Up-regulated novel-miR-17 promotes hypothermic reperfusion arrhythmias by negatively targeting Gja1 and mediating activation of the PKC/c-Jun signaling pathway

BACKGROUND

Hypothermic ischemia-reperfusion arrhythmia is a common complication of cardiothoracic surgery under cardiopulmonary bypass, but few studies have focused on this type of arrhythmia. Our prior study discovered reduced myocardial Cx43 protein levels may be linked to hypothermic reperfusion arrhythmias. However, more detailed molecular mechanism research is required.

METHOD

The microRNA and mRNA expression levels in myocardial tissues were detected by real-time quantitative PCR (RT-qPCR). Besides, the occurrence of hypothermic reperfusion arrhythmias and changes in myocardial electrical conduction were assessed by electrocardiography and ventricular epicardial activation mapping. Furthermore, bioinformatics analysis, applying antagonists of miRNA, western blotting, immunohistochemistry, a dual luciferase assay, and pearson correlation analysis were performed to investigate the underlying molecular mechanisms.

RESULTS

The expression level of novel-miR-17 was up-regulated in hypothermic ischemia-reperfusion myocardial tissues. Inhibition of novel-miR-17 upregulation ameliorated cardiomyocyte edema, reduced apoptosis, increased myocardial electrical conduction velocity, and shortened the duration of reperfusion arrhythmias. Mechanistic studies showed that novel-miR-17 reduced the expression of Cx43 by directly targeting Gja1 while mediating the activation of the PKC/c-Jun signaling pathway.

CONCLUSION

Up-regulated novel-miR-17 is a newly discovered pro-arrhythmic microRNA that may serve as a potential therapeutic target and biomarker for hypothermic reperfusion arrhythmias.

Del Nido cardioplegia versus cold blood cardioplegia in adult cardiac surgery: a meta-analysis of randomized clinical trials

OBJECTIVE

Systematic evaluation of the safety of del Nido cardioplegia compared to cold blood cardioplegia in adult cardiac surgery.

METHODS

We systematically searched PubMed, EMbase, The Cochrane Library and ClinicalTrials.gov for randomized clinical trials (published by 14 January 2024) comparing del Nido cardioplegia to cold blood cardioplegia in adult. Our main endpoints were myocardial injury markers and clinical outcomes. We assessed pooled data by use of a random-effects model or a fixed-effects model.

RESULTS

A total of 10 studies were identified, incorporating 889 patients who received del Nido cardioplegia and 907 patients who received cold blood cardioplegia. The meta-analysis results showed that compared with the cold blood cardioplegia, the del Nido cardioplegia had less volume of cardioplegia, higher rate of spontaneous rhythm recovery after cross clamp release, lower levels of postoperative cardiac troponin T and creatinine kinase-myocardial band, all of which were statistically significant. However, there was no statistically significant difference in postoperative troponin I and postoperative left ventricular ejection fraction. The clinical outcomes including mechanical ventilation time, intensive care unit stay time, hospital stay time, postoperative stroke, postoperative new-onset atrial fibrillation, postoperative heart failure requiring intra-aortic balloon pump mechanical circulation support, and in-hospital mortality of both are comparable.

CONCLUSION

Existing evidence suggests that del Nido cardioplegia reduced volume of cardioplegia administration and attempts of defibrillation. The superior postoperative results in CTnT and CK-MB may provide a direction for further research on improvement of the composition of cardioplegia.

European Association of Cardio-Thoracic Surgery (EACTS) expert consensus statement on perioperative myocardial infarction after cardiac surgery

Cardiac surgery may lead to myocardial damage and release of cardiac biomarkers through various mechanisms such as cardiac manipulation, systemic inflammation, myocardial hypoxia, cardioplegic arrest and ischaemia caused by coronary or graft occlusion. Defining perioperative myocardial infarction (PMI) after cardiac surgery presents challenges, and the association between the current PMI definitions and postoperative outcomes remains uncertain. To address these challenges, the European Association of Cardio-Thoracic Surgery (EACTS) facilitated collaboration among a multidisciplinary group to evaluate the existing evidence on the mechanisms, diagnosis and prognostic implications of PMI after cardiac surgery. The review found that the postoperative troponin value thresholds associated with an increased risk of mortality are markedly higher than those proposed by all the current definitions of PMI. Additionally, it was found that large postoperative increases in cardiac biomarkers are prognostically relevant even in absence of additional supportive signs of ischaemia. A new algorithm for PMI detection after cardiac surgery was also proposed, and a consensus was reached within the group that establishing a prognostically relevant definition of PMI is critically needed in the cardiovascular field and that PMI should be included in the primary composite outcome of coronary intervention trials.

The New Delivery Method for Cardioplegic Solution in Type A Aortic Dissection

Adequate myocardial protection is crucial for a successful cardiac surgery. In type A aortic dissection, standard methods of delivery of cardioplegic solution may not be adequately effective. Ineffectiveness may happen due to both features of the anatomy of the dissection and to peculiarities of the delivery method itself. We present a new method of delivering a cardioplegic solution using a Foley catheter through the orifice of the brachiocephalic trunk or the left common carotid artery.

Which is better for pediatric and adult cardiac surgery: del Nido or St. Thomas cardioplegia? A systematic review and meta-analysis

Background

Although recently it has been extended for use in adult cardiac surgery, del Nido cardioplegia was originally indicated for pediatric cardiac surgery. In this meta-analysis, we compare del Nido cardioplegia vs St. Thomas cardioplegia in pediatric and adult cardiac surgery.

Methods

A comprehensive systematic literature review was performed to identify observational and randomized controlled trials (RCTs) comparing del Nido cardioplegia with St. Thomas cardioplegia. An analysis of both random and fixed effects was conducted. The measure of the effect was by the mean difference (MD) and the risk ratio (RR) with a 95% confidence interval (95% CI).

Results

A total of 1893 patients from 12 studies were included (5 RCTs and 7 observational studies). Compared to St. Thomas solution, del Nido cardioplegia was associated with a shorter aortic cross-clamp in adult cardiac surgery (RCT MD - 19.83, 95% CI - 21.89-17.78; observational - 5.85; 95% CI - 11.59, - 0.11 respectively), but no difference in pediatric cardiac surgery. Additionally, del Nido cardioplegia was associated with lower cardiopulmonary bypass time in both adults (observational, MD - 29.15; 95% CI - 31.76-26.55) and pediatric cardiac surgery (RCTs, MD - 7.15; 95% CI - 13.25-1.05). Defibrillation rates were also significantly lower with del Nido cardioplegia group in both adult (RR 0.35, 95% CI 0.24-0.50, I2 = 50%) and pediatric cardiac surgery (odds ratio (OR) 0.30, 95% CI 0.18-0.49, I2 = 92%).

Conclusion

In both adults and pediatric cardiac surgery, del Nido cardioplegia helps in lowering cardiopulmonary bypass duration, defibrillation rates, and hospital stay, compared to St. Thomas solution. Among adults, del Nido cardioplegia lessens the aortic cross clamp times with no difference observed in all-cause mortality, intensive care unit stay, or mechanical ventilation.

Considerations on the Management of Acute Postoperative Ischemia After Cardiac Surgery: A Scientific Statement From the American Heart Association

Acute postoperative myocardial ischemia (PMI) after cardiac surgery is an infrequent event that can evolve rapidly and become a potentially life-threatening complication. Multiple factors are associated with acute PMI after cardiac surgery and may vary by the type of surgical procedure performed. Although the criteria defining nonprocedural myocardial ischemia are well established, there are no universally accepted criteria for the diagnosis of acute PMI. In addition, current evidence on the management of acute PMI after cardiac surgery is sparse and generally of low methodological quality. Once acute PMI is suspected, prompt diagnosis and treatment are imperative, and options range from conservative strategies to percutaneous coronary intervention and redo coronary artery bypass grafting. In this document, a multidisciplinary group including experts in cardiac surgery, cardiology, anesthesiology, and postoperative care summarizes the existing evidence on diagnosis and treatment of acute PMI and provides clinical guidance.

The Use of Cardioprotective Devices and Strategies in Patients Undergoing Percutaneous Procedures and Cardiac Surgery

In the United States, about one million people are seen to visit the operating theater for cardiac surgery annually. However, nearly half of these visits result in complications such as renal, neurological, and cardiac injury of varying degrees. Historically, many mechanisms and approaches have been explored in attempts to reduce injuries associated with cardiac surgery and percutaneous procedures. Devices such as cardioplegia, mechanical circulatory support, and other methods have shown promising results in managing and preventing life-threatening cardiac-surgery-related outcomes such as heart failure and cardiogenic shock. Comparably, cardioprotective devices such as TandemHeart, Impella family devices, and venoarterial extracorporeal membrane oxygenation (VA-ECMO) have also been proven to show significant cardioprotection through mechanical support. However, their use as interventional agents in the prevention of hemodynamic changes due to cardiac surgery or percutaneous interventions has been correlated with adverse effects. This can lead to a rebound increased risk of mortality in high-risk patients who undergo cardiac surgery. Further research is necessary to delineate and stratify patients into appropriate cardioprotective device groups. Furthermore, the use of one device over another in terms of efficacy remains controversial and further research is necessary to assess device potential in different settings. Clinical research is also needed regarding novel strategies and targets, such as transcutaneous vagus stimulation and supersaturated oxygen therapy, aimed at reducing mortality among high-risk cardiac surgery patients. This review explores the recent advances regarding the use of cardioprotective devices in patients undergoing percutaneous procedures and cardiac surgery.

Efficacy of dexmedetomidine on myocardial ischemia/reperfusion injury in patients undergoing cardiac surgery with cardiopulmonary bypass: A protocol for systematic review and meta-analysis

BACKGROUND

Cardiac surgery using cardiopulmonary bypass has been shown to cause reversible postischemic cardiac dysfunction and is associated with reperfusion injury and myocardial cell death. Therefore, it is very important to have a series of measures in place to reduce oxygen consumption and provide myocardial protection. We performed a protocol for systematic review and meta-analysis to evaluate the effect of dexmedetomidine administration on myocardial ischemia/reperfusion injury in patients undergoing cardiac surgery with cardiopulmonary bypass.

METHODS

This review protocol is registered in the PROSPERO International Prospective Register of systematic reviews, registration number CRD42023386749. A literature search is performed in January 2023 without restriction to regions, publication types or languages. The primary sources were the electronic databases of PubMed, Embase, Web of Science, the Cochrane Central Register of Controlled Trials, Chinese National Knowledge Infrastructure database, Chinese Biomedical Database, and Chinese Science and Technology Periodical database. Risk of bias will be assessed according to the Cochrane Risk of Bias Tool. The meta-analysis is performed using Reviewer Manager 5.4.

RESULTS

The results of this meta-analysis will be submitted to a peer-reviewed journal for publication.

CONCLUSION

This meta-analysis will evaluate the efficacy and safety of dexmedetomidine in patients undergoing cardiac surgery with cardiopulmonary bypass.

Cardiac Electrophysiological Changes and Downregulated Connexin 43 Prompts Reperfusion Arrhythmias Induced by Hypothermic Ischemia-Reperfusion Injury in Isolated Rat Hearts

The purpose of this study was to determine the utility of the monophasic action potential (MAP) changes as an arrhythmic biomarker in hypothermic ischemia-reperfusion. The hypothermic ischemia-reperfusion model was subjected to 60 min of cardioplegic arrest while the isolated rat hearts were preserved with a multidose cold K-H solution at 4 °C. During the reperfusion period, the heart's arrhythmia and monophasic action potential were also monitored. The myocardial damage was assessed using HE and TTC stains. Immunohistochemistry and Western blotting were used to assess the expression and distribution of Connexin 43 (Cx43) and Akt. Collectively, prolonged action potential durations, increased dispersion of repolarization, and downregulated and lateralized Cx43 all contribute to the derangement of electrical impulse propagation that may underlie arrhythmogenesis in the cold ischemic heart following cardioplegic arrest. MAP might be used as a biomarker for arrhythmias caused by hypothermic ischemia-reperfusion.

Cardioprotective Effects of Glucose-Insulin-Potassium Infusion in Patients Undergoing Cardiac Surgery: A Systematic Review and Meta-Analysis

The infusion of glucose-insulin-potassium (GIK) has yielded conflicting results in terms of cardioprotective effects. We conducted a meta-analysis to examine the impact of perioperative GIK infusion in early outcome after cardiac surgery. Randomized controlled trials (RCTs) were eligible if they examined the efficacy of GIK infusion in adults undergoing cardiac surgery. The main study endpoint was postoperative myocardial infarction (MI) and secondary outcomes were hemodynamics, any complications and hospital resources utilization. Subgroup analyses explored the impact of the type of surgery, GIK composition and timing of administration. Odds ratio (OR) or mean difference (MD) with 95% confidence interval (CI) were calculated with a random-effects model. Fifty-three studies (n=6129) met the inclusion criteria. Perioperative GIK infusion was effective in reducing MI (k=32 OR 0.66[0.48, 0.89] P=0.0069), acute kidney injury (k=7 OR 0.57[0.4, 0.82] P=0.0023) and hospital length of stay (k=19 MD -0.89[-1.63, -0.16] days P=0.0175). Postoperatively, the GIK-treated group presented higher cardiac index (k=14 MD 0.43[0.29, 0.57] L/min P<0.0001) and lesser hyperglycemia (k=20 MD -30[-47, -13] mg/dL P=0.0005) than in the usual care group. The GIK-associated protection for MI was effective when insulin infusion rate exceeded 2 mUI/kg/min and after coronary artery bypass surgery. Certainty of evidence was low given imprecision of the effect estimate, heterogeneity in outcome definition and risk of bias. Perioperative GIK infusion is associated with improved early outcome and reduced hospital resource utilization after cardiac surgery. Supporting evidence is heterogenous and further research is needed to standardize the optimal timing and composition of GIK solutions.

Theoretical and Practical Aspects in the Use of Bretschneider Cardioplegia

The race for an ideal cardioplegic solution has remained enthusiastic since the beginning of the modern cardiac surgery era. The Bretschneider solution, belonging to the “intracellular cardioplegic” group, is safe and practical in myocardial protection during ischemic time. Over time, some particular concerns have arisen regarding the effects on cardiac metabolism and postoperative myocardial functioning. This paper reviews the most important standpoints in terms of theoretical and practical analyses.

Myocardial Revascularization Surgery: JACC Historical Breakthroughs in Perspective

Coronary artery bypass grafting (CABG) was introduced in the 1960s as the first procedure for direct coronary artery revascularization and rapidly became one of the most common surgical procedures worldwide, with an overall total of more than 20 million operations performed. CABG continues to be the most common cardiac surgical procedure performed and has been one of the most carefully studied therapies. Best CABG techniques, optimal bypass conduits, and appropriate patient selection have been rigorously tested in landmark clinical trials, some of which have resolved controversy and most of which have stoked further debate and trials. The evolution of CABG cannot be properly portrayed without presenting it in the context of the parallel development of percutaneous coronary intervention. In this Historical Perspective, we a provide a broad overview of the history of coronary revascularization with a focus on the foundations, evolution, best evidence, and future directions of CABG.