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.

Protective Effect and Mechanism of Traditional Chinese Medicine on Myocardial Ischemia Reperfusion Injury

After acute myocardial infarction, early restoration of myocardial perfusion by thrombolysis or percutaneous coronary intervention is the most effective way to reduce the size of myocardial infarction and improve clinical outcomes. However, recovery of blood flow to the ischemic myocardium may cause ischemia-reperfusion (I/R) injury, a phenomenon that instead reduces the efficacy of myocardial reperfusion. Traditional Chinese medicine (TCM) has long been used for the treatment of cardiovascular diseases and has shown remarkable efficacy. Many studies have shown that some TCMs and their active components can exert protective effects against myocardial I/R injury through different mechanisms. This review summarized the protective mechanisms and current research advances of TCMs in myocardial I/R injury.

Balloon Deflation Strategy during Primary Percutaneous Coronary Intervention in Acute ST-Segment Elevation Myocardial Infarction: A Randomized Controlled Clinical Trial and Numerical Simulation-Based Analysis

Background

Primary percutaneous coronary intervention (PCI) is the best available reperfusion strategy in patients with acute ST-segment elevation myocardial infarction (STEMI). However, PCI is associated with a serious problem known as no-reflow phenomenon, resulting in poor clinical and functional outcomes. This study aimed to compare the influences of different balloon deflation velocity on coronary flow and cardiovascular events during primary PCI in STEM as well as transient hemodynamic changes in in vitro experiments. Method and Results. 211 STEMI patients were randomly assigned to either a rapid or a slow balloon deflation group during stent deployment. The primary end point was coronary flow at the end of PCI procedure, and secondary end points included myocardial infarct size. Transient hemodynamic changes were evaluated through an in vitro experimental apparatus and a computer model. In clinical practice, the level of corrected TIMI frame count (cTFC) in slow balloon deflation after primary PCI was significantly lower than that of rapid balloon deflation, which was associated with smaller infarct size. Numerical simulations revealed that the rapid deflation led to a sharp acceleration of flow in the balloon-vessel gap and a concomitant abnormal rise in wall shear stress (WSS).

Conclusion

This randomized study demonstrated that the slow balloon deflation during stent implantation improved coronary flow and reduced infarct size in reperfused STEMI. The change of flow in the balloon-vessel gap and WSS resulted from different balloon deflation velocity might be partly accounted for this results.

Formononetin may protect aged hearts from ischemia/reperfusion damage by enhancing autophagic degradation

Myocardial infarction is a leading cause of mortality worldwide, and timely blood/oxygen reperfusion may substantially improve the outcome of infarction. However, ischemia/reperfusion (I/R) may cause severe side effects through excess reactive oxygen species generation. To develop novel methods to relieve I/R induced cell damage, the present study used a component of traditional Chinese medicine. In the present study, isolated heart tissue from aged mice and H9C2 cells with chemically‑induced aging were used as experimental subjects, and it was demonstrated that formononetin was able to alleviate I/R‑induced cell or tissue apoptosis. By applying formononetin to I/R‑damaged tissue or cells, it was demonstrated that formononetin was able to enhance autophagy and thus alleviate I/R‑induced cell damage. Furthermore, it was observed that I/R was able to inhibit lysosomal degradation processes in aged tissues or cells by impairing the lysosome acidification level, and formononetin was able to reverse this process via the re‑acidification of lysosomes. In conclusion, the present study demonstrated that formononetin was able to alleviate I/R‑induced cellular apoptosis in aged cells by facilitating autophagy.

A systematic review and meta-analysis evaluating ischemic conditioning during percutaneous coronary intervention

AIM

A systematic review and meta-analysis, evaluating ischemic conditioning during percutaneous coronary intervention (PCI).

METHODS & RESULTS

A database search of randomized trials of ischemic conditioning in PCI created three subgroups for meta-analysis: mortality in elective PCI with remote ischemic preconditioning (RIPreC; subgroup 1a, n = 3) - no outcome difference between RIPreC and control (odds ratio: 0.34; 95% CI: 0.08-1.56), myocardial salvage index in ST-elevation myocardial infarction (STEMI) with RIPreC (subgroup 1b, n = 2) - favored RIPreC (mean difference: 0.13; 95% CI: 0.07-0.19), and infarct size in STEMI with local ischemic postconditioning (LIPostC) (subgroup 4b, n = 12) - favored LIPostC (mean difference: -4.13 g.m^-2; 95% CI: -7.36 to -0.90 g.m^-2).

CONCLUSION

RIPreC and LIPostC improve myocardial salvage index and myocardial infarct size respectively in PCI for STEMI. No mortality benefit detected with RIPreC in elective PCI.

Clinical effect of postconditioning in ST-elevation myocardial infarction patients treated with primary percutaneous coronary intervention: a meta-analysis of randomized controlled trials

OBJECTIVE

To evaluate the clinical effect of postconditioning on patients with ST-elevation myocardial infarction (STEMI) treated with primary percutaneous coronary intervention (PCI).

METHODS

Randomized controlled trials were identified by searching relevant databases published up to April 2nd, 2014. A meta-analysis of eligible studies was performed by Stata 12.0 and Review Manager 5.2 with a fixed-effect model.

RESULTS

Ten studies providing adverse cardiac events in a total of 1346 STEMI patients treated with primary PCI were identified. The occurrence of heart failure was significantly reduced in patients treated with postconditioning compared with usual care (risk ratio (RR) 0.533; 95% confidence intervals (CI) 0.368-0.770), whereas non-fatal reinfarction slightly increased in the postconditioning group (RR 2.746; 95% CI 1.007-7.488). No significant difference in total major adverse cardiac events (MACEs) was observed between the two groups (RR 0.876; 95% CI 0.671-1.144).

CONCLUSIONS

Postconditioning in STEMI patients undergoing primary PCI significantly reduces the risk of heart failure, but fails to decrease the incidence of total MACEs and the risk of non-fatal reinfarction.

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.

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.

Targeting mitochondria for cardioprotection: examining the benefit for patients

ABSTRACT: 

Mitochondria are critical for sustaining life, not only as the essential powerhouses of cells but as critical mediators of cell survival and death. Mitochondrial dysfunction has been identified as a key perturbation underlying numerous pathologies including myocardial ischemia–reperfusion injury and the subsequent development of impaired left ventricular systolic function and compensatory cardiac hypertrophy. This article outlines the role of mitochondrial dysfunction in these important cardiac pathologies and highlights current cardioprotective strategies and their clinical efficacy in acute myocardial infarction and heart failure patients. Finally, we explore novel mitochondrial targets and evaluate their potential future translation for clinical cardioprotection.

Cardioprotective effect of remote ischemic postconditioning on children undergoing cardiac surgery: a randomized controlled trial

BACKGROUND

Remote ischemic postconditioning (RPostC) is a noninvasive intervention that has demonstrated cardioprotection and neuroprotection in animal studies.

OBJECTIVE

Our goal was to investigate the cardio-cerebral protective effects of RPostC on children undergoing open-heart surgery for repair of congenital heart defects (CHD).

METHODS

Children undergoing open-heart repair of CHD were randomly assigned to a RPostC or control group. RPostC was induced by three 5-min cycles of lower limb ischemia and reperfusion using a blood pressure cuff (200 mmHg) at the onset of aortic unclamping. Serum cardiac troponin I (cTnI), creatine kinase-MB (CK-MB), neuron-specific enolase (NSE), S100β, cytokines, and clinical outcomes were assessed.

RESULTS

There were 35 children in the control group and 34 in the RPostC group. The mean age (3.64 ± 1.95 years vs. 3.45 ± 3.02 years, P = 0.80), weight (15.11 ± 6.91 kg vs. 13.40 ± 6.33 kg, P = 0.37), surgical time (144.82 ± 38.51 min vs. 129.92 ± 30.76 min, P = 0.15), and bypass time (78.01 ± 27.22 min vs. 72.52 ± 26.05 min, P = 0.49) were not different. Compared with the control group, the postoperative levels of cTnI (P = 0.037) and CK-MB (P = 0.046) were significantly reduced in the RPostC group. Furthermore, the MAP was higher (P = 0.008), and ICU stay (36.87 ± 3.30 h vs. 60.57 ± 7.35 h, P = 0.006) and postoperative hospital stay (8.56 ± 1.50 days vs. 10.06 ± 2.41 days, P = 0.048) were shorter in the RPostC group than in the control group. However, the postoperative CVP and the concentrations of NSE, S100β, CRP, TNF-α, IL-1β, IL-6, and IL-10 were not significantly different.

CONCLUSION

RPostC significantly alleviates cardiac injury in children undergoing open-heart repair of CHD and may also reduce cerebral injury.

Discharge after primary angioplasty at 24 h: feasible and safe or a step too far?

Current clinical practice regarding surveillance period and length of hospital stay after an ST elevation myocardial infarction is very variable among different countries and hospitals. In general, there has been a significant reduction in length of stay overall, which is mainly due to the increasing use of primary percutaneous coronary intervention. Length of stay after a ST elevation myocardial infaction, which is a rather common event, has a major impact on health care costs and patients' quality of life. We try to evaluate how far we could push the limits.