Rationale, design, and baseline characteristics of 2 large, simple, randomized trials evaluating telmisartan, ramipril, and their combination in high-risk patients: the Ongoing Telmisartan Alone and in Combination with Ramipril Global Endpoint Trial/Telmisartan Randomized Assessment Study in ACE Intolerant Subjects with Cardiovascular Disease (ONTARGET/TRANSCEND) trials

The renin-angiotensin-aldosterone system: a pivotal role in insulin sensitivity and glycemic control

PURPOSE OF REVIEW

Diabetes mellitus is an exploding epidemic costing billions of dollars yearly. Type 2 diabetes mellitus is characterized by insulin resistance and is closely associated with arterial hypertension. Emerging literature has demonstrated that modulation of the renin-angiotensin-aldosterone system by use of angiotensin-converting enzyme inhibitors or angiotensin II receptor blockers leads to improved insulin sensitivity, glycemic control and possibly prevention of type 2 diabetes mellitus.

RECENT FINDINGS

Several major studies investigating angiotensin II receptor blocker or angiotensin-converting enzyme inhibitor use in either hypertensive or heart failure patients have found lower incidence of type 2 diabetes mellitus when compared with placebo, beta-blocker, calcium-channel blocker or diuretic. None of these trials, however, studied prevention of diabetes as a primary endpoint. The Dream Trial and upcoming NAVIGATOR, ONTARGET/TRANSCEND trials specifically look at the prevention of diabetes as a primary endpoint. Several studies have evaluated possible mechanisms of how the renin-angiotensin-aldosterone system can alter insulin sensitivity and glycemic control.

SUMMARY

This review will focus on the recent literature that demonstrates renin-angiotensin-aldosterone system modulation and its effects on diabetes prevention, glycemic control and insulin sensitivity, as well as possible mechanisms for achieving this goal.

Oral direct renin inhibition: premise, promise, and potential limitations of a new antihypertensive drug

The first oral direct renin inhibitor, aliskiren, recently received approval for the treatment of hypertension. This article addresses the premise, promise, and potential limitations of this new class of renin-angiotensin system inhibitor. Although aliskiren adds to a list of more than 100 drugs approved for the treatment of hypertension, its introduction into clinical medicine is of particular interest because of the novel mechanism of action: inhibition of renin's catalytic activity, the most proximal and rate-limiting step in renin-angiotensin system activation. By producing more complete renin-angiotensin system inhibition than with existing agents, direct renin inhibitors may afford greater protection from hypertensive complications. Other potential advantages include additional blood pressure reduction when used in combination therapy, a placebo-like side-effect profile, avid renal concentration, and long duration of action. Potential limitations include modest levels of blood pressure reduction that are equivalent to but not greater than angiotensin receptor blockers, reduced gastrointestinal absorption with a high-fat meal, and large reactive increases in renin secretion--the functional importance of which is under intense investigation. The results of outcomes trials are eagerly awaited.

Inhibiting the renin-angiotensin system with ACE Inhibitors or ARBs after MI

As part of the recommended modern post-myocardial infarction (MI) management, including reperfusion strategies, antiplatelet therapy, and beta-blockers, we may wonder whether the impact of early inhibition of the renin-angiotensin system (RAS) is as important as it was 20 years ago. This review demonstrates that significant clinical benefit can be derived from angiotensin-converting enzyme (ACE) inhibitors and angiotensin receptor blockers (ARBs) even when added to other currently recommended treatment strategies in post-MI patients. Moreover, the effects of RAS inhibition extend far beyond the early post-MI neurohormonal activation and left ventricular remodeling phases. The favorable effects of RAS inhibition on important prognostic markers such as atrial fibrillation, renal function, and diabetes have recently been unraveled. Post-MI RAS inhibition also benefits all age groups, including elderly patients.

Slowing nephropathy progression: focus on proteinuria reduction

Blood pressure control reduces decline of kidney function. Angiotensin-converting enzyme inhibitors and angiotensin receptor blockers offer renoprotection to a small extent beyond that attributable to blood pressure lowering. These agents also reduce proteinuria, a risk marker for renal disease progression. Accumulating evidence indicates that their antiproteinuric effect correlates with their additional renal benefits.

Stroke in chronic kidney disease: prevention and management

The incidence of stroke is elevated among individuals with kidney disease. Traditional risk factors seem to account for much but not all of this excess risk. Blood pressure control is the most important aspect of stroke prevention. Multiple classes of antihypertensive agents, including diuretics, calcium channel blockers, angiotensin-converting enzyme inhibitors, and angiotensin II receptor blockers, have reduced stroke risk. Some physiologic and clinical evidence suggests that angiotensin II receptor blockers may offer superior benefit to that of angiotensin-converting enzyme inhibitors for the same level of blood pressure control; however, few head-to-head trials have compared these two agent classes directly using stroke as an outcome.

Non-antiarrhythmic medications for atrial fibrillation: from bench to clinical practice

Many treatment modalities have been developed over the years for the management of atrial fibrillation (AF). While they are still considered the first line of treatment for suppression of AF, antiarrhythmics often lead to treatment failure, complications and undesired consequences. Pulmonary vein ablation is an invasive procedure which is not always curative. Recently, there have been a variety of studies reporting the potential antiarrhythmic effects of various nonantiarrhythmic agents. This paper aims to provide a comprehensive review of the findings reported thus far about the antiarrhythmic effects of agents which are not antiarrhythmic drugs themselves, but which have been found to offer promise in the prevention and treatment of AF.

Effect of statins, angiotensin-converting enzyme inhibitors, and beta blockers on survival in patients >or=65 years of age with heart failure and preserved left ventricular systolic function

About half of all patients with heart failure (HF) have preserved left ventricular systolic function. Statins, angiotensin-converting enzyme inhibitors, and beta blockers have been shown to improve survival in patients with HF and low ejection fraction. However, no large national study has investigated these agents in patients with HF and preserved left ventricular ejection fraction. We evaluated a nationwide sample of 13,533 eligible Medicare beneficiaries aged >or=65 years who were hospitalized with a primary discharge diagnosis of HF and had chart documentation of preserved left ventricular ejection fraction between April 1998 and March 1999 or between July 2000 and June 2001. In Cox proportional hazard model accounting for demographic profile, clinical characteristics, treatments, physician specialty, and hospital characteristics, discharge statin therapy was associated with significant improvements in 1- and 3-year mortality (RR 0.69, 95% confidence interval [CI] 0.61 to 0.78; RR 0.73, 95% CI 0.68 to 0.79, respectively). Irrespective of total cholesterol level or coronary artery disease status, diabetes, hypertension, and age, statin therapy was associated with significant differences in mortality rates. Similarly, angiotensin-converting enzyme inhibitors were associated with better survival at 1 year (RR 0.88, 95% CI 0.82 to 0.95) and 3 years (RR 0.93, 95% CI 0.89 to 0.98). Beta-blocker therapy was associated with a nonsignificant trend at 1 year (RR 0.93, 95% CI 0.87 to 1.10) and significant survival benefits at 3 years (RR 0.92%, 95% CI 0.87 to 0.97). In conclusion, our data demonstrate that statins, angiotensin-converting enzyme inhibitors, and beta blockers are associated with better short- and long-term survival in patients >or=65 years with HF and preserved left ventricular ejection fraction.

Early vascular aging (EVA): consequences and prevention

It has often been recognized that a discrepancy exists during the clinical consultation between the chronological age of a patient on the one hand with the signs and symptoms of biological age that can be recorded on the other hand. In cardiovascular medicine this is obvious when a heavy smoker presents with features of early biological aging, for example skin appearance and impaired lung function. This could also be extrapolated to vascular function as the target for numerous cardiovascular risk factors, thereby increasing the risk of early cardiovascular disease (CVD). Both new and old treatment modalities can play a role for the prevention of early vascular aging, first of all smoking cessation and improved lifestyle in general, but later on also the use of drugs such as statins or agents that block the renin-angiotensin system (RAS). New classes of drugs are currently being tested for CVD prevention, including glitazones and rimonabant, even if adverse effects (heart failure and depression) might restrict their usefulness. Results from ongoing intervention studies will eventually cast new light on possibilities to prevent the development of vascular aging.

Rationale for combination angiotensin receptor blocker and angiotensin-converting enzyme inhibitor treatment and end-organ protection in patients with chronic kidney disease

Chronic kidney disease (CKD) is a major public health problem that has received increasing attention because of the high rate of associated cardiovascular morbidity and mortality. Mounting evidence indicates that angiotensin-converting enzyme (ACE) inhibitors and angiotensin receptor blockers (ARBs), drugs that inhibit the renin-angiotensin-aldosterone system (RAAS) safely slow down progression of CKD. There is also growing evidence supporting combination treatment of nephropathies with an ACE inhibitor plus an ARB to more completely block the RAAS and provide greater renoprotection than either an ACE inhibitor-based or ARB-based regimen. The National Kidney Foundation suggests that ACE inhibitors and ARBs may be used in combination to reduce proteinuria in patients with kidney disease; however, larger outcomes trials are needed.

Supratherapeutic doses of angiotensin receptor blockers to decrease proteinuria in patients with chronic kidney disease

An important endpoint in treating chronic kidney disease, a prevalent disease that can lead to kidney failure and cardiovascular disease, is reducing proteinuria. Proteinuria is an independent risk factor for disease progression and the development of cardiovascular disease and is a key factor that can be used to guide therapy designed to maximize kidney protection. Proteinuria is targeted by using pharmacologic agents that suppress the renin-angiotensin-aldosterone system (RAAS), a regulator of intravascular volume and blood pressure; this has been shown to decrease proteinuria, slow disease progression, and improve coronary disease outcome, independent of effects on blood pressure. The efficacy of RAAS blockers, including angiotensin receptor blockers and angiotensin-converting enzyme inhibitors, may be limited by currently recommended doses, which are based on treatment of hypertension. Data are now emerging from clinical trials demonstrating that use of 'supratherapeutic doses' (doses greater than those approved for lowering blood pressure), compared with standard doses, has favorable safety, tolerability, and efficacy in reducing proteinuria in both diabetic and nondiabetic patients with chronic kidney disease. Supratherapeutic dosing may be a valuable approach for optimizing RAAS blockade and providing renoprotection.

NF-kappaB-dependent transcriptional regulation of the cardiac scn5a sodium channel by angiotensin II

Angiotensin II (ANG II) increases oxidative stress and is associated with increased risk of sudden cardiac death. The cardiac Na(+) channel promoter contains elements that confer redox sensitivity. We tested the hypothesis that ANG II-mediated oxidative stress may modulate Na(+) channel current through altering channel transcription. In H9c2 myocytes treated for 48 h with ANG II (100 nmol/l) or H(2)O(2) (10 micromol/l) showed delayed macroscopic inactivation, increased late current, and 59.6% and 53.8% reductions in Na(+) current, respectively (P < or = 0.01). By quantitative real-time RT-PCR, the cardiac Na(+) channel (scn5a) mRNA abundance declined by 47.3% (P < 0.01) in H9c2 myocytes treated for 48 h with 100 nmol/l ANG II. A similar change occurred with 20 micromol/l H(2)O(2) (46.9%, P < 0.01) after 48 h. Comparable effects were seen in acutely isolated ventricular myocytes. The effects of ANG II could be inhibited by prior treatment of H9c2 cells with scavengers of reactive oxygen species or an inhibitor of the NADPH oxidase. Mutation of the scn5a promoter NF-kappaB binding site prevented decreased activity in response to ANG II and H(2)O(2). Gel shift and chromosomal immunoprecipitation assays confirmed that nuclear factor (NF)-kappaB bound to the scn5a promoter in response to ANG II and H(2)O(2). Overexpression of the p50 subunit of NF-kappaB in H9c2 cells reduced scn5a mRNA (77.3%, P < 0.01). In conclusion, ANG II can decrease scn5a transcription and current. This effect appears to be through production of H(2)O(2) resulting in NF-kappaB binding to the Na(+) channel promoter.

Non-Antiarrhythmic Drugs in Atrial Fibrillation: A Review of Non-Antiarrhythmic Agents in Prevention of Atrial Fibrillation

This article reviews current evidence of non-antiarrhythmic agents for the prevention and maintenance of sinus rhythm in patients with atrial fibrillation. These nontraditional agents include angiotensin converting enzyme inhibitors, angiotensin receptor blockers, antiinflammatory agents, calcium channel blockers, and beta-blockers. The mechanisms of action and clinical trials regarding the effectiveness of these agents in atrial fibrillation prevention are reviewed.

Reducing cardiovascular risk by blockade of the renin-angiotensin-aldosterone system

Many factors contribute to the overall risk of cardiovascular disease (CVD) in a given patient. Activation of the renin-angiotensin-aldosterone system (RAAS) is pivotal in the pathophysiology of CVD and renal disease and appears to place individuals at high risk for cardiovascular (CV) and renal events. Results from many large-scale, long-term clinical trials have demonstrated that RAAS blockade with an angiotensin-converting-enzyme inhibitor (ACEI) or an angiotensin receptor blocker (ARB) can significantly decrease CV and renal morbidity and mortality in a wide range of patients. Some of the clinical benefits derived from use of these agents appears to be independent of their ability to lower blood pressure. The combined use of an ACEI and an ARB for antihypertensive therapy has begun to receive considerable attention. Such an approach may seem counterintuitive, but ACEIs and ARBs have distinct and potentially complementary pharmacologic effects. Results from clinical trials thus far suggest that combination therapy with an ACEI plus an ARB may be a rational choice in patients with chronic activation of the RAAS, including those with heart failure or impaired left ventricular systolic function, diabetes, proteinuria, impaired renal function, recent myocardial infarction, or multiple CV risk factors. Results from ongoing, large-scale, clinical endpoint trials will provide important additional information about the benefits of dual RAAS inhibition in patients at high risk for CV morbidity and mortality.

The role of renin-angiotensin system blockade in the management of hypertension associated with the cardiometabolic syndrome

The mounting epidemic of overweight and obesity has made understanding the relationship between excess weight and associated comorbidities more urgent. Obesity is one of the strongest predictors of the development of hypertension and is an independent risk factor for cardiovascular disease, renal disease, and diabetes mellitus. The concomitant presence of obesity and hypertension, as commonly occurs in the cardiometabolic syndrome, magnifies the risk for cardiovascular and renal disease. The term "obesity-hypertension" thus serves to underscore the link between these two deleterious conditions and to emphasize the imperative for clinical intervention. Adipose tissue is now known to produce hormones and cytokines that promote inflammation, lipid accumulation, and insulin resistance. In addition, adipose tissue contains all the components of the renin-angiotensin system (RAS), which is upregulated in the presence of obesity. Evidence implicates activation of the systemic and adipose tissue RAS, as well as the sympathetic nervous system, as key obesity-related mechanisms of hypertension and other components of the cardiometabolic syndrome. RAS blockade therefore becomes a potential therapeutic strategy in patients with obesity-related hypertension and in persons with the cardiometabolic syndrome. Clinical trials of angiotensin-converting enzyme inhibitors and angiotensin II receptor blockers conducted in predominantly overweight/obese populations have demonstrated significant reductions in cardiovascular and renal disease risk among a range of at-risk patients. RAS blockade also is associated with a reduced risk of new-onset diabetes compared with other classes of antihypertensive therapy. Randomized, controlled trials conducted specifically in patients with obesity and hypertension are needed to determine the optimal therapeutic approach for these patients.

Hypertension, vascular cognitive disorders and neuroprotection

OBJECTIVE

The role of the antihypertensive therapy in preventing vascular cognitive disorders in elderly persons without a history of stroke is a matter of debate. This review focuses on cognitive disorders in elderly hypertensive patients.

METHODS

Relevant papers were identified by searches in PubMed from 1946 until February 2007 using the keywords 'cerebral blood flow autoregulation', 'vascular cognitive disorders', 'neuroimaging in hypertension', 'antihypertensive treatment' and 'neuroprotection in cerebral ischemia'.

RESULTS

Excessive blood pressure lowering in patients with long-standing hypertension may increase the risk of cerebral hypoperfusion, white matter lesions and consequent cognitive decline. White matter lesions have been found in the majority of patients with long-standing hypertension. They correlate with vascular cognitive disorders, particularly impairments of attention and executive function, while memory is relatively preserved. Cerebral small vessel disease in elderly patients should be taken into account when antihypertensive treatment is considered. Renin-angiotensin blockade, some calcium channel blockers and statins are thought to possess neuroprotective action.

CONCLUSION

For prevention of cerebral hypoperfusion in elderly hypertensives blood pressure lowering should be cautiously controlled. The increased risk of white matter lesions is an indication for early neuroprotection. The combination of renin-angiotensin blockade or calcium channel blockers with statins may become a promising preventive strategy against cognitive decline in elderly hypertensives. Cerebral white matter protection is a future challenge.

Pharmacoeconomics and quality of life analysis of telmisartan in hypertension treatment

Hypertension is a major public health problem, being one of the leading causes of death and disability worldwide and a major risk factor for cardiovascular disease. The renin-angiotensin-aldosterone system plays an important role in volume homeostasis and blood pressure regulation, and is a target for several groups of pharmaceutical agents. Telmisartan, a highly selective AT1 receptor antagonist, fulfills all new criteria for antihypertensive agents: high effectiveness, high specificity, high compliance and fewer adverse effects. Several clinical trials and the clinical practice setting indicate substantial evidence that telmisartan, either as monotherapy or in combination with other antihypertensive drugs, provides long-term antihypertensive efficacy. In fact, telmisartan has the property to sustain blood pressure control throughout the 24-h dosage interval. Furthermore, telmisartan can play an important role in improving compliance, because of its documented good tolerability profile, which limits the adverse effects. This article provides the most recent data of the pharmacoeconomic position of telmisartan and its treatment effects on quality of life.

Impact of ramipril on the incidence of atrial fibrillation: results of the Heart Outcomes Prevention Evaluation study

OBJECTIVES

We evaluated the effect of angiotensin-converting enzyme (ACE) inhibitor ramipril on the incidence of atrial fibrillation (AF) in patients enrolled in the Heart Outcomes Prevention Evaluation trial.

BACKGROUND

Atrial fibrillation is the most common arrhythmia affecting the general population and is associated with increased morbidity and mortality. Retrospective secondary analyses of some of the large trials of ACE inhibitors have suggested that ACE inhibitors may prevent AF.

METHODS

We evaluated the occurrence of AF by reviewing the electrocardiogram tracings at entry, at 2 years, and at the end of the study, as well as hospitalizations among 8335 high-risk participants from the Heart Outcomes Prevention Evaluation study, > or = 55 years, without known heart failure or left ventricular (LV) systolic dysfunction and followed for a median period of 4.5 years. We compared the impact of ramipril and matched placebo on occurrence of AF. The results were compared to similar trials.

RESULTS

Over the 4.5 years follow-up, the incidence of new AF was low (2.1%, 177/8335), and ramipril did not significantly reduce the rate of new AF compared with placebo (86/4291 [2.0%] vs 91/4044 [2.2%]) with an odds ratio of 0.92 (95% confidence interval, 0.68-1.24; P = .57). These results added to the previous ACE inhibitor trials (excluding trials in patients with LV dysfunction) showed no significant reduction in new AF among patients treated with these agents (1088/20,930 [5.0%] vs 1343/22,878 [5.9%]; relative risk, 0.92; 95% confidence interval, 0.80-1.05).

CONCLUSION

Although the incidence of AF was low, treatment with ramipril in this population without known LV systolic dysfunction did not significantly reduce this dysrhythmia.

The role of angiotensin II type 1 receptor blockers in the prevention and management of diabetes mellitus

Angiotensin II Receptor blockers (ARBs) are an important addition to the current range of medications available for treating a wide spectrum of diseases including cardiovascular diseases. Coronary heart disease (CHD) is the most common cause of death in the United Kingdom and worldwide. More importantly, the presence of the metabolic syndrome and the likelihood of diabetes mellitus taking on epidemic proportions in the years to come all threaten to maintain the mortality rate due to CHD. This review article focuses on the clinical studies that have helped define the trends in the usage of these agents in the prevention and treatment of diabetes mellitus and its complications and also explores possible mechanisms of action and future developments.

Is the development of diabetes with antihypertensive therapy a problem?--Pro

Some questions about new-onset diabetes (NOD) must still be completely addressed: 1) its incidence; 2) the possible association between NOD and some classes of antihypertensive drugs; and 3) its prognostic impact. It is well known that diuretics and beta blockers can increase plasma glucose and, in available hypertension trials, diuretics and beta blockers caused a higher incidence of NOD than new antihypertensive drugs. NOD heralds a high risk of major cardiovascular events, but the absolute difference between old and new drugs was too small to significantly drive the differences in cardiovascular event rates between the two groups of treatment. This evidence suggests a judicious use of drugs more frequently associated with NOD in subjects at high risk of diabetes (impaired fasting glucose, overweight, family history of diabetes, low high-density lipoprotein cholesterol levels). The lowest effective dose of these drugs should be used, plasma glucose should be checked periodically, and concomitant lifestyle measures to prevent diabetes should be implemented with resolution.

The effect of angiotensin receptor blockers for preventing atrial fibrillation

Atrial fibrillation is the most common sustained cardiac arrhythmia in clinical practice, and causes significant burden to patients and health care systems. Clinicians treat existing atrial fibrillation with anticoagulation and/or drugs that utilize either a rate or rhythm control strategy. It remains unclear how best to reduce cardiovascular morbidity and mortality in this population. Prevention of atrial fibrillation using angiotensin receptor blockers, which affect ion currents and refractoriness in atrial myocytes, regress or prevent atrial fibrosis, decrease left atrial size, regress left ventricular hypertrophy, modulate sympathetic nerve activity, reduce inflammation, and reduce blood pressure, may become an important and desirable alternative.

Prevention of stroke in patients with hypertension

Despite the substantial evidence of the benefits of lowering blood pressure, conventional treatment does not normalize the burden of major cardiovascular events in patients with hypertension. Data now suggest that the nature of the antihypertensive agent used may have an important impact on long-term cardiovascular outcomes, including stroke. Optimal treatment should provide powerful 24-hour blood pressure control, including during the early morning hours when the risk of stroke is highest. In addition, antihypertensive therapies selected should have positive blood pressure-independent effects on stroke risk. In contrast to angiotensin-converting enzyme inhibitors, angiotensin II receptor blockers (ARBs) provide consistent benefits in stroke protection beyond blood pressure lowering. The ARB telmisartan has a particularly interesting profile for stroke management. Selective angiotensin II type 1 receptor blockade and 24-hour blood pressure control with telmisartan provide the potential for improved stroke prevention. This will be investigated in the Prevention Regimen for Effectively Avoiding Second Strokes (PROFESS) study.

Angiotensin receptor blockers versus angiotensin-converting enzyme inhibitors: where do we stand now?

Cardiovascular disease represents a continuum that starts with risk factors, such as hypertension, and progresses to atherosclerosis, target organ damage, and ultimately leads to heart failure or stroke. Renin-angiotensin-aldosterone system (RAAS) blockade with angiotensin-converting enzyme (ACE) inhibitors or angiotensin receptor blockers (ARBs) has been shown to be beneficial at all stages of this continuum. Both classes of agent can prevent or reverse endothelial dysfunction and atherosclerosis, thereby potentially reducing the risk of cardiovascular events. Such a reduction has been shown with ACE inhibitors in patients with coronary artery disease, but no such data are currently available for ARBs. Both ACE inhibitors and ARBs have been shown to reduce damage in target organs, such as the heart and kidney, and to decrease cardiovascular mortality and morbidity in patients with congestive heart failure. Trials, such as the Ongoing Telmisartan Alone in Combination with Ramipril Global Endpoint Trial (ONTARGET) and the Telmisartan Randomised Assessment Study in ACE-Intolerant Subjects with Cardiovascular Disease (TRANSCEND), that compare telmisartan, ramipril, and their combination in high-risk patients with vascular end-organ damage, should provide important new insights into the benefits of intervention with RAS blockade along the cardiorenovascular continuum.

Rationale for double renin-angiotensin-aldosterone system blockade

The clinical benefits of both angiotensin-converting enzyme (ACE) inhibitors and angiotensin receptor blockers (ARBs) extend beyond blood pressure reduction to encompass tissue-protective effects in target organs, such as the heart, vasculature, and kidneys, that underlie the reductions in cardiovascular mortality and morbidity seen in large outcome trials. However, these effects are achieved by different mechanisms. ACE inhibitors reduce circulating and tissue angiotensin II levels and potentiate the beneficial effects of bradykinin, including generation of nitric oxide (NO). By contrast, the protective effects of ARBs are owing to the blockade of the angiotensin II type 1 (AT(1)) receptors and possibly also to the stimulation of angiotensin II type 2 (AT(2)) receptors, again resulting in NO release. In addition, some ARBs, such as telmisartan, are selective activators of peroxisome proliferator-activated receptor-gamma (PPAR-gamma), thereby increasing insulin sensitivity. In contrast to other PPAR-gamma ligands, such as the thiazolidinediones, activation of this receptor by telmisartan does not result in weight gain. The complementary mechanisms of action of ACE inhibitors and ARBs create a rationale for combination therapy in high-risk patients. The benefits of this approach with telmisartan are being investigated in clinical trials, such as the Ongoing Telmisartan Alone in Combination with Ramipril Global Endpoint Trial (ONTARGET).

The effect of telmisartan and ramipril on early morning blood pressure surge: a pooled analysis of two randomized clinical trials

OBJECTIVES

The period of early morning blood pressure surge is associated with a higher incidence of cardiovascular events than at other times of the day. Antihypertensive medication given once daily in the morning may not protect against this surge if its duration of action is too short. We compared telmisartan, an angiotensin II receptor blocker with a trough-to-peak ratio >90%, with ramipril, an angiotensin-converting enzyme inhibitor with a trough-to-peak ratio of around 50%.

METHODS

Data from two prospective, randomized, open-label, blinded endpoint studies comparing telmisartan force titrated to 80 mg once daily and ramipril 10 mg once daily were pooled. Patients had mild-to-moderate hypertension and were assessed using 24-h ambulatory blood pressure monitoring at baseline and endpoint. Early morning blood pressure surge was defined as the difference between mean blood pressure within 2 h after arising and night-time low. Patients were grouped into quartiles according to their baseline systolic surge.

RESULTS

Data from 1279 patients were analyzed. Telmisartan changed the overall mean (SE) systolic surge by -1.5 (0.47) mmHg, and ramipril by +0.3 (0.47) mmHg (P=0.0049). The magnitude of surge reduction was greatest in the quartile with highest baseline systolic surge: telmisartan -12.7 (0.91), ramipril -7.8 (1.02) mmHg (P=0.0004). Telmisartan also reduced the surge compared with ramipril in dippers, but there were no differences between the two groups in nondippers.

CONCLUSIONS

Telmisartan significantly reduced the early morning systolic blood pressure surge compared with ramipril. A reduction in this surge may help to reduce cardiovascular events in the morning period.

Sexual function, satisfaction, and association of erectile dysfunction with cardiovascular disease and risk factors in cardiovascular high-risk patients: substudy of the ONgoing Telmisartan Alone and in Combination with Ramipril Global Endpoint Trial/Telmisartan Randomized AssessmeNT Study in ACE-INtolerant Subjects with Cardiovascular Disease (ONTARGET/TRANSCEND)

BACKGROUND

Erectile dysfunction (ED) is a common disorder in middle-aged men and is significantly influenced by cardiovascular risk factors (CVRFs) and cardiovascular disease. The substudy of the ONTARGET/TRANSCEND trials evaluates the relationship of erectile function to baseline characteristics and current treatment in cardiovascular high-risk patients who have been enrolled in these trials. The effects of treatment with telmisartan and ramipril, alone or in combination, including a telmisartan versus placebo arm will be determined prospectively during a follow-up of 4 years.

METHODS

One thousand three hundred fifty-seven patients were evaluated in 13 countries at baseline, 2 years, and 4 years, with ED determined using the ED score of the Cologne Male Survey (Kölner [Cologne] Evaluation of Erectile Dysfunction) and the 5-item International Index of Erectile Function. Erectile dysfunction scores were related to CVRF and the use of cardiovascular drugs.

RESULTS

Prevalence of ED was 50.7% (Kölner [Cologne] Evaluation of Erectile Dysfunction) and 54.3% (5-item International Index of Erectile Function), respectively, with a decline of sexual activity after the diagnosis of cardiovascular disease. In multivariate analysis, diabetes mellitus (P < .00001), stroke (P = .00026), pelvic surgery (P = .025), and age of >65 years (P < .00001) correlated with the degree of ED. No significant associations were observed for cholesterol levels, hypertension, and smoking status as well as current treatment with angiotensin-converting enzyme inhibitors, angiotensin I antagonists, diuretics, beta-blockers, or calcium-channel blockers.

CONCLUSIONS

The ONTARGET/TRANSCEND-ED substudy shows a significant influence of cardiovascular disease on erectile function. In contrast to prior smaller studies, drug therapy and CVRF seem to play a minor role in cardiovascular high-risk patients. Follow-up data will provide information whether angiotensin-converting enzyme inhibitors, angiotensin I antagonists, or a combination thereof are able to improve erectile function.

Drug therapy for the secondary prevention of stroke in hypertensive patients: current issues and options

Hypertension is the major risk factor for ischaemic and haemorrhagic clinical strokes as well as for silent brain infarcts with a continuous association between both systolic and diastolic blood pressures. Epidemiological data highlight the increasing burden to come over the next decades. Without any doubt, antihypertensive treatment is the most important therapy to reduce the risk of stroke by approximately 30-40%. International guidelines recommend antihypertensive treatment for primary prevention with evidence level A. Recurrent strokes or transient ischaemic attack (TIA) are an important practical, clinical and economic problem, and have a major impact on the development of vascular dementia. All stroke patients and patients with TIA have to be regarded as very high-risk patients. Hypertension increases the risk of recurrent strokes. Only limited data directly address the role of blood pressure treatment among individuals with stroke or TIA. There is a general lack of definitive data regarding when to start antihypertensive treatment in the initial phase, and treatment of hypertension in the acute period after stroke is still under debate. Experimental and clinical data suggest that reducing the activity of the renin-angiotensin aldosterone system (RAAS) may have beneficial effects beyond the lowering of blood pressure. There is increasing evidence of cerebroprotective effects for medication influencing the RAAS, such as angiotensin receptor antagonists or ACE inhibitors. The MOSES study showed for the first time superiority of an angiotensin receptor antagonist compared with a calcium channel antagonist in antihypertensive treatment for secondary stroke prevention. Optimal blood pressure range in secondary prevention seems to be 120-140/80-90 mm Hg, but questions about a J- or U-shaped curve are still not answered sufficiently. The effects of additional antihypertensive treatment in the evening for stroke patients with 'non-dipping' blood pressure need to be investigated.Currently, the most important goal in primary and secondary prevention of stroke is a strict normotensive blood pressure control. Antihypertensive treatment is recommended for both prevention of recurrent stroke and prevention of other vascular events in individuals who have had an ischaemic stroke or TIA (class I, level of evidence A). Many open questions remain and funding of stroke research needs to be increased in the near future.

Blood pressure-dependent and independent effects of agents that inhibit the renin-angiotensin system

OBJECTIVES

To evaluate the blood pressure-dependent and independent effects of angiotensin-converting enzyme inhibitors (ACEI) and angiotensin receptor blockers (ARB) on major cardiovascular events.

METHODS

Using data from 26 large-scale trials comparing an ACEI or an ARB with placebo or another drug class, meta-regression analyses were conducted in which treatment-specific relative risks for major cause-specific outcomes [stroke, major coronary heart disease (CHD) events and heart failure] were regressed against follow-up blood pressure differences.

RESULTS

From a total of 146 838 individuals with high blood pressure or an elevated risk of cardiovascular disease, 22 666 major cardiovascular events were documented during follow-up. The analyses showed comparable blood pressure-dependent reductions in risk with ACEI and ARB (P >or= 0.3 for all three outcomes). The analyses also showed that ACEI produced a blood pressure-independent reduction in the relative risk of CHD of approximately 9% (95% confidence interval 3-14%). No similar effect was detected for ARB, and there was some evidence of a difference between ACEI and ARB in this regard (P = 0.002). For both stroke and heart failure there was no evidence of any blood pressure-independent effects of either ACEI or ARB.

CONCLUSION

There are similar blood pressure-dependent effects of ACEI and ARB for the risks of stroke, CHD and heart failure. For ACEI, but not ARB, there is evidence of blood pressure-independent effects on the risk of major coronary disease events.

Recruitment strategies in the Action to Control Cardiovascular Risk in Diabetes (ACCORD) trial

The Action to Control Cardiovascular Risk in Diabetes (ACCORD) trial is a randomized, multicenter clinical trial using a double 2 x 2 factorial design in 10,251 participants with type 2 diabetes mellitus at high risk for cardiovascular disease (CVD) events. ACCORD is testing 3 complementary medical treatment strategies that may reduce high rates of major CVD morbidity and mortality in patients with type 2 diabetes. The ACCORD vanguard phase, conducted at 59 clinics in the United States and Canada, recruited 1,174 participants in 20 weeks from January through June 1, 2001, with a recruitment efficiency (R-factor) of 0.65. The recruitment strategies used in this vanguard phase were almost exclusively chart and database review within clinical practices and institutions. Recruitment for the main trial began in February 2003, involved 77 clinics, and resulted in an additional 9,077 participants by October 29, 2005 (total, 10,251). The R-factor during main trial recruitment was 0.96. Although new and refined recruitment strategies were formulated from the vanguard experience, the most powerful determinant of improved recruitment efficiency was the immediate start of enrollment by most clinics at the beginning of the main trial. Recruitment in the main trial required only a brief extension of 3 months and facilitated the nearly complete capture of the expected number of person-years of observation. Described herein are vanguard and main trial recruitment activities, including strategy implementation, screening procedures, randomization results, problems encountered, and lessons learned.

Prevention of type 2 diabetes: an update

With the rising tide of the diabetes epidemic leading to increased morbidity and mortality (primarily from cardiovascular disease), together with failure to control the disease and its associated complications, prevention of diabetes appears to be the logical option for curbing this epidemic. Several trials have been completed, and others ongoing, using various strategies for diabetes prevention. In this review, we provide an update on diabetes prevention strategies, highlighting the rationale behind such interventions, together with an outlook of the ongoing efforts that are likely to provide additional options for patients at risk for diabetes.

Complications of hypertension and the role of angiotensin receptor blockers in hypertension trials

Hypertension is a high-prevalence disease that may affect several organs. In recent years, data have accumulated indicating that angiotensin II receptor blockers (ARBs) may have a supplementary effect beyond lowering blood pressure. The aim of this review is to evaluate the impact of ARBs on the most important complications of hypertension--heart, cerebrovascular and renal diseases, and metabolic complications--based on the findings from large clinical hypertension trials. The results may indicate that ARBs have a superior effect compared with placebo or other antihypertensive drugs in order to prevent left ventricular hypertrophy, atrial fibrillation, stroke, renal disease and diabetes mellitus, while there appears to be no blood pressure-independent superior effect of ARBs regarding prevention of myocardial infarction or heart failure.

Renin-angiotensin-system blockade in the prevention of diabetes

Type 2 diabetes often occurs in association with hypertension and cardiovascular disease, and markedly increases cardiovascular risk. Strategies to reduce the incidence of diabetes in patients with cardiovascular disease or at high risk for such disease are therefore important. Certain classes of antihypertensive agents, namely the thiazide diuretics and beta-blockers, have an adverse impact on the metabolic profile and increase the risk for new-onset diabetes in hypertensive subjects. In contrast, angiotensin-converting enzyme (ACE) inhibitors and angiotensin receptor blockers (ARBs), which are blockers of the renin-angiotensin system (RAS), have been shown to increase insulin sensitivity. They may also reduce the risk of diabetes in patients with hypertension or cardiovascular disorders. Some of the evidence in favour of ACE inhibitors and ARBs has come from studies with active comparators that have potential adverse metabolic effects. However, the Candesartan in Heart failure-Assessment of Reduction in Mortality and morbidity (CHARM) programme demonstrated that the ARB candesartan reduced the incidence of diabetes in heart failure patients in comparison to placebo. The mechanisms responsible for the beneficial effects of RAS blockade remain to be established. Nevertheless, a treatment that can control hypertension and reduce the risk of onset of type 2 diabetes at the same time is certainly desirable.

Molecular Genetics of Experimental Hypertension and the Metabolic Syndrome

Genetic studies of human and experimental hypertension provide a means to identify key pathways that predispose individuals to increased blood pressure and associated risk factors for cardiovascular and metabolic diseases. The pathways so identified can then serve as targets for therapeutic intervention. This article discusses genetic studies in animal models of hypertension in which specific genes have been identified that regulate blood pressure and biochemical features of the metabolic syndrome. Consistent with studies in humans with monogenic disorders of blood pressure regulation, studies in rat models have demonstrated that naturally occurring genetic variation in pathways regulating sodium chloride transport can contribute to inherited variation in blood pressure. Such studies have also indicated that naturally occurring variation in genes, such as Cd36, that regulate fatty acid metabolism and ectopic accumulation of fat and fat metabolites can influence both biochemical and hemodynamic features of the metabolic syndrome and mediate the antidiabetic effects of drugs that activate the peroxisome proliferator-activated receptor-gamma. Angiotensin II receptor blockers with the ability to selectively modulate activity of peroxisome proliferator-activated receptor-gamma and expression of genes in these fat metabolism pathways may represent useful prototypes for a new class of transcription modulating drugs aimed at treating patients with hypertension and the metabolic syndrome.

A review of telmisartan in the treatment of hypertension: blood pressure control in the early morning hours

Measurement of blood pressure in the clinic may provide a false impression of blood pressure control. Ambulatory blood pressure monitoring (ABPM) allows the automatic recording of the circadian variation in blood pressure and evaluation of the efficacy of antihypertensive medication throughout the dosing interval. Ambulatory blood pressure provides more effective prediction of cardiovascular risk; blood pressure control at the time of heightened risk in the early morning after waking and before taking the next dose of medication is becoming important in order to improve long-term prognosis. To achieve blood pressure control in the early morning, a long-acting antihypertensive agent is essential. Telmisartan, an angiotensin II receptor blocker, as well as having a terminal elimination half-life of 24 h, has a large volume of distribution due to its high lipophilicity. The efficacy of telmisartan 80 mg monotherapy has been demonstrated using ABPM, with superior reduction in mean values for the last 6 h of the dosing interval compared with ramipril 10 mg and valsartan 80 mg. In addition, telmisartan 80 mg provides superior blood pressure control after a missed dose compared with valsartan 160mg. When combined with hydrochlorothiazide (HCTZ) 12.5 mg, telmisartan 40mg and 80mg is more effective than losartan/HCTZ (50/12.5 mg) at the end of the dosing interval. Furthermore, greater reductions in last 6 h mean systolic blood pressure (SBP) and diastolic blood pressure (DBP) are achieved with telmisartan/HCTZ (80/12.5 mg) than with valsartan/HCTZ (160/12.5 mg) in obese patients with type 2 diabetes and hypertension. Recent data from a large group of patients show that telmisartan 80 mg controls the early morning blood pressure surge more effectively than ramipril 5-10 mg and, thus, may have a greater beneficial effect on long-term cardiovascular risk. This supposition is being tested in the ONgoing Telmisartan Alone and in combination with Ramipril Global Endpoint Trial (ONTARGET) programme.

Glucose levels predict hospitalization for congestive heart failure in patients at high cardiovascular risk

BACKGROUND

Patients with diabetes mellitus (DM) are at high risk of developing congestive heart failure (CHF). However, the relationships between glucose levels and CHF in people with or without a history of DM have not been well characterized.

METHODS AND RESULTS

We evaluated the associations between fasting plasma glucose and risk of hospitalization for CHF during follow-up in patients at high cardiovascular risk and without CHF enrolled in a large-scale clinical trials program. Baseline fasting plasma glucose levels were assessed in 31,546 high-risk subjects with > or = 1 coronary, peripheral, or cerebrovascular disease or DM with end-organ damage who are participating in 2 ongoing parallel trials evaluating the effects of telmisartan, ramipril, or their combination (Ongoing Telmisartan Alone and in Combination With Ramipril Global Endpoint Trial [ONTARGET]; n=25,620) and the effects of telmisartan against placebo in angiotensin-converting enzyme-intolerant patients (Telmisartan Randomized Assessment Study in ACE Intolerant Subjects With Cardiovascular Disease [TRANSCEND]; n=5926). Interim analyses blinded for randomized treatment were performed to compare baseline fasting plasma glucose with the adjusted CHF event rate at a mean follow-up of 886 days. Multivariable Cox regression models were performed, and associations were reported as hazard ratios and 95% confidence intervals. Among all subjects (mean age, 67 years; 69% men), of whom 11,708 (37%) had known DM and 1006 (3.2%) had newly diagnosed DM at baseline, 668 patients were hospitalized for CHF during follow-up. After adjustment for age and sex, a 1-mmol/L-higher fasting plasma glucose was associated with a 1.10-fold-increased risk of CHF hospitalization (95% confidence interval, 1.08 to 1.12; P<0.0001). The association persisted after adjustment for age, sex, smoking, previous myocardial infarction, hypertension, waist-to-hip ratio, creatinine, DM, and use of aspirin, beta-blockers, or statins (hazard ratio, 1.05; 95% confidence interval, 1.02 to 1.08; P<0.001).

CONCLUSIONS

Fasting plasma glucose is an independent predictor of hospitalization for CHF in high-risk subjects. These data provide theoretical support for potential direct beneficial effects of glucose lowering in reducing the risk of CHF and suggests the need for specific studies targeted at this issue.

Prevención de la fibrilación auricular en el paciente hipertenso

A large percentage of patients with hypertension suffer from atrial fibrillation (AF). The presence of hypertension increases the risk of AF, which in turn aggravates hypertension. The ability of drugs to interfere with specific signal transduction pathways easing the presence of AF in hypertensive patients is promising. To date, the most effective mechanism appears to be the inhibition of the renin-angiotensin-aldosterone system with angiotensin-converting enzyme inhibitors (ACEIs) or angiotensin-II receptor blockers (ARBs). This approach is under active investigation. Several trials have assessed the effectiveness of these drugs in the prevention of AF. Data show that both, ACEIs and ARBs, appear effective to prevent AF. However, a lack of prospective randomized double-blind trials data limits their application in absence of any other indication.

Combination ACE Inhibitor and Angiotensin Receptor Blocker Therapy-Future Considerations

Angiotensin-converting enzyme inhibitors and angiotensin receptor blockers are regularly prescribed for the management of hypertension. Each of these drug classes has also been shown to provide survival benefits for patients with heart failure, proteinuric chronic kidney disease, and/or a high cardiac risk profile. The individual gains seen with each of these drug classes have led to speculation that their combination might offer additive if not synergistic outcome benefits. The foundation of this hypothesis, although biologically possible, has thus far not been sufficiently well proven to support the everyday use of these 2 drug classes in combination. Additional outcomes trials, which are currently proceeding to their conclusion, may provide the necessary proof to support an expanded use of these 2 drug classes in combination.

Incident diabetes in clinical trials of antihypertensive drugs: a network meta-analysis

BACKGROUND

The effect of different classes of antihypertensive drugs on incident diabetes mellitus is controversial because traditional meta-analyses are hindered by heterogeneity across trials and the absence of trials comparing angiotensin-converting-enzyme (ACE) inhibitors with angiotensin-receptor blockers (ARB). We therefore undertook a network meta-analysis, which accounts for both direct and indirect comparisons to assess the effects of antihypertensive agents on incident diabetes.

METHODS

We undertook a systematic review up to Sept 15, 2006, and identified 48 randomised groups of 22 clinical trials with 143,153 participants who did not have diabetes at randomisation and so were eligible for inclusion in our analysis. 17 trials enrolled patients with hypertension, three enrolled high-risk patients, and one enrolled those with heart failure. The main outcome was the proportion of patients who developed diabetes.

FINDINGS

Initial drug therapy used in the trials (and the number of patients with diabetes of the total number at risk) included: an ARB (1189 of 14,185, or 8.38%), ACE inhibitor (1618 of 22,941, or 7.05%), calcium-channel blocker (CCB, 2791 of 38,607, or 7.23%), placebo (1686 of 24,767, or 6.81%), beta blocker (2705 of 35,745, or 7.57%), or diuretic (998 of 18,699, or 5.34%). With an initial diuretic as the standard of comparison (eight groups), the degree of incoherence (a measure of how closely the entire network fits together) was small (omega=0.000017, eight degrees of freedom). The odds ratios were: ARB (five groups) 0.57 (95% CI 0.46-0.72, p<0.0001); ACE inhibitor (eight groups) 0.67 (0.56-0.80, p<0.0001); CCB (nine groups): 0.75 (0.62-0.90, p=0.002); placebo (nine groups) 0.77 (0.63-0.94, p = 0.009); beta blocker (nine groups) 0.90 (0.75-1.09, p=0.30). These estimates changed little in many sensitivity analyses.

INTERPRETATION

The association of antihypertensive drugs with incident diabetes is therefore lowest for ARB and ACE inhibitors followed by CCB and placebo, beta blockers and diuretics in rank order.

The role of renin–angiotensin system inhibition in the treatment of hypertension in metabolic syndrome: are all the angiotensin receptor blockers equal?

The metabolic syndrome (MetS) is a strong predictor of cardiovascular morbidity and mortality, as well as new Type 2 diabetes. MetS consists of visceral obesity, elevated blood pressure, impaired glucose metabolism, atherogenic dyslipidaemia (elevated triglycerides and low levels of high-density lipoprotein cholesterol), as well as other metabolic abnormalities. The underlying pathophysiology seems to be largely, but not uniquely, attributable to insulin resistance. Existing antihypertensive drugs were designed to lower blood pressure rather than to modify the metabolic abnormalities associated with hypertension. This review considers the role of renin-angiotensin system inhibition and especially the use of angiotensin receptor blockers (ARBs) in the treatment of hypertension in MetS. There are differences among ARBs. Among them is the uricosuric effect of losartan. Furthermore, telmisartan may function as a partial agonist of the peroxisome proliferator-activated receptor-gamma (PPAR-gamma).

Treating patients for cardiovascular protection: combination therapy to achieve complete renin-angiotensin system blockade

Inhibition of the renin-angiotensin system (RAS) with angiotensin-converting enzyme (ACE) inhibitors or angiotensin receptor blockers (ARBs) is a proven antihypertensive strategy. Understanding of the pathophysiologic effects of chronic RAS activation and clinical data indicate that RAS inhibition may exert beneficial effects in addition to blood pressure reduction. Studies indicate that monotherapy with ACE inhibitors and ARBs slows progression of diabetic and non-diabetic renal disease. Vascular protective effects of RAS inhibition have also been demonstrated in patients at high risk for cardiovascular events in the absence of significant blood pressure elevation or left ventricular dysfunction. Combining the complementary effects of ACE inhibitors and ARBs to achieve more complete RAS blockade is a promising approach to further reducing cardiovascular risk. This review will present the rationale for dual RAS inhibition, clinical data relating to its efficacy, and ongoing studies designed to evaluate its utility in patients at high risk for cardiovascular events.