Long-Term Benefit of Early Pre-Reperfusion Metoprolol Administration in Patients With Acute Myocardial Infarction

Early initiation of oral beta-blocker improves long-term survival in patients with acute myocardial infarction who underwent primary percutaneous coronary intervention

BACKGROUND

The optimal timing for the initiation of oral beta-blockers after acute myocardial infarction (MI) remains unclear within the context of current primary percutaneous coronary intervention (PCI) practice.

METHODS

This retrospective cohort study included 412 consecutive patients admitted with a diagnosis of acute MI between January 2007 and August 2016 who underwent successful primary PCI and were given oral carvedilol during hospitalization. Early and late carvedilol groups were based on initiation within the first 24 h or after. Propensity score matching (1:1) incorporating 21 baseline characteristics yielded 47 matched pairs. Timing of carvedilol initiation was evaluated in relation to patient outcomes including time to all-cause mortality, using Kaplan-Meier estimates on the matched cohort and additional confirmation in multivariable regression analysis among the entire cohort.

RESULTS

Median follow-up period was 828 days. All-cause death occurred in 14 patients (4.7%) and 18 patients (15.8%) of the early and late carvedilol groups. After propensity score matching, initiation of oral carvedilol within the first 24 h was associated with lower all-cause mortality (6.4% vs. 25.5%, hazard ratio 0.28, 95% confidence interval 0.06 - 0.89, p = 0.036), as well as lower in-hospital mortality (0 vs. 14.9%, p = 0.018).

CONCLUSIONS

These results provide evidence that initiation of oral carvedilol within the first 24 h reduces the risk of long-term mortality, in acute MI patients who underwent primary PCI, supporting current guidelines recommendation.

Machine learning models to predict 30-day mortality for critical patients with myocardial infarction: a retrospective analysis from MIMIC-IV database

Background

The identification of efficient predictors for short-term mortality among patients with myocardial infarction (MI) in coronary care units (CCU) remains a challenge. This study seeks to investigate the potential of machine learning (ML) to improve risk prediction and develop a predictive model specifically tailored for 30-day mortality in critical MI patients.

Method

This study focused on MI patients extracted from the Medical Information Mart for Intensive Care-IV database. The patient cohort was randomly stratified into derivation (n = 1,389, 70%) and validation (n = 595, 30%) groups. Independent risk factors were identified through eXtreme Gradient Boosting (XGBoost) and random decision forest (RDF) methodologies. Subsequently, multivariate logistic regression analysis was employed to construct predictive models. The discrimination, calibration and clinical utility were assessed utilizing metrics such as receiver operating characteristic (ROC) curve, calibration plot and decision curve analysis (DCA).

Result

A total of 1,984 patients were identified (mean [SD] age, 69.4 [13.0] years; 659 [33.2%] female). The predictive performance of the XGBoost and RDF-based models demonstrated similar efficacy. Subsequently, a 30-day mortality prediction algorithm was developed using the same selected variables, and a regression model was visually represented through a nomogram. In the validation group, the nomogram (Area Under the Curve [AUC]: 0.835, 95% Confidence Interval [CI]: [0.774-0.897]) exhibited superior discriminative capability for 30-day mortality compared to the Sequential Organ Failure Assessment (SOFA) score [AUC: 0.735, 95% CI: (0.662-0.809)]. The nomogram (Accuracy: 0.914) and the SOFA score (Accuracy: 0.913) demonstrated satisfactory calibration. DCA indicated that the nomogram outperformed the SOFA score, providing a net benefit in predicting mortality.

Conclusion

The ML-based predictive model demonstrated significant efficacy in forecasting 30-day mortality among MI patients admitted to the CCU. The prognostic factors identified were age, blood urea nitrogen, heart rate, pulse oximetry-derived oxygen saturation, bicarbonate, and metoprolol use. This model serves as a valuable decision-making tool for clinicians.

In-hospital cardiac arrest after STEMI: prevention strategies and post-arrest care

INTRODUCTION

In-Hospital Cardiac Arrest (IHCA) after ST-segment Elevation Myocardial Infarction (STEMI) is a subset of IHCA with high morbidity. While information on this selected group of patients is limited, closer inspection reveals that this is a challenging patient population with certain risk factors for IHCA following treatment of STEMI.

AREAS COVERED

In this review article, strategies for prevention of IHCA post STEMI are reviewed, as well as best-practices for the care of STEMI patients post-IHCA.

EXPERT OPINION

Early and successful reperfusion is key for the prevention of IHCA and has a significant impact on in-hospital mortality. A number of pharmacological treatments have also been studied that can impact the progression to IHCA. Development of cardiogenic shock post-STEMI increases mortality and raises the risk of cardiac arrest. The treatment of IHCA follows the ACLS algorithm with some notable exceptions.

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.

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.

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.

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.

A novel vaccine targeting β1-adrenergic receptor

Beta-blockers are widely used in the treatment of hypertension, heart failure and ischemic heart disease. However, unstandardized medication results in diverse clinical outcomes in patients. The main causes are unattained optimal doses, insufficient follow-up and patients' poor adherence. To improve the medication inadequacy, our team developed a novel therapeutic vaccine targeting β1-adrenergic receptor (β1-AR). The β1-AR vaccine named ABRQβ-006 was prepared by chemical conjugation of a screened β1-AR peptide with Qβ virus like particle (VLP). The antihypertensive, anti-remodeling and cardio-protective effects of β1-AR vaccine were evaluated in different animal models. The ABRQβ-006 vaccine was immunogenic that induced high titers of antibodies against β1-AR epitope peptide. In the NG-nitro-L-arginine methyl ester (L-NAME) + Sprague Dawley (SD) hypertension model, ABRQβ-006 lowered systolic blood pressure about 10 mmHg and attenuated vascular remodeling, myocardial hypertrophy and perivascular fibrosis. In the pressure-overload transverse aortic constriction (TAC) model, ABRQβ-006 significantly improved cardiac function, decreased myocardial hypertrophy, perivascular fibrosis and vascular remodeling. In the myocardial infarction (MI) model, ABRQβ-006 effectively improved cardiac remodeling, reduced cardiac fibrosis and inflammatory infiltration, which was superior to metoprolol. Moreover, no significant immune-mediated damage was observed in immunized animals. The ABRQβ-006 vaccine targeting β1-AR showed the effects on hypertension and heart rate control, myocardial remodeling inhibition and cardiac function protection. These effects could be differentiated in different types of diseases with diverse pathogenesis. ABRQβ-006 could be a novel and promising method for the treatment of hypertension and heart failure with different etiologies.

Negative findings but positive contributions in cardiovascular research

Researchers have always concluded that results that do not support the hypothesis as unimportant, unworthy, or simply not good enough for publication. However, negative findings are essential for the progress of science and its self-correcting nature. We also believe in the importance and indispensability of negative results. Therefore, in this review, we discussed the factors contributing to the publication bias of negative results and the problems to assess the factuality and validity of negative results. Moreover, we emphasized the importance of reporting negative results in cardiovascular research, including treatments, and suggest that the negative results could clarify previously controversial topics in the treatment of cardiovascular diseases and prompt the translation of research on precision cardiovascular disease prevention and treatment.

Neutrophil β1 adrenoceptor blockade blunts stroke-associated neuroinflammation

BACKGROUND AND PURPOSE

Reperfusion therapy is the standard of care for ischaemic stroke; however, there is a need to identify new therapeutic targets able to ameliorate cerebral damage. Neutrophil β₁ adrenoceptors (β1AR) have been linked to neutrophil migration during exacerbated inflammation. Given the central role of neutrophils in cerebral damage during stroke, we hypothesize that β1AR blockade will improve stroke outcomes.

EXPERIMENTAL APPROACH

Rats were subjected to middle cerebral artery occlusion-reperfusion to evaluate the effect on stroke of the selective β1AR blocker metoprolol (12.5 mg·kg^-1 ) when injected i.v. 10 min before reperfusion.

KEY RESULTS

Magnetic resonance imaging and histopathology analysis showed that pre-reperfusion i.v. metoprolol reduced infarct size. This effect was accompanied by reduced cytotoxic oedema at 24 h and vasogenic oedema at 7 days. Metoprolol-treated rats showed reduced brain neutrophil infiltration and those which infiltrated displayed a high proportion of anti-inflammatory phenotype (N2, YM1⁺ ). Additional inflammatory models demonstrated that metoprolol specifically blocked neutrophil migration via β1AR and excluded a significant effect on the glia compartment. Consistently, metoprolol did not protect the brain in neutrophil-depleted rats upon stroke. In patients suffering an ischaemic stroke, β1AR blockade by metoprolol reduced circulating neutrophil-platelet co-aggregates.

CONCLUSIONS AND IMPLICATIONS

Our findings describe that β1AR blockade ameliorates cerebral damage by targeting neutrophils, identifying a novel therapeutic target to improve outcomes in patients with stroke. This therapeutic strategy is in the earliest stages of the translational pathway and should be further explored.

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.

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.

The Roles of Neutrophils Linking Periodontitis and Atherosclerotic Cardiovascular Diseases

Inflammation plays a crucial role in the onset and development of atherosclerosis. Periodontitis is a common chronic disease linked to other chronic inflammatory diseases such as atherosclerotic cardiovascular disease (ASCVD). The mechanistic pathways underlying this association are yet to be fully understood. This critical review aims at discuss the role of neutrophils in mediating the relationship between periodontitis and ASCVD. Systemic inflammation triggered by periodontitis could lead to adaptations in hematopoietic stem and progenitor cells (HSPCs) resulting in trained granulopoiesis in the bone marrow, thereby increasing the production of neutrophils and driving the hyper-responsiveness of these abundant innate-immune cells. These alterations may contribute to the onset, progression, and complications of atherosclerosis. Despite the emerging evidence suggesting that the treatment of periodontitis improves surrogate markers of cardiovascular disease, the resolution of periodontitis may not necessarily reverse neutrophil hyper-responsiveness since the hyper-inflammatory re-programming of granulopoiesis can persist long after the inflammatory inducers are removed. Novel and targeted approaches to manipulate neutrophil numbers and functions are warranted within the context of the treatment of periodontitis and also to mitigate its potential impact on ASCVD.

The effectiveness of alprostadil in treating coronary microcirculation dysfunction following ST-segment elevation myocardial infarction in a pig model

Though alprostadil has been reported to improve the impaired microcirculation of patients with pulmonary arterial hypertension, its effectiveness as a treatment for coronary microvasculature dysfunction (CMD) following ST-segment elevation myocardial infarction (STEMI) is unknown. A total of 18 miniature pigs with CMD following STEMI were randomized into three groups that received an intracoronary injection of 5 ml of normal saline, 2 mg of nicorandil or 10 µg of alprostadil immediately after measurement of the index of microcirculatory resistance (IMR) and then an intravenous drip containing 5 ml of normal saline, 2 mg of nicorandil or 10 µg of alprostadil once a day for 6 days. The IMR, cardiac function using ultrasound, infarct areas and heparanase levels in infarct areas were measured and compared between the three groups. The IMR decreased markedly 10 min after alprostadil or nicorandil intracoronary injection (both P<0.05) but not following saline injection (P>0.05). After 7 days, the IMR was substantially lower in the alprostadil and nicorandil groups compared with the saline group (both P<0.05) and the ejection fraction was considerably higher in the alprostadil and nicorandil groups compared with the saline group (both P<0.05). Differences in infarct areas and the relative heparanase expression levels among the 3 groups were similar to the differences in the ejection fraction. No significant differences in the above assessment indexes were identified in the alprostadil and nicorandil groups. Alprostadil infusion improved coronary microcirculation function, reduced the infarct area and limited left ventricular dilatation in a pig coronary microvasculature dysfunction model following STEMI.

Long-Term Effect of Non-Selective Beta-Blockers in Patients With Rheumatoid Arthritis After Myocardial Infarction-A Nationwide Cohort Study

Objectives: Rheumatoid arthritis (RA) is an independent nontraditional risk factor for incidence of myocardial infarction (MI) and post-MI outcome is impaired in the RA population. Use of beta-blockers improves the long-term survival after MI in the general population while the protective effect of beta-blockers in RA patients is not clear. We investigate the impact of beta-blockers on the long-term outcome of MI among RA patients.

Methods: We identified RA subjects from the registries for catastrophic illness and myocardial infarction from 2003 to 2013. The enrolled subjects were divided into three groups according to the prescription of beta-blockers (non-user, non-selective, and β1-selective beta-blockers). The primary endpoint was all-cause mortality. We adjusted clinical variables and utilized propensity scores to balance confounding bias. Cox proportional hazards regression models were used to estimate the incidence of mortality in different groups.

Results: A total of 1,292 RA patients with myocardial infarction were enrolled, where 424 (32.8%), 281 (21.7%), and 587 (45.5%) subjects used non-user, non-selective, and β1-selective beta-blockers, respectively. Use of beta-blockers was associated with lower risk of all-cause mortality after adjustment with comorbidities, medications (adjusted hazard ratio [HR] 0.871; 95% confidence interval [CI] 0.727–0.978), and propensity score (HR 0.882; 95% CI 0.724–0.982). Compared with β1-selective beta-blockers, treatment with non-selective beta-blockers (HR 0.856; 95% CI 0.702–0.984) was significantly related to lower risk of mortality. The protective effect of non-selective beta-blockers remained in different subgroups including sex and different anti-inflammatory drugs.

Conclusion: Use of beta-blockers improved prognosis in post-MI patients with RA. Treatment with non-selective beta-blockers was significantly associated with reduced risk of mortality in RA patients after MI rather than β1-selective beta-blockers.

Metoprolol in Critically Ill Patients With COVID-19

BACKGROUND

Severe coronavirus disease-2019 (COVID-19) can progress to an acute respiratory distress syndrome (ARDS), which involves alveolar infiltration by activated neutrophils. The beta-blocker metoprolol has been shown to ameliorate exacerbated inflammation in the myocardial infarction setting.

OBJECTIVES

The purpose of this study was to evaluate the effects of metoprolol on alveolar inflammation and on respiratory function in patients with COVID-19-associated ARDS.

METHODS

A total of 20 COVID-19 patients with ARDS on invasive mechanical ventilation were randomized to metoprolol (15 mg daily for 3 days) or control (no treatment). All patients underwent bronchoalveolar lavage (BAL) before and after metoprolol/control. The safety of metoprolol administration was evaluated by invasive hemodynamic and electrocardiogram monitoring and echocardiography.

RESULTS

Metoprolol administration was without side effects. At baseline, neutrophil content in BAL did not differ between groups. Conversely, patients randomized to metoprolol had significantly fewer neutrophils in BAL on day 4 (median: 14.3 neutrophils/µl [Q1, Q3: 4.63, 265 neutrophils/µl] vs median: 397 neutrophils/µl [Q1, Q3: 222, 1,346 neutrophils/µl] in the metoprolol and control groups, respectively; P = 0.016). Metoprolol also reduced neutrophil extracellular traps content and other markers of lung inflammation. Oxygenation (PaO2:FiO2) significantly improved after 3 days of metoprolol treatment (median: 130 [Q1, Q3: 110, 162] vs median: 267 [Q1, Q3: 199, 298] at baseline and day 4, respectively; P = 0.003), whereas it remained unchanged in control subjects. Metoprolol-treated patients spent fewer days on invasive mechanical ventilation than those in the control group (15.5 ± 7.6 vs 21.9 ± 12.6 days; P = 0.17).

CONCLUSIONS

In this pilot trial, intravenous metoprolol administration to patients with COVID-19-associated ARDS was safe, reduced exacerbated lung inflammation, and improved oxygenation. Repurposing metoprolol for COVID-19-associated ARDS appears to be a safe and inexpensive strategy that can alleviate the burden of the COVID-19 pandemic.

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.

Intravenous metoprolol during ongoing STEMI ameliorates markers of ischemic injury: a METOCARD-CNIC trial electrocardiographic study

Besides its protective effect against neutrophil-mediated injury at reperfusion, intravenous (IV) metoprolol was recently shown to reduce the progression of ischemic injury in a pig model of ST-segment elevation myocardial infarction (STEMI). Here, we tested the hypothesis that IV metoprolol administration in humans with ongoing STEMI blunts the time‑dependent progression of ischemic injury assessed by serial electrocardiogram (ECG) evaluations before reperfusion. The METOCARD-CNIC trial randomized 270 anterior STEMI patients to IV metoprolol or control before reperfusion by percutaneous coronary intervention (PCI). In 139 patients (69 IV metoprolol, 70 controls), two ECGs were available (ECG-1 before randomization, ECG-2 pre-PCI). Between-group ECG differences were analyzed using univariate and multivariate regression models. No significant between-group differences were observed on ECG-1. On ECG-2, patients who received IV metoprolol had a narrower QRS than those in the control group (84 ms vs. 90 ms, p = 0.029), a lower prevalence of QRS distortion (10% vs. 26%, p = 0.017), and a lower sum of anterior and total ST-segment elevation (10.1 mm vs. 13.6 mm, p = 0.014 and 10.4 mm vs. 14.0 mm, p = 0.015, respectively). Adjusted analysis revealed similar results. Significant associations were observed between ECG-2 variables and cardiac magnetic resonance imaging measurements (extent of myocardial edema, infarct size, microvascular obstruction, and left-ventricular ejection fraction) after STEMI. In summary, IV metoprolol administration before reperfusion ameliorates ECG markers of myocardial ischemia in anterior STEMI patients. These data confirm that IV metoprolol is able to reduce ischemic injury and highlight the ability of ECG analysis to provide relevant real-time information on the effect of cardioprotective therapies before reperfusion.

Culprit site extracellular DNA and microvascular obstruction in ST-elevation myocardial infarction

AIMS

Extracellular chromatin and deoxyribonuclease (DNase) have been identified as important players of thrombosis, inflammation and homeostasis in a murine model. We previously demonstrated that activated neutrophils release neutrophil extracellular traps (NETs) at the culprit site in ST elevation myocardial infarction (STEMI), which significantly contribute to extracellular chromatin burden, and are associated with larger infarcts. To understand the correlation between neutrophil activation, extracellular chromatin and infarct size (IS), we investigated these parameters in a porcine myocardial infarction model, and at different time points and sites in a prospective STEMI trial with cardiac magnetic resonance (CMR) endpoints.

METHODS AND RESULTS

In a prospective STEMI trial (NCT01777750), 101 STEMI patients were included and blood samples were obtained from first medical contact until 6 months after primary percutaneous coronary intervention (pPCI) including direct sampling from the culprit site. CMR was performed 4 ± 2 days and 6 months after pPCI. Neutrophil counts, markers of extracellular chromatin and inflammation were measured. Double-stranded DNA (dsDNA), citrullinated histone 3, nucleosomes, myeloperoxidase, neutrophil elastase and interleukin (IL)-6 were significantly increased, while DNase activity was significantly decreased at the culprit site in STEMI patients. High neutrophil counts and dsDNA levels at the culprit site correlated with high microvascular obstruction (MVO) and low ejection fraction (EF). High DNase activity at the culprit site correlated with low MVO and high EF.In correspondence, dsDNA correlated with IS in the porcine myocardial infarction model. In porcine infarcts, neutrophils and extracellular chromatin were detected in congested small arteries corresponding with MVO. Markers of neutrophil activation, extracellular chromatin, DNase activity and CMR measurements correlated with markers of systemic inflammation C-reactive protein and IL-6 in patients.

CONCLUSIONS

NETs and extracellular chromatin are important determinants of MVO in STEMI. Rapid degradation of extracellular chromatin by DNases appears to be crucial for microvascular patency and outcome.

TRANSLATIONAL PERSPECTIVE

We show that NETs and extracellular DNA obstruct microvessels in the porcine myocardial infarction model and is connected to increased infarct size. We are able to prove this observation in human STEMI patients. DNase is capable to counteract these effects. Extracellular DNA could be a new treatment target in STEMI.

Heart Repair Induced by Cardiac Progenitor Cell Delivery within Polypyrrole-Loaded Cardiogel Post-ischemia

Myocardial infarction (MI) irreversibly injures the heart tissue. Cardiovascular tissue engineering has been developed as a promising therapeutic approach for post-MI repair. Previously, we discovered the ability of a polypyrrole (PPy)-incorporated cardiogel (CG) for improvement of maturity and functional synchrony of rat neonatal cardiomyocytes. Here, we used the cross-linked form of PPy-incorporated CG (CG-PPy), in order to improve electromechanical properties of scaffold, for application in cardiac progenitor cell (CPC) transplantation on post-MI rat hearts. Improved mechanical property and electrical conductivity (sixfold) were evident in the cross-linked CG-PPy (P1) compared to cross-linked CG (C1) scaffolds. Transplantation of CPC-loaded P1 (P1-CPC) resulted in substantial improvement of cardiac functional properties. Furthermore, lower fibrotic tissue and higher CPC retention were observed. The grafted cells showed cardiomyocyte characteristics when stained with human cardiac troponin T and connexin43 antibodies, while neovessel formation was similarly prominent. These findings highlight the therapeutic promise of the P1 scaffold as a CPC carrier for functional restoration of the heart post-MI.

Management strategies for STE-ACS

ABSTRACT

Using guideline-driven interventions, NPs are well suited for management of ST-segment elevation (STE)-acute coronary syndrome (ACS). This second article in a two-part series on ACS management presents an updated overview to help NPs in applying evidence-based interventions while caring for patients with STE-ACS.

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.

Metoprolol exerts a non-class effect against ischaemia-reperfusion injury by abrogating exacerbated inflammation

Aims

Clinical guidelines recommend early intravenous β-blockers during ongoing myocardial infarction; however, it is unknown whether all β-blockers exert a similar cardioprotective effect. We experimentally compared three clinically approved intravenous β-blockers.

Methods and results

Mice undergoing 45 min/24 h ischaemia–reperfusion (I/R) received vehicle, metoprolol, atenolol, or propranolol at min 35. The effect on neutrophil infiltration was tested in three models of exacerbated inflammation. Neutrophil migration was evaluated in vitro and in vivo by intravital microscopy. The effect of β-blockers on the conformation of the β1 adrenergic receptor was studied in silico. Of the tested β-blockers, only metoprolol ameliorated I/R injury [infarct size (IS) = 18.0% ± 0.03% for metoprolol vs. 35.9% ± 0.03% for vehicle; P < 0.01]. Atenolol and propranolol had no effect on IS. In the three exacerbated inflammation models, neutrophil infiltration was significantly attenuated only in the presence of metoprolol (60%, 50%, and 70% reductions vs. vehicle in myocardial I/R injury, thioglycolate-induced peritonitis, and lipopolysaccharide-induced acute lung injury, respectively). Migration studies confirmed the particular ability of metoprolol to disrupt neutrophil dynamics. In silico analysis indicated different intracellular β1 adrenergic receptor conformational changes when bound to metoprolol than to the other two β-blockers.

Conclusions

Metoprolol exerts a disruptive action on neutrophil dynamics during exacerbated inflammation, resulting in an infarct-limiting effect not observed with atenolol or propranolol. The differential effect of β-blockers may be related to distinct conformational changes in the β1 adrenergic receptor upon metoprolol binding. If these data are confirmed in a clinical trial, metoprolol should become the intravenous β-blocker of choice for patients with ongoing infarction.

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. 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.

Left Ventricular Ejection Fraction 1 Year After Acute Myocardial Infarction Identifies the Benefits of the Long-Term Use of β-Blockers: Analysis of Data From the KAMIR-NIH Registry

[Figure: see text].

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.

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.

The impact of optimal medical therapy on patients with recurrent acute myocardial infarction: Subanalysis from the BleeMACS study

BACKGROUND

Acute myocardial infarction (AMI) recurrence is still high despite great progress in secondary prevention. Patients with recurrent AMI suffer worse prognosis compared to those with first AMI. The objective was to evaluate the effect of optimal medical therapy (OMT) on these patients with recurrent AMI.

METHODS AND RESULTS

Sub-analysis was performed including 13,343 patients with AMI from the international multicenter Bleeding complications in a Multicenter registry of patients discharged with diagnosis of Acute Coronary Syndrome (BleeMACS) registry. OMT was defined as the combination of aspirin, any P2Y12 inhibitor, statin, angiotensin converting enzyme inhibitor/angiotensin receptor blocker, and beta-blocker. Among 1285 patients with prior AMI, 56.8% received OMT prescription. Patients receiving OMT suffered from less congestive heart failure, peripheral artery disease, malignancy, and bleeding history. Kaplan-Meier survival estimates revealed that OMT was strongly related to decreased in all-cause death (4.2% vs. 10.1%, p < .001) and the composite endpoint of death/re-AMI (11.1% vs. 16.9%, p = .005) at 1-year follow-up. OMT was the independent protect factor of primary endpoint even after adjusting for multiple possible confounders (HR, 0.46; 95% CI, 0.27-0.78; p = .004). However, no significant difference was observed regarding re-AMI between OMT and non-OMT groups. OMT also reduced all-cause death in patients with recurrent AMI after propensity score matching.

CONCLUSIONS

The prescription of OMT was seriously insufficient in patients with recurrent AMI, especially high-risk patients, even though OMT was associated with improved prognosis. Further improvements in pharmacological therapy are needed to reduce subsequent recurrent events.

Cardioprotection of pharmacological postconditioning on myocardial ischemia/reperfusion injury

Acute myocardial infarction is associated with high rates of morbidity and mortality and can cause irreversible myocardial damage. Timely reperfusion is critical to limit infarct size and salvage the ischemic myocardium. However, reperfusion may exacerbate lethal tissue injury, a phenomenon known as myocardial ischemia/reperfusion (I/R) injury. Pharmacological postconditioning (PPC), a strategy involving medication administration before or during the early minutes of reperfusion, is more efficient and flexible than preconditioning or ischemic conditioning. Previous studies have shown that various mechanisms are involved in the effects of PPC. In this review, we summarize the relative effects and potential underlying mechanisms of PPC to provide a foundation for future research attempting to develop novel treatments against myocardial I/R injury.

Five-Year Outcomes and Prognostic Value of Feature-Tracking Cardiovascular Magnetic Resonance in Patients Receiving Early Prereperfusion Metoprolol in Acute Myocardial Infarction

The aim of the present study was to investigate the long-term impact of early intravenous metoprolol in ST-segment elevation myocardial infarction (STEMI) patients in terms of left ventricular (LV) strain with feature-tracking cardiovascular magnetic resonance (CMR) and its association with prognosis. A total of 270 patients with first anterior STEMI enrolled in the randomized METOCARD-CNIC clinical trial, assigned to receive up to 15 mg intravenous metoprolol before primary percutaneous coronary intervention versus conventional STEMI therapy, were included. LV global circumferential (GCS) and longitudinal (GLS) strain were assessed with feature-tracking CMR at 1 week after STEMI in 215 patients. The occurrence of major adverse cardiac events (MACE) at 5-year follow-up was the primary end point. Among 270 patients enrolled, 17 of 139 patients assigned to metoprolol arm and 31 of 131 patients assigned to control arm experienced MACE (hazard ratio [HR] 0.500, 95% confidence interval [CI] 0.277 to 0.903; p = 0.022). Impaired LV GCS and GLS strain were significantly associated with increased occurrence of MACE (GCS: HR 1.208, 95% CI 1.076 to 1.356, p =0.001; GLS: HR 1.362, 95% CI 1.180 to 1.573, p < 0.001). On multivariable analysis, LV GLS provided incremental prognostic value over late gadolinium enhancement (LGE) and LV ejection fraction (LVEF) (LGE + LVEF chi-square = 12.865, LGE + LVEF + GLS chi-square = 18.459; p =0.012). Patients with GLS ≥-11.5% (above median value) who received early intravenous metoprolol were 64% less likely to experience MACE than their counterparts with same degree of GLS impairment (HR 0.356, 95% CI 0.129 to 0.979; p = 0.045). In conclusion, early intravenous metoprolol has a long-term beneficial prognostic effect, particularly in patients with severely impaired LV systolic function. LV GLS with feature-tracking CMR early after percutaneous coronary intervention offers incremental prognostic value over conventional CMR parameters in risk stratification of STEMI patients.

2020 Korean Society of Myocardial Infarction Expert Consensus Document on Pharmacotherapy for Acute Myocardial Infarction

Clinical practice guidelines published by the European Society of Cardiology and the American College of Cardiology/American Heart Association summarize the available evidence and provide recommendations for health professionals to enable appropriate clinical decisions and improve clinical outcomes for patients with acute myocardial infarction (AMI). However, most current guidelines are based on studies in non-Asian populations in the pre-percutaneous coronary intervention (PCI) era. The Korea Acute Myocardial Infarction Registry is the first nationwide registry to document many aspects of AMI from baseline characteristics to treatment strategies. There are well-organized ongoing and published randomized control trials especially for antiplatelet therapy among Korean patients with AMI. Here, members of the Task Force of the Korean Society of Myocardial Infarction review recent published studies during the current PCI era, and have summarized the expert consensus for the pharmacotherapy of AMI.

Coexistence of transmural and lateral wavefront progression of myocardial infarction in the human heart

INTRODUCTION AND OBJECTIVES

According to the wavefront phenomenon described in the late 1970s, myocardial infarction triggered by acute coronary occlusion progresses with increasing duration of ischemia as a transmural wavefront from the subendocardium toward the subepicardium. However, whether wavefront progression of necrosis also occurs laterally has been disputed. We aimed to assess the transmural and lateral spread of myocardial damage after acute myocardial infarction in humans and to evaluate the impact of metoprolol on these.

METHODS

We assessed myocardial infarction in the transmural and lateral dimensions in a cohort of 220 acute ST-segment elevation myocardial infarction (STEMI) patients from the METOCARD-CNIC trial (Effect of Metoprolol in Cardioprotection During an Acute Myocardial Infarction). The patients underwent cardiac magnetic resonance imaging at 5 to 7 days and 6 months post-STEMI.

RESULTS

On day 5 to 7 post-STEMI cardiac magnetic resonance, there was a strong linear correlation between the transmural and lateral extent of infarction (delayed gadolinium enhancement) (r=-0.88; P<.001). Six months after STEMI, myocardial scarring (delayed gadolinium enhancement) was significantly less extensive in the transmural and lateral dimensions, suggesting that infarct resorption occurs in both. Furthermore, progression in both directions occurred both in patients receiving metoprolol and control patients, implying that myocardial salvage occurs both in the transmural and the lateral direction.

CONCLUSIONS

Our findings challenge the assumption that irreversible injury does not spread laterally. A "circumferential" or multidirectional wavefront would imply that cardioprotective therapies might produce meaningful salvage at lateral borders of the infarct. This trial was registered at ClinicalTrial.gov (Identifier: NCT01311700).

Metoprolol blunts the time-dependent progression of infarct size

Early metoprolol administration protects against myocardial ischemia–reperfusion injury, but its effect on infarct size progression (ischemic injury) is unknown. Eight groups of pigs (total n = 122) underwent coronary artery occlusion of varying duration (20, 25, 30, 35, 40, 45, 50, or 60 min) followed by reperfusion. In each group, pigs were randomized to i.v. metoprolol (0.75 mg/kg) or vehicle (saline) 20 min after ischemia onset. The primary outcome measure was infarct size (IS) on day7 cardiac magnetic resonance (CMR) normalized to area at risk (AAR, measured by perfusion computed tomography [CT] during ischemia). Metoprolol treatment reduced overall mortality (10% vs 26%, p = 0.03) and the incidence and number of primary ventricular fibrillations during infarct induction. In controls, IS after 20-min ischemia was ≈ 5% of the area AAR. Thereafter, IS progressed exponentially, occupying almost all the AAR after 35 min of ischemia. Metoprolol injection significantly reduced the slope of IS progression (p = 0.004 for final IS). Head-to-head comparison (metoprolol treated vs vehicle treated) showed statistically significant reductions in IS at 30, 35, 40, and 50-min reperfusion. At 60-min reperfusion, IS was 100% of AAR in both groups. Despite more prolonged ischemia, metoprolol-treated pigs reperfused at 50 min had smaller infarcts than control pigs undergoing ischemia for 40 or 45 min and similar-sized infarcts to those undergoing 35-min ischemia. Day-45 LVEF was higher in metoprolol-treated vs vehicle-treated pigs (41.6% vs 36.5%, p = 0.008). In summary, metoprolol administration early during ischemia attenuates IS progression and reduces the incidence of primary ventricular fibrillation. These data identify metoprolol as an intervention ideally suited to the treatment of STEMI patients identified early in the course of infarction and requiring long transport times before primary angioplasty.

Effects of chronic beta-blocker treatment on admission haemodynamics in STEMI patients treated with primary angioplasty

Background:

The association between chronic beta-blocker treatment and haemodynamics at admission in patients with ST-segment elevation myocardial infarction treated by primary percutaneous coronary intervention is not well studied. We investigated the impact of chronic beta-blocker treatment on the risk of cardiogenic shock and pre-shock at admission in patients with ST-segment elevation myocardial infarction treated by primary percutaneous coronary intervention.

Methods and results:

A total of 4907 patients with ST-segment elevation myocardial infarction treated with primary percutaneous coronary intervention were included in the study. A total of 1148 patients (23.3%) were on chronic beta-blocker treatment. Cardiogenic shock was observed in 264 patients (5.3%). Pre-shock was defined as a shock index (the ratio of heart rate and systolic blood pressure) of 0.7 or greater, and was observed in 1022 patients (20.8%). The risk of cardiogenic shock in patients with chronic beta-blocker treatment was not increased (adjusted hazard ratio (HR) 0.97, 95% confidence interval (CI) 0.65–1.46, P=0.90). Chronic beta-blocker treatment was also not associated with an increased risk of pre-shock (adjusted HR 0.86, 95% CI 0.68–1.07, P=0.19). Also after propensity score matched analysis, there was no increased risk of cardiogenic shock or pre-shock in patients with chronic beta-blocker treatment (respectively HR 0.97, 95% CI 0.61–1.51, P=0.88 and HR 0.82, 95% CI 0.65–1.06, P=0.12).

Conclusion:

In ST-segment elevation myocardial infarction, chronic beta-blocker treatment is not associated with an increased risk of cardiogenic shock or pre-shock.

Novel Findings and Therapeutic Targets on Cardioprotection of Ischemia/ Reperfusion Injury in STEMI

Acute ST-segment elevation myocardial infarction (STEMI) remains a leading cause of morbidity and mortality around the world. A large number of STEMI patients after the infarction gradually develop heart failure due to the infarcted myocardium. Timely reperfusion is essential to salvage ischemic myocardium from the infarction, but the restoration of coronary blood flow in the infarct-related artery itself induces myocardial injury and cardiomyocyte death, known as ischemia/reperfusion injury (IRI). The factors contributing to IRI in STEMI are complex, and microvascular obstruction, inflammation, release of reactive oxygen species, myocardial stunning, and activation of myocardial cell death are involved. Therefore, additional cardioprotection is required to prevent the heart from IRI. Although many mechanical conditioning procedures and pharmacological agents have been identified as effective cardioprotective approaches in animal studies, their translation into the clinical practice has been relatively disappointing due to a variety of reasons. With new emerging data on cardioprotection in STEMI over the past few years, it is mandatory to reevaluate the effectiveness of "old" cardioprotective interventions and highlight the novel therapeutic targets and new treatment strategies of cardioprotection.

Randomized controlled trial of landiolol, a short-acting beta-1 adrenergic receptor blocker, illustrating changes in high-molecular weight adiponectin levels after elective percutaneous coronary intervention

Adiponectin (APN) has cardioprotective properties and bisoprolol has been reported to increase myocardial APN expression and reduce myocardial damage. Administration of landiolol, which has a higher cardio-selectivity and shorter half-life than bisoprolol, during the percutaneous coronary intervention (PCI) may increase serum APN and high-molecular weight (HMW)-APN, an active form of APN, in patients with stable angina pectoris (SAP). We recruited 70 patients with SAP and randomized them to intravenous landiolol during PCI (N = 35) or control group (N = 35). The primary endpoint was serum APN and HMW-APN level 3 days after PCI. There was no difference in the primary endpoint between the landiolol and control groups (8.93 ± 5.24 vs. 10.18 ± 5.81 μg/mL, p = 0.35 and 3.36 ± 2.75 vs. 4.28 ± 3.13 μg/mL, p = 0.20) for APN and HMW-APN levels, respectively. APN and HMW-APN level were significantly decreased 1 day after PCI [-0.55 ± 0.92 μg/mL (9.87-9.32 μg/mL), p < 0.001 and -0.20 ± 0.45 μg/mL (3.89-3.69 μg/mL), p < 0.001, respectively]. Additionally, the absolute change in HMW-APN was significantly smaller in the landiolol group compared to the control group (-0.08 ± 0.27 vs. -0.31 ± 0.55 μg/mL, p = 0.031). Multiple linear regression analysis showed that use of landiolol was an independent predictor of change in HMW-APN (β = 0.276, p = 0.014). Serum APN and HMW-APN level 3 days after PCI were similar between patients treated with and without landiolol. APN and HMW-APN decreased 1 day after PCI in the SAP and landiolol mitigated decrease in HMW-APN.

Left ventricular functional recovery of infarcted and remote myocardium after ST-segment elevation myocardial infarction (METOCARD-CNIC randomized clinical trial substudy)

BACKGROUND

We aimed to evaluate the effect of early intravenous metoprolol treatment, microvascular obstruction (MVO), intramyocardial hemorrhage (IMH) and adverse left ventricular (LV) remodeling on the evolution of infarct and remote zone circumferential strain after acute anterior ST-segment elevation myocardial infarction (STEMI) with feature-tracking cardiovascular magnetic resonance (CMR).

METHODS

A total of 191 patients with acute anterior STEMI enrolled in the METOCARD-CNIC randomized clinical trial were evaluated. LV infarct zone and remote zone circumferential strain were measured with feature-tracking CMR at 1 week and 6 months after STEMI.

RESULTS

In the overall population, the infarct zone circumferential strain significantly improved from 1 week to 6 months after STEMI (- 8.6 ± 9.0% to - 14.5 ± 8.0%; P < 0.001), while no changes in the remote zone strain were observed (- 19.5 ± 5.9% to - 19.2 ± 3.9%; P = 0.466). Patients who received early intravenous metoprolol had significantly more preserved infarct zone circumferential strain compared to the controls at 1 week (P = 0.038) and at 6 months (P = 0.033) after STEMI, while no differences in remote zone strain were observed. The infarct zone circumferential strain was significantly impaired in patients with MVO and IMH compared to those without (P < 0.001 at 1 week and 6 months), however it improved between both time points regardless of the presence of MVO or IMH (P < 0.001). In patients who developed adverse LV remodeling (defined as ≥ 20% increase in LV end-diastolic volume) remote zone circumferential strain worsened between 1 week and 6 months after STEMI (P = 0.036), while in the absence of adverse LV remodeling no significant changes in remote zone strain were observed.

CONCLUSIONS

Regional LV circumferential strain with feature-tracking CMR allowed comprehensive evaluation of the sequelae of an acute STEMI treated with primary percutaneous coronary intervention and demonstrated long-lasting cardioprotective effects of early intravenous metoprolol.

TRIAL REGISTRATION

ClinicalTrials.gov, NCT01311700. Registered 8 March 2011 - Retrospectively registered.

Intensive care for human hearts in pluripotent stem cell models

Successful drug discovery is ultimately contingent on the availability of workable, relevant, predictive model systems. Conversely, for cardiac muscle, the lack of human preclinical models to inform target validation and compound development has likely contributed to the perennial problem of clinical trial failures, despite encouraging non-human results. By contrast, human cardiomyocytes produced from pluripotent stem cell models have recently been applied to safety pharmacology, phenotypic screening, target validation and high-throughput assays, facilitating cardiac drug discovery. Here, we review the impact of human pluripotent stem cell models in cardiac drug discovery, discussing the range of applications, readouts, and disease models employed, along with the challenges and prospects to advance this fruitful mode of research further.

Pathophysiology and diagnosis of coronary microvascular dysfunction in ST-elevation myocardial infarction

Early mechanical reperfusion of the epicardial coronary artery by primary percutaneous coronary intervention (PCI) is the guideline-recommended treatment for ST-elevation myocardial infarction (STEMI). Successful restoration of epicardial coronary blood flow can be achieved in over 95% of PCI procedures. However, despite angiographically complete epicardial coronary artery patency, in about half of the patients perfusion to the distal coronary microvasculature is not fully restored, which is associated with increased morbidity and mortality. The exact pathophysiological mechanism of post-ischaemic coronary microvascular dysfunction (CMD) is still debated. Therefore, the current review discusses invasive and non-invasive techniques for the diagnosis and quantification of CMD in STEMI in the clinical setting as well as results from experimental in vitro and in vivo models focusing on ischaemic-, reperfusion-, and inflammatory damage to the coronary microvascular endothelial cells. Finally, we discuss future opportunities to prevent or treat CMD in STEMI patients.

CIBER-CLAP (CIBERCV Cardioprotection Large Animal Platform): A multicenter preclinical network for testing reproducibility in cardiovascular interventions

Despite many cardioprotective interventions have shown to protect the heart against ischemia/reperfusion injury in the experimental setting, only few of them have succeeded in translating their findings into positive proof-of-concept clinical trials. Controversial and inconsistent experimental and clinical evidence supports the urgency of a disruptive paradigm shift for testing cardioprotective therapies. There is a need to evaluate experimental reproducibility before stepping into the clinical arena. The CIBERCV (acronym for Spanish network-center for cardiovascular biomedical research) has set up the "Cardioprotection Large Animal Platform" (CIBER-CLAP) to perform experimental studies testing the efficacy and reproducibility of promising cardioprotective interventions based on a pre-specified design and protocols, randomization, blinding assessment and other robust methodological features. Our first randomized, control-group, open-label blinded endpoint experimental trial assessing local ischemic preconditioning (IPC) in a pig model of acute myocardial infarction (n = 87) will be carried out in three separate sets of experiments performed in parallel by three laboratories. Each set aims to assess: (A) CMR-based outcomes; (B) histopathological-based outcomes; and (C) protein-based outcomes. Three core labs will assess outcomes in a blinded fashion (CMR imaging, histopathology and proteomics) and 2 methodological core labs will conduct the randomization and statistical analysis.

Beta-blockers for suspected or diagnosed acute myocardial infarction

BACKGROUND

Cardiovascular disease is the number one cause of death globally. According to the World Health Organization, 7.4 million people died from ischaemic heart diseases in 2012, constituting 15% of all deaths. Acute myocardial infarction is caused by blockage of the blood supplied to the heart muscle. Beta-blockers are often used in patients with acute myocardial infarction. Previous meta-analyses on the topic have shown conflicting results ranging from harms, neutral effects, to benefits. No previous systematic review using Cochrane methodology has assessed the effects of beta-blockers for acute myocardial infarction.

OBJECTIVES

To assess the benefits and harms of beta-blockers compared with placebo or no intervention in people with suspected or diagnosed acute myocardial infarction.

SEARCH METHODS

We searched CENTRAL, MEDLINE, Embase, LILACS, Science Citation Index Expanded and BIOSIS Citation Index in June 2019. We also searched the WHO International Clinical Trials Registry Platform, ClinicalTrials.gov, Turning Research into Practice, Google Scholar, SciSearch, and the reference lists of included trials and previous reviews in August 2019.

SELECTION CRITERIA

We included all randomised clinical trials assessing the effects of beta-blockers versus placebo or no intervention in people with suspected or diagnosed acute myocardial infarction. Trials were included irrespective of trial design, setting, blinding, publication status, publication year, language, and reporting of our outcomes.

DATA COLLECTION AND ANALYSIS

We followed the Cochrane methodological recommendations. Four review authors independently extracted data. Our primary outcomes were all-cause mortality, serious adverse events according to the International Conference on Harmonization - Good Clinical Practice (ICH-GCP), and major adverse cardiovascular events (composite of cardiovascular mortality and non-fatal myocardial infarction during follow-up). Our secondary outcomes were quality of life, angina, cardiovascular mortality, and myocardial infarction during follow-up. Our primary time point of interest was less than three months after randomisation. We also assessed the outcomes at maximum follow-up beyond three months. Due to risk of multiplicity, we calculated a 97.5% confidence interval (CI) for the primary outcomes and a 98% CI for the secondary outcomes. We assessed the risks of systematic errors through seven bias domains in accordance to the instructions given in the Cochrane Handbook. The quality of the body of evidence was assessed by GRADE.

MAIN RESULTS

We included 63 trials randomising a total of 85,550 participants (mean age 57.4 years). Only one trial was at low risk of bias. The remaining trials were at high risk of bias. The quality of the evidence according to GRADE ranged from very low to high. Fifty-six trials commenced beta-blockers during the acute phase of acute myocardial infarction and seven trials during the subacute phase. At our primary time point 'less than three months follow-up', meta-analysis showed that beta-blockers versus placebo or no intervention probably reduce the risk of a reinfarction during follow-up (risk ratio (RR) 0.82, 98% confidence interval (CI) 0.73 to 0.91; 67,562 participants; 18 trials; moderate-quality evidence) with an absolute risk reduction of 0.5% and a number needed to treat for an additional beneficial outcome (NNTB) of 196 participants. However, we found little or no effect of beta-blockers when assessing all-cause mortality (RR 0.94, 97.5% CI 0.90 to 1.00; 80,452 participants; 46 trials/47 comparisons; high-quality evidence) with an absolute risk reduction of 0.4% and cardiovascular mortality (RR 0.99, 95% CI 0.91 to 1.08; 45,852 participants; 1 trial; moderate-quality evidence) with an absolute risk reduction of 0.4%. Regarding angina, it is uncertain whether beta-blockers have a beneficial or harmful effect (RR 0.70, 98% CI 0.25 to 1.84; 98 participants; 3 trials; very low-quality evidence) with an absolute risk reduction of 7.1%. None of the trials specifically assessed nor reported serious adverse events according to ICH-GCP. Only two trials specifically assessed major adverse cardiovascular events, however, no major adverse cardiovascular events occurred in either trial. At maximum follow-up beyond three months, meta-analyses showed that beta-blockers versus placebo or no intervention probably reduce the risk of all-cause mortality (RR 0.93, 97.5% CI 0.86 to 0.99; 25,210 participants; 21 trials/22 comparisons; moderate-quality evidence) with an absolute risk reduction of 1.1% and a NNTB of 91 participants, and cardiovascular mortality (RR 0.90, 98% CI 0.83 to 0.98; 22,457 participants; 14 trials/15 comparisons; moderate-quality evidence) with an absolute risk reduction of 1.2% and a NNTB of 83 participants. However, it is uncertain whether beta-blockers have a beneficial or harmful effect when assessing major adverse cardiovascular events (RR 0.81, 97.5% CI 0.40 to 1.66; 475 participants; 4 trials; very low-quality evidence) with an absolute risk reduction of 1.7%; reinfarction (RR 0.89, 98% CI 0.75 to 1.08; 6825 participants; 14 trials; low-quality evidence) with an absolute risk reduction of 0.9%; and angina (RR 0.64, 98% CI 0.18 to 2.0; 844 participants; 2 trials; very low-quality evidence). None of the trials specifically assessed nor reported serious adverse events according to ICH-GCP. None of the trials assessed quality of life. We identified two ongoing randomised clinical trials investigating the effect of early administration of beta-blockers after percutaneous coronary intervention or thrombolysis to patients with an acute myocardial infarction and one ongoing trial investigating the effect of long-term beta-blocker therapy.

AUTHORS' CONCLUSIONS

Our present review indicates that beta-blockers for suspected or diagnosed acute myocardial infarction probably reduce the short-term risk of a reinfarction and the long-term risk of all-cause mortality and cardiovascular mortality. Nevertheless, it is most likely that beta-blockers have little or no effect on the short-term risk of all-cause mortality and cardiovascular mortality. Regarding all remaining outcomes (serious adverse events according to ICH-GCP, major adverse cardiovascular events (composite of cardiovascular mortality and non-fatal myocardial infarction during follow-up), the long-term risk of a reinfarction during follow-up, quality of life, and angina), further information is needed to confirm or reject the clinical effects of beta-blockers on these outcomes for people with or suspected of acute myocardial infarction.