Angiotensin receptor blockade in the challenging era of systolic hypertension

Irbesartan/hydrochlorothiazide for the treatment of isolated systolic hypertension: a subgroup analysis of the INCLUSIVE trial

This post hoc analysis of the Irbesartan/Hydrochlorothiazide (HCTZ) Blood Pressure Reductions in Diverse Patient Populations (INCLUSIVE) trial evaluated the efficacy and safety of fixed-dose irbesartan/HCTZ in patients with isolated systolic hypertension. Adults with uncontrolled systolic blood pressure (SBP) (140-179 mm Hg; 130-179 mm Hg in type 2 diabetes) after 4 weeks or more of antihypertensive monotherapy once-daily treatment with placebo for 4-5 weeks, followed by HCTZ 12.5 mg for 2 weeks, irbesartan/HCTZ 150/12.5 mg for 8 weeks, and then irbesartan/HCTZ 300/25 mg for 8 weeks, in a prospective, multicenter, open-label, single-arm study. In patients with isolated systolic hypertension (n = 443) and the total study population (n = 736), irbesartan/HCTZ treatment for 16 weeks provided comparable mean blood pressure (BP) reductions from baseline (21.4/10.1 mm Hg vs 21.5/10.4 mm Hg; p < .001 vs baseline) and high SBP control rates (74% vs 77%). Patients with isolated systolic hypertension and concomitant type 2 diabetes experienced smaller BP reductions (17.9/8.7 mm Hg vs 22.9/10.7 mm Hg) and lower rates of SBP control (< 130 mm Hg, 47%) than those without diabetes (< 140 mm Hg, 87%). BP reductions from baseline and SBP control rates were similar across isolated systolic hypertension subgroups (> or = 65 vs < 65 years, sex, race, and metabolic syndrome status). Irbesartan/HCTZ was well tolerated, with drug-related adverse events (dizziness, < or = 3%; upper respiratory tract infection, < or = 2%) occurring with similar rates in the isolated systolic hypertension and total population. Fixed-dose irbesartan/HCTZ combination treatment provided effective and well-tolerated BP lowering in a diverse population of patients with isolated systolic hypertension.

Evaluation of arterial stiffness in morning hypertension under high-dose valsartan compared to valsartan plus low-dose diuretic

Morning hypertension has been reported to be an important risk factor for cardiovascular events, and arterial stiffness bears a relationship with cardiovascular risk. The aim of this study was to evaluate whether high-dose angiotensin II receptor blocker (ARB) treatment has a more beneficial effect on arterial stiffness than regular-dose ARB plus low-dose diuretic treatment in patients with morning hypertension. Forty-three patients, in whom the home systolic blood pressure (BP) in the morning was higher than 140 mm Hg and in the evening was lower than 135 mm Hg, despite treatment with 80 mg valsartan, were randomly assigned to receive 160 mg valsartan (V group, n=22) or 80 mg valsartan plus low-dose trichlormethiazide (1 mg) (V+D group, n=21) for 6 months. There were no differences in the patient background characteristics between the two groups. There were no significant differences in BP measured at home between the two groups. The brachial-ankle pulse wave velocity (baPWV) at the time of diagnosis of morning hypertension was similar in the two groups; however, after 6 months of treatment, a greater degree of reduction of the baPWV and a greater degree of reduction of BP in the supine position were observed in the V group compared with the V+D group. Thus, though both high-dose valsartan and valsartan plus diuretic reduced the BP to a similar degree in patients with morning hypertension, high-dose valsartan exerted a greater beneficial effect on arterial stiffness than did valsartan plus diuretic.

Combination pharmacotherapy in hypertension

Combination pharmacotherapy with two or more drugs is required in order to reach the currently recommended blood pressure goals in the majority of hypertensive patients, particularly those with a goal of <130/80 mm Hg. Further to the potentiation of the antihypertensive effects, benefits of combination therapy include the potential of fewer adverse affects and of improvement of patients' compliance. Current guidelines recommend that combination pharmacotherapy might also be considered as initial treatment in patients with significant elevation of blood pressure and evidence of complications. Several effective and well-tolerated antihypertensive drug classes available today offer multiple options for combination therapy. The choice of antihypertensive agents should be made on the basis of current recommendations regarding first line drugs and compelling indications. Specific drug combinations might have additional beneficial or detrimental long-term metabolic effects, beyond their effects on blood pressure. However, more outcome data comparing antihypertensive drug combinations are required. The implementation of an intensive up-titration treatment strategy, together with a systematic use of full doses of multiple drug combinations, is expected to achieve optimal blood pressure control in the vast majority of hypertensive patients.

Angiotensin II antagonists: clinical experience in the treatment of hypertension, prevention of cardiovascular outcomes and renal protection in diabetic nephropathy and proteinuria

Angiotensin II antagonists (AIIAs) were introduced to treat hypertension about 10 years ago. During this period they were evaluated not only in terms of efficacy and safety but also in several large studies with clinical outcomes. They are efficacious in all clinical forms of hypertension and are effective also in all ethnic groups. Cardiovascular and renal protection in proteinuric diabetic nephropathy beyond blood pressure reduction was proved in major clinical studies: Losartan Intervention For Endpoint reduction in hypertension study (LIFE), Reduction of Endpoint in Non-Insulin dependent Diabetes Mellitus with the AII Antagonist Losartan (RENAAL) and Irbesartan Type 2 Diabetic Nephropathy Trial (IDNT). Their blood pressure independent protective effect is also mentioned by the blockade of AT1 receptor. As a class AIIs have a tolerability profile similar to placebo.

Angiotensin II antagonists--therapeutic benefits spanning the cardiovascular disease continuum from hypertension to heart failure and diabetic nephropathy

BACKGROUND

The cardiovascular benefits of angiotensin II antagonists (AIIAs) have been evaluated not only in terms of their ability to lower blood pressure but also on their ability to prevent strokes, cardiac events, and target organ damage. This review summarizes the body of evidence-based data demonstrating the efficacy of AIIAs across the spectrum of cardiovascular disease.

METHODS

A PubMed/MEDLINE search of English-language articles (1990 to September 2005) was used to identify articles describing clinical studies, particularly outcome trials, or mechanisms of therapeutic action pertinent to the therapy of cardiovascular disease or nephropathy.

FINDINGS

The antihypertensive efficacy of AIIAs is apparent across a wide spectrum of hypertensive patients, including black and Asian patients and patients with isolated systolic hypertension. More importantly, large outcome-based studies have demonstrated the efficacy of AIIAs across the continuum of cardiovascular disease, including hypertension, heart failure, post-myocardial infarction, and diabetic nephropathy. The Losartan Intervention For Endpoint reduction in hypertension study (LIFE), Reduction of Endpoints in Non-insulin-dependent Diabetes Mellitus with the AII Antagonist Losartan (RENAAL), and the Irbesartan Type 2 Diabetic Nephropathy Trial (IDNT) indicate that AIIAs confer cardiovascular and renal protective effects beyond their ability to lower blood pressure. These bloodpressure independent protective benefits of AIIAs may arise not only by blocking the deleterious effects of AII mediated via the AT1-receptor but may also be due to beneficial molecule-specific effects. As a class, AIIAs are well tolerated with an overall adverse event profile generally comparable to placebo and superior to that typically seen with calcium channel blockers, ACE inhibitors, diuretics, and beta-blockers.

CONCLUSIONS

By utilizing the body of clinical trial evidence as a guide to rational prescribing of AIIAs, practitioners can expect to deliver clinical benefits to their patients in terms of survival, prognosis, and quality of life.

Comparison of antihypertensive effects of an angiotensin-converting enzyme inhibitor, a calcium antagonist and a diuretic in patients with hypertension not controlled by angiotensin receptor blocker monotherapy

OBJECTIVE

To compare the additional antihypertensive effects of an angiotensin-converting enzyme inhibitor (ACEI), a dihydropyridine calcium antagonist and a diuretic in patients whose hypertension is not controlled by full-dose angiotensin receptor blocker (ARB) monotherapy.

DESIGN AND METHODS

Individuals with an ambulatory blood pressure (ABP) that was not controlled by valsartan 160 mg once daily were allocated randomly to two groups: those in group A (n = 35) were assigned randomly to treatment with benazepril 20 mg once daily or chlorthalidone 12.5 mg once daily, whereas patients in group B (n = 29) were assigned randomly to benazepril 20 mg once daily or amlodipine 5 mg once daily. All individuals continued to receive background valsartan 160 mg once daily. After 5 weeks, patients crossed over to the alternative valsartan-based combination treatment of each group for a second 5-week period. Twenty-four-hour ABP monitoring was performed before the random allocation to groups and at the end of each randomized combination pharmacotherapy period.

RESULTS

Sixty-four individuals completed the study: 32 men and 32 women (mean +/- SD age 48.2 +/- 7.9 years, average 24-h ABP on valsartan monotherapy 143.4 +/- 12.6/87.7 +/- 7.8 mmHg). Significant additional antihypertensive effects on the average 24-h ABP were obtained with benazepril (8.6 +/- 8.8/6.3 +/- 6.7 mmHg), amlodipine (15.2 +/- 12.9/9.9 +/- 6.8 mmHg) and chlorthalidone (13.5 +/- 11.6/9.5 +/- 7.7 mmHg) (P < 0.001 for all additional antihypertensive effects). The additional effects of amlodipine and chlorthalidone added to valsartan were approximately 6/3.5 mmHg (P < 0.05) greater than that of benazepril.

CONCLUSIONS

In patients in whom hypertension was not controlled by full-dose ARB monotherapy, a diuretic, a calcium antagonist or an ACE inhibitor provided significant additional antihypertensive effect. The antihypertensive effects of the ARB-diuretic and the ARB-calcium antagonist combinations were superior to that of the ARB-ACE inhibitor combination.