Effect of enalapril on myocardial infarction and unstable angina in patients with low ejection fractions

Imagine how many lives you save: angiotensin-converting enzyme inhibition for atherosclerotic vascular disease in the present era of risk reduction

INTRODUCTION

Angiotensin-converting enzyme (ACE) inhibition is clearly beneficial in patients with hypertension, heart failure, and post-myocardial infarction left ventricular (LV) dysfunction. However, whereas initial trials had reported a benefit of ACE inhibition in high-risk vascular patients, current trials of ACE inhibition have failed to demonstrate a clear benefit in vascular patients who are receiving risk-reduction interventions. The purpose of this review is to analyze the reasons behind the failure of the most recent trials of ACE inhibitors in vascular patients without overt LV dysfunction. The reader will gain an understanding of the time-dependent trend towards a reduction in the absolute benefit conferred by ACE inhibition in patients with vascular atherosclerosis as risk reduction interventions are increasingly implemented.

AREAS COVERED

Major trials with a follow-up period of at least 1 year assessing the use of ACE inhibitors in patients with a history of cardiac or vascular events were identified via a PubMed literature search. All-cause and cardiovascular mortality outcomes were reported for each trial, as well as the use of aspirin, lipid-lowering drugs and β-blockers, and the mean LV ejection fraction.

EXPERT OPINION

The findings of recent trials do not support the use of ACE inhibitors in vascular patients who, adherent with risk reduction therapy, do not have hypertension, diabetes, or LV dysfunction.

Do we need more than just powerful blood pressure reductions? New paradigms in end-organ protection

Antihypertensive therapy can lower the risk of cardiovascular morbidity and mortality. Yet, partly because of inadequate dosing, wrong pharmacological choices, and poor patient adherence, hypertension control remains suboptimal in the majority of hypertensive patients. Achieving greater blood pressure control requires a multifaceted approach that raises awareness of hypertension, uses effective therapies, and improves adherence. Particular classes of antihypertensive therapy have beneficial actions beyond blood pressure and studies have evaluated differences in cardiovascular protection among classes. The LIFE and HOPE studies showed between-class differences that may be due to effects other than blood pressure-lowering. In the ONTARGET study, telmisartan and ramipril provided similar cardiovascular protection but adherence was higher with telmisartan, which was better tolerated. This difference in compliance is likely to be important for long-term therapy. The selection of an agent for cardiovascular protection should depend on an appreciation of its composite properties, including any beneficial effects on tolerability and increased patient adherence, as these are likely to be advantageous for the long-term management of hypertension. This review examines the evidence that the effects beyond blood pressure provided by some antihypertensive agents can also lower the risk of cardiovascular, cerebrovascular, and renal events in patients with hypertension.

Flash pulmonary edema

Flash pulmonary edema (FPE) is a general clinical term used to describe a particularly dramatic form of acute decompensated heart failure. Well-established risk factors for heart failure such as hypertension, coronary ischemia, valvular heart disease, and diastolic dysfunction are associated with acute decompensated heart failure as well as with FPE. However, endothelial dysfunction possibly secondary to an excessive activity of renin-angiotensin-aldosterone system, impaired nitric oxide synthesis, increased endothelin levels, and/or excessive circulating catecholamines may cause excessive pulmonary capillary permeability and facilitate FPE formation. Renal artery stenosis particularly when bilateral has been identified has a common cause of FPE. Lack of diurnal variation in blood pressure and a widened pulse pressure have been identified as risk factors for FPE. This review is an attempt to delineate clinical and pathophysiological mechanisms responsible for FPE and to distinguish pathophysiologic, clinical, and therapeutic aspects of FPE from those of acute decompensated heart failure.

Residual risk for secondary ischemic events in patients with atherothrombotic disease: opportunity for future improvements in patient care

Atherothrombotic disease is highly prevalent in Western countries and is associated with morbidity, mortality, and a significant economic burden. The primary pathophysiological mechanism of acute ischemic events in patients with atherothrombotic disease is complex but involves thrombotic occlusion in response to rupture or erosion of atherosclerotic lesions. Current treatments for long-term secondary prevention in patients with established atherothrombotic disease, such as those with prior myocardial infarction, ischemic stroke/transient ischemic attack, or symptomatic peripheral artery disease, include therapies aimed at preventing rupture/erosion of atherosclerotic lesions (life-style modification and blood pressure reduction, in addition to statins and angiotensin II-active agents) and thrombus formation (primarily antiplatelet agents, such as aspirin, thienopyridines (clopidogrel, prasugrel, ticlopidine), and, to a lesser degree, anticoagulants). Despite the proven benefits and broad use of these therapies, the long-term rates of mortality and recurrent ischemic events remain high. This residual risk can be attributed to the fact that atherothrombosis continues in the presence of current treatments; because these agents each inhibit relatively specific pathways, atherosclerosis, thrombus formation, and other processes may progress. These considerations suggest that novel therapies with a different mechanism of action may provide additional reductions in morbidity and mortality beyond those observed with current agents.

Reinventing the ACE inhibitors: some old and new implications of ACE inhibition

Since their inception, angiotensin-converting enzyme (ACE) inhibitors have been used as first-line therapy for the treatment of cardiovascular and renal diseases. They restore the balance between the vasoconstrictive salt-retentive and hypertrophy-causing peptide angiotensin II (Ang II) and bradykinin, a vasodilatory and natriuretic peptide. As ACE is a promiscuous enzyme, ACE inhibitors alter the metabolism of a number of other vasoactive substances. ACE inhibitors decrease systemic vascular resistance without increasing heart rate and promote natriuresis. They have been proven effective in the treatment of hypertension, and reduce mortality in congestive heart failure and left ventricular dysfunction after myocardial infarction. They inhibit ischemic events and stabilize plaques. Furthermore, they delay the progression of diabetic nephropathy and neuropathy and act as antioxidants. Ongoing studies have elucidated protective roles for them in both memory-related disorders and cancer. Lastly, N- and C-domain selective ACE inhibitors have led to new uses for ACE inhibitors.

Linking diabetes and atherosclerosis

Cardiovascular diseases are the major causes of morbidity and mortality in people with diabetes. Macroangiopathy in diabetes is manifested by more accelerated and progressive atherosclerosis, which is more widely distributed. The pathogenesis of this accelerated atherosclerosis is multifactorial and includes very complex interactions. Several abnormalities - such as hyperglycemia, dyslipidemia, hypertension, endothelial dysfunction, renin-angiotensin system activation and chronic subclinical inflammation - all appear to play important roles in the development of diabetes-induced atherosclerosis. Treatment of the residual risk, other than glycemia, blood pressure and low-density lipoprotein cholesterol, remains important as the rate of diabetes increases worldwide. A synergistic multifactorial approach against both conventional cardiovascular risk factors and emerging risk factors, such as vasoactive systems, the AGE-RAGE axis, novel proteins, such as TRAIL, and the complement system, as well as oxidative stress and inflammation, may be a promising way to prevent macrovascular disease in diabetes. In this review we focus on the major causes and mechanisms of atherosclerotic disease in patients with diabetes and highlight emerging targets for therapeutic intervention.

Dual renin-angiotensin system blockade in the ONTARGET study: clinically relevant risk for the kidney?

Inhibition of the renin-angiotensin system contributes to reductions in proteinuria and in progression of chronic kidney disease. Indeed, monotherapy with either an angiotensin-converting enzyme (ACE) inhibitor or an angiotensin receptor blocker (ARB) has been shown to decrease proteinuria and slow the decline of chronic kidney disease, but incompletely. Therefore, there is increasing interest in whether combination strategies will provide more complete blockade of the renin-angiotensin system, which may translate into superior renoprotective and cardioprotective effects compared with either agent alone. There have been several reports on combination strategies. However, the recent report of the Ongoing Telmisartan Alone and in Combination with Ramipril Global Endpoint Trial (ONTARGET) has received much of the attention. The renal outcomes in ONTARGET suggest that combined ACE inhibitor and ARB therapy contributes to a higher rate of adverse renal outcomes than monotherapy. Therefore, this review explores data from ONTARGET in relation to other available evidence on the use of combination therapies.

Blocking the renin-angiotensin system: dual- versus mono-therapy

The renin-angiotensin system (RAS) plays an important role in the pathogenesis of cardiovascular disease. One of the effects of the activated RAS is target-organ damage, in part due to their effects on causing hypertension. Blocking angiotensin-converting enzyme (ACE) with inhibitors has been shown to attenuate the pathological effects of the RAS. Clinical trials have shown that ACE inhibition improves outcomes in the prevention of acute myocardial infarction, lowering the morbidity and mortality in congestive heart failure, and attenuates renal dysfunction. There is recent evidence to show that angiotensin receptor blockers (ARBs) have similar efficacy to ACE inhibitors in reducing cardiovascular outcomes. The wealth of information obtained regarding the beneficial effects of RAS inhibition on clinical outcome has been focused on monotherapy with either ARB or ACE inhibition. Evidence from some trials suggests that better overall inhibition of RAS by dual therapy may improve clinical outcomes. Combination therapy has been shown to be beneficial in patients with congestive heart failure or renal disease. The Valsartan in Acute Myocardial Infarction Trial (VALIANT) trial showed equal benefit of either ARB or ACE inhibition with reduction in primary end points in postmyocardial infarction patients, but there was no further benefit from dual therapy in reducing outcomes. In the recent ONTARGET study, there was further evidence that ARBs are equal to ACE inhibitors in reducing cardiovascular events. In Ongoing Telmisartan, Ramipril, or Both in Patients at High Risk for Vascular Events (ONTARGET), combined RAS blockade did not have any added benefit but resulted in increased risk of adverse outcomes. In the Candesartan in Heart Failure (CHARM) and the Valsartan Heart Failure Trial (Val-HeFT) trials of patients with severe heart failure, the addition of an ARB to an ACE inhibitor reduced cardiac mortality and lowered hospital admissions. Whether or not dual therapy is beneficial in patients with diabetic renal failure should be clarified by future studies. Overall, patients receiving dual therapy, if clinically justified, should be monitored closely for potential adverse effects.

Class effects and evidence-based medicine

Drugs grouped into a therapeutic class on the basis of a common mechanism of action often have considerably different pharmacodynamic and pharmacokinetic properties. Among angiotensin-converting enzyme (ACE) inhibitors, differences with potential clinical relevance include potency, whether the drug is an active compound or requires metabolic activation, lipophilicity, route(s) of elimination, and half-life. Large clinical trials have documented the clinical benefits of several ACE inhibitors in various patient populations, and many clinical effects of ACE inhibitors are likely to be the same. However, there are possible quantitative differences among ACE inhibitors that may alter the overall therapeutic benefits for specific patient populations and indications. Equipotency in terms of clinical efficacy is difficult to determine. Since the concept of "class effect" is a term of convenience that has no universally accepted definition and subsequently should not form the basis for the practice of evidence-based medicine, untested drugs of a "class" should be considered to be unproven drugs.

Overview of the relationship between ischemia and congestive heart failure

Ischemic heart disease is the principal etiology of heart failure in the Western world. Myocardial ischemia is important in cardiac remodeling, a process that leads to a progressive change in the shape and size of the heart and significantly worsens the prognosis of patients with heart failure. Preventing ischemic events, therefore, is an important goal in the management of patients with coronary artery disease. Statins have been shown to reduce the number of ischemic events in these patients, whereas the benefit of beta-blocker and aldosterone antagonist therapy on ischemic causes of heart failure remains unclear. Several large trials involving patients with asymptomatic left ventricular dysfunction after myocardial infarction or heart failure have shown that angiotensin-converting enzyme (ACE) inhibitors reduce the incidence of progressive heart failure, death, and ischemic events, thus establishing ACE inhibitors as first-line therapy for these patients. Other lines of evidence have suggested that ACE inhibitor therapy may also benefit patients with preserved left ventricular function, a hypothesis that is being evaluated in three large, controlled, randomized trials. One of these trials, the Heart Outcomes Prevention Evaluation (HOPE) study, was terminated prematurely because it demonstrated the significant positive effects of the ACE inhibitor ramipril on cardiovascular outcomes in patients with coronary artery disease and preserved left ventricular function. A growing body of data confirms the relationship between ischemia and heart failure and the benefits of ACE inhibitor treatment in a broad range of high-risk patients.

Angiotensin-converting enzyme inhibition with perindopril in patients with prior myocardial infarction and/or revascularization: a subgroup analysis of the EUROPA trial

BACKGROUND

The European trial on Reduction Of cardiac events with Perindopril in patients with stable coronary Artery disease (EUROPA) demonstrated the benefits of perindopril with respect to secondary prevention of cardiovascular risk in patients with stable coronary artery disease.

AIMS

To describe the clinical effects of perindopril in a subpopulation of patients from EUROPA with a history of myocardial infarction and/or revascularization.

PATIENTS AND METHODS

Of the 12,218 patients in the EUROPA study, 10,962 had a history of myocardial infarction and/or revascularization. In this EUROPA subpopulation, 7910 patients had a history of myocardial infarction and 6709 had a history of revascularization. Patients were randomized to treatment with perindopril 8mg/day or placebo. The primary endpoint was a composite of cardiovascular mortality, myocardial infarction and resuscitated cardiac arrest.

RESULTS

After a mean follow-up of 4.2 years, treatment with perindopril 8mg/day was associated with a 22.4% reduction in the primary endpoint compared with placebo (p<0.001) in patients with a history of myocardial infarction. Patients with a history of myocardial revascularization showed a 17.3% reduction in the primary endpoint with perindopril versus placebo (p<0.05). In the combined population of patients with a history of myocardial infarction and/or revascularization, treatment with perindopril produced a 22.4% reduction in the primary endpoint compared with placebo (p<0.001).

CONCLUSIONS

This study confirms the benefits of a high dose of angiotensin-converting enzyme inhibitor for the secondary prevention of cardiovascular risk among patients with a history of myocardial infarction and/or revascularization.

Impact of hospitalization for acute coronary events on subsequent mortality in patients with chronic heart failure

AIMS

We explored the impact of having a hospital admission for an acute coronary syndrome (ACS) on the subsequent prognosis among patients with chronic heart failure (CHF).

METHODS AND RESULTS

A total of 7599 patients with CHF, New York Heart Association Classes II-IV, were randomly assigned to candesartan or placebo. We assessed the risk of death after a first ACS using time-updated Cox proportional hazard models adjusted for baseline predictors. During a mean follow-up of 3.3 years, 1174 patients experienced at least one ACS. Myocardial infarction (MI) was the first ACS in 442 subjects and unstable angina (UA) in 732. After these events, 219 (49.5%) and 167 (22.8%) patients died during follow-up. The early risk of death was more pronounced after MI: 30.2% died within 30 days compared with 3.6% after UA. After an ACS event, the risk of death declined steadily over time, although 18 months after an MI the risk was still twice that of patients without an ACS.

CONCLUSION

Patients with CHF, who develop an ACS, have markedly increased subsequent mortality, particularly in the early phase after an MI.

Determining the most appropriate components for a composite clinical trial outcome

BACKGROUND

Because composite end points augment event rates, they are often thought to increase statistical power. This may not be true if the intervention has a lesser effect on some components of the composite. Consequently, treatment effect size may depend on the choice of composite.

METHODS

To explore this issue, we performed a meta-analysis to determine the effect of angiotensin-converting enzyme inhibitors or angiotensin receptor blockers on individual cardiovascular (CV) outcomes. We then applied these treatment effects to 2 different composite CV outcomes generated using blinded data from the ongoing Nateglinide and Valsartan in Impaired Glucose Tolerance (IGT) Outcomes Research (NAVIGATOR) trial and analyzed them on a time-to-first-event basis. The composites were CV death, nonfatal myocardial infarction, nonfatal stroke, or hospitalization for heart failure and an "extended" composite that included hospitalization for angina and coronary revascularization.

RESULTS

The odds reductions due to angiotensin-converting enzyme/angiotensin receptor blocker treatment estimated from the meta-analysis were as follows: CV death: 13%, P < .0001; nonfatal myocardial infarction: 16%, P < .00001; nonfatal stroke: 14%, P = .006; heart failure: 28%, P < .00001; hospitalization for angina: 7%, P = .02; and revascularization: 5%, P = .17. For the CV composites, the projected odds reduction was larger (17.8%, 95% CI 0.452-1.189) for the narrower composite compared with the extended CV composite (11.7%, 95% CI 0.623-1.136); that is, use of the extended composite reduced power to detect a difference between treatment groups.

CONCLUSIONS

Although the use of CV composites augments event rates, it may not increase statistical power. Inclusion of events little influenced by an intervention may reduce the precision of the composite end point and mask treatment effects.

Insulin resistance and atherosclerosis

Insulin resistance characterizes type 2 diabetes and the metabolic syndrome, disorders associated with an increased risk of death due to macrovascular disease. In the past few decades, research from both the basic science and clinical arenas has enabled evidence-based use of therapeutic modalities such as statins and angiotensin-converting enzyme inhibitors to reduce cardiovascular (CV) mortality in insulin-resistant patients. Recently, promising drugs such as the thiazolidinediones have come under scrutiny for possible deleterious CV effects. Ongoing research has broadened our understanding of the pathophysiology of atherosclerosis, implicating detrimental effects of inflammation and the cellular stress response on the vasculature. In this review, we address current thinking that is shaping our molecular understanding of insulin resistance and atherosclerosis.

Management of hypertension in patients with cardiac disease: use of renin-angiotensin blocking agents

Inhibition of renin-angiotensin system (RAS) activity using angiotensin-converting enzyme inhibitors or angiotensin II receptor blockers (ARBs) is beneficial in patient populations with left ventricular dysfunction or systolic heart failure (HF) and other forms of heart disease. In high-risk patients with coronary heart disease (CHD), treatment with these agents reduces the mortality rate and improves secondary outcomes. Individuals with stable CHD who are at lower risk benefit less from treatment. RAS inhibition also provides some clinical benefit to patients with diastolic HF and preserved left ventricular function. Left ventricular hypertrophy (LVH) is a strong predictor of cardiovascular events and all-cause mortality in patients with hypertension. Treatment with an ARB reduces the risk for adverse cardiovascular outcomes in patients with hypertension and LVH. The benefits correlate with regression of LVH, and the effect is independent of the degree of blood pressure lowering. Finally, studies indicate that a history of hypertension in patients who have not had a myocardial infarction (MI) increases the risk for HF after MI; the risk is decreased in patients with hypertension who receive treatment with a RAS inhibitor.

Short-term effects of angiotensin receptor blockers on blood pressure control, and plasma inflammatory and fibrinolytic parameters in patients taking angiotensin-converting enzyme inhibitors

INTRODUCTION

Angiotensin-converting enzyme (ACE) inhibitors reduce cardiovascular events in patients with established vascular disease and heart failure (HF). ACE-inhibitors have important effects on fibrinolytic balance, which may be the underlying mechanism for a reduction in cardiovascular events. Although angiotensin-receptor blockers (ARBs) offer greater tolerability than ACE-inhibitors, the major ARB trials have demonstrated a lack of reduction in myocardial infarction (MI) occurrence and mortality in contrast to ACE-inhibitors. In this study, we investigated the combined effects of ARBs and ACE-inhibitors on fibrinolytic and inflammatory parameters in patients with uncontrolled hypertension.

METHODS

Twenty-four patients with uncontrolled hypertension despite taking adequate doses of ACE-inhibitor therapy were selected. Patients were started on Candesartan 16 mg once a day. Plasma plasminogen activator inhibitor (PAI-1) antigen (Ag), tissue plasminogen activator (t-PA) Ag, thrombin-activatable fibrinolysis inhibitor (TAFI) % activity and high sensitivity C-reactive protein (hsCRP) levels, were measured during low salt intake at baseline and two weeks after therapy with an ARB.

RESULTS

Addition of ARB to the regimen reduced systolic (155+/-17 vs. 139+/-13, p<0.001), and diastolic (91+/-9 vs. 81+/-8, p<0.001) blood pressures (BP). No significant changes were observed in PAI-1 Ag (66+/-51 vs. 68+/-52, p=0.9), t-PA Ag (12.6+/-5.3 vs. 13.3+/-4.7, p=0.3), TAFI % activity (119+/-30 vs. 118+/-32, p=0.9) and hsCRP (3.9+/-3.4 vs. 3.6+/-3.6, p=0.7) levels after adding an ARB.

CONCLUSIONS

Combined ARB and ACE-inhibitor use provide better BP control without any detrimental effect in plasma inflammatory and fibrinolytic parameters.

Carvedilol in the treatment of elderly patients with chronic heart failure

Chronic heart failure (CHF) is common, and increases in incidence and prevalence with age. There are compelling data demonstrating reduced mortality and hospitalizations with adrenergic blockade in older patients with CHF. Despite this, many older patients remain under-treated. The aim of the present article is to review the potential mechanisms of the benefits of adrenergic blockade in CHF and the clinical data available from the large randomized studies, focusing particularly on older patients.

Renin Inhibition by Aliskiren Prevents Atherosclerosis Progression

Hypertension is associated with increased risk of cardiovascular diseases. Antihypertensive treatment, particularly blockade of the renin-angiotensin system, contributes to prevent atherosclerosis-mediated cardiovascular events. Direct comparison of different antihypertensive treatments on atherosclerosis and particularly plaque stabilization is sparse. ApoE −/− mice with vulnerable (2-kidney, 1-clip renovascular hypertension model) or stable (1-kidney, 1-clip renovascular hypertension model) atherosclerotic plaques were used. Mice were treated with aliskiren (renin inhibitor), irbesartan (angiotensin-receptor blocker), atenolol (β-blocker), or amlodipine (calcium channel blocker). Atherosclerosis characteristics were assessed. Hemodynamic and hormonal parameters were measured. Aliskiren and irbesartan significantly prevented atherosclerosis progression in 2-kidney, 1-clip mice. Indeed, compared with untreated animals, plaques showed thinner fibrous cap ( P <0.05); smaller lipid core ( P <0.05); decreased media degeneration, layering, and macrophage content ( P <0.05); and increased smooth muscle cell content ( P <0.05). Interestingly, aliskiren significantly increased the smooth muscle cell compared with irbesartan. Despite similar blood pressure lowering, only partial plaque stabilization was attained by atenolol and amlodipine. Amlodipine increased plaque smooth muscle cell content ( P <0.05), whereas atenolol decreased plaque inflammation ( P <0.05). This divergent effect was also observed in 1-kidney, 1-clip mice. Normalizing blood pressure by irbesartan increased the plasma renin concentration (5932±1512 ng/mL per hour) more than normalizing it by aliskiren (16085±5628 ng/mL per hour). Specific renin-angiotensin system blockade prevents atherosclerosis progression. First, evidence is provided that direct renin inhibition mediates atherosclerotic plaque stabilization. In contrast, β-blocker and calcium channel blocker treatment only partially stabilize plaques differently influencing atherogenesis. Angiotensin II decisively mediates plaque vulnerability. The plasma renin concentration measurement by an indirect method did not confirm the excessive increase of plasma renin concentration reported in the literature during aliskiren compared with irbesartan or amlodipine treatment.

Heart failure in the twenty-first century: is it a coronary artery disease or hypertension problem?

Hypertension and coronary disease are major risk factors for the incidence and progression of heart failure. These two risk factors frequently coexist, and have additive and synergistic effects that promote both left ventricular remodeling and heart failure in the general population. The relative contributions of these two risk factors to heart failure burden in the community may vary based on age, gender, and race. In general, attribution of heart failure in the community to solely one of these two risk factors is inappropriate. Prevention of both hypertension and coronary disease is important for preventing heart failure in the twenty-first century.

ACE inhibition and endothelial function: main findings of PERFECT, a sub-study of the EUROPA trial

Background

ACE inhibition results in secondary prevention of coronary artery disease (CAD) through different mechanisms including improvement of endothelial dysfunction. The Perindopril-Function of the Endothelium in Coronary artery disease Trial (PERFECT) evaluated whether long-term administration of perindopril improves endothelial dysfunction.

Methods

PERFECT is a 3-year double blind randomised placebo controlled trial to determine the effect of perindopril 8 mg once daily on brachial artery endothelial function in patients with stable CAD without clinical heart failure. Endothelial function in response to ischaemia was assessed using ultrasound. Primary endpoint was difference in flow-mediated vasodilatation (FMD) assessed at 36 months.

Results

In 20 centers, 333 patients randomly received perindopril or matching placebo. Ischemia-induced FMD was 2.7% (SD 2.6). In the perindopril group FMD went from 2.6% at baseline to 3.3% at 36 months and in the placebo group from 2.8 to 3.0%. Change in FMD after 36 month treatment was 0.55% (95% confidence interval −0.36, 1.47; p = 0.23) higher in perindopril than in placebo group. The rate of change in FMD per 6 months was 0.14% (SE 0.05, p = 0.02) in perindopril and 0.02% (SE 0.05, p = 0.74) in placebo group (0.12% difference in rate of change p = 0.07).

Conclusion

Perindopril resulted in a modest, albeit not statistically significant, improvement in FMD.

Effect of losartan in treatment of exercise-induced myocardial ischemia

Because no controlled clinical studies are available about the possible role of angiotensin II receptor blockers in preventing effort myocardial ischemia, we evaluated the effect of angiotensin II receptor blocker/losartan in preventing exercise-induced myocardial ischemia in patients with coronary artery disease. Twenty-four sedentary patients with chronic stable ischemia were prospectively randomized to 28 days (double blind) of losartan 100 mg or losartan placebo in 2 divided doses. In each patient the treatment was crossed over to the alternative regimen (28 days, double blind) after a 1-week placebo period (single blind). At the end of each phase a new exercise stress test was performed. At baseline, systolic blood pressure was significantly decreased after losartan 100 mg compared with losartan placebo. At submaximal exercise, systolic blood pressure and rate-pressure product were lower after losartan 100 mg administration compared with losartan placebo, and these findings remained significant at 1-mm ST depression and at peak exercise. Losartan 100 mg administration versus losartan placebo significantly delayed the time to 1-mm ST-depression onset and decreased ST-segment depression at peak exercise and time to recovery of ST-segment depression. Losartan 100 mg administration compared with losartan placebo was able to significantly increase exercise duration and maximal workload during exercise stress testing. In conclusion, in our study, losartan decreased electrocardiographic parameters of myocardial ischemia in patients with coronary artery disease, suggesting a possible role of this drug in treatment of patients with effort myocardial ischemia.

Cardiovascular drug therapy in the elderly

Pharmacokinetic considerations in the elderly include absorption, bioavailablility, drug distribution, half-life, drug metabolism, and drug excretion. There are numerous physiologic changes with aging that affect pharmacodynamics with alterations in end-organ responsiveness. This article discusses use of cardiovascular drugs in the elderly including digoxin, diuretics, beta-adrenergic blockers, angiotensin-converting enzyme inhibitors, angiotensin-II receptor blockers, nitrates, calcium channel blockers, alpha-adrenergic blockers, antiarrhythmic drugs, lipid-lowering drugs, and anticoagulants. This article also discusses the adverse effects of cardiovascular drugs in the elderly, medications best to avoid in the elderly, and the prudent use of medications in the elderly.

Management of non-ST-Segment Elevation Myocardial Infarction

Non-ST-segment elevation myocardial infarction (NSTEMI) is a major cause of cardiovascular morbidity and mortality in the United States. It represents the highest risk category of non-ST-segment elevation acute coronary syndromes (NSTEACS), for which timely diagnosis and appropriate therapy are paramount to improve outcomes. Evidence-based treatment, with combination of antiplatelet and anticoagulant therapy, and with serious consideration of early coronary angiography and revascularization along with anti-ischemic medical therapy, is the mainstay of management for NSTEMI. Aggressive risk-factor control after the acute event is imperative for secondary prevention of cardiovascular events. Applying in practice the American College of Cardiology/American Heart Association (ACC/AHA) guideline recommendations results in improved outcomes.

[Postinfarction management]

Postinfarction management of patients must be individualized. The essential prognostic factor is the ejection fraction, measured at one month. The four basic drugs to be used in combination are antithrombotics, beta-blockers, converting enzyme inhibitors and statins. The objective of treatment is to reach the dose regimens used in clinical trials. Cardiovascular rehabilitation and treatment education must be proposed widely to improve control of risk factors, explain the role of each drug prescribed and teach the appropriate use of nitroglycerin and of emergency medical services. Indications for myocardial revascularization depend on the coronary anatomy. Indications for an implantable defibrillator and for cardiac replacement depend on the ejection fraction and on the existence of heart failure uncontrolled by drug treatment.

Long-term trandolapril treatment is associated with reduced aortic stiffness: the prevention of events with angiotensin-converting enzyme inhibition hemodynamic substudy

The Prevention of Events with Angiotensin Converting Enzyme inhibition (PEACE) trial evaluated angiotensin-converting enzyme inhibition with trandolapril versus placebo added to conventional therapy in patients with stable coronary disease and preserved left ventricular function. The PEACE hemodynamic substudy evaluated effects of trandolapril on pulsatile hemodynamics. Hemodynamic studies were performed in 300 participants from 5 PEACE centers a median of 52 months (range, 25 to 80 months) after random assignment to trandolapril at a target dose of 4 mg per day or placebo. Central pulsatile hemodynamics and carotid-femoral pulse wave velocity were assessed by using echocardiography, tonometry of the carotid and femoral arteries, and body surface transit distances. Patients randomly assigned to trandolapril tended to be older (mean+/-SD: 64.2+/-7.9 versus 62.9+/-7.7 years; P=0.14), with a higher body mass index (28.5+/-4.0 versus 27.8+/-3.9 kg/m(2); P=0.09) and lower ejection fraction (57.1+/-8.1% versus 58.7+/-8.4%; P<0.01). At the time of the hemodynamic substudy, the trandolapril group had lower mean arterial pressure (93.1+/-10.2 versus 96.3+/-11.3 mm Hg; P<0.01) and lower carotid-femoral pulse wave velocity (geometric mean [95% CI]: 10.4 m/s [10.0 to 10.9 m/s] versus 11.2 m/s [10.7 to 11.8 m/s]; P=0.02). The difference in carotid-femoral pulse wave velocity persisted (P<0.01) in an analysis that adjusted for baseline characteristics and follow-up mean pressure. In contrast, there was no difference in aortic compliance, characteristic impedance, augmentation index, or total arterial compliance. Angiotensin-converting enzyme inhibition with trandolapril produced a modest reduction in carotid-femoral pulse wave velocity, a measure of aortic wall stiffness, beyond what would be expected from blood pressure lowering or differences in baseline characteristics alone.

Canadian Cardiovascular Society Consensus Conference recommendations on heart failure update 2007: Prevention, management during intercurrent illness or acute decompensation, and use of biomarkers

Heart failure is common, yet it is difficult to treat. It presents in many different guises and circumstances in which therapy needs to be individualized. The Canadian Cardiovascular Society published a comprehensive set of recommendations in January 2006 on the diagnosis and management of heart failure, and the present update builds on those core recommendations. Based on feedback obtained through a national program of heart failure workshops during 2006, several topics were identified as priorities because of the challenges they pose to health care professionals. New evidence-based recommendations were developed using the structured approach for the review and assessment of evidence adopted and previously described by the Society. Specific recommendations and practical tips were written for the prevention of heart failure, the management of heart failure during intercurrent illness, the treatment of acute heart failure, and the current and future roles of biomarkers in heart failure care. Specific clinical questions that are addressed include: which patients should be identified as being at high risk of developing heart failure and which interventions should be used? What complications can occur in heart failure patients during an intercurrent illness, how should these patients be monitored and which medications may require a dose adjustment or discontinuation? What are the best therapeutic, both drug and nondrug, strategies for patients with acute heart failure? How can new biomarkers help in the treatment of heart failure, and when and how should BNP be measured in heart failure patients? The goals of the present update are to translate best evidence into practice, to apply clinical wisdom where evidence for specific strategies is weaker, and to aid physicians and other health care providers to optimally treat heart failure patients to result in a measurable impact on patient health and clinical outcomes in Canada.

Antithrombotic therapy in patients with chronic heart failure: rationale, clinical evidence and practical implications

Chronic heart failure (CHF) is traditionally associated with increased risk of thromboembolic complications. Key features of CHF pathophysiology, such as impairment of intracardiac hemodynamics, peripheral blood flow deceleration, neuroendocrine activation, chronic oxidative stress and proinflammatory changes, could explain the predisposition to thromboembolism. However, conclusive epidemiologic data on thromboembolic event incidence in CHF are lacking. Furthermore, the place of antithrombotic therapy in CHF management is still uncertain. Apart from established indications for warfarin (e.g. atrial fibrillation and previous embolic events), there is no robust evidence to support administration of vitamin K antagonists to other patients with CHF, particularly to patients in sinus rhythm. The role of aspirin in preventing thromboembolism in these patients is also controversial. Large randomized trial data on the effectiveness and risks of warfarin and aspirin use in CHF patients with sinus rhythm are forthcoming. This article provides a brief overview of the epidemiologic and pathobiological background of thromboembolism in CHF, and discusses the up-to-date clinical evidence on antithrombotic therapy in detail.

Systemic inhibition of the angiotensin-converting enzyme limits lipopolysaccharide-induced lung neutrophil recruitment through both bradykinin and angiotensin II-regulated pathways

Recruitment of neutrophils to the lung is a sentinel event in acute lung inflammation. Identifying mechanisms that regulate neutrophil recruitment to the lung may result in strategies to limit lung damage and improve clinical outcomes. Recently, the renin angiotensin system (RAS) has been shown to regulate neutrophil influx in acute inflammatory models of cardiac, neurologic, and gastrointestinal disease. As a role for the RAS in LPS-induced acute lung inflammation has not been described, we undertook this study to examine the possibility that the RAS regulates neutrophil recruitment to the lung after LPS exposure. Pretreatment of mice with the angiotensin-converting enzyme (ACE) inhibitor enalapril, but not the anti-hypertensive hydralazine, decreased pulmonary neutrophil recruitment after exposure to LPS. We hypothesize that inhibition of LPS-induced neutrophil accumulation to the lung with enalapril occurred through both an increase in bradykinin, and a decrease in angiotensin II (ATII), mediated signaling. Bradykinin receptor blockade reversed the inhibitory effect of enalapril on neutrophil recruitment. Similarly, pretreatment with bradykinin receptor agonists inhibited IL-8-induced neutrophil chemotaxis and LPS-induced neutrophil recruitment to the lung. Inhibition of ATII-mediated signaling, with the ATII receptor 1a inhibitor losartan, decreased LPS-induced pulmonary neutrophil recruitment, and this was suggested to occur through decreased PAI-1 levels. LPS-induced PAI-1 levels were diminished in animals pretreated with losartan and in those deficient for the ATII receptor 1a. Taken together, these results suggest that ACE regulates LPS-induced pulmonary neutrophil recruitment via modulation of both bradykinin- and ATII-mediated pathways, each regulating neutrophil recruitment by separate, but distinct, mechanisms.

CX3CR1 receptor is up-regulated in monocytes of coronary artery diseased patients: Impact of pre-inflammatory stimuli and renin–angiotensin system modulators

Fractalkine/CX3CR1 pathway is considered a major modulator of atherosclerosis. In the present study, expression of CX3CR1 on PBMCs/monocytes of healthy individuals and coronary artery diseased patients was initially assessed by flow cytometry. Effects of pre-inflammatory cytokines interferon (INF)-gamma and tumor necrosis factor (TNF)-alpha on expression of CX3CR1 and a single representative of each major chemokine family (CCR5 and CXCR4) were further assessed in three cell models: THP-1 monocytes, Jurkat T lymphocytes and primary monocytes isolated from healthy donors. Finally, effects of angiotensin-converting enzyme (ACE) inhibitors captopril, lisinopril and angiotensin receptor blocker (ARB) losartan on chemokine receptor expression were evaluated in the same cell models either in a naive or stimulated state. INF-gamma significantly affected the chemokine receptor phenotype of THP-1 cells by increasing the rate of CX3CR1-positive cells. Pre-treatment with the ACE inhibitors, captopril and lisinopril, and the ARB, losartan, did not influence these effects. Captopril and lisinopril similarly had no effect on either stimulated or naive primary monocytes. Yet, a small but repeatable increase in CX3CR1 expression after treatment with losartan was noted. Nevertheless, the latter observation did not retain statistical significance after applying the Bonferroni correction. In conclusion, our data did not indicate any significant effect of the ACE inhibitors on the chemokine receptor phenotype of monocytes.

Vasopeptidase inhibition normalizes blood pressure and restores endothelial function in renovascular hypertension

BACKGROUND/AIMS

Vasopeptidase inhibitors by definition inhibit both angiotensin-converting enzyme (ACE) and neutral endopeptidase (NEP), therefore they may exceed the effect of ACE inhibitors in the treatment of hypertension. The present study investigated the effect of the vasopeptidase inhibitor AVE7688 in comparison to the ACE inhibitor ramipril on systolic blood pressure (SBP) and endothelial function in renovascular hypertension.

METHODS

Wistar-Kyoto rats with renovascular hypertension (two-kidney one-clamp-model) were randomized 2 weeks after unilateral clamping of the right renal artery for 3 weeks' oral treatment with either AVE7688 (30 mg/kg/day), ramipril (1 mg/kg/day) or placebo. SBP was measured by the tail-cuff method and endothelium-dependent and -independent vascular function was assessed in isolated preconstricted (norepinephrine 10(-7) mol/l) aortic rings as relaxation to acetylcholine (10(-10)-10(-4) mol/l) and sodium nitroprusside (10(-10)-10(-4) mol/l), respectively.

RESULTS

Two weeks after clamping, SBP was significantly elevated (196 +/- 16 vs. 145 +/- 8 mm Hg for sham-operated rats; p < 0.01) and further increased in placebo-treated animals to 208 +/- 19 mm Hg. Treatment with AVE7688 and ramipril had a similar blood pressure-lowering effect (119 +/- 8 and 124 +/- 10 mm Hg, respectively; p < 0.01 vs. placebo). Maximum endothelium-dependent relaxation was reduced in hypertensive rats (72 +/- 6 vs. 99 +/- 7% in control rats; p < 0.05). Endothelium-dependent relaxation was restored by AVE7688 (101 +/- 6%) and ramipril (94 +/- 8%), respectively, whereas endothelium-independent relaxation was comparable in all groups.

CONCLUSION

In renovascular hypertension the vasopeptidase inhibitor AVE7688 exhibited similar blood pressure-lowering and endothelial protective properties as compared to the ACE inhibitor ramipril. Therefore, in high renin models of hypertension, vasopeptidase inhibition may be considered an alternative treatment option to ACE inhibition.

Cost effectiveness of perindopril in reducing cardiovascular events in patients with stable coronary artery disease using data from the EUROPA study

BACKGROUND

The EUropean trial on Reduction Of cardiac events with Perindopril in stable coronary Artery disease (EUROPA) trial has recently reported.

OBJECTIVE

To assess the cost effectiveness of perindopril in stable coronary heart disease in the UK.

METHODS

Clinical and resource use data were taken from the EUROPA trial. Costs included drugs and hospitalisations. Health-related quality of life values were taken from published sources. A cost-effectiveness analysis is presented as a function of the risk of a primary event (non-fatal myocardial infarction, cardiac arrest or cardiovascular death) in order to identify people for whom treatment offers greatest value for money.

RESULTS

The median incremental cost of perindopril for each quality-adjusted life year (QALY) gained across the heterogeneous population of EUROPA was estimated as 9700 pounds(interquartile range 6400-14,200 pounds). Overall, 88% of the EUROPA population had an estimated cost per QALY below 20,000 pounds and 97% below 30,000 pounds. For a threshold value of cost effectiveness of 30,000 pounds per QALY gained, treatment of people representing the 25th, 50th (median) and 75th centiles of the cost effectiveness distribution for perindopril has a probability of 0.999, 0.99 and 0.93 of being cost effective, respectively. Cost effectiveness was strongly related to higher risk of a primary event under standard care.

CONCLUSIONS

Whether the use of perindopril can be considered cost effective depends on the threshold value of cost effectiveness of healthcare systems. For the large majority of patients included in EUROPA, the incremental cost per QALY gained was lower than the apparent threshold used by the National Institute for Health and Clinical Excellence in the UK.