and pressure-volume loop analysis. At 12 weeks of follow-up the heart was excised for histological analysis and infarct size calculations.

RESULTS

Directly following AMI, LVEF was severely reduced compared to baseline in the LAD group (-17.1 ± 1.6%, P = 0.009) compared to only a moderate reduction in the LCx group (-5.9 ± 1.5%, P = 0.02) and this effect remained unchanged during 12 weeks of follow-up.

CONCLUSION

Two models of chronic MI, representative for different patient groups, can reproducibly be created through clinically relevant ischemia-reperfusion of the mid-LAD and proximal LCx.

Remote ischemic preconditioning reduces perioperative cardiac and renal events in patients undergoing elective coronary intervention: a meta-analysis of 11 randomized trials

Background

Results from randomized controlled trials (RCT) concerning cardiac and renal effect of remote ischemic preconditioning(RIPC) in patients with stable coronary artery disease(CAD) are inconsistent. The aim of this study was to explore whether RIPC reduce cardiac and renal events after elective percutaneous coronary intervention (PCI).

Methods and Results

RCTs with data on cardiac or renal effect of RIPC in PCI were searched from Pubmed, EMBase, and Cochrane library (up to July 2014). Meta-regression and subgroup analysis were performed to identify the potential sources of significant heterogeneity(I²≥40%). Eleven RCTs enrolling a total of 1713 study subjects with stable CAD were selected. Compared with controls, RIPC significantly reduced perioperative incidence of myocardial infarction (MI) [odds ratio(OR)  = 0.68; 95% CI, 0.51 to 0.91; P = 0.01; I² = 41.0%] and contrast-induced acute kidney injury(AKI) (OR = 0.61; 95% CI, 0.38 to 0.98; P = 0.04; I² = 39.0%). Meta-regression and subgroup analyses confirmed that the major source of heterogeneity for the incidence of MI was male proportion (coefficient  = −0.049; P = 0.047; adjusted R² = 0.988; P = 0.02 for subgroup difference).

Conclusions

The present meta-analysis of RCTs suggests that RIPC may offer cardiorenal protection by reducing the incidence of MI and AKI in patients undergoing elective PCI. Moreover, this effect on MI is more pronounced in male subjects. Future high-quality, large-scale clinical trials should focus on the long-term clinical effect of RIPC.

Ischaemic postconditioning reduces infarct size: systematic review and meta-analysis of randomized controlled trials

BACKGROUND

Infarct size (IS) is a major determinant of patient outcome after acute ST-segment elevation myocardial infarction (STEMI). Interventions aimed at reducing reperfusion injury, such as cardiac ischaemic postconditioning (IPost), may reduce IS and improve clinical outcomes. IPost has been shown to be feasible in patients with STEMI treated by primary percutaneous coronary intervention (PPCI).

AIMS

To provide an updated summary of the efficacy of IPost, assessed by analysing accurate surrogate markers of IS.

METHODS

We performed a meta-analysis of randomized controlled trials that evaluated the efficacy of IPost in STEMI patients undergoing PPCI. The main outcome was area under the curve of serum creatine kinase release (CK-AUC). Secondary outcomes were other surrogate biomarkers of IS, complete ST-segment resolution, direct measurement of IS by single-photon emission computed tomography and estimation of IS by cardiac magnetic resonance (CMR-IS).

RESULTS

Eleven studies were retrieved, including 1313 STEMI patients undergoing PPCI with or without IPost. Compared with controls, we observed a significant reduction in CK-AUC (standard mean difference [SMD] -2.84 IU/L, 95% CI -5.43 to -0.25 IU/L; P=0.03). Other surrogate markers, such as CMR-IS (SMD -0.36, 95% CI -0.88 to 0.15; P=0.16), showed a non-significant IS reduction in the IPost group.

CONCLUSIONS

This meta-analysis, dealing with accurate surrogate markers of IS, suggests that IPost reduces IS. However, results should be interpreted cautiously because of limited sample sizes and significant heterogeneity. Whether this translates into improvements in cardiac function and patient prognosis still needs to be demonstrated in larger prospective randomized controlled studies that are powered sufficiently.

Sevoflurane in acute myocardial infarction: a pilot randomized study

BACKGROUND

Experimental evidence suggests that the inhalational anesthetic sevoflurane has a cardioprotective effect. Our objective was to determine if sedation with sevoflurane will reduce infarct size in patients with acute myocardial infarction (MI) who are treated with primary percutaneous coronary intervention (PCI).

METHODS

We randomized 50 patients presenting with a first acute ST-elevation MI treated by primary PCI within 6 hours from symptom onset to sedation with sevoflurane inhalation or standard sedation (control). Coronary flow at the end of PCI was assessed by corrected Thrombolysis In Myocardial Infarction frame count. Myocardial reperfusion was assessed by ST-segment resolution 60 minutes post-PCI. Infarct size was assessed by release of creatinine kinase (CK) and troponin T.

RESULTS

There was no difference in the primary end point: troponin T or CK release adjusted to the area at risk, between groups. However, among patients with anterior MI, there was a trend toward lower CK (P = .05) and nonsignificant decrease in troponin (P = .11) levels in the sevoflurane group. Corrected Thrombolysis In Myocardial Infarction frame count was 12.3 ± 1.5 in the sevoflurane group and 15.6 ± 9.1 in the control group (P = .16). There was more ST resolution in patients treated by sevoflurane 80.7% ± 25.8% versus 56.6% ± 35.7% (P = .01). Sevoflurane had no significant adverse effect during administration.

CONCLUSIONS

Sevoflurane administration during primary PCI did not reduce infarct size. There was a trend toward a reduction in infarct size among patients with anterior MI. Sevoflurane administration was associated with improvement in ST-segment resolution.

Cardioprotective role of ischemic postconditioning in acute myocardial infarction: a systematic review and meta-analysis

BACKGROUND

Evidence suggests that ischemic postconditioning (IPoC) may reduce the extent of reperfusion injury. We performed a meta-analysis of randomized controlled trials, which compared the role of IPoC during primary percutaneous coronary intervention (PCI) to PCI alone (control group) in ST-segment elevation myocardial infarction.

METHODS

Several databases were searched, which yielded 19 studies. The outcomes of interest were measures of myocardial damage (serum cardiac enzymes and infarct size by imaging) and left ventricular function (left ventricular ejection fraction and wall motion score index). Mean difference (MD) and standardized mean difference (SMD) were used to assess the treatment effect. An inverse variance method was used to pool data into a random-effects model.

RESULTS

Ischemic postconditioning demonstrated a decrease in serum cardiac enzymes (SMD -0.48, 95% CI -0.92 to -0.05, I(2) = 92%), reduction in infarct size by imaging (SMD -0.30, 95% CI -0.58 to -0.01, I(2) = 80%), wall motion score index (MD -0.19, 95% CI -0.29 to -0.09, I(2) = 44%), and showed improvement in left ventricular ejection fraction (IPoC 52 ± 0.4, control 49.7 ± 0.4) (MD 2.78, 95% CI 0.66-4.91, I(2) = 69%). All included studies were limited by high risk of performance and publication bias.

CONCLUSIONS

Ischemic postconditioning during PCI in ST-segment elevation myocardial infarction appears to be superior to PCI alone in reduction of both myocardial injury or damage and improvement in global and regional left ventricular function. The effect seems to be more pronounced when a greater myocardial area is at risk. Given the limitations of the current available evidence, additional data from large randomized controlled trials are warranted.

Meta-analysis of randomized trials of postconditioning in ST-elevation myocardial infarction

Clinical benefit of postconditioning in patients with ST-elevation myocardial infarction (STEMI) treated by primary percutaneous coronary intervention is still controversial. We performed a meta-analysis of available randomized clinical trials (RCTs) to define the role of postconditioning in STEMI. Fourteen RCTs evaluating postconditioning in a total of 778 patients with STEMI were identified in PubMed, EMBase, and Cochrane databases from January 1998 to February 2014. Overall, postconditioning was found to be cardioprotective in term of infarct size reduction (weighted standardized mean differences -0.5837, 95% confidence interval -0.9609 to -0.2066, p <0.05), but significant heterogeneity across the trials was detected (I(2) = 84%). Univariate meta-regression analysis did not identify clinical or procedural variables associated with a more pronounced effect of postconditioning effects on infarct size with the exception of using cardiac magnetic resonance (CMR) to evaluate infarct size (p <0.01). Restricting the analysis to 6 RCTs including a total of 448 patients and evaluating the postconditioning effect on infarct size by means of CMR led to the disappearance of benefit of postconditioning on infarct size. In conclusion, the results of this meta-analysis of RCTs suggested that postconditioning reduces infarct size, as expressed by weighted standardized mean differences. However, if the analysis was limited to trials with a more accurate quantification of infarct size reduction, namely by CMR, the benefit was lost. More data are required before adoption of postconditioning in clinical practice.

Surrogate and clinical outcomes following ischemic postconditioning during primary percutaneous coronary intervention of ST--segment elevation myocardial infarction: a meta-analysis of 15 randomized trials

OBJECTIVES

To conduct a meta-analysis on surrogate and clinical outcomes with myocardial ischemic postconditioning (IPoC) following revascularization with primary percutaneous intervention (PPCI) for ST-segment myocardial infarction (STEMI) compared with PPCI alone.

BACKGROUND

Reperfusion injury remains an important problem following PPCI for STEMI. Trials of IPoC have mainly focused on cardiac biomarkers; the impact on clinical outcomes is unknown.

METHODS

Clinical trials that randomized STEMI patients to IPoC as compared with conventional PPCI were included for analysis.

RESULTS

A total of 15 randomized trials with 1,545 patients met our selection criteria (785 underwent IPoC + PPCI, 760 PPCI alone). Mean follow-up for clinical outcomes was 4.7 months. The mean ischemic time was 225 min. ST-segment resolution (Relative Risk [RR] = 0.98; 95% Confidence Intervals [CI] 0.85-1.13; P = 0.75) and infarct size (Weighted mean difference [WMD] = -2.53%, 95% CI -6.10 to 1.05; P = 0.17) were similar between the IPoC + PPCI vs. PPCI arms. Left ventricular ejection fraction at follow-up was marginally higher in the IPoC (WMD = 4.15%, 95% CI 0.19-8.12%, P = 0.04). No differences were noted in any of the clinical outcomes studied, including mortality (RR = 1.52; 95% CI 0.77-2.99; P = 0.23), recurrent MI (RR = 3.04; 95% CI 0.74-12.54; P = 0.12); stent thrombosis (RR = 1.24, 95% CI 0.51-3.04; P = 0.83) or the composite MACE outcome (RR = 1.53; 95% CI 0.89-2.63; P = 0.13).

CONCLUSIONS

IPoC following PPCI is not associated with improvements in surrogate or clinical outcomes at 5 months as compared with PPCI alone. Our findings indicate no role for IPoC in the routine management of patients with STEMI.

Remote ischemic postconditioning during percutaneous coronary interventions: remote ischemic postconditioning-percutaneous coronary intervention randomized trial

BACKGROUND

Remote ischemic preconditioning may result in reduction in infarct size during percutaneous coronary intervention (PCI). It is unclear whether remote ischemic postconditioning (RIPost) will reduce the incidence of myocardial injury after PCI, and whether ischemic conditioning of a larger remote organ (thigh versus arm) would provide further myocardial protection.

METHODS AND RESULTS

We randomized 360 patients presenting with stable or unstable angina (28% of patients) and negative Troponin T at baseline to 3 groups: 2 groups received RIPost (induced by ischemia to upper or lower limb), and a third was the control group. RIPost was applied during PCI immediately after stent deployment, by three 5-minute cycles of blood pressure cuff inflation to >200 mm Hg in the arm or thigh (20 mm Hg in the control) with 5-minute breaks between each cycle. The primary end-point was the proportion of patients with Troponin T levels >3×ULN postprocedure (at 6 or 18-24 hours), where ULN stands for upper limit of normal. A total of 120 patients were randomized to each group. There were no differences in baseline characteristics between the 3 groups. The primary outcome occurred in 30%, 35%, and 35% of the arm, thigh, and control groups, respectively (P=0.64). There were no differences in creatine kinase or high sensitivity C-reactive protein levels after PCI or in the incidence of acute kidney injury between the groups.

CONCLUSIONS

RIPost during PCI did not reduce the incidence of periprocedural myocardial injury. Similar effect was obtained when remote ischemia was induced to the upper or lower limb.

CLINICAL TRIAL REGISTRATION URL

http://www.clinicaltrials.gov. Unique identifier: NCT00970827.