The role of angiotensin receptor blockers in the management of chronic heart failure

Clinical and basic science research has repeatedly confirmed the importance of the renin-angiotensin-aldosterone system in the pathophysiology of chronic heart failure. Accordingly, blockade of this system by angiotensin-converting enzyme (ACE) inhibitors has assumed a central role in the treatment of heart failure. Recently, angiotensin II receptor blockers (ARBs) have gained prominence as a possible substitute for ACE inhibitors in therapy for heart failure. However, clinical data compiled on this use of ARBs have shown them to be useful only as alternative therapy in ACE inhibitor-intolerant patients. Continuing large-scale clinical investigations may lead to an expansion of their role in therapy for various cardiovascular diseases.     

The role of angiotensin II receptor blockers in the treatment of heart failure patients

Evidence from large, randomized, controlled clinical trials supports the use of angiotensin-converting enzyme (ACE) inhibitors, beta blockers, and spironolactone to reduce mortality and morbidity. Despite these effective therapies, event rates related to heart failure remain high. Although ACE inhibitors reduce angiotensin II production, they do not fully suppress the increased angiotensin II production in heart failure. Angiotensin II receptor blockers (ARBs) directly block the effect of angiotensin II, derived from any source, at the receptor level and have the potential to be as effective or even more effective than ACE inhibitors. The results of a number of clinical studies have demonstrated ARBs are effective and well tolerated. However, no studies have demonstrated a convincing decrease in mortality with ARB use, although a decrease has been observed for heart failure hospitalization. The results from further studies are awaited to clarify the role of ARBs in the treatment of heart failure.     

A hard look at angiotensin receptor blockers in heart failure

Multiple trials over the past several years have examined indications for angiotensin receptor blockers (ARBs) in the treatment of left ventricular dysfunction, both acutely after myocardial infarction and in chronic heart failure. Yet despite these data, there is still confusion regarding the efficacy of ARBs as monotherapy in these patient populations, as well as the specific indications for combination ARB/angiotensin-converting enzyme (ACE) inhibitor therapy. We examine the key differences among the trials-including the ACE inhibitor dose, the ARB and its dose, blood pressure reduction, and patient populations-to present our perspective on ARB use, alone or in combination with ACE inhibitors, in patients with chronic heart failure and post-myocardial infarction left ventricular dysfunction. We conclude that ACE inhibitors remain the first-line therapy for left ventricular dysfunction. Angiotensin receptor blockers should be reserved for monotherapy in ACE intolerant patients and for combination therapy in symptomatic class II/III patients with chronic heart failure.     

Beta-adrenergic receptor blockers in heart failure

Opinion statement Congestive heart failure is a progressive disease with high morbidity and mortality if left untreated. Standard therapy for patients with systolic left ventricular dysfunction now includes angiotensin-converting enzyme inhibitors and β blockers. β Blockers have been demonstrated to decrease mortality, reduce hospitalizations, improve functional class, decrease left ventricular dimensions, and improve ejection fraction in several large-scale, randomized, placebo-controlled trials. In addition to reducing deaths due to progressive heart failure, β blockers also reduce the incidence of sudden death. Therapy with β blockers can successfully be initiated in most patients with heart failure if recommended titration schedules are followed. β Blockers are an important component of medical therapy for all stages of heart failure.     

血管紧张素受体阻滞剂在慢性心力衰竭治疗中的重要作用

肾素-血管紧张素-醛固酮系统（RAAS）在心血管疾病的发生、发展以及疾病的预后和并发症产生上均起着极其重要的作用。血管紧张素转换酶抑制剂（ACEI）作为一种阻断RAAS的药物,在心血管疾病的预防和治疗上功不可没。美国和中国的收缩期心力衰竭指南均将ACEI列为治疗的基石。但ACEI也有其缺陷或局限性：如对血管紧张素Ⅱ生成的阻遏作用是不完全的;对组织RAAS的阻遏作用可能并不理想,而组织RAAS对靶器官损害和预后有重要影响;长期使用会出现血管紧张素Ⅱ升高（逃逸现象）;临床上咳嗽的不良反应发生率较高,     

Angiotensin type-1 receptor blockers in heart failure

Chronic heart failure is a common condition with a poor prognosis, usually associated with poor exercise tolerance and debilitating symptoms despite optimal modern therapy. Standard therapy includes diuretics, digoxin, angiotensin-converting enzyme inhibitors (ACEIs) and beta-blockers. Despite this, many patients remain symptomatic, and interest is high as to whether the angiotensin receptor blockers (ARBs) would offer further advantage to a patient already receiving quadruple therapy. In addition, some patients are intolerant of ACEIs, and for this group the ARBs seem a logical choice. This article reviews the evidence for the use of ARBs as a class in heart failure concentrating on clinical recommendations and clinical needs and evidence rather than purely on statistical issues of significance in trials. The trials to date have demonstrated clearly similar hemodynamic effects to those seen with ACEIs and variety of ancillary benefits such as improvements in endothelial function, anti-thrombotic effects, and effects on neurohormonal inhibition. There is consistent evidence of a preservation of exercise tolerance when patients with heart failure are crossed over from stable ACEI therapy, and when added to ACEIs exercise tolerance appears to increase with ARBs. In terms of major outcomes, the two largest trials, Elite-II and Val-Heft, demonstrate that angiotensin receptor blockers probably have a clinical role in improving mortality and morbidity as an alternative to ACEIs in those patients unable to tolerate these agents, which remain, however, the first choice in unselected patients with heart failure. There is a worrying suggestion of a negative interaction when ARBs are added to beta-blockers, which is a reason for caution in using the ARBs, not a reason not to use beta-blockers.     

Angiotensin II receptor blockers in congestive heart failure

The benefits of angiotensin-converting enzyme (ACE) inhibitors for the treatment of congestive heart failure (CHF) are well-established. A newer class of medications, angiotensin II receptor blockers (ARBs), may be a suitable replacement for ACE inhibitors as a result of a more complete inhibition of angiotensin II and better tolerability among patients. To examine the current literature on the efficacy and safety of ARBs in the setting of CHF, a Medline search was conducted of the English language literature for the years 1987 to 2005. Clinical trials that reported data on cardiac outcomes were reviewed. The earlier trials were direct ARB to ACE inhibitor comparisons (ELITE I and ELITE II). These studies indicated that ARBs do not confer an improvement in cardiac outcomes over ACE inhibitors. RESOLVD, Val-HeFT, and the 3 separate trials of the CHARM program investigated the addition of an ARB to standard therapy. The RESOLVD trial showed no significant differences in clinical events among ACE inhibitor, ARB, and their combination. Although no mortality benefit was evident in the Val-HeFT trial, a substantial reduction in CHF rehospitalizations was reported among patients who were not receiving ACE inhibitor therapy. The CHARM-Overall program demonstrated a significant benefit in cardiovascular death and hospital admissions for CHF with the addition of ARB to standard therapy, a benefit that was more pronounced in patients with depressed left ventricular ejection fraction. In the setting of CHF, rates of cardiac outcomes do not differ substantially between ARBs and ACE inhibitors. However, their combination may improve outcomes for patients with CHF.     

Aldosterone receptor blockers in the treatment of heart failure

Opinion statement Heart failure is associated with neurohormonal activation, including activation of the renin-angiotensin-aldosterone system. Plasma aldosterone levels are elevated in patients with heart failure in spite of the use of angiotensin-converting enzyme (ACE) inhibitors or angiotensin receptor blockers because of angiotensin-independent stimuli for aldosterone production. In addition to its long recognized role in sodium retention, aldosterone has a number of other deleterious effects, including the increase in myocardial and vascular fibrosis and myocardial remodeling in patients with heart failure. Based on strong clinical trial data, low-dose aldosterone receptor blockers are recommended to improve morbidity and mortality in patients with severe chronic heart failure due to left ventricular systolic dysfunction and in patients with heart failure associated with left ventricular systolic dysfunction after acute myocardial infarction, and in patients already on standard therapy including ACE inhibitors (or angiotensin receptor blockers) and β blockers. In view of the potential for serious hyperkalemia with the use of aldosterone receptor blockers, it is essential to monitor serum potassium closely and to adjust the dose of aldosterone antagonists based on serum potassium levels. Close adherence to the dosing regimens used in the clinical trials (RALES [Randomized Aldactone Evaluation Study] and EPHESUS [Eplerenone Post-AMI Heart Failure Efficacy and Survival Study]) is recommended. These agents should not be initiated in patients with severe renal insufficiency and closer monitoring is warranted in those with mild to moderate renal insufficiency or diabetes.     

The pleiotropic effects of angiotensin receptor blockers

The angiotensin receptor blockers (ARBs) are very effective and safe antihypertensive drugs. They exert their antihypertensive effect through blockage of the angiotensin II, type 1 receptor and quite possibly through stimulation by angiotensin II of the unoccupied type 2 receptor. Besides hypertension, the ARBs have been found recently to be of value in the treatment of heart failure and diabetic nephropathy. In addition, ARBs have emerged lately as being very effective and perhaps superior to other antihypertensive drugs in the prevention of de novo or recurrent strokes. Other actions that may account for their stroke-protective effects include their antiatherogenic, antidiabetic, antiplatelet aggregating, hypouricemic, and atrial antifibrillatory actions. All these actions make the ARBs a true pleiotropic class of drugs. Each of the foregoing effects will be discussed briefly in this concise review.     

The role of aldosterone blockers in the management of chronic heart failure

The neurohormonal model of congestive heart failure (CHF) has replaced the previously accepted hemodynamic model. A shift in this paradigm has allowed alterations in therapy of CHF such that agents that target the neurohormonal axis and specifically the renin-angiotensin-aldosterone system, with drugs such as angiotensin-converting enzyme inhibitors, angiotensin receptor blockers, and beta-blockers, are utilized. Employment of these drugs markedly improves survival in patients with CHF. Recent animal and human data demonstrate that aldosterone is directly pathogenic in this disease process and is insufficiently suppressed by these agents. Furthermore, when aldosterone is directly antagonized, vascular and myocardial damage is greatly ameliorated in both experimental animals and humans. Significant mortality benefits of aldosterone antagonists in patients with CHF from systolic dysfunction have been subsequently witnessed. Herein, the pathophysiology of CHF, the beneficial role of aldosterone antagonists in this disease process, and potential adverse consequences of these agents are reviewed.     

Angiotensin II receptor blockers in the treatment of heart failure

Heart failure treatment centers on antagonism of the renin-angiotensin-aldosterone system and adrenergic nervous system. Angiotensin-converting enzyme (ACE) inhibitors have been shown to benefit patients with left ventricular systolic dysfunction irrespective of symptoms. Despite ACE inhibitor use, left ventricular dysfunction continues to progress in most patients. In addition, ACE inhibitors are substantially underused in patients who would benefit, in large part due to physician concern over potential adverse effects. Angiotensin receptor blockers (ARBs) have been proposed as either potential substitutes for ACE inhibitors or as additive therapy for heart failure patients. The authors will review the importance of the renin-angiotensin-aldosterone system in the progression of heart failure, as well as the mechanisms by which ACE inhibitors and ARBs counteract this effect. The clinical evidence to date supporting the use of ARBs in heart failure also will be reviewed. Based on current trials, ARBs are suitable substitutes for ACE inhibitors in patients who have true ACE inhibitor intolerance, but ACE inhibitors should still be considered first-line therapy in the treatment of left ventricular systolic dysfunction and heart failure. ARBs are a reasonable additive therapy in patients on maximal ACE inhibitor therapy who remain symptomatic, especially in patients unable to tolerate beta blockade.     

The place of aldosterone receptor blockers in the treatment of chronic heart failure

The paper contains presentation of basics of clinical pharmacology of aldosterone receptor blockers specifically that of spironolactone and eplerenone, and discussion of results of 2 large randomized placebo controlled trials which showed that long term use of aldosterone receptor blockers allowed to improve prognosis of patients with severe chronic heart failure and postinfarction systolic left ventricular dysfunction, and to reduce requirements in repetitive hospitalizations.