Stable Angina Medical Therapy Management Guidelines: A Critical Review of Guidelines from the European Society of Cardiology and National Institute for Health and Care Excellence

Most patients with stable angina can be managed with lifestyle changes, especially smoking cessation and regular exercise, along with taking antianginal drugs. Randomised controlled trials show that antianginal drugs are equally effective and none of them reduced mortality or the risk of MI, yet guidelines prefer the use of beta-blockers and calcium channel blockers as a first-line treatment. The European Society of Cardiology guidelines for the management of stable coronary artery disease provide classes of recommendation with levels of evidence that are well defined. The National Institute for Health and Care Excellence (NICE) guidelines for the management of stable angina provide guidelines based on cost and effectiveness using the terms first-line and second-line therapy. Both guidelines recommend using low-dose aspirin and statins as disease-modifying agents. The aim of this article is to critically appraise the guidelines’ pharmacological recommendations for managing patients with stable angina.

The risk of cardiovascular side effects with anti-anginal drugs

INTRODUCTION

Angina pectoris is a common presenting symptom of underlying coronary artery disease or reduced coronary flow reserve. Patients with angina have impaired quality of life; and need to be treated optimally with antianginal drugs to control symptoms and improve exercise performance. A wide range of antianginal medications are approved for the treatment of angina, and often more than one class of antianginal drugs are used to adequately control the symptoms. This expert opinion highlights the likely cardiac adverse effects of available antianginal drugs, and how to minimize these in individual patients and especially during combination treatment. Areas covered: All approved antianginal drugs, including the older and newly approved medications with different mechanism of action to the older drugs as well as some of the unapproved herbal medications. The safety profiles and potential cardiac side effects of these medications when used as monotherapy or as combination therapy are discussed and highlighted. Expert opinion: Because of the different cardiac safety profiles and possible side effects, we recommend selection of initial drug or adjustment of therapy based on the resting heart rate; blood pressure, hemodynamic status; and resting left ventricular function, concomitant medications and any associated comorbidities.

Hypertrophic cardiomyopathy: a review

Hypertrophic cardiomyopathy (HCM) is a global disease with cases reported in all continents, affecting people of both genders and of various racial and ethnic origins. Widely accepted as a monogenic disease caused by a mutation in 1 of 13 or more sarcomeric genes, HCM can present catastrophically with sudden cardiac death (SCD) or ventricular arrhythmias or insidiously with symptoms of heart failure. Given the velocity of progress in both the fields of heart failure and HCM, we present a review of the approach to patients with HCM, with particular attention to those with HCM and the clinical syndrome of heart failure.

I(f) blocking potency of ivabradine is preserved under elevated endotoxin levels in human atrial myocytes

Lower heart rate is associated with better survival in patients with multiple organ dysfunction syndrome (MODS), a disease mostly caused by sepsis. The benefits of heart rate reduction by ivabradine during MODS are currently being investigated in the MODI_fY clinical trial. Ivabradine is a selective inhibitor of the pacemaker current I_f and since I_f is impaired by lipopolysaccharide (LPS, endotoxin), a trigger of sepsis, we aimed to explore I_f blocking potency of ivabradine under elevated endotoxin levels in human atrial cardiomyocytes. Treatment of myocytes with S-LPS (containing the lipid A moiety, a core oligosaccharide and an O-polysaccharide chain) but not R595 (an O-chain lacking LPS-form) caused I_f inhibition under acute and chronic septic conditions. The specific interaction of S-LPS but not R595 to pacemaker channels HCN2 and HCN4 proves the necessity of O-chain for S-LPS–HCN interaction. The efficacy of ivabradine to block I_f was reduced under septic conditions, an observation that correlated with lower intracellular ivabradine concentrations in S-LPS- but not R595-treated cardiomyocytes. Computational analysis using a sinoatrial pacemaker cell model revealed that despite a reduction of I_f under septic conditions, ivabradine further decelerated pacemaking activity. This novel finding, i.e. I_f inhibition by ivabradine under elevated endotoxin levels in vitro, may provide a molecular understanding for the efficacy of this drug on heart rate reduction under septic conditions in vivo, e.g. the MODI_fY clinical trial.

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S-LPS impairs I_f via interaction of its O-chain to HCN channels.

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Efficacy of ivabradine for I_f blockage is reduced under elevated endotoxin levels.

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S-LPS reduces intracellular ivabradine concentrations.

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Ivabradine is efficient to decelerate sinoatrial pacemaking activity under septic conditions in silico.

Pharmacological treatment options for hypertrophic cardiomyopathy: high time for evidence

Hypertrophic cardiomyopathy (HCM) is the most common genetic heart disease, affecting over one million individuals in Europe. Hypertrophic cardiomyopathy patients often require pharmacological intervention for control of symptoms, dynamic left ventricular outflow obstruction, supraventricular and ventricular arrhythmias, and microvascular ischaemia. Current treatment strategies in HCM are predicated on the empirical use of long-standing drugs, such as beta-adrenergic and calcium blockers, although with little evidence supporting their clinical benefit in this disease. In the six decades since the original description of the disease, <50 pharmacological studies enrolling little over 2000 HCM patients have been performed, the majority of which were small, non-randomized cohorts. As our understanding of the genetic basis and pathophysiology of HCM improves, the availability of transgenic and preclinical models uncovers clues to novel and promising treatment modalities. Furthermore, the number of patients identified and followed at international referral centres has grown steadily over the decades. As a result, the opportunity now exists to implement adequately designed pharmacological trials in HCM, using established as well as novel drug therapies, to potentially intervene on the complex pathophysiology of the disease and alter its natural course. Therefore, it is timely to review the available evidence for pharmacological therapy of HCM patients, highlight the most relevant gaps in knowledge, and address some of the most promising areas for future pharmacological research, in an effort to move HCM into the era of evidence-based management.

The biological effects of ivabradine in cardiovascular disease

A large number of studies in healthy and asymptomatic subjects, as well as patients with already established cardiovascular disease (CAD) have demonstrated that heart rate (HR) is a very important and major independent cardiovascular risk factor for prognosis. Lowering heart rate reduces cardiac work, thereby diminishing myocardial oxygen demand. Several experimental studies in animals, including dogs and pigs, have clarified the beneficial effects of ivabradine associated with HR lowering. Ivabradine is a selective inhibitor of the hyperpolarisation activated cyclic-nucleotide-gated funny current (If) involved in pacemaker generation and responsiveness of the sino-atrial node (SAN), which result in HR reduction with no other apparent direct cardiovascular effects. Several studies show that ivabradine substantially and significantly reduces major risks associated with heart failure when added to guideline-based and evidence-based treatment. However the biological effect of ivabradine have yet to be studied. This effects can appear directly on myocardium or on a systemic level improving endothelial function and modulating immune cell migration. Indeed ivabradine is an 'open-channel' blocker of human hyperpolarization-activated cyclic nucleotide gated channels of type-4 (hHCN4), and a 'closed-channel' blocker of mouse HCN1 channels in a dose-dependent manner. At endothelial level ivabradine decreased monocyte chemotactin protein-1 mRNA expression and exerted a potent anti-oxidative effect through reduction of vascular NADPH oxidase activity. Finally, on an immune level, ivabradine inhibits the chemokine-induced migration of CD4-positive lymphocytes. In this review, we discuss the biological effects of ivabradine and highlight its effects on CAD.