Should β-blockers still be routine after myocardial infarction?

Differential Effects of β-Blockers, Angiotensin II Receptor Blockers, and a Novel AT2R Agonist NP-6A4 on Stress Response of Nutrient-Starved Cardiovascular Cells

In order to determine differences in cardiovascular cell response during nutrient stress to different cardiovascular protective drugs, we investigated cell responses of serum starved mouse cardiomyocyte HL-1 cells and primary cultures of human coronary artery vascular smooth muscles (hCAVSMCs) to treatment with β-blockers (atenolol, metoprolol, carvedilol, nebivolol, 3μM each), AT1R blocker losartan (1μM) and AT2R agonists (CGP42112A and novel agonist NP-6A4, 300nM each). Treatment with nebivolol, carvedilol, metoprolol and atenolol suppressed Cell Index (CI) of serum-starved HL-1 cells (≤17%, ≤8%, ≤15% and ≤15% respectively) as measured by the Xcelligence Real-Time Cell Analyzer (RTCA). Conversely, CI was increased by Ang II (≥9.6%), CGP42112A (≥14%), and NP-6A4 (≥25%) respectively and this effect was blocked by AT2R antagonist PD123319, but not by AT1R antagonist losartan. Thus, the CI signature for each drug could be unique. MTS cell proliferation assay showed that NP-6A4, but not other drugs, increased viability (≥20%) of HL-1 and hCAVSMCs. Wheat Germ Agglutinin (WGA) staining showed that nebivolol was most effective in reducing cell sizes of HL-1 and hCAVSMCs. Myeloid Cell Leukemia 1 (MCL-1) is a protein critical for cardiovascular cell survival and implicated in cell adhesion. β-blockers significantly suppressed and NP-6A4 increased MCL-1 expression in HL-1 and hCAVSMCs as determined by immunofluorescence. Thus, reduction in cell size and/or MCL-1 expression might underlie β-blocker-induced reduction in CI of HL-1. Conversely, increase in cell viability and MCL-1 expression by NP-6A4 through AT2R could have resulted in NP-6A4 mediated increase in CI of HL-1. These data show for the first time that activation of the AT2R-MCL-1 axis by NP-6A4 in nutrient-stressed mouse and human cardiovascular cells (mouse HL-1 cells and primary cultures of hCAVSMCs) might underlie improved survival of cells treated by NP-6A4 compared to other drugs tested in this study.

Meta-Analysis of Relation Between Oral β-Blocker Therapy and Outcomes in Patients With Acute Myocardial Infarction Who Underwent Percutaneous Coronary Intervention

The aim of the present review was to investigate the association between the use of oral β-blockers and prognosis in patients with acute myocardial infarction (AMI) who underwent percutaneous coronary intervention (PCI) treatment. A systematic literature search was conducted in Pubmed (from inception to September 27, 2014) and Embase (Ovid SP, from 1974 to September 29, 2014) to identify studies that compared the outcome of patients with AMI taking oral β-blockers with that of patients not taking after PCI. Systematic review and meta-analysis were performed with random-effects model or fixed-effects model. Ten observational studies with a total of 40,873 patients were included. Use of β-blockers was associated with a reduced risk of all-cause death (unadjusted relative risk 0.58, 95% confidential interval 0.48 to 0.71; adjusted hazard ratio 0.76, 95% confidential interval 0.62 to 0.94). The potential benefit of β-blockers in preventing all-cause death was not similar in all population but was restricted to those with reduced ejection fraction, with low use proportion of other secondary prevention drugs or with non-ST-segment elevation myocardial infarction. The association between the use of β-blockers and improved survival rate was significant in ≤1-year follow-up duration. Rates of cardiac death, myocardial infarction, and heart failure readmission in patients using β-blockers were not significantly different from those in patients without β-blocker therapy. In conclusion, there is lack of evidence to support routine use of β-blockers in all patients with AMI who underwent PCI. Further trials are urgently needed to address the issue.

Challenges and solutions in medically managed ACS in the Asia-Pacific region: expert recommendations from the Asia-Pacific ACS Medical Management Working Group

Acute coronary syndromes (ACS) remain a leading cause of mortality and morbidity in the Asia-Pacific (APAC) region. International guidelines advocate invasive procedures in all but low-risk ACS patients; however, a high proportion of ACS patients in the APAC region receive solely medical management due to a combination of unique geographical, socioeconomic, and population-specific barriers. The APAC ACS Medical Management Working Group recently convened to discuss the ACS medical management landscape in the APAC region. Local and international ACS guidelines and the global and APAC clinical evidence-base for medical management of ACS were reviewed. Challenges in the provision of optimal care for these patients were identified and broadly categorized into issues related to (1) accessibility/systems of care, (2) risk stratification, (3) education, (4) optimization of pharmacotherapy, and (5) cost/affordability. While ACS guidelines clearly represent a valuable standard of care, the group concluded that these challenges can be best met by establishing cardiac networks and individual hospital models/clinical pathways taking into account local risk factors (including socioeconomic status), affordability and availability of pharmacotherapies/invasive facilities, and the nature of local healthcare systems. Potential solutions central to the optimization of ACS medical management in the APAC region are outlined with specific recommendations.

Eight challenges faced by general practitioners caring for patients after an acute coronary syndrome

The general practitioner is essential in the management of the patient who has recently been discharged from hospital following an acute coronary syndrome (ACS), particularly as duration of hospital stay is shorter than in previous decades. GPs caring for patients after an ACS face numerous challenges. Often, the first of these is insufficient or delayed documentation from the discharging hospital, although electronic discharge summaries are alleviating this problem. Post-ACS patients often have comorbidities, and GPs play a key role in managing these. Patients taking dual antiplatelet therapy who need surgery, and post-ACS patients with atrial fibrillation, require particular care from GPs. Patients will often approach their GP for advice on the safety of other drugs, such as smoking cessation medication, and phosphodiesterase type 5 inhibitors for erectile dysfunction. For patients complaining of persistent lethargy after an ACS, GPs must consider several differential diagnoses, including depression, hypotension, hypovolaemia, and side effects of β-blockers. GPs play an important ongoing role in ensuring that target cholesterol levels are reached with statin therapy; this includes ensuring long-term adherence. They may also need to advise patients who want to stop statin therapy, usually due to perceived side effects. Many of these challenges can be met with improved and respectful communication between the hospital, the treating cardiologist and the GP. The patient needs to be closely involved in the decision-making process, particularly when balancing the risks of bleeding versus thrombosis.

Usefulness of Beta blockade in contemporary management of patients with stable coronary heart disease

Considerable progress has been made over the last few decades in the management of clinically stable coronary heart disease (SCHD), including improvements in interventions (e.g., percutaneous revascularization), pharmacological management, and risk factor control (e.g., smoking, diet, activity level, hypercholesterolemia, hypertension). Although β blockers have long been used for the treatment of SCHD, their efficacy was established in the era before widespread use of reperfusion interventions, modern medical therapy (e.g., angiotensin-converting enzyme inhibitors, angiotensin receptor blockers), or preventive treatments (e.g., aspirin, statins). On the basis of these older data, β blockers are assumed beneficial, and their use has been extrapolated beyond patients with heart failure and previous myocardial infarction, which provided the best evidence for efficacy. However, there are no randomized clinical trials demonstrating that β blockers decrease clinical events in patients with SCHD in the modern era. Furthermore, these agents are associated with weight gain, problems with glycemic control, fatigue, and bronchospasm, underscoring the fact that their use is not without risk. In conclusion, data are currently lacking to support the widespread use of β blockers for all SCHD patients, but contemporary data suggest that they be reserved for a well-defined high-risk group of patients with evidence of ongoing ischemia, left ventricular dysfunction, heart failure, and perhaps some arrhythmias.