Effects of Telmisartan, Ramipril, and Their Combination on Left Ventricular Hypertrophy in Individuals at High Vascular Risk in the Ongoing Telmisartan Alone and in Combination With Ramipril Global End Point Trial and the Telmisartan Randomized Assessment Study in ACE Intolerant Subjects With Cardiovascular Disease

Renin-angiotensin system blocking drugs

The two major classes of drugs that target the RAS are the angiotensin-converting enzyme (ACE) inhibitors and the selective AT1 receptor blockers (ARBs). Although both of these drug classes target angiotensin II, the differences in their mechanisms of action have implications for their effects on other pathways and receptors that may have therapeutic implications. Both ACEIs and ARBs are effective antihypertensive agents that have been shown to reduce the risk of cardiovascular and renal events. Direct inhibition of renin -the most proximal aspect of the RAS -became clinically feasible from 2007 with the introduction of aliskiren. This latter drug has been shown to be efficacious for the management of hypertension. Combined therapy of direct renin-inhibitors with ACEIs or ARBs has been tested in some clinical situations as congestive HF and proteinuria with diverse results. This article tries to offer an updated review of current knowledge on the use of RAS blocking drugs in clinical settings.

An evaluation of the latest evidence relating to renin-angiotensin system inhibitors

INTRODUCTION

In the last few years, a number of important clinical trials have been completed that have investigated the inhibition of the renin-angiotensin system. New drugs, focusing on this system, have now emerged as a result.

AREAS COVERED

The authors review the most relevant information available, reported from the last 5 years, pertaining to the most important clinical trials on renin-angiotensin system blockers (ARBs). The authors' data review includes the trials of aliskiren, telmisartan, olmesartan and azilsartan. The authors also review the possible risk of cancer with ARBs.

EXPERT OPINION

The results of ASPIRE and ALTITUDE trials strongly suggested that dual inhibition of aliskiren with either ARBS or angiotensin converting enzyme inhibitors (ACEi) should be avoided. Olmesartan is an effective and safe antihypertensive agent, but special attention should be paid to high-risk patients, such as those with coronary disease, to avoid an excessive reduction in blood pressure. The authors also note that while azilsartan is probably the most potent ARB, there is still a lack of data regarding potential organ damage and the incidence of cardiovascular events. Lastly, recent evidence has shown a lack of a relationship between ARB therapy and the occurrence of cancer.

Preventing cardiovascular events with angiotensin II receptor blockers: a closer look at telmisartan and valsartan

Angiotensin II receptor blockers (ARBs) inhibit the renin-angiotensin system. As a result, these agents provide beneficial effects in terms of cardiovascular (CV) and renal protection, independent of their blood pressure-lowering effects. Telmisartan and valsartan are the most intensively studied ARBs for the effects on CV outcomes. Randomized clinical trials assessing morbidity and mortality end points have included a range of patient types, including those with hypertension, hypertension with Type 2 diabetes, high CV risk without hypertension, ischemic heart disease, stroke and heart failure. Few head-to-head comparisons between telmisartan and valsartan have been performed. However, some blood pressure-independent properties of these two ARBs can be scrutinized from separate studies in the available literature.

Telmisartan for the reduction of cardiovascular morbidity and mortality

Cardiovascular disease (CVD) poses a significant healthcare and economic burden on societies and individuals. Angiotensin II is a key component of the renin-angiotensin system that plays a central role in atherosclerotic mechanisms that contribute to CVD. Renin-angiotensin system blockers are widely used to reduce cardiovascular (CV) risk owing to their potential both to lower blood pressure, a CV risk factor, and to attenuate the atherosclerotic disease process directly. Telmisartan has a number of pharmacological properties that distinguish it from other angiotensin II receptor blockers (ARBs) - the longest plasma half-life, highest lipophilicity and strongest receptor binding affinity in class. The ONTARGET(®) trial showed that telmisartan is as effective as ramipril in reducing CV morbidity (including myocardial infarction and stroke) and mortality in a broad range of patients at increased CV risk. Evidence from other ARBs remains largely restricted to patients with heart failure, diabetic nephropathy or specific subsets of hypertensive patients. Telmisartan is, therefore, the only ARB with a broad indication for CV risk reduction in patients with atherothrombotic disease or diabetes with end-organ damage.

Angiotensin-converting enzyme inhibitors and angiotensin II receptor blockers for treatment of ischemic heart disease: Future research needs prioritization

BACKGROUND

A recent review evaluated the comparative effectiveness of angiotensin-converting enzyme inhibitors (ACE-Is) and angiotensin II receptor blockers (ARBs) in patients with or at high risk for stable ischemic heart disease (IHD). The prioritization of future research needs has customarily been an informal process that is not responsive to the needs of all relevant stakeholders.

METHODS

As part of the Agency for Healthcare Research and Quality Effective Healthcare Program, the Duke Evidence-Based Practice Center engaged a diverse stakeholder group in 3 exercises designed to prioritize future research needs pertaining to the comparative effectiveness of ACE-I/ARB in patients with stable IHD.

RESULTS

Our stakeholders prioritized the following areas of research pertaining to the comparative effectiveness of ACE-I/ARB in stable IHD: (1) strategies to enhance greater evidence-based use, (2) impact of adherence on effectiveness or harms, (3) impact of comorbidities on effectiveness or harms, (4) medication impact on patient quality of life, (5) impact of demographic differences on effectiveness or harms, and (6) medication impact on incidence of new diagnoses. This project also yielded suggestions regarding potential study designs to address these future research needs.

CONCLUSIONS

Our stakeholders prioritized research designed to facilitate (1) tailored ACE-I/ARB treatment based on individual patient characteristics and (2) implementation of ACE-I/ARB use among patients most likely to benefit. With respect to suggested study designs, it was felt that analysis of existing data would sufficiently address many of the top-tier future research needs (FRNs).

Beyond blood pressure: evidence for cardiovascular, cerebrovascular, and renal protective effects of renin-angiotensin system blockers

For patients with hypertension, effective control of blood pressure (BP) reduces cardiovascular (CV), and renal risk. Antihypertensive agents that offer benefits that extend beyond those associated with BP reduction alone, to include tissue protective effects and effects on the vasculature, may be of benefit for many patients with increased CV risk due to comorbidities or prior history of CV events. Renin-angiotensin system (RAS) blockers [angiotensin-converting enzyme inhibitors (ACEIs) and angiotensin II receptor blockers (ARBs)] are guideline-recognized, highly effective antihypertensive agents that exert their BP-lowering action through different mechanisms at different levels of the RAS. Large-scale clinical studies suggest that small, between-treatment differences in BP lowering do not account for observed outcome differences between RAS blockers and other antihypertensive agents. Analysis of data from seminal clinical studies and meta-analyses identify that, controlling for effects on BP control, RAS blockers may be more effective than calcium channel blockers (CCBs) in reducing risk of myocardial infarction and congestive heart failure; ARBs may be more effective than either ACEIs or β blockers in stroke prevention; CCBs may be more effective than RAS blockers in stroke prevention; and ARBs may be more effective than β blockers in reducing left ventricular hypertrophy. This review considers the rationale and evidence for benefits of RAS blockade beyond BP lowering, and highlights the differences between ARBs and ACEIs, and between agents within these drug classes.

Telmisartan: just an antihypertensive agent? A literature review

INTRODUCTION

The modulation of the renin angiotensin aldosterone system (RAAS) is an important pathway in managing high blood pressure, and its overexpression plays a key role in target end-organ damage. Telmisartan is an angiotensin II receptor blocker (ARB) with unique pharmacologic properties, including the longest half-life among all ARBs; this leads to a significant and 24-h sustained reduction of blood pressure. Telmisartan has well-known antihypertensive properties, but there is also strong clinical evidence that it reduces left ventricular hypertrophy, arterial stiffness and the recurrence of atrial fibrillation, and confers renoprotection.

AREAS COVERED

This paper reviews telmisartan's pharmacological properties in terms of efficacy for hypertension control and, importantly, focuses on its new therapeutic indications and their clinical implications.

EXPERT OPINION

ONTARGET (ongoing telmisartan alone and in combination with ramipril global endpoint trial) demonstrated, that telmisartan confers cardiovascular protective effects similar to those of ramipril, but with a better tolerability. Moreover, recent investigations focused on the capability of telmisartan to modulate the peroxisome proliferator-activated receptor-gamma (PPAR-γ), an established target in the treatment of insulin resistance, diabetes and metabolic syndrome, whose activation is also correlated to anti-inflammatory and, finally, anti-atherosclerotic properties. Telmisartan shows peculiar features that go beyond blood pressure control. It presents promising and unique protective properties against target end-organ damage, potentially able to open a scenario of new therapeutic approaches to cardiovascular disease.