How high should an ACE inhibitor or angiotensin receptor blocker be dosed in patients with diabetic nephropathy?

Angiotensin-converting enzyme (ACE) inhibitors and angiotensin receptor blockers (ARBs), two drug classes that effectively block the actions of the renin-angiotensin system (RAS), have unique capabilities as antihypertensive agents. Recent landmark clinical trials have demonstrated their important roles as primary therapy for the prevention of renal disease in diabetes. The optimal dosage of these RAS blockers required to slow the progression of renal disease or impair the development of cardiovascular risk is not known. However, data from many studies strongly support the use of the higher doses of ACE inhibitors or ARBs to reduce proteinuria. All studies of kidney disease progression demonstrate benefit on slowing only when blood pressure is reduced when using higher doses. In order to accrue the optimum benefit from ACE inhibitors and ARBs, the dose-response relationship for diabetic renal disease will have to be determined. The best strategy, ie, supramaximal doses of ACE inhibitors or ARBs or combining them, is still a matter of debate but may be resolved soon by results of ongoing studies.     

Angiotensin receptor blockers: evidence for preserving target organs

Hypertension is a major problem throughout the developed world. Although current antihypertensive treatment regimens reduce morbidity and mortality, patients are often noncompliant, and medications may not completely normalize blood pressure. As a result, current therapy frequently does not prevent or reverse the cardiovascular remodeling that often occurs when blood pressure is chronically elevated. Blockade of the renin-angiotensin system (RAS) is effective in controlling hypertension and treating congestive heart failure. Both angiotensin-converting enzyme (ACE) inhibitors and angiotensin receptor blockers (ARBs) inhibit the activity of the RAS, but these two classes of antihypertensive medications have different mechanisms of action and different pharmacologic profiles. Angiotensin-converting enzyme inhibitors block a single pathway in the production of angiotensin II (Ang II). In addition, angiotensin I is not the only substrate for ACE. The ACE inhibitors also block the degradation of bradykinin that may have potential benefits in cardiovascular disease. Bradykinin is, however, the presumed cause of cough associated with ACE inhibitor therapy. Data from clinical trials on ACE inhibitors serve to support the involvement of the RAS in the development of cardiovascular disease. Angiotensin receptor blockers act distally in the RAS to block the Ang II type 1 (AT1) receptor selectively. Thus, ARBs are more specific agents and avoid many side effects. Experimental and clinical trials have documented the efficacy of ARBs in preserving target-organ function and reversing cardiovascular remodeling. In some instances, maximal benefit may be obtained with Ang II blockade using both ARBs and ACE inhibitors. This review describes clinical trials that document the efficacy of ARBs in protecting the myocardium, blood vessels, and renal vasculature.     

Role of the renin-angiotensin-aldosterone system in atrial fibrillation and cardiac remodeling

PURPOSE OF REVIEW: This review summarizes recent clinical trial evidence showing a reduction in the development and recurrence of atrial fibrillation with angiotensin-converting enzyme (ACE) inhibitors and angiotensin receptor-blocking agents (ARBs). It then explores the possible mechanisms for this effect based on current animal models and limited human study. RECENT FINDINGS: Post hoc analyses of trials in patients with heart failure, hypertension, or myocardial infarction have observed reductions in atrial fibrillation among patients treated with ACE inhibitors or ARBs. Recent studies of these agents in animal models of atrial fibrillation suggest that they may prevent atrial fibrillation by reversing the cardiac structural and electrical changes, known as cardiac remodeling, that lead to the development of atrial fibrillation. This concept is also supported by two prospective studies showing that ACE inhibitors and ARBs prevent the recurrence of atrial fibrillation after electrical cardioversion. SUMMARY: Inhibition of the renin-angiotensin-aldosterone system is a novel concept for the treatment of atrial fibrillation that may target the underlying substrate of atrial fibrillation. Further human research is required to determine whether ACE inhibitors and ARBs prevent atrial fibrillation, and if so, whether this is a result of blood pressure lowering alone or a specific effect of these agents. Ongoing research will establish whether ACE inhibitors or ARBs have specific benefits in patients with atrial fibrillation.     

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.     

From evidence to rationale: cardiovascular protection by angiotensin II receptor blockers compared with angiotensin-converting enzyme inhibitors

Clinical trials have shown the efficacy of angiotensin II receptor blockers (ARBs) in patients with hypertension and have suggested that ARBs are noninferior to angiotensin-converting enzyme (ACE) inhibitors in patients with ischemic heart disease and heart failure. The Heart Outcomes Prevention Evaluation (HOPE), a landmark study in high cardiovascular risk management, demonstrated the cardioprotection of the ACE inhibitor ramipril. Thus, in the recent Ongoing Telmisartan Alone and in Combination with Ramipril Global Endpoint Trial (ONTARGET?) ramipril was selected as a comparator when exploring the cardioprotective potential of telmisartan in the first head-to-head comparison of an ACE inhibitor and an ARB in a broad cross-sectional cohort of cardiovascular high-risk patients. ONTARGET showed that telmisartan is as effective as ramipril in the management of these patients but is better tolerated. The combination of ramipril and telmisartan did not confer a further benefit but did bring about an increased rate of adverse events such as renal dysfunction. In previous ARB outcome trials, cardiovascular risk profile, nature and severity of the underlying cardiovascular disease, dosing regimens and concomitant therapies, follow-up, and endpoints have varied greatly so that caution is warranted in extrapolating evidence gained from high-risk patients to other conditions such as acute myocardial infarction or chronic heart failure.     

Use of angiotensin-converting enzyme inhibitor/angiotensin II receptor blocker therapy to reduce cardiovascular events in high-risk patients: Part 1

Cardiovascular disease is understood as a continuum; risk factors induce a pathophysiologic cascade that culminates in end-organ failure. The renin-angiotensin system (RAS) influences multiple aspects of the pathophysiology via hemodynamic and nonhemodynamic effects. Many long-term clinical trials provide overwhelming evidence of benefits of angiotensin-converting enzyme (ACE) inhibitors and angiotensin II receptor blockers (ARBs) across the cardiovascular continuum, including benefits regarding hypertension, myocardial infarction, stroke, renal disease, and heart failure. Trials also indicate additive or synergistic effects of combination therapy in renal disease and heart failure, a possibility supported by the basic biochemistry of the agents. Discussion of these trials is included in part 1 of this 2-part review. Part 2 of the review will discuss the extensive interaction of the RAS with the cellular and molecular pathophysiology of cardiovascular disease and the cross-continuum effects of ARBs and ACE inhibitors, which raise the possibility that RAS inhibition can offer protection in high-risk patients who do not have symptoms. The benefits of combined ACE inhibitor/ARB therapy in high-risk patients await confirmation; ongoing clinical research in this area will be discussed.     

Hypertension mega-trials with cardiovascular end points: effect of angiotensin-converting enzyme inhibitors and angiotensin receptor blockers

Background

The renin-angiotensin-aldosterone system has a pivotal role in the short- and long-term regulation of blood pressure through its principal mediator, angiotensin II. Angiotensin-converting enzyme (ACE) inhibitors and angiotensin II-receptor blockers (ARBs) decrease the deleterious effects of angiotensin II on the vasculature and heart, but have different mechanisms of action. Although the blood pressure-lowering effect of ACE inhibitors and ARBs is equivalent to that of most other antihypertensive agents, emerging data suggest that these drug classes may have a greater effect on decreasing cardiovascular morbidity and mortality rates in specific patient populations.

Methods

We reviewed large (approximately ≥5000 patients) hypertension clinical trials using ACE inhibitors and ARBs and with cardiovascular morbidity/mortality end points.

Results

Six trials of ACE inhibitors and 5 trials of ARBs (3 completed, 2 ongoing) were selected for this analysis. Data from these hypertension mega-trials suggest that ACE inhibitors and ARBs may decrease cardiovascular morbidity and mortality rates, especially in patients with diabetes mellitus, renal dysfunction, and left ventricular hypertrophy. However, some trials showed important blood-pressure differences and are therefore partly inconclusive for particular drug effects.

Conclusions

Analysis of recently reported and ongoing mega-trials of renin-angiotensin-aldosterone system inhibitors may support the notion that their vasculoprotective properties confer greater benefit by virtue of their effects beyond blood-pressure reduction. Results from trials that will be completed in the next few years may provide further support of blocking the renin-angiotensin-system in cardiovascular protection in the management of hypertension.     

Angiotensin-converting enzyme inhibitors and angiotensin receptor blockers in atherosclerosis

Angiotensin-converting enzyme (ACE) inhibitors and angiotensin receptor blockers (ARBs) effectively interfere with the renin-angiotensin system and exert various beneficial actions on cardiac and vascular structure and function, beyond their blood pressure-lowering effects. Randomized, controlled clinical trials have shown that ACE inhibitors improve endothelial function, cardiac and vascular remodeling, retard the anatomic progression of atherosclerosis, and reduce the risk of myocardial infarction, stroke, and cardiovascular death. Therefore, these agents are recommended in the treatment of a wide range of patients at risk for adverse cardiovascular outcomes, including those with coronary disease, prior stroke, peripheral arterial disease, high-risk diabetes, hypertension, and heart failure. ARBs are effective blood pressure-lowering and renoprotective agents and can be used in heart failure in patients who do not tolerate ACE inhibitors. The role of ARBs in the prevention of atherosclerosis and its sequelae is currently under investigation. The use of combined ACE inhibitor plus ARB therapy offers theoretical advantages over the use of each of these agents alone and is also under investigation in large, randomized clinical trials.     

Establishing a new option for target-organ protection: rationale for ARB plus ACE inhibitor combination therapy

Activation of the renin-angiotensin system (RAS) plays an important role in the promotion of cardiovascular disease and target-organ damage, mediated in part by hypertension. Combination therapy targeting RAS activation may reduce target-organ damage and provide superior blood pressure (BP) control; combining angiotensin-converting enzyme (ACE) inhibitors and angiotensin II receptor blockers (ARBs) represents one possible approach. In monotherapy studies, both ACE inhibitors and ARBs have demonstrated similar positive effects on BP and on RAS-related target-organ damage, including nephropathy and congestive heart failure. Studies of combination therapy, most of which involved addition of an ARB to existing ACE inhibitor therapy, have demonstrated benefits among patients with congestive heart failure and renal disease. However, variances in study design and populations, dosing and titration methods, and clinical end points, in addition to inherent differences between agents, limit the ability to reach clinically meaningful conclusions about the value of dual RAS inhibition. Trials designed to document such efficacy are currently underway.     

Inhibiting the renin-angiotensin system in myocardial infarction and heart failure: lessons from SAVE, VALIANT and CHARM, and other clinical trials

PURPOSE OF REVIEW: Inhibition of the renin-angiotensin-aldosterone system has become a cornerstone of modern heart failure and myocardial infarction therapy. This article will review the background and major clinical trials that have shaped this field over the past 15 years. RECENT FINDINGS: Major clinical trials have firmly established angiotensin converting enzyme (ACE) inhibitors as the standard of care in patients with heart failure and following myocardial infarction. Over the past several years, a number of trials have tested the hypothesis that an angiotensin II receptor blocker (ARB) could be as effective as, or more effective than, ACE inhibitors in these clinical settings. The results of these trials, while establishing a clear role for ARBs, have been subtly different in distinct patient populations. SUMMARY: The most recent trials of ARBs in heart failure and myocardial infarction patients suggest a role for angiotensin receptor blockers in patients with heart failure who are intolerant to ACE inhibitors and who are on optimal ACE inhibitor therapy. In patients with acute high-risk myocardial infarction, the VALIANT trial has established that the ARB was as effective as an ACE inhibitor following myocardial infarction. These studies have thus provided clinicians with alternatives to ACE inhibitors in these important clinical syndromes.     

Update in pharmacologic treatment of hypertension.

Initial pharmacologic therapy for hypertension is low-dose thiazide diuretics, beta-blockers, and ACE inhibitors. Increasing data have confirmed that ACE inhibitors have specific benefit in patients with diabetes, atherosclerosis, left ventricular dysfunction, and renal insufficiency. CCBs are alternative agents for ISH in the elderly and appear to decrease stroke with perhaps less protection against progression of renal insufficiency and proteinuria, CAD mortality and new onset heart failure versus other initial agents, especially ACE inhibitors. ARBs are well tolerated and effective blood pressure lowering agents but have not been confirmed as effective as ACE inhibitors for reducing renal progression, clinical events, or mortality from heart failure. Effective pharmacologic antihypertensive therapy may avoid disabling and undetected cerebrovascular disease, cognitive dysfunction, and disturbing symptoms of elevated blood pressure. Vasopeptidase inhibitor, such as omapatrilat, and endothelin-1 antagonist, such as bosentan, may become future agents approved for the reduction of morbidity and mortality with hypertension. The ALLHAT trial continues to examine the potential benefits and harms of amlodipine versus chlorthalidone and lisinopril in a diverse high-risk population. Based on ALLHAT data, however, doxazosin is no longer an acceptable initial pharmacological agent. Intensive pharmacologic treatment with blood pressure lowering to less than 130/85 mm Hg is recommended with diabetes, renal insufficiency, and heart failure with additional goal of less than 125/75 mm Hg with renal failure and proteinuria greater than 1 g/24 h, based on multiple outcome studies.     

The role of ACE inhibitors and angiotensin receptor blockers in the treatment of hypertension and cardiovascular disease

Pharmacologic attenuation of the renin-angiotensin-aldosterone system (RAAS) either through angiotensin-converting enzyme (ACE) inhibition or angiotensin II receptor blockade now occupies a central role in the management of hypertension, diabetes, heart failure, and cardiovascular and renal disease. Although our understanding and use of these agents has expanded significantly over the past decade, the relative and differential benefits of ACE inhibitors and angiotensin receptor blockers (ARBs) are still not entirely clear. The data continue to support the first-line use of ACE inhibitors for all indications. Results for combination ACE inhibitor and ARB therapy in clinical outcome trials have been disappointing and do not support its use. New strategies for RAAS modulation bring hope for further progress in the treatment of hypertensive and cardiovascular disease.     

Angiotensin converting enzyme inhibitors or angiotensin receptor blockers in nephropathy from type 2 diabetes

Type 2 diabetes is the most common cause of end-stage renal disease in the United States, and type 2 diabetes has been shown to be a myocardial infarction equivalent in regard to risk of death from a cardiovascular event. Proteinuria is a surrogate marker for renal disease progression, and although data favor both the angiotensin converting enzyme (ACE) inhibitors and angiotensin receptor blockers (ARBs) in reducing proteinuria, data for renal outcomes, such as time to dialysis, only exist for the ARBs, which clearly increase the duration to dialysis. Conversely, ACE inhibitors have overwhelming data that show substantial risk reduction from cardiovascular events and death in people with type 2 diabetes. Similar data on cardiovascular risk reduction are not yet available with ARBs, although two trials of renal disease progression did have cardiovascular endpoints as secondary outcomes. There were no significant differences between the ARB and control group except for first hospitalization with heart failure, where losartan reduced the risk by 32%, but there was a trend, albeit not significant, toward reduction of myocardial infarction. The first information regarding ARB effects on cardiovascular events as primary outcomes will come from the Losartan Intervention for Endpoint (LIFE) Reduction in Hypertension study. Therefore, as of this writing, all patients with type 2 diabetes and no evidence of nephropathy, ie, proteinuria and an elevated creatinine > 1.5 mg/dL, should be placed on an ACE inhibitor for cardiovascular risk reduction. If nephropathy is present, the evidence would support an ARB for therapy in concert with a a-blocker for cardiovascular risk reduction and renoprotection.     

Efficacy of Angiotensin Receptor Blockers in Cardiovascular Disease

The cardiovascular continuum describes the progression of pathophysiologic events from cardiovascular risk factors to symptomatic cardiovascular disease (CVD) and life-threatening events. Pharmacologic intervention early in the continuum may prevent or slow CVD development and improve quality of life. The renin–angiotensin–aldosterone system (RAAS) is central to the pathophysiology of CVD at many stages of the continuum. Numerous clinical trials of angiotensin converting enzyme (ACE) inhibitors and angiotensin receptor blockers (ARBs) have shown that RAAS blockade provides benefits to patients across the continuum. ARBs are as effective as ACE inhibitors in the treatment of hypertension; however tolerability and adherence to therapy appear to be improved with ARBs. Large clinical trials have shown that ARBs may provide therapeutic benefits beyond blood pressure control in patients with diabetes, heart failure or at risk of heart failure following a myocardial infarction. In addition, ARBs have been shown to provide protective effects in patients with impaired renal function or left ventricular hypertrophy. Additional clinical trials are ongoing to further characterize the role of ARBs in CVD management.     

Heart failure in very elderly population-a profile of heart failure in patients over the age of eighty

Objective Heart failure is an epidemic in the elderly, but there is a striking lack of data in this clinically important patient population. We investigated the demographics, cardiac performance, and medication management of a segment of the hospital popula- tion in at least their eighth decade of life. Methods We retrospectively reviewed 75 records of heart failure patients who were 80 years of age or older. Records were reviewed for demographic information, presence or absence of diastolic dysfunction, evaluation of ejection fraction, and medication usage including angiotensin-concerting enzyme (ACE) inhibitors, angiotensin receptor antagonists (ARBs), beta-adrenergic blockers, digoxin, and aldosterone antagonists. Assessment for contra-indications to ACE inhibitor or ARBs use was also performed to assess co-morbidities that limit treatment of heart failure. Results The population of very elderly with heart failure is heterogeneous. We found a higher proportion of females as well as higher rates of diastolic dysfunction in patients aged ≥ 90 years compared to patients between the ages of 80-89 years. Usage of ACE inhibitors, ARBs and beta-adrenergic blockers was strikingly low throughout the very elderly population. While co-morbid conditions limited use of agents in many cases, there was a lack of explicit contra-indication in most patients not on an ACE inhibitor or an ARB. Conclusions Heart failure is not a single disease processes, but a continuum of disease processes that vary with age. The elderly with heart failure are an undertreated population, in part due to the multitude of co-morbidities that affect them. Further prospective studies are needed to better understand the physiology and ideal treatment regiment in this growing population.     

Angiotensin-Converting Enzyme Inhibitors in Hypertension: To Use or Not to Use?

Most guidelines for the management of patients with cardiovascular disease recommend angiotensin-converting enzyme (ACE) inhibitors as first-choice therapy, whereas angiotensin receptor blockers (ARBs) are merely considered an alternative for ACE inhibitor–intolerant patients. The aim of this review was to compare outcomes and adverse events between ACE inhibitors and ARBs in patients. In patients with hypertension and hypertension with compelling indications, we found no difference in efficacy between ARBs and ACE inhibitors with regard to the surrogate endpoint of blood pressure and outcomes of all-cause mortality, cardiovascular mortality, myocardial infarction, heart failure, stroke, and end-stage renal disease. However, ACE inhibitors remain associated with cough and a very low risk of angioedema and fatalities. Overall withdrawal rates because of adverse events are lower with ARBs than with ACE inhibitors. Given the equal outcome efficacy but fewer adverse events with ARBs, risk-to-benefit analysis in aggregate indicates that at present there is little, if any, reason to use ACE inhibitors for the treatment of hypertension or its compelling indications.     

The clinical use of angiotensin-converting enzyme inhibitors

Through an integrative understanding of cardiovascular pathophysiologic characteristics at the multiorgan level, significant achievements in cardiovascular therapeutics have been achieved and enabled the rationale design and development of drugs such as the angiotensin-converting enzyme (ACE) inhibitors and angiotensin receptor blockers (ARBs). In this article, we present a detailed review of the physiologic features of the renin-angiotensin-aldosterone system (RAAS), ACE inhibitors and ARB clinical pharmacologic characteristics, and specific diseases in which they are considered to be the standard of the care as supported by important clinical trial data. It is envisioned that an updated and detailed understanding of ACE inhibitors and ARBs will facilitate their successful use in the treatment of heart failure, myocardial infarction, hypertension, renal failure, and diabetic nephropathy.     

Target‐organ protection with combination renin‐angiotensin‐system blockade

Pharmacologic blockade of the renin‐angiotensin‐aldosterone system (RAS) has antihypertensive, anti‐atherogenic, antioxidant, and anti‐inflammatory effects. Treatment with angiotensin‐converting enzyme inhibitors (ACEIs) and angiotensin receptor blockers (ARBs) has been demonstrated to prevent atrial fibrillation and new‐onset diabetes, and provide cardiac, cerebral, and renal protection. Combination therapy with ACEIs and ARBs, compared with monotherapy, provides enhanced reno‐ and cardioprotection, although available data indicate that combination RAS blockade may be beneficial only in select patient groups, such as those with diabetes mellitus, chronic kidney disease, or heart failure (HF). In certain high‐risk patients, the use of ARBs provides comparable efficacy to that observed with ACEIs. The efficacy of these agents may stem from pleiotropic effects beyond blood pressure (BP) reduction. Several studies demonstrate achievement of clinical endpoints without significant effects on BP. Copyright © 2009 Wiley Periodicals, Inc.     

The addition of angiotensin receptor blockers to angiotens-inconverting enzyme inhibitors—What has time told us?

The neurohormonal hypothesis for the pathogenesis of heart failure found an early champion in the angiotensinconverting enzyme (ACE) inhibitors. More recently, the β-blockers and aldosterone receptor antagonists have provided significant support by demonstrating marked additive clinical benefit. Within this context, angiotensin receptor blockers (ARBs) were specifically designed to antagonize one of the most potent contributors to the development and progression of heart failure, angiotensin. This review discusses the recent evidence for the addition of ARBs to standard therapy with ACE inhibitors and suggests how this evidence may be used to care for patients.