Rationale and design of a double-blind, multicenter, randomized, placebo-controlled clinical trial of early administration of intravenous β-blockers in patients with ST-elevation myocardial infarction before primary percutaneous coronary intervention: EARLY β-blocker administration before primary PCI in patients with ST-elevation myocardial infarction trial

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.

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.

Pre-treatment with a combination of Shenmai and Danshen injection protects cardiomyocytes against hypoxia/reoxygenation- and H2O2-induced injury by inhibiting mitochondrial permeability transition pore opening

Increasing evidence has indicated that opening of the mitochondrial permeability transition pore (mPTP) has a vital role in myocardial ischemia/reperfusion (I/R) injury. Shenmai injection (SMI) plus Danshen injection (DSI) combination, termed Yiqi Yangyin Huoxue (YYH) therapy is used in the clinic to treat cardiovascular diseases, including myocardial I/R injury. Previous studies by our group have demonstrated the protective effect of pretreatment with YYH against myocardial I/R injury in isolated rat hearts. The present study aimed to examine the protective effect of YYH against hypoxia/reoxygenation (H/R)- and H₂O₂-induced cardiomyocyte injury, and to determine whether this effect is produced by inhibition of mPTP opening. Primary cardiomyocytes isolated from neonatal rats were cultured and randomly grouped into a control group, injury group and pretreatment group, with six duplicated wells in each group during each assay. Cardiomyocytes in the injury group were subjected to H/R to simulate I/R or exposed to H₂O₂ for 2 h to induce oxidative injury. Cellular injury was assessed via release of creatine kinase (CK) and lactate dehydrogenase (LDH), and cell viability was measured by an MTT assay. The mitochondrial membrane potential (ΔΨm) and cytosolic reactive oxygen species (ROS) were detected using the fluorescent probes rhodamine123 (Rh123) and chloromethyl-2,7-dichlorodihydrofluorescein diacetate (CM-H₂DCFDA), respectively. Intracellular Ca²⁺, mitochondrial Ca²⁺ and mPTP opening were measured using fluo-4 acetoxymethyl (Fluo-4/AM), rhodamine-2 acetoxymethyl (Rhod-2/AM) and calcein acetoxymethyl (Calcein/AM) probes, respectively. The results indicated that pretreatment with YYH enhanced cell viability, increased ΔΨm, reduced CK and LDH release, and decreased intracellular ROS and Ca²⁺, thus reducing cardiomyocyte injury induced by H/R or H₂O₂. LY294002, a specific phosphoinositide 3-kinase (PI3K) inhibitor, and PD98059, a specific inhibitor of the extracellular signal-regulated kinase 1/2 (Erk1/2) pathway, eliminated the protective effects of the combination therapy on cell viability and the change in the ΔΨm in cardiomyocytes. In conclusion, pre-treatment with YYH has cardioprotective effects against H/R injury and oxidative stress via activation of the PI3K/Akt and Erk1/2 signaling pathways, which reduces mPTP opening, overproduction of ROS and calcium overload.

Beyond Reperfusion: Acute Ventricular Unloading and Cardioprotection During Myocardial Infarction

Heart failure is a major cause of morbidity and mortality around the world, and myocardial infarction is its leading cause. Myocardial infarction destroys viable myocardium, and this dead tissue is replaced by a non-contractile scar that results in impaired cardiac function and a significantly increased likelihood of the patient developing heart failure. Limiting infarct scar size has been the target of pre-clinical and clinical investigations for decades. However, beyond reperfusion, few therapies have translated into the clinic that limit its formation. New approaches are needed. This review will focus on new clinical and pre-clinical data demonstrating that acute ventricular unloading prior to reperfusion by means of percutaneous left ventricular support devices reduces ischemia-reperfusion injury and limits infarct scar size. Emphasis will be given to summarizing our current mechanistic understanding of this new therapeutic approach to treating myocardial infarction.

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

BACKGROUND

The impact of intravenous (IV) beta-blockers before primary percutaneous coronary intervention (PPCI) on infarct size and clinical outcomes is not well established.

OBJECTIVES

This study sought to conduct the first double-blind, placebo-controlled international multicenter study testing the effect of early IV beta-blockers before PPCI in a general ST-segment elevation myocardial infarction (STEMI) population.

METHODS

STEMI patients presenting <12 h from symptom onset in Killip class I to II without atrioventricular block were randomized 1:1 to IV metoprolol (2 × 5-mg bolus) or matched placebo before PPCI. Primary endpoint was myocardial infarct size as assessed by cardiac magnetic resonance imaging (CMR) at 30 days. Secondary endpoints were enzymatic infarct size and incidence of ventricular arrhythmias. Safety endpoints included symptomatic bradycardia, symptomatic hypotension, and cardiogenic shock.

RESULTS

A total of 683 patients (mean age 62 ± 12 years; 75% male) were randomized to metoprolol (n = 336) or placebo (n = 346). CMR was performed in 342 patients (54.8%). Infarct size (percent of left ventricle [LV]) by CMR did not differ between the metoprolol (15.3 ± 11.0%) and placebo groups (14.9 ± 11.5%; p = 0.616). Peak and area under the creatine kinase curve did not differ between both groups. LV ejection fraction by CMR was 51.0 ± 10.9% in the metoprolol group and 51.6 ± 10.8% in the placebo group (p = 0.68). The incidence of malignant arrhythmias was 3.6% in the metoprolol group versus 6.9% in placebo (p = 0.050). The incidence of adverse events was not different between groups.

CONCLUSIONS

In a nonrestricted STEMI population, early intravenous metoprolol before PPCI was not associated with a reduction in infarct size. Metoprolol reduced the incidence of malignant arrhythmias in the acute phase and was not associated with an increase in adverse events. (Early-Beta blocker Administration before reperfusion primary PCI in patients with ST-elevation Myocardial Infarction [EARLY-BAMI]; EudraCT no: 2010-023394-19).

Impact of the Timing of Metoprolol Administration During STEMI on Infarct Size and Ventricular Function

BACKGROUND

Pre-reperfusion administration of intravenous (IV) metoprolol reduces infarct size in ST-segment elevation myocardial infarction (STEMI).

OBJECTIVES

This study sought to determine how this cardioprotective effect is influenced by the timing of metoprolol therapy having either a long or short metoprolol bolus-to-reperfusion interval.

METHODS

We performed a post hoc analysis of the METOCARD-CNIC (effect of METOprolol of CARDioproteCtioN during an acute myocardial InfarCtion) trial, which randomized anterior STEMI patients to IV metoprolol or control before mechanical reperfusion. Treated patients were divided into short- and long-interval groups, split by the median time from 15 mg metoprolol bolus to reperfusion. We also performed a controlled validation study in 51 pigs subjected to 45 min ischemia/reperfusion. Pigs were allocated to IV metoprolol with a long (-25 min) or short (-5 min) pre-perfusion interval, IV metoprolol post-reperfusion (+60 min), or IV vehicle. Cardiac magnetic resonance (CMR) was performed in the acute and chronic phases in both clinical and experimental settings.

RESULTS

For 218 patients (105 receiving IV metoprolol), the median time from 15 mg metoprolol bolus to reperfusion was 53 min. Compared with patients in the short-interval group, those with longer metoprolol exposure had smaller infarcts (22.9 g vs. 28.1 g; p = 0.06) and higher left ventricular ejection fraction (LVEF) (48.3% vs. 43.9%; p = 0.019) on day 5 CMR. These differences occurred despite total ischemic time being significantly longer in the long-interval group (214 min vs. 160 min; p < 0.001). There was no between-group difference in the time from symptom onset to metoprolol bolus. In the animal study, the long-interval group (IV metoprolol 25 min before reperfusion) had the smallest infarcts (day 7 CMR) and highest long-term LVEF (day 45 CMR).

CONCLUSIONS

In anterior STEMI patients undergoing primary angioplasty, the sooner IV metoprolol is administered in the course of infarction, the smaller the infarct and the higher the LVEF. These hypothesis-generating clinical data are supported by a dedicated experimental large animal study.

Novel directions in inflammation as a therapeutic target in atherosclerosis

PURPOSE OF REVIEW

Atherosclerosis is a chronic disease of the arterial wall largely driven by inflammation; hence, therapeutics targeting inflammatory pathways are considered an attractive strategy in atherosclerotic cardiovascular disease (ASCVD). The purpose of this review is to describe the randomized, placebo-controlled clinical trials currently investigating the impact of anti-inflammatory strategies in ASCVD patients, to discuss novel insights and targets into the role of innate immunity in atherosclerosis and to address the promise of local drug delivery as opposed to systemic therapies in atherosclerotic disease.

RECENT FINDINGS

The first clinical trials using systemic anti-inflammatory drugs in ASCVD patients might be able to strengthen the case for immunomodulation once showing an improved ASCVD outcome. Several specific targets in innate immunity bear therapeutic potential, of which some have already entered the clinical arena. To prevent immunosuppression by systemic effects, drug delivery systems are increasingly being applied to locally attenuate plaque inflammation.

SUMMARY

Anti-inflammatory therapies seem promising for future treatment of ASCVD. In view of the risk of immunosuppression in case of long term and systemic use of anti-inflammatory drugs, there is a clinical need for highly selective and targeted therapies in patients with atherosclerosis.

Influence of the previous use of β-blockers on the early clinical course of acute coronary syndromes

Recent studies have recently questioned the current role of β-blockers in myocardial infarction. Our purpose is to analyze the influence of the previous use of β-blockers on the early course of patients admitted because of acute coronary syndrome (ACS). We analyzed the data of 37.359 patients included in the ARIAM-Andalucia Registry. Of them, 7759 (20.8%) were previously receiving β-blockers. BB patients were older, more often female, had more risk factors and vascular disease, and less often had an ST-elevation myocardial infarction. In the unadjusted analysis, BB patients less often had ventricular fibrillation or atrioventricular block, and more often a Killip classification >1, and no difference of in-hospital mortality (5.7 vs 5.6%). After logistic regression analysis and propensity score matching, no differences in complications or mortality (odds ratio 0.997, 95% confidence interval 0.882-1.128) were found in relationship to previous β-blockers. In conclusion, we find that the previous administration of β-blockers is not an independent predictor of the early prognosis of ACS.