Randomised, double-blind, placebo-controlled trial of ivabradine in patients with acute coronary syndrome: effects of the If current inhibitor ivabradine on reduction of inflammation markers in patients with acute coronary syndrome--RIVIERA trial study design and rationale

Effect of Ivabradine on a Hypertensive Heart and the Renin-Angiotensin-Aldosterone System in L-NAME-Induced Hypertension

Ivabradine, the selective inhibitor of the If current in the sinoatrial node, exerts cardiovascular protection by its bradycardic effect and potentially pleiotropic actions. However, there is a shortage of data regarding ivabradine's interaction with the renin-angiotensin-aldosterone system (RAAS). This study investigated whether ivabradine is able to protect a hypertensive heart in the model of L-NAME-induced hypertension and to interfere with the RAAS. Four groups (n = 10/group) of adult male Wistar rats were treated as follows for four weeks: control, ivabradine (10 mg/kg/day), L-NAME (40 mg/kg/day), and L-NAME plus ivabradine. L-NAME administration increased systolic blood pressure (SBP) and left ventricular (LV) weight, enhanced hydroxyproline concentration in the LV, and deteriorated the systolic and diastolic LV function. Ivabradine reduced heart rate (HR) and SBP, and improved the LV function. The serum concentrations of angiotensin Ang 1⁻8 (Ang II), Ang 1⁻5, Ang 1⁻7, Ang 1⁻10, Ang 2⁻8, and Ang 3⁻8 were decreased in the L-NAME group and ivabradine did not modify them. The serum concentration of aldosterone and the aldosterone/Ang II ratio were enhanced by L-NAME and ivabradine reduced these changes. We conclude that ivabradine improved the LV function of the hypertensive heart in L-NAME-induced hypertension. The protective effect of ivabradine might have been associated with the reduction of the aldosterone level.

Ticagrelor vs. clopidogrel in non-ST-elevation acute coronary syndromes

AIM

The aim of this study was to evaluate the bradyarrhythmic events associated with ticagrelor combination therapy in the management of patients presenting with non-ST-segment elevation myocardial infarction (NSTEMI).

PATIENTS AND METHODS

The study comprised 300 patients with NSTEMI who were treated via percutaneous coronary intervention (PCI). Patients were randomly assigned to two groups: the clopidogrel group (initial dose of 300 mg and then maintenance dose of 75 mg once daily, n = 151) and the ticagrelor group (initial dose of 180 mg and then maintenance dose of 90 mg twice daily, n = 149). All patients were followed up in the outpatient clinic. Follow-up included 12-lead electrocardiography and 24-h Holter monitoring performed 1, 6, and 12 months after the revascularization procedure.

RESULTS

Of the 300 patients, 112 patients (36.7 %) had a decrease in heart rate at the 12-month follow-up. Of these, 80 patients were in the ticagrelor group (53.3 %) vs. 32 patients in the clopidogrel group (24.7 %; p < 0.05). However, the difference was not statistically significant at the 1-month and 6-month follow-up visits. After adjusting for potential confounders, the reduction in heart rate with ticagrelor combination therapy remained independently associated with a reduced risk of major adverse cardiovascular events (hazard ratio, 2.1; 95 % CI, 1.90-2.23), while ticagrelor therapy reduced the risk to a level equivalent to that of patients in the clopidogrel group.

CONCLUSION

Ticagrelor can lower the resting heart rate of patients and cause bradyarrhythmias in the 12th month after PCI.

Potential additive effects of ticagrelor, ivabradine, and carvedilol on sinus node

A 51-year-old male patient presented to the emergency room with an anterior ST-elevation myocardial infarction. After a loading dose of both ticagrelor and aspirin, the patient underwent primary-PCI on the left anterior descending coronary artery with stent implantation. After successful revascularization, medical therapy included beta-blockers, statins, and angiotensin II receptor antagonists. Two days later, ivabradine was also administered in order to reduce heart rate at target, but the patient developed a severe symptomatic bradycardia and sinus arrest, even requiring administration of both atropine and adrenaline. Ivabradine and ticagrelor have been then suspended and this latter changed with prasugrel. Any other similar event was not reported during the following days. This clinical case raised concerns about the safety of the combination of beta-blockers and ivabradine in patients treated with ticagrelor, particularly during the acute phase of an acute coronary syndrome. These two latter drugs, in particular, might interact with the same receptor. In fact, ivabradine directly modulates the If-channel which is also modulated by the cyclic adenosine monophosphate levels. These latter have been shown to increase after ticagrelor assumption via inhibition of adenosine uptake by erythrocytes. Further studies are warrant to better clarify the safety of this association.

Stable angina pectoris: antianginal therapies and future directions

Advances in pharmacotherapy for stable angina have produced a wide choice of drugs with various mechanisms of action, potentially enabling individualized, patient-specific treatment strategies to be developed. In this Review, the various treatment options for patients with stable angina are discussed. Data from randomized, clinical trials of established and novel drugs are reviewed, with particular emphasis on the proposed mechanisms of action, benefits of therapy, and adverse-effect profiles. The role of coronary revascularization in conjunction with optimal medical therapy as a treatment strategy is discussed, although drug therapy might reduce the need for prompt revascularization if the procedure is being considered solely for the purpose of alleviating angina. Finally, trials to investigate stimulation of angiogenesis using growth-factor, gene, and cell therapy are used to illustrate the challenges of chemically inducing the growth of adequate, durable blood vessels.

Increased heart rate and atherosclerosis: potential implications of ivabradine therapy

Despite all the therapeutic advances in the field of cardiology, cardiovascular diseases, and in particular coronary artery disease, remain the leading cause of death and disability worldwide, thereby underlining the importance of acquiring new therapeutic options in this field. A reduction in elevated resting heart rate (HR) has long been postulated as a therapeutic approach in the management of cardiovascular disease. An increased HR has been shown to be associated with increased progression of coronary atherosclerosis in animal models and patients. A high HR has also been associated with a greatly increased risk of plaque rupture in patients with coronary atherosclerosis. Endothelial function may be an important link between HR and atherosclerosis. An increased HR has been shown experimentally to cause endothelial dysfunction. Inflammation plays a significant role in the pathogenesis and progression of atherosclerosis. In the literature, there is data that shows an association between HR and circulating markers of vascular inflammation. In addition, HR reduction by pharmacological intervention with ivabradine (a selective HR-lowering agent that acts by inhibiting the pacemaker ionic current I(f) in sinoatrial node cells) reduces the formation of atherosclerotic plaques in animal models of lipid-induced atherosclerosis. The aim of this editorial is to review the possible role of ivabradine on atherosclerosis.

Ivabradine: recent and potential applications in clinical practice

INTRODUCTION

published data indicate that heart rate is an independent strong predictor of cardiovascular and all-cause mortality in men and women of all ages, with and without cardiovascular disease, including atherosclerosis, ventricular arrhythmias, and left ventricular dysfunction. Ivabradine is a pure heart-rate-lowering agent with well-documented antianginal and anti-ischemic properties comparable to well-established anti-anginal agents.

AREAS COVERED

this short review explores recent results with ivabradine, a new medication that lowers heart rate by selectively inhibiting the I (f) current. This review also describes future potential applications.

EXPERT OPINION

measurement of heart rate represents an important component of the assessment of patients with coronary artery disease and chronic heart failure, and should be viewed in the same light as other risk factors, because a high heart rate has direct detrimental effects not only on myocardial ischemia but also on the progression of atherosclerosis, ventricular arrhythmias and left ventricular function. Ivabradine has anti-ischemic and antianginal efficacy equivalent to that of β-blockers and calcium channel antagonists in the treatment of chronic stable angina pectoris. Recently ivabradine has been shown to improve cardiac outcomes in stable coronary artery disease and left ventricular systolic dysfunction in patients who have heart rates of ≥ 70 bpm and in patients with stable angina.