Early Intravenous Beta-Blockers in Patients With ST-Segment Elevation Myocardial Infarction Before Primary Percutaneous Coronary Intervention

Development and translation of thiometallate sulfide donors using a porcine model of coronary occlusion and reperfusion

Sulfide-releasing compounds reduce reperfusion injury by decreasing mitochondria-derived reactive oxygen species production. We previously characterised ammonium tetrathiomolybdate (ATTM), a clinically used copper chelator, as a sulfide donor in rodents. Here we assessed translation to large mammals prior to clinical testing. In healthy pigs an intravenous ATTM dose escalation revealed a reproducible pharmacokinetic/pharmacodynamic (PK/PD) relationship with minimal adverse clinical or biochemical events. In a myocardial infarction (1-h occlusion of the left anterior descending coronary artery)-reperfusion model, intravenous ATTM or saline was commenced just prior to reperfusion. ATTM protected the heart (24-h histological examination) in a drug-exposure-dependent manner (r2 = 0.58, p < 0.05). Blood troponin T levels were significantly (p < 0.05) lower in ATTM-treated animals while myocardial glutathione peroxidase activity, an antioxidant selenoprotein, was elevated (p < 0.05). Overall, our study represents a significant advance in the development of sulfides as therapeutics and underlines the potential of ATTM as a novel adjunct therapy for reperfusion injury. Mechanistically, our study suggests that modulating selenoprotein activity could represent an additional mode of action of sulfide-releasing drugs.

Cardioprotection in cardiovascular surgery

Since the invention of cardiopulmonary bypass, cardioprotective strategies have been investigated to mitigate ischemic injury to the heart during aortic cross-clamping and reperfusion injury with cross-clamp release. With advances in cardiac surgical and percutaneous techniques and post-operative management strategies including mechanical circulatory support, cardiac surgeons are able to operate on more complex patients. Therefore, there is a growing need for improved cardioprotective strategies to optimize outcomes in these patients. This review provides an overview of the basic principles of cardioprotection in the setting of cardiac surgery, including mechanisms of cardiac injury in the context of cardiopulmonary bypass, followed by a discussion of the specific approaches to optimizing cardioprotection in cardiac surgery, including refinements in cardiopulmonary bypass and cardioplegia, ischemic conditioning, use of specific anesthetic and pharmaceutical agents, and novel mechanical circulatory support technologies. Finally, translational strategies that investigate cardioprotection in the setting of cardiac surgery will be reviewed, with a focus on promising research in the areas of cell-based and gene therapy. Advances in this area will help cardiologists and cardiac surgeons mitigate myocardial ischemic injury, improve functional post-operative recovery, and optimize clinical outcomes in patients undergoing cardiac surgery.

Reperfusion Injury in Patients With Acute Myocardial Infarction: JACC Scientific Statement

Despite impressive improvements in the care of patients with ST-segment elevation myocardial infarction, mortality remains high. Reperfusion is necessary for myocardial salvage, but the abrupt return of flow sets off a cascade of injurious processes that can lead to further necrosis. This has been termed myocardial ischemia-reperfusion injury and is the subject of this review. The pathologic and molecular bases for myocardial ischemia-reperfusion injury are increasingly understood and include injury from reactive oxygen species, inflammation, calcium overload, endothelial dysfunction, and impaired microvascular flow. A variety of pharmacologic strategies have been developed that have worked well in preclinical models and some have shown promise in the clinical setting. In addition, there are newer mechanical approaches including mechanical unloading of the heart prior to reperfusion that are in current clinical trials.

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.

Prognostic Impact of Early Administration of β-Blockers in Critically Ill Patients with Acute Myocardial Infarction

In critically ill patients with acute myocardial infarction (AMI), the relationship between the early administration of β-blockers and the risks of in-hospital and long-term mortality remains controversial. Furthermore, there are conflicting evidences for the efficacy of the early administration of intravenous followed by oral β-blockers in AMI. We conducted a retrospective analysis of critically ill patients with AMI who received the early administration of β-blockers within 24 hours of admission. The data were extracted from the Medical Information Mart for Intensive Care IV database. We enrolled 2467 critically ill patients with AMI in the study, with 1355 patients who received the early administration of β-blockers and 1112 patients who were non-users. Kaplan-Meier survival analysis and Cox proportional hazards models showed that the early administration of β-blockers was associated with a lower risk of in-hospital mortality (adjusted hazard ratio [aHR] 0.52; 95% confidence interval [95%CI] 0.42-0.64), 1-year mortality (aHR 0.54, 95%CI 0.47-0.63), and 5-year mortality (aHR 0.60, 95%CI 0.52-0.69). Furthermore, the early administration of both oral β-blockers and intravenous β-blockers followed by oral β-blockers may reduce the mortality risk, compared with non-users. The risks of in-hospital and long-term mortality were significantly decreased in patients who underwent revascularization with the early administration of β-blockers. We found that the early administration of β-blockers could lower the risks of in-hospital and long-term mortality. Furthermore, the early administration of both oral β-blockers and intravenous β-blockers followed by oral β-blockers may reduce the mortality risk, compared with non-users. Notably, patients who underwent revascularization with the early administration of β-blockers showed the lowest risks of in-hospital and long-term mortality.

Chinese expert consensus on the diagnosis and treatment of coronary microvascular diseases (2023 Edition)

Since the four working groups of the Chinese Society of Cardiology issued first expert consensus on coronary microvascular diseases (CMVD) in 2017, international consensus documents on CMVD have increased rapidly. Although some of these documents made preliminary recommendations for the diagnosis and treatment of CMVD, they did not provide classification of recommendations and levels of evidence. In order to summarize recent progress in the field of CMVD, standardize the methods and procedures of diagnosis and treatment, and identify the scientific questions for future research, the four working groups of the Chinese Society of Cardiology updated the 2017 version of the Chinese expert consensus on CMVD and adopted a series of measures to ensure the quality of this document. The current consensus has raised a new classification of CMVD, summarized new epidemiological findings for different types of CMVD, analyzed key pathological and molecular mechanisms, evaluated classical and novel diagnostic technologies, recommended diagnostic pathways and criteria, and therapeutic strategies and medications, for patients with CMVD. In view of the current progress and knowledge gaps of CMVD, future directions were proposed. It is hoped that this expert consensus will further expedite the research progress of CMVD in both basic and clinical scenarios.

Updating a Healthcare System-wide Clinical Pathway for Managing Chest Pain and Acute Coronary Syndromes

Clinical pathways are useful tools for conveying and reinforcing best practices to standardize care and optimize patient outcomes across myriad conditions. The NewYork-Presbyterian Healthcare System has utilized a clinical chest pain pathway for more than 20 years to facilitate the timely recognition and management of patients presenting with chest pain syndromes and acute coronary syndromes. This chest pain pathway is regularly updated by an expanding group of key stakeholders, which has extended from the Columbia University Irving Medical Center to encompass the entire regional healthcare system, which includes 8 hospitals. In this 2023 update of the NewYork-Presbyterian clinical chest pain pathway, we present the key changes to the healthcare system-wide clinical chest pain pathway.

Health position paper and redox perspectives on reactive oxygen species as signals and targets of cardioprotection

The present review summarizes the beneficial and detrimental roles of reactive oxygen species in myocardial ischemia/reperfusion injury and cardioprotection. In the first part, the continued need for cardioprotection beyond that by rapid reperfusion of acute myocardial infarction is emphasized. Then, pathomechanisms of myocardial ischemia/reperfusion to the myocardium and the coronary circulation and the different modes of cell death in myocardial infarction are characterized. Different mechanical and pharmacological interventions to protect the ischemic/reperfused myocardium in elective percutaneous coronary interventions and coronary artery bypass grafting, in acute myocardial infarction and in cardiotoxicity from cancer therapy are detailed. The second part keeps the focus on ROS providing a comprehensive overview of molecular and cellular mechanisms involved in ischemia/reperfusion injury. Starting from mitochondria as the main sources and targets of ROS in ischemic/reperfused myocardium, a complex network of cellular and extracellular processes is discussed, including relationships with Ca2+ homeostasis, thiol group redox balance, hydrogen sulfide modulation, cross-talk with NAPDH oxidases, exosomes, cytokines and growth factors. While mechanistic insights are needed to improve our current therapeutic approaches, advancements in knowledge of ROS-mediated processes indicate that detrimental facets of oxidative stress are opposed by ROS requirement for physiological and protective reactions. This inevitable contrast is likely to underlie unsuccessful clinical trials and limits the development of novel cardioprotective interventions simply based upon ROS removal.

Early beta-blocker therapy improves in-hospital mortality of patients with non-ST-segment elevation myocardial infarction - a meta-analysis

BACKGROUND

Although current guidelines endorse early beta-blocker therapy in stable patients with STEMI, there is no clear recommendation on the early use of these drugs in patients with NSTEMI.

METHODS

Literature search was conducted by 3 independent researchers using PubMed/MEDLINE, CDSR, CENTRAL, CCAs, EBM Reviews, Web of Science and LILACS. Studies were eligible if (P) patients included were ≥ 18 years of age and had non-ST-segment elevation myocardial infarction (NSTEMI), (I) early (<24 h) treatment with intravenous or oral beta-blockers was compared to (C) no treatment with beta-blockers and data on (O) in-hospital mortality and/or in-hospital cardiogenic shock were depicted. Odds ratios and 95% confidence intervals were calculated using random effects models with the Mantel-Haenszel method. The Hartung-Knapp-Sidik-Jonkman method was used as estimator for τ2.

RESULTS

977 records were screened for eligibility, which led to the inclusion of 4 retrospective, nonrandomized, observational cohort studies comprising a total of N = 184,951 patients. After pooling of the effect sizes, early therapy with beta-blockers resulted in a reduction of in-hospital mortality (OR 0.43 [0.36-0.51], p = 0.0022) despite no significant effect on the prevalence of cardiogenic shock (OR 0.36 [0.07-1.91], p = 0.1196).

CONCLUSION

Early treatment with beta-blockers was associated with an attenuation of in-hospital mortality despite no increase in cardiogenic shock. Thus, early therapy with these drugs could elicit beneficial effects on top of reperfusion therapy, similar to the effects seen in STEMI-patients. The low number of studies (k = 4) has to be considered when interpreting the findings of this analysis.

Dapagliflozin attenuates high glucose-and hypoxia/reoxygenation-induced injury via activating AMPK/mTOR-OPA1-mediated mitochondrial autophagy in H9c2 cardiomyocytes

This study investigated the protective effect of dapagliflozin on H9c2 cardiomyocyte function under high glucose and hypoxia/reoxygenation (HG-H/R) conditions and identified the underlying molecular mechanisms. Dapagliflozin reduced the level of lactate dehydrogenase and reactive oxygen species in cardiomyocytes under HG-H/R conditions and was accompanied by a decrease in caspase-3/9 activity. In addition, Dapagliflozin significantly reduced mitochondrial permeability transition pore opening and increased ATP content, accompanied by upregulation of OPA1 with autophagy-related protein molecules and activation of the AMPK/mTOR signalling pathway in HG-H/R treated cardiomyocytes. OPA1 knockdown or compound C treatment attenuated the protective effects of dapagliflozin on the cardiomyocytes under HG-H/R conditions. Downregulation of OPA1 expression increased mitochondrial intolerance in cardiomyocytes during HG-H/R injury and the AMPK-mTOR-autophagy signalling is a key mechanism for protecting mitochondrial function and reducing cardiomyocyte apoptosis. Collectively, dapagliflozin exerted protective effects on the cardiomyocytes under HG-H/R conditions. Dapagliflozin attenuated myocardial HG-H/R injury by activating AMPK/mTOR-OPA1-mediated mitochondrial autophagy.

Coronary No-Reflow after Primary Percutaneous Coronary Intervention-Current Knowledge on Pathophysiology, Diagnosis, Clinical Impact and Therapy

Coronary no-reflow (CNR) is a frequent phenomenon that develops in patients with ST-segment elevation myocardial infarction (STEMI) following reperfusion therapy. CNR is highly dynamic, develops gradually (over hours) and persists for days to weeks after reperfusion. Microvascular obstruction (MVO) developing as a consequence of myocardial ischemia, distal embolization and reperfusion-related injury is the main pathophysiological mechanism of CNR. The frequency of CNR or MVO after primary PCI differs widely depending on the sensitivity of the tools used for diagnosis and timing of examination. Coronary angiography is readily available and most convenient to diagnose CNR but it is highly conservative and underestimates the true frequency of CNR. Cardiac magnetic resonance (CMR) imaging is the most sensitive method to diagnose MVO and CNR that provides information on the presence, localization and extent of MVO. CMR imaging detects intramyocardial hemorrhage and accurately estimates the infarct size. MVO and CNR markedly negate the benefits of reperfusion therapy and contribute to poor clinical outcomes including adverse remodeling of left ventricle, worsening or new congestive heart failure and reduced survival. Despite extensive research and the use of therapies that target almost all known pathophysiological mechanisms of CNR, no therapy has been found that prevents or reverses CNR and provides consistent clinical benefit in patients with STEMI undergoing reperfusion. Currently, the prevention or alleviation of MVO and CNR remain unmet goals in the therapy of STEMI that continue to be under intense research.

No robust reduction of infarct size and no-reflow by metoprolol pretreatment in adult Göttingen minipigs

Whereas prior experiments in juvenile pigs had reported infarct size reduction by intravenous metoprolol early during myocardial ischaemia, two major clinical trials in patients with reperfused acute myocardial infarction were equivocal. We, therefore, went back and tested the translational robustness of infarct size reduction by metoprolol in minipigs. Using a power analysis-based prospective design, we pretreated 20 anaesthetised adult Göttingen minipigs with 1 mg kg-1 metoprolol or placebo and subjected them to 60-min coronary occlusion and 180-min reperfusion. Primary endpoint was infarct size (triphenyl tetrazolium chloride staining) as a fraction of area at risk; no-reflow area (thioflavin-S staining) was a secondary endpoint. There was no significant reduction in infarct size (46 ± 8% of area at risk with metoprolol vs. 42 ± 8% with placebo) or area of no-reflow (19 ± 21% of infarct size with metoprolol vs. 15 ± 23% with placebo). However, the inverse relationship between infarct size and ischaemic regional myocardial blood flow was modestly, but significantly shifted downwards with metoprolol, whereas ischaemic blood flow tended to be reduced by metoprolol. With an additional dose of 1 mg kg-1 metoprolol after 30-min ischaemia in 4 additional pigs, infarct size was also not reduced (54 ± 9% vs. 46 ± 8% in 3 contemporary placebo, n.s.), and area of no-reflow tended to be increased (59 ± 20% vs. 29 ± 12%, n.s.).Infarct size reduction by metoprolol in pigs is not robust, and this result reflects the equivocal clinical trials. The lack of infarct size reduction may be the result of opposite effects of reduced infarct size at any given blood flow and reduced blood flow, possibly through unopposed alpha-adrenergic coronary vasoconstriction.

Rationale and design of the RESTORE trial: A multicenter, randomized, double-blinded, parallel-group, placebo-controlled trial to evaluate the effect of Shenfu injection on myocardial injury in STEMI patients after primary PCI

BACKGROUND

The mortality following ST-segment elevation myocardial infarction (STEMI) remains substantial in the reperfusion era. Shenfu injection, as a traditional Chinese herbal formula, can alleviate ischemia-reperfusion injury through multiple pharmacologic effects. However, no robust data are available regarding the role of Shenfu injection in reducing infarct size for patients with STEMI undergoing primary percutaneous coronary intervention (PPCI).

METHODS/DESIGN

This RESTORE trial is a multicenter, randomized, double-blind, parallel-group, placebo-controlled trial (NCT04493840). A total of 326 eligible patients with first-time anterior STEMI undergoing PPCI within 12 h of symptom onset will be enrolled from 10 centers in mainland China. Patients are randomized in a 1:1 fashion to receive either intravenous Shenfu injection (80mL Shenfu injection + 70mL 5% glucose injection) or placebo group (150mL 5% glucose injection) before reperfusion and followed by once a day until 5 days after PPCI. The primary end point is infarct size assessed by cardiac magnetic resonance (CMR) imaging 5±2 days after PPCI. The major secondary end points include enzymatic infarct size, microvascular obstruction, intramyocardial hemorrhage, left ventricular volume and ejection fraction assessed by CMR, as well as cardiovascular events at 30 days.

CONCLUSIONS

The RESTORE trial is sufficiently powered to demonstrate the clinical effects of Shenfu injection on myocardial injury in STEMI patients undergoing PPCI in the contemporary era.

Clinical Efficacy and Safety of Early Intravenous Administration of Beta-Blockers in Patients Suffering from Acute ST-Segment Elevation Myocardial Infarction Without Heart Failure Undergoing Primary Percutaneous Coronary Intervention: A Study-Level Meta-Analysis of Randomized Clinical Trials

BACKGROUND

Several clinical studies have produced diverse results regarding the efficacy and safety of early intravenous beta-blockers in patients with acute ST-segment elevation myocardial infarction (STEMI). A study-level meta-analysis of randomized clinical trials (RCTs) comparing early intravenous beta-blockers versus placebo or routine care in STEMI patients undergoing primary percutaneous coronary intervention (PCI) was performed.

METHODS

A database search was conducted using PubMed, EMBASE, the Cochrane Library, and Clinicaltrials.gov for randomized clinical trials (RCTs) that compared intravenous beta-blockers versus placebo or routine care in STEMI patients who underwent primary PCI. The efficacy outcomes were infarct size (IS, % of LV) and the myocardial salvage index (MSI) based on magnetic resonance imaging, electrocardiographic findings, heart rate, ST-segment reduction percent (STR%), and complete STR. Safety outcomes included arrhythmias in the first 24 h (ventricular tachycardia and fibrillation [VT/VF], atrial fibrillation [AF], bradycardia, and advanced atrioventricular [AV] block), cardiogenic shock and hypotension during hospitalization, left ventricular ejection fraction (LVEF), and major adverse cardiovascular events (cardiac death, stroke, reinfarction, and heart failure readmission) at follow-up.

RESULTS

Seven RCTs with 1428 patients were included in this study, with 709 patients in the intravenous beta-blockers and 719 in the control group. Intravenous beta-blockers improved MSI compared to the control group (weighted mean difference [WMD] 8.46, 95% confidence interval [CI] 3.12-13.80, P = 0.002, I² = 0%), but no differences were observed in IS (% of LV) between groups. Compared to the control group, the intravenous beta-blockers group had a lower risk of VT/VF (relative risk [RR] 0.65, 95% CI 0.45-0.94, P = 0.02, I² = 35%) without an increase of AF, bradycardia, and AV-block and significantly decreased HR, hypotension. LVEF at 1 week ± 7 days (WMD 2.06, 95% CI 0.25-3.88, P = 0.03, I² = 12%) and 6 months ± 7 days (WMD 3.24, 95% CI 1.54-4.95, P = 0.0002, I² = 0%) was improved in the intravenous beta-blockers group compared to the control group. Subgroup analysis showed that intravenous beta-blockers before PCI decreased the risk of VT/VF and improved LVEF compared to the control group. Furthermore, sensitivity analysis showed that patients with a left anterior descending (LAD) artery lesion had a smaller IS (% of LV) in the intravenous beta-blockers group compared to the control group.

CONCLUSION

Intravenous beta-blockers improved the MSI, decreased the risk of VT/VF in the first 24 h, and were associated with increased LVEF at 1 week and 6 months following PCI. In particular, intravenous beta-blockers started before PCI is beneficial for patients with LAD lesions.

Interaction of Cardiovascular Nonmodifiable Risk Factors, Comorbidities and Comedications With Ischemia/Reperfusion Injury and Cardioprotection by Pharmacological Treatments and Ischemic Conditioning

Preconditioning, postconditioning, and remote conditioning of the myocardium enhance the ability of the heart to withstand a prolonged ischemia/reperfusion insult and the potential to provide novel therapeutic paradigms for cardioprotection. While many signaling pathways leading to endogenous cardioprotection have been elucidated in experimental studies over the past 30 years, no cardioprotective drug is on the market yet for that indication. One likely major reason for this failure to translate cardioprotection into patient benefit is the lack of rigorous and systematic preclinical evaluation of promising cardioprotective therapies prior to their clinical evaluation, since ischemic heart disease in humans is a complex disorder caused by or associated with cardiovascular risk factors and comorbidities. These risk factors and comorbidities induce fundamental alterations in cellular signaling cascades that affect the development of ischemia/reperfusion injury and responses to cardioprotective interventions. Moreover, some of the medications used to treat these comorbidities may impact on cardioprotection by again modifying cellular signaling pathways. The aim of this article is to review the recent evidence that cardiovascular risk factors as well as comorbidities and their medications may modify the response to cardioprotective interventions. We emphasize the critical need for taking into account the presence of cardiovascular risk factors as well as comorbidities and their 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 comorbidities. SIGNIFICANCE STATEMENT: Ischemic heart disease is a major cause of mortality; however, there are still no cardioprotective drugs on the market. Most studies on cardioprotection have been undertaken in animal models of ischemia/reperfusion in the absence of comorbidities; however, ischemic heart disease develops with other systemic disorders (e.g., hypertension, hyperlipidemia, diabetes, atherosclerosis). Here we focus on the preclinical and clinical evidence showing how these comorbidities and their routine medications affect ischemia/reperfusion injury and interfere with cardioprotective strategies.

Role of β-blockers in Preventing Heart Failure and Major Adverse Cardiac Events Post Myocardial Infarction

β-blockers have been widely utilized as a part of acute myocardial infarction (AMI) treatment for the past 40 years. Patients receiving β-adrenergic blockers for an extended period following myocardial infarction have a higher chance of surviving. Although many patients benefited from β-blockers, many do not, including those with myocardial infarction, left ventricle dysfunction, chronic pulmonary disease, and elderly people. In individuals with the post-acute coronary syndrome and normal left ventricular ejection fraction (LVEF), the appropriate duration of betablocker therapy is still unknown. There is also no time limit for those without angina and those who do not need β-blockers for arrhythmia or hypertension. Interestingly, β-blockers have been prescribed for more than four decades. The novel mechanism of action on cellular compartments has been found continually, which opens a new way for their potential application in cardiac failure and other cardiac events like post-myocardial infarction. Here, in this review, we studied β-blocker usage in these circumstances and the current recommendations for β-blocker use from clinical practice guidelines.

Beta-Blockers in the Prevention and Treatment of Ischemic Heart Disease: Evidence and Clinical Practice

Coronary artery disease (CAD) is the most prevalent cardiovascular disease characterized by atherosclerotic plaque buildup that can lead to partial or full obstruction of blood flow in the coronary arteries. Treatment for CAD involves a combination of lifestyle changes, pharmacologic therapy, and modern revascularization procedures. Beta-adrenoceptor antagonists (or beta-blockers) have been widely used for decades as a key therapy for CAD. In this review, prior studies are examined to better understand beta-adrenoceptor antagonist use in patients with acute coronary syndrome, stable coronary heart disease, and in the perioperative setting. The evidence for the benefit of beta-blocker therapy is well established for patients with acute myocardial infarction, but it diminishes as the time from the index cardiac event elapses. The evidence for benefit in the perioperative setting is not strong.

Effect of early metoprolol before PCI in ST-segment elevation myocardial infarction on infarct size and left ventricular ejection fraction. A systematic review and meta-analysis of clinical trials

Aim

This meta‐analysis aims to look at the impact of early intravenous Metoprolol in ST‐segment elevation myocardial infarction (STEMI) before percutaneous coronary intervention (PCI) on infarct size, as measured by cardio magnetic resonance (CMR) and left ventricular ejection fraction.

Methods

We searched the following databases: PubMed, Scopus, Cochrane library, and Web of Science. We included only randomized control trials that reported the use of early intravenous Metoprolol in STEMI before PCI on infarct size, as measured by CMR and left ventricular ejection fraction. RevMan software 5.4 was used for performing the analysis.

Results

Following a literature search, 340 publications were found. Finally, 18 studies were included for the systematic review, and 8 clinical trials were included in the meta‐analysis after the full‐text screening. At 6 months, the pooled effect revealed a statistically significant association between Metoprolol and increased left ventricular ejection fraction (LVEF) (%) compared to controls (mean difference [MD] = 3.57, [95% confidence interval [CI] = 2.22–4.92], p < .00001), as well as decreased infarcted myocardium(g) compared to controls (MD = −3.84, [95% [CI] = −5.75 to −1.93], p < .0001). At 1 week, the pooled effect revealed a statistically significant association between Metoprolol and increased LVEF (%) compared to controls (MD = 2.98, [95% CI = 1.26−4.69], p = .0007), as well as decreased infarcted myocardium(%) compared to controls (MD = −3.21, [95% CI = −5.24 to −1.18], p = .002).

Conclusion

A significant decrease in myocardial infarction and increase in LVEF (%) was linked to receiving Metoprolol at 1 week and 6‐month follow‐up.

Topical Neck Cooling Without Systemic Hypothermia Attenuates Myocardial Ischemic Injury and Post-ischemic Reperfusion Injury

Background

Following acute myocardial infarction (MI), irreversible damage to the myocardium can only be reduced by shortening the duration between symptom onset and revascularization. While systemic hypothermia has shown promising results in slowing pre-revascularization myocardial damage, it is resource intensive and not conducive to prehospital initiation. We hypothesized that topical neck cooling (NC), an easily implemented therapy for en route transfer to definitive therapy, could similarly attenuate myocardial ischemia-reperfusion injury (IRI).

Methods

Using an in vivo mouse model of myocardial IRI, moderate systemic hypothermia or NC was applied following left coronary artery (LCA) occlusion and subsequent reperfusion, at early, late, and post-reperfusion intervals. Vagotomy was performed after late NC in an additional group. Hearts were harvested to measure infarct size.

Results

Both hypothermia treatments equally attenuated myocardial infarct size by 60% compared to control. The infarct-sparing effect of NC was temperature-dependent and timing-dependent. Vagotomy at the gastroesophageal junction abolished the infarct-sparing effect of late NC. Cardiac perfusate isolated following ischemia had significantly reduced cardiac troponin T, HMGB1, cell-free DNA, and interferon α and β levels after NC.

Conclusions

Topical neck cooling attenuates myocardial IRI in a vagus nerve-dependent manner, with an effect comparable to that of systemic hypothermia. NC attenuated infarct size when applied during ischemia, with earlier initiation resulting in superior infarct sparing. This novel therapy exerts a cardioprotective effect without requiring significant change in core temperature and may be a promising practical strategy to attenuate myocardial damage while patients await definitive revascularization.

Small molecules as modulators of regulated cell death against ischemia/reperfusion injury

Ischemia/reperfusion (IR) injury contributes to disability and mortality worldwide. Due to the complicated mechanisms and lack of proper therapeutic targets, few interventions are available that specifically target the pathogenesis of IR injury. Regulated cell death (RCD) of endothelial and parenchymal cells is recognized as the promising intervening target. Recent advances in IR injury suggest that small molecules exhibit beneficial effects on various RCD against IR injury, including apoptosis, necroptosis, autophagy, ferroptosis, pyroptosis, and parthanatos. Here, we describe the mechanisms behind these novel promising therapeutic targets and explain the machinery powering the small molecules. These small molecules exert protection by targeting endothelial or parenchymal cells to alleviate IR injury. Therapies of the ideal combination of small molecules targeting multiple cell types have shown potent synergetic therapeutic effects, laying the foundation for novel strategies to attenuate IR injury.

Early donepezil monotherapy or combination with metoprolol significantly prevents subsequent chronic heart failure in rats with reperfused myocardial infarction

Despite the presence of clinical guidelines recommending that β-blocker treatment be initiated early after reperfused myocardial infarction (RMI), acute myocardial infarction remains a leading cause of chronic heart failure (CHF). In this study, we compared the effects of donepezil, metoprolol, and their combination on the progression of cardiac remodeling in rats with RMI. The animals were randomly assigned to untreated (UT), donepezil-treated (DT), metoprolol-treated (MT), and a combination of donepezil and metoprolol (DMT) groups. On day 8 after surgery, compared to the UT, the DT and DMT significantly improved myocardial salvage, owing to the suppression of macrophage infiltration and apoptosis. After the 10-week treatment, the DT and DMT exhibited decreased heart rate, reduced myocardial infarct size, attenuated cardiac dysfunction, and decreased plasma levels of brain natriuretic peptide and catecholamine, thereby preventing subsequent CHF. These results suggest that donepezil monotherapy or combined therapy with β-blocker may be an alternative pharmacotherapy post-RMI.

“No-Reflow” Phenomenon: A Contemporary Review

Primary percutaneous angioplasty (pPCI), represents the reperfusion strategy of choice for patients with STEMI according to current international guidelines of the European Society of Cardiology. Coronary no-reflow is characterized by angiographic evidence of slow or no anterograde epicardial flow, resulting in inadequate myocardial perfusion in the absence of evidence of mechanical vessel obstruction. No reflow (NR) is related to a functional and structural alteration of the coronary microcirculation and we can list four main pathophysiological mechanisms: distal atherothrombotic embolization, ischemic damage, reperfusion injury, and individual susceptibility to microvascular damage. This review will provide a contemporary overview of the pathogenesis, diagnosis, and treatment of NR.

Complementary Pharmacotherapy for STEMI Undergoing Primary PCI: An Evidence-Based Clinical Approach

Antithrombotic therapy is the cornerstone of pharmacological treatment in patients undergoing primary percutaneous coronary intervention (PCI). However, the acute management of ST elevation myocardial infarction (STEMI) patients includes therapy for pain relief and potential additional strategies for cardioprotection. The safety and efficacy of some commonly used treatments have been questioned by recent evidence. Indeed a concern about morphine use is the interaction between opioids and oral P2Y₁₂ inhibitors; early beta-blocker treatment has shown conflicting results for the improvement of clinical outcomes; and supplemental oxygen therapy lacks benefit in patients without hypoxia and may be of potential harm. Other additional strategies remain disappointing; however, some treatments may be selectively used. Therefore, we intend to present a critical updated review of complementary pharmacotherapy for a modern treatment approach for STEMI patients undergoing primary PCI.

The duration of beta-blocker therapy and outcomes in patients without heart failure or left ventricular systolic dysfunction after acute myocardial infarction: A multicenter prospective cohort study

Background

The duration of beta‐blocker therapy in patients without heart failure (HF) or left ventricular systolic dysfunction after acute myocardial infarction (AMI) is unclear.

Hypothesis

Continuous beta‐blocker therapy is associated with an improved prognosis.

Methods

This is a prospective, multicenter, cohort study. One thousand four hundred and eighty‐three patients eventually met the inclusion criteria. The study groups included the continuous beta‐blocker therapy group (lasted ≥6 months) and the discontinuous beta‐blocker therapy group (consisting of the no‐beta‐blocker therapy group and the beta‐blocker therapy <6 months group). The inverse probability treatment weighting was used to control confounding factors. The study tried to learn the role of continuous beta‐blocker therapy on outcomes. The median duration of follow‐up was 13.0 months. The primary outcomes were cardiac death and major adverse cardiovascular events (MACE). The secondary outcomes were all‐cause death, stroke, unstable angina, rehospitalization for HF, and recurrent myocardial infarction (MI).

Results

Compared with discontinuous beta‐blocker therapy, continuous beta‐blocker therapy was associated with a reduced risk of unstable angina, recurrent MI, and MACE (hazard ratio [HR]: 0.51; 95% CI: 0.32–0.82; p = 0.006); but this association was not available for cardiac death (HR: 0.57; 95% CI: 0.24–1.36; p = 0.206). When compared to the subgroups of no‐beta‐blocker therapy and beta‐blocker therapy <6 months, respectively, continuous beta‐blocker therapy was still observed to be associated with a reduced risk of unstable angina, recurrent MI, and MACE.

Conclusions

Continuous beta‐blocker therapy was associated with a reduced risk of unstable angina or recurrent MI or MACE in patients without HF or left ventricular systolic dysfunction after AMI.

Ischemia preconditioning alleviates ischemia/reperfusion injury-induced coronary no-reflow and contraction of microvascular pericytes in rats

BACKGROUND

Ischemia preconditioning (IPC) ameliorates coronary no-reflow induced by ischemia/reperfusion (I/R) injury, and pericytes play an important role in microvascular function. However, it is unclear whether IPC exerts a protective effect on coronary microcirculation and regulates the pericytes.

OBJECTIVE

The purpose of this study was to assess whether IPC improves coronary microvascular perfusion and reduces pericyte constriction after myocardial I/R injury.

METHODS

Rats were randomly divided into three groups: the sham group, the I/R group, and the IPC + I/R group. The left anterior descending artery (LAD) of rats in the I/R group were ligated for 45 min, and the rats in the IPC + I/R group received 4 episodes of 6min occlusion followed by 6min reperfusion before the LAD was ligated. After 24 h of reperfusion, the area of no-reflow, and area at risk were evaluated with thioflavin-S and Evens blue staining, and infarct size with triphenyl tetrazolium chloride staining, respectively. Besides, fluorescent microspheres were perfused to enable visualization of the non-obstructed coronary vessels. Cardiac pericytes and microvascular were observed by immunofluorescence, and the diameter of microvascular at the site of the pericyte somata was analyzed.

RESULTS

The infarct size, and area of no-reflow in the IPC + I/R group were significantly reduced compared with the I/R group (infarct size, 33.5% ± 11.9% vs. 49.2% ± 9.4%, p = 0.021；no-reflow, 12.7% ± 5.2% vs. 26.6% ± 5.0%, p < 0.001). IPC improved microvascular perfusion and reduced the percentage of the blocked coronary capillary. Moreover, we found that cardiac pericytes were widely distributed around the microvascular in various regions of the heart, and expressed the contractile protein α-smooth muscle actin. The microvascular lumen diameter at pericyte somata was reduced after I/R (4.3 ± 1.0 μm vs. 6.5 ± 1.2 μm, p < 0.001), which was relieved in IPC + I/R group compared with the I/R group (5.2 ± 1.0 μm vs. 4.3 ± 1.0 μm, p < 0.001). Besides, IPC could reduce the proportion of apoptotic pericytes compared to the I/R group (22.1% ± 8.4% vs. 38.5% ± 7.5%, p < 0.001).

CONCLUSION

IPC reduced no-reflow and inhibited the contraction of microvascular pericytes induced by cardiac I/R injury, suggesting that IPC might play a protective role by regulating the pericyte function.

CU06-1004 enhances vascular integrity and improves cardiac remodeling by suppressing edema and inflammation in myocardial ischemia-reperfusion injury

Ischemia-reperfusion (I/R) injury accelerates the cardiomyocytes (CMs) death by oxidative stress, and thereby deteriorates cardiac function. There has been a paradigm shift in the therapeutic perspective more towards the prevention or amelioration of damage caused by reperfusion. Cardiac microvascular endothelial cells (CMECs) are more vulnerable to reperfusion injury and play the crucial roles more than CMs in the pathological process of early I/R injury. In this study, we investigate that CU06-1004, as a vascular leakage blocker, can improve cardiac function by inhibiting CMEC's hyperpermeability and subsequently reducing the neutrophil's plugging and infiltration in infarcted hearts. CU06-1004 was delivered intravenously 5 min before reperfusion and the rats were randomly divided into three groups: (1) vehicle, (2) low-CU06-1004 (1 mg/kg, twice at 24 h intervals), and (3) high-CU06-1004 (5 mg/kg, once before reperfusion). CU06-1004 treatment reduced necrotic size and cardiac edema by enhancing vascular integrity, as demonstrated by the presence of intact junction proteins on CMECs and surrounding pericytes in early I/R injury. It also decreased the expression of vascular cell adhesion molecule 1 (VCAM-1) on CMECs, resulting in reduced infiltration of neutrophils and macrophages. Echocardiography showed that the CU06-1004 treatment significantly improved cardiac function compared with the vehicle group. Interestingly, single high-dose treatment with CU06-1004 provided a greater functional improvement than repetitive low-dose treatment until 8 weeks post I/R. These findings demonstrate that CU06-1004 enhances vascular integrity and improves cardiac function by preventing lethal myocardial I/R injury. It can provide a promising therapeutic option, as potential adjunctive therapy to current reperfusion strategies.

Intramyocardial Hemorrhage and the "Wave Front" of Reperfusion Injury Compromising Myocardial Salvage

BACKGROUND

Reperfusion therapy for acute myocardial infarction (MI) is lifesaving. However, the benefit of reperfusion therapy can be paradoxically diminished by reperfusion injury, which can increase MI size.

OBJECTIVES

Hemorrhage is known to occur in reperfused MIs, but whether hemorrhage plays a role in reperfusion-mediated MI expansion is not known.

METHODS

We studied cardiac troponin kinetics (cTn) of ST-segment elevation MI patients (n = 70) classified by cardiovascular magnetic resonance to be hemorrhagic (70%) or nonhemorrhagic following primary percutaneous coronary intervention. To isolate the effects of hemorrhage from ischemic burden, we performed controlled canine studies (n = 25), and serially followed both cTn and MI size with time-lapse imaging.

RESULTS

CTn was not different before reperfusion; however, an increase in cTn following primary percutaneous coronary intervention peaked earlier (12 hours vs 24 hours; P < 0.05) and was significantly higher in patients with hemorrhage (P < 0.01). In hemorrhagic animals, reperfusion led to rapid expansion of myocardial necrosis culminating in epicardial involvement, which was not present in nonhemorrhagic cases (P < 0.001). MI size and salvage were not different at 1 hour postreperfusion in animals with and without hemorrhage (P = 0.65). However, within 72 hours of reperfusion, a 4-fold greater loss in salvageable myocardium was evident in hemorrhagic MIs (P < 0.001). This paralleled observations in patients with larger MIs occurring in hemorrhagic cases (P < 0.01).

CONCLUSIONS

Myocardial hemorrhage is a determinant of MI size. It drives MI expansion after reperfusion and compromises myocardial salvage. This introduces a clinical role of hemorrhage in acute care management, risk assessment, and future therapeutics.

Acute Coronary Syndromes (ACS)-Unravelling Biology to Identify New Therapies-The Microcirculation as a Frontier for New Therapies in ACS

In acute coronary syndrome (ACS) patients, restoring epicardial culprit vessel patency and flow with percutaneous coronary intervention or coronary artery bypass grafting has been the mainstay of treatment for decades. However, there is an emerging understanding of the crucial role of coronary microcirculation in predicting infarct burden and subsequent left ventricular remodelling, and the prognostic significance of coronary microvascular obstruction (MVO) in mortality and morbidity. This review will elucidate the multifaceted and interconnected pathophysiological processes which underpin MVO in ACS, and the various diagnostic modalities as well as challenges, with a particular focus on the invasive but specific and reproducible index of microcirculatory resistance (IMR). Unfortunately, a multitude of purported therapeutic strategies to address this unmet need in cardiovascular care, outlined in this review, have so far been disappointing with conflicting results and a lack of hard clinical end-point benefit. There are however a number of exciting and novel future prospects in this field that will be evaluated over the coming years in large adequately powered clinical trials, and this review will briefly appraise these.

Beta-blocker effect on ST-segment: a prespecified analysis of the EARLY-BAMI randomised trial

Objective

The effect of early intravenous (IV) beta-blockers (BBs) administration in patients undergoing primary percutaneous coronary intervention (pPCI) on ST-segment deviation is unknown. We undertook a prespecified secondary analysis of the Early Beta-blocker Administration before primary PCI in patients with ST-elevation Myocardial Infarction (EARLY-BAMI) trial to investigate the effect of early IV BB on ST-segment deviation.

Methods

The EARLY-BAMI trial randomised patients with ST-elevation myocardial infarction (STEMI) to IV metoprolol (2×5 mg bolus) or matched placebo before pPCI. The prespecified outcome, evaluated by an independent core laboratory blinded to study treatment, was the residual ST-segment deviation 1 hour after pPCI (ie, the percentage of patients with >3 mm cumulative ST deviation at 1 hour after pPCI).

Results

An ECG for the evaluation of residual ST-segment deviation 1 hour after pPCI was available in 442 out of 683 randomised patients. The BB group had a lower heart rate after pPCI compared with placebo (71.2±13.2 vs 74.3±13.6, p=0.016); however, no differences were noted in the percentages of patients with >3 mm cumulative ST deviation at 1 hour after pPCI (58.6% vs 54.1%, p=0.38, in BB vs placebo, respectively) neither a significant difference was found for the percentages of patients in each of the four prespecified groups (normalised ST-segment; 1–3 mm; 4–6 mm;>6 mm residual ST-deviation).

Conclusions

In patients with STEMI, who were being transported for primary PCI, early IV BB administration did not significantly affect ST-segment deviation after pPCI compared with placebo. The neutral result of early IV BB administration on an early marker of pharmacological effect is consistent with the absence of subsequent improvement of clinical outcomes.

Reducing Cardiac Injury during ST-Elevation Myocardial Infarction: A Reasoned Approach to a Multitarget Therapeutic Strategy

The significant reduction in ‘ischemic time’ through capillary diffusion of primary percutaneous intervention (pPCI) has rendered myocardial-ischemia reperfusion injury (MIRI) prevention a major issue in order to improve the prognosis of ST elevation myocardial infarction (STEMI) patients. In fact, while the ischemic damage increases with the severity and the duration of blood flow reduction, reperfusion injury reaches its maximum with a moderate amount of ischemic injury. MIRI leads to the development of post-STEMI left ventricular remodeling (post-STEMI LVR), thereby increasing the risk of arrhythmias and heart failure. Single pharmacological and mechanical interventions have shown some benefits, but have not satisfactorily reduced mortality. Therefore, a multitarget therapeutic strategy is needed, but no univocal indications have come from the clinical trials performed so far. On the basis of the results of the consistent clinical studies analyzed in this review, we try to design a randomized clinical trial aimed at evaluating the effects of a reasoned multitarget therapeutic strategy on the prevention of post-STEMI LVR. In fact, we believe that the correct timing of pharmacological and mechanical intervention application, according to their specific ability to interfere with survival pathways, may significantly reduce the incidence of post-STEMI LVR and thus improve patient prognosis.

Impact of Bisoprolol on Ventricular Arrhythmias in Experimental Myocardial Infarction

Following acute myocardial infarction (AMI), early use of beta-blockers (BBs) reduced the incidences of ventricular arrhythmia (VA) and death in the pre reperfusion era. However, some studies have reported a worsening of clinical outcomes and therefore, this study used a porcine model of AMI to evaluate the efficacy of bisoprolol on VAs and mortality. Twenty pigs were divided into two groups with one group using oral bisoprolol which was given for 3 hours before the experiment and then maintained for 7 days. A loop recorder was implanted, AMI was induced by balloon occlusion for 60 min, and then, reperfusion. One week later, the echocardiography and loop recorder data were analyzed in the surviving animals. Bisoprolol did not increase the heart rate (62.9±14.5 vs 79.0±20.3; p=0.048), lower the rate of premature ventricular contractions (PVC) (0.8±0.8 vs 11.0±12.8; p=0.021) or tend to lower recurrent VA (0.6±0.5 vs 1.1±1.1; p=0.131) during coronary artery occlusion. After reperfusion, bisoprolol did reduce VA in the early AMI period (0.1±0.3 vs 4.2±4.6; p=0.001) and it was not associated with the extent of myocardial recovery. In this porcine model, early oral bisoprolol might help reduce the incidences of PVC and recurrent VA and determine whether effects are more pronounced during the early AMI period. Our results suggest that bisoprolol might help reduce lethal VA and cardiac death following AMI in this reperfusion era.

Safety measures for COVID-19 do not compromise the outcomes of patients undergoing primary percutaneous coronary intervention: a single center retrospective study

Coronavirus disease 2019 (COVID-19) is a global pandemic impacting nearly 170 countries/regions and millions of patients worldwide. Patients with acute myocardial infarction (AMI) still need to be treated at percutaneous coronary intervention (PCI) centers with relevant safety measures. This retrospective study was conducted to assess the therapeutic outcomes of PCI performed under the safety measures and normal conditions. AMI patients undergoing PCI between January 24 to April 30, 2020 were performed under safety measures for COVID-19. Patients received pulmonary computed tomography (CT) and underwent PCI in negative pressure ICU. Cardiac catheterization laboratory (CCL) staff and physicians worked with level III personal protection. Demographic and clinical data, such as door-to-balloon (DTB) time, operation time, complications for patients in this period (COVID-19 group) and the same period in 2019 (2019 group) were retrieved and analyzed. COVID-19 and 2019 groups had 37 and 96 patients, respectively. There was no significant difference in age, gender, BMI and comorbidity between the two groups. DTB time and operation time were similar between the two groups (60.0 ± 12.39 vs 58.83 ± 12.85 min, p = 0.636; 61.46 ± 9.91 vs 62.55 ± 10.72 min, p = 0.592). Hospital stay time in COVID-19 group was significantly shorter (6.78 ± 2.14 vs 8.85 ± 2.64 days, p < 0.001). The incidences of malignant arrhythmia and Takotsubo Syndrome in COVID-19 group were higher than 2019 group significantly (16.22% vs 5.21%, p = 0.039; 10.81% vs 1.04% p = 0.008). During hospitalization and 3-month follow-up, the incidence of major adverse cardiovascular events and mortality in the two groups were statistically similar (35.13% vs 14.58%, p = 0.094; 16.22% vs 8.33%, p = 0.184). The risk of major adverse cardiac events (MACE) was associated with cardiogenic shock (OR, 11.53; 95% CI, 2.888-46.036; p = 0.001), malignant arrhythmias (OR, 7.176; 95% CI, 1.893-27.203; p = 0.004) and advanced age (≥ 75 years) (OR, 6.718; 95% CI, 1.738-25.964; p = 0.006). Cardiogenic shock (OR, 17.663; 95% CI, 5.5-56.762; p < 0.001) and malignant arrhythmias (OR, 4.659; 95% CI, 1.481-14.653; p = 0.008) were also associated with death of 3 months. Our analysis showed that safety measures undertaken in this hospital, including screening of COVID-19 infection and use of personal protection equipment for conducting PCI did not compromise the surgical outcome as compared with PCI under normal condition, although there were slight increases in incidence of malignant arrhythmia and Takotsubo Syndrome.

Should We Be Using Upstream Beta-Blocker Therapy for Acute Myocardial Infarction?

Purpose of Review

Controversy exists whether beta-blockers should be given before primary percutaneous coronary intervention (PCI) or to defer their administration for up to 24 hours.

Recent Findings

Animal studies, most of them conducted in the 1970s and 1980s, showed evidence that early beta-blocker administration may reduce infarct size. Subsequent human studies had mixed results on infarct size and survival. More specifically, in the current primary PCI era, only four studies evaluated the impact of early intravenous beta-blocker administration after acute myocardial infarction, only two of them before PCI. All studies agree that in hemodynamically stable patients, early intravenous beta-blocker administration is safe and protected against malignant arrhythmias. Nevertheless, results on infarct size and mortality are equivocal.

Summary

Considering the heterogeneity of currently available data, further studies are still needed to assess the benefit of early injection of metoprolol in STEMI patients in a large double-blinded and randomized design versus placebo.

Is metoprolol more cardioprotective than other beta-blockers?

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Pharmacologic Prevention of Myocardial Ischemia-Reperfusion Injury in Patients With Acute Coronary Syndrome Undergoing Percutaneous Coronary Intervention

ABSTRACT

Establishing efficient perfusion into the myocardium is the main purpose in patients with acute coronary syndrome, but the process of reperfusion is not without risk and can damage the myocardium paradoxically. Unfortunately, there is no effective treatment for reperfusion injury, and efforts to find an efficient preventive approach are still ongoing. In the past 3 decades, there have been many successful animal studies on how to prevent reperfusion injury; nonetheless, translation to the clinical setting has almost always proven disappointing. In this article, we review clinical studies on the prevention of reperfusion injury in patients with acute coronary syndrome undergoing primary percutaneous coronary intervention in a pharmacologic-based approach. We categorize all the agents that are evaluated for the prevention of myocardial reperfusion injury based on their mechanisms of action into 5 groups: drugs that can reduce oxidative stress, drugs that can affect cellular metabolism, rheological agents that target microvascular obstruction, anti-inflammatory agents, and agents with mixed mechanisms of action. Then, review all the clinical studies of these agents in the setting of primary percutaneous coronary intervention. Finally, we will discuss the possible reasons for the failure in translation of studies into practice and propose potential solutions to overcome this problem.

Adjunctive Intracoronary Fibrinolytic Therapy During Primary Percutaneous Coronary Intervention

Despite routinely restoring epicardial coronary patency, with primary percutaneous coronary intervention (PCI), microvascular obstruction affects approximately half of patients and confers an adverse prognosis. There are no evidence-based treatments for microvascular obstruction. A key contributor to microvascular obstruction is distal embolisation and microvascular thrombi. Adjunctive intracoronary fibrinolytic therapy may reduce thrombotic burden, potentially reducing distal embolisation of atherothrombotic debris to the microcirculation. In this review, the evidence from published randomised trials on the effects of adjunctive intracoronary fibrinolytic therapy during primary PCI is critically appraised, the ongoing randomised trials are described, and conclusions are made from the available evidence. Clinical uncertainties, to be addressed by future research, are highlighted.

Predictors of Microvascular Reperfusion After Myocardial Infarction

Purpose of Review

In acute ST-segment elevation myocardial infarction (STEMI), successful restoration of blood flow in the infarct-related coronary artery may not secure effective myocardial reperfusion. The mortality and morbidity associated with acute MI remain significant. Microvascular obstruction (MVO) represents failed microvascular reperfusion. MVO is under-recognized, independently associated with adverse cardiac prognosis and represents an unmet therapeutic need.

Recent Findings

Multiple factors including clinical presentation, patient characteristics, biochemical markers, and imaging parameters are associated with MVO after MI.

Summary

Impaired microvascular reperfusion is common following percutaneous coronary intervention (PCI). New knowledge about disease mechanisms underpins precision medicine with individualized risk assessment, investigation, and stratified therapy. To date, there are no evidence-based therapies to prevent or treat MVO post-MI. Identifying novel therapy for MVO is the next frontier.

Usefulness of universal beta-blocker therapy in patients after ST-elevation myocardial infarction

The use of beta-blockers (BB) in the context of ST-segment elevation myocardial infarction (STEMI) was a universal practice in the pre-reperfusion era. Since then, evidence of their use for secondary prevention after STEMI is scarce. Our aim is to determine treatment results associated with BB therapy after a STEMI at 1-year follow-up in a contemporary nationwide cohort.A prospective analysis involving 49 national centers, including patients admitted with STEMI, enrolled between October 2010 and September 2019 was conducted. The primary outcome was defined as the composite of all-cause mortality or hospital re-admission for a cardiovascular (CV) cause in the first year after STEMI. The patients were distributed into 2 groups, depending on whether they received therapy with BB at hospital discharge or not (BB and NB group, respectively).A total of 3145 patients were included in the analysis, of which 2526 (80.3%) in the BB group. A total of 12.2% of patients reached the primary outcome. Regarding the univariate Cox regression analysis, the BB group presented lower mortality or re-admission for CV cause at 1-year follow-up [hazard ratio (HR) 0.69, confidence interval (CI) 95% 0.55-0.87, P = .001]. However, after adjustment for significant covariates, this association was lost (HR 0.73, CI 95% 0.51-1.04, P = .081). In patients with preserved (HR 0.73, CI 95% 0.51-1.04, P = .081) and mid-range (HR 1.01, CI 95% 0.64-1.61, P = .959) left ventricular ejection fraction (LVEF), the primary outcome was similar between the 2 groups, while in patients with reduced LVEF, the BB group presented a better prognosis, with fewer patients reaching the primary outcome (HR 0.431, CI 95% 0.262-0.703, P = .001).BB universal therapy after STEMI has not proved useful, but it seems to be beneficial in patients with reduced LVEF.

Perioperative Cardioprotection: Clinical Implications

Perioperative cardioprotection aims to minimize the consequences of myocardial ischemia-reperfusion injury. In isolated tissue and animal experiments, several treatments have been identified providing cardioprotection. Some of these strategies have been confirmed in clinical proof-of-concept studies. However, the final translation of cardioprotective strategies to really improve clinical outcome has been disappointing: large randomized controlled clinical trials mostly revealed inconclusive, neutral, or negative results. This review provides an overview of the currently available evidence regarding clinical implications of perioperative cardioprotective therapies from an anesthesiological perspective, highlighting nonpharmacological as well as pharmacological strategies. We discuss reasons why translation of promising experimental results into clinical practice and outcome improvement is hampered by potential confounders and suggest future perspectives to overcome these limitations.

Pre- and Post-Conditioning of the Heart: An Overview of Cardioprotective Signaling Pathways

Since the discovery of ischemic pre- and post-conditioning, more than 30 years ago, the knowledge about the mechanisms and signaling pathways involved in these processes has significantly increased. In clinical practice, on the other hand, such advancement has yet to be seen. This article provides an overview of ischemic pre-, post-, remote, and pharmacological conditioning related to the heart. In addition, we reviewed the cardioprotective signaling pathways and therapeutic agents involved in the above-mentioned processes, aiming to provide a comprehensive evaluation of the advancements in the field. The advancements made over the last decades cannot be ignored and with the exponential growth in techniques and applications. The future of pre- and post-conditioning is promising.

Sonothrombolysis in the ambulance for ST-elevation myocardial infarction: rationale and protocol

Background

Treatment of ST-elevation myocardial infarction (STEMI) has improved over the years. Current challenges in the management of STEMI are achievement of early reperfusion and the prevention of microvascular injury. Sonothrombolysis has emerged as a potential treatment for acute myocardial infarction, both for epicardial recanalisation as well as improving microvascular perfusion. This study aims to determine safety and feasibility of sonothrombolysis application in STEMI patients in the ambulance.

Methods

Ten patients with STEMI will be included and treated with sonothrombolysis in the ambulance during transfer to the PCI centre. Safety will be assessed by the occurrence of ventricular arrhythmias and shock during sonothrombolysis intervention. Feasibility will be assessed by the extent of protocol completion and myocardial visibility. Efficacy will be determined by angiographic patency rate, ST-elevation resolution, infarct size and left ventricular volumes, and function measured with cardiovascular magnetic resonance imaging, and contrast and strain echocardiography. A comparison will be made with matched controls using an existing STEMI database.

Discussion

Sonothrombolysis is a novel technique for the treatment of cardiovascular thromboembolic disease. The first clinical trials on its use for STEMI have demonstrated promising results. This study will be the first to examine the feasibility of in-ambulance sonothrombolysis for STEMI.

Trial registration

EU Clinical Trials Register (identifier: 2019-001883-31), registered 2020-02-25.

Cardiac arrhythmias in the emergency settings of acute coronary syndrome and revascularization: an European Heart Rhythm Association (EHRA) consensus document, endorsed by the European Association of Percutaneous Cardiovascular Interventions (EAPCI), and European Acute Cardiovascular Care Association (ACCA)

Despite major therapeutic advances over the last decades, complex supraventricular and ventricular arrhythmias (VAs), particularly in the emergency setting or during revascularization for acute myocardial infarction (AMI), remain an important clinical problem. Although the incidence of VAs has declined in the hospital phase of acute coronary syndromes (ACS), mainly due to prompt revascularization and optimal medical therapy, still up to 6% patients with ACS develop ventricular tachycardia and/or ventricular fibrillation within the first hours of ACS symptoms. Despite sustained VAs being perceived predictors of worse in-hospital outcomes, specific associations between the type of VAs, arrhythmia timing, applied treatment strategies and long-term prognosis in AMI are vague. Atrial fibrillation (AF) is the most common supraventricular tachyarrhythmia that may be asymptomatic and/or may be associated with rapid haemodynamic deterioration requiring immediate treatment. It is estimated that over 20% AMI patients may have a history of AF, whereas the new-onset arrhythmia may occur in 5% patients with ST elevation myocardial infarction. Importantly, patients who were treated with primary percutaneous coronary intervention for AMI and developed AF have higher rates of adverse events and mortality compared with subjects free of arrhythmia. The scope of this position document is to cover the clinical implications and pharmacological/non-pharmacological management of arrhythmias in emergency presentations and during revascularization. Current evidence for clinical relevance of specific types of VAs complicating AMI in relation to arrhythmia timing has been discussed.