Effects of losartan on hypertension and left ventricular mass: a long-term study

First-line diuretics versus other classes of antihypertensive drugs for hypertension

BACKGROUND

Different first-line drug classes for patients with hypertension are often assumed to have similar effectiveness with respect to reducing mortality and morbidity outcomes, and lowering blood pressure. First-line low-dose thiazide diuretics have been previously shown to have the best mortality and morbidity evidence when compared with placebo or no treatment. Head-to-head comparisons of thiazides with other blood pressure-lowering drug classes would demonstrate whether there are important differences.

OBJECTIVES

To compare the effects of first-line diuretic drugs with other individual first-line classes of antihypertensive drugs on mortality, morbidity, and withdrawals due to adverse effects in patients with hypertension. Secondary objectives included assessments of the need for added drugs, drug switching, and blood pressure-lowering.

SEARCH METHODS

Cochrane Hypertension's Information Specialist searched the Cochrane Hypertension Specialized Register, CENTRAL, MEDLINE, Embase, and trials registers to March 2021. We also checked references and contacted study authors to identify additional studies. A top-up search of the Specialized Register was carried out in June 2022.

SELECTION CRITERIA

Randomized active comparator trials of at least one year's duration were included. Trials had a clearly defined intervention arm of a first-line diuretic (thiazide, thiazide-like, or loop diuretic) compared to another first-line drug class: beta-blockers, calcium channel blockers, alpha adrenergic blockers, angiotensin converting enzyme (ACE) inhibitors, angiotensin II receptor blockers, direct renin inhibitors, or other antihypertensive drug classes. Studies had to include clearly defined mortality and morbidity outcomes (serious adverse events, total cardiovascular events, stroke, coronary heart disease (CHD), congestive heart failure, and withdrawals due to adverse effects).

DATA COLLECTION AND ANALYSIS

We used standard Cochrane methodological procedures.

MAIN RESULTS

We included 20 trials with 26 comparator arms randomizing over 90,000 participants. The findings are relevant to first-line use of drug classes in older male and female hypertensive patients (aged 50 to 75) with multiple co-morbidities, including type 2 diabetes. First-line thiazide and thiazide-like diuretics were compared with beta-blockers (six trials), calcium channel blockers (eight trials), ACE inhibitors (five trials), and alpha-adrenergic blockers (three trials); other comparators included angiotensin II receptor blockers, aliskiren (a direct renin inhibitor), and clonidine (a centrally acting drug). Only three studies reported data for total serious adverse events: two studies compared diuretics with calcium channel blockers and one with a direct renin inhibitor. Compared to first-line beta-blockers, first-line thiazides probably result in little to no difference in total mortality (risk ratio (RR) 0.96, 95% confidence interval (CI) 0.84 to 1.10; 5 trials, 18,241 participants; moderate-certainty), probably reduce total cardiovascular events (5.4% versus 4.8%; RR 0.88, 95% CI 0.78 to 1.00; 4 trials, 18,135 participants; absolute risk reduction (ARR) 0.6%, moderate-certainty), may result in little to no difference in stroke (RR 0.85, 95% CI 0.66 to 1.09; 4 trials, 18,135 participants; low-certainty), CHD (RR 0.91, 95% CI 0.78 to 1.07; 4 trials, 18,135 participants; low-certainty), or heart failure (RR 0.69, 95% CI 0.40 to 1.19; 1 trial, 6569 participants; low-certainty), and probably reduce withdrawals due to adverse effects (10.1% versus 7.9%; RR 0.78, 95% CI 0.71 to 0.85; 5 trials, 18,501 participants; ARR 2.2%; moderate-certainty). Compared to first-line calcium channel blockers, first-line thiazides probably result in little to no difference in total mortality (RR 1.02, 95% CI 0.96 to 1.08; 7 trials, 35,417 participants; moderate-certainty), may result in little to no difference in serious adverse events (RR 1.09, 95% CI 0.97 to 1.24; 2 trials, 7204 participants; low-certainty), probably reduce total cardiovascular events (14.3% versus 13.3%; RR 0.93, 95% CI 0.89 to 0.98; 6 trials, 35,217 participants; ARR 1.0%; moderate-certainty), probably result in little to no difference in stroke (RR 1.06, 95% CI 0.95 to 1.18; 6 trials, 35,217 participants; moderate-certainty) or CHD (RR 1.00, 95% CI 0.93 to 1.08; 6 trials, 35,217 participants; moderate-certainty), probably reduce heart failure (4.4% versus 3.2%; RR 0.74, 95% CI 0.66 to 0.82; 6 trials, 35,217 participants; ARR 1.2%; moderate-certainty), and may reduce withdrawals due to adverse effects (7.6% versus 6.2%; RR 0.81, 95% CI 0.75 to 0.88; 7 trials, 33,908 participants; ARR 1.4%; low-certainty). Compared to first-line ACE inhibitors, first-line thiazides probably result in little to no difference in total mortality (RR 1.00, 95% CI 0.95 to 1.07; 3 trials, 30,961 participants; moderate-certainty), may result in little to no difference in total cardiovascular events (RR 0.97, 95% CI 0.92 to 1.02; 3 trials, 30,900 participants; low-certainty), probably reduce stroke slightly (4.7% versus 4.1%; RR 0.89, 95% CI 0.80 to 0.99; 3 trials, 30,900 participants; ARR 0.6%; moderate-certainty), probably result in little to no difference in CHD (RR 1.03, 95% CI 0.96 to 1.12; 3 trials, 30,900 participants; moderate-certainty) or heart failure (RR 0.94, 95% CI 0.84 to 1.04; 2 trials, 30,392 participants; moderate-certainty), and probably reduce withdrawals due to adverse effects (3.9% versus 2.9%; RR 0.73, 95% CI 0.64 to 0.84; 3 trials, 25,254 participants; ARR 1.0%; moderate-certainty). Compared to first-line alpha-blockers, first-line thiazides probably result in little to no difference in total mortality (RR 0.98, 95% CI 0.88 to 1.09; 1 trial, 24,316 participants; moderate-certainty), probably reduce total cardiovascular events (12.1% versus 9.0%; RR 0.74, 95% CI 0.69 to 0.80; 2 trials, 24,396 participants; ARR 3.1%; moderate-certainty) and stroke (2.7% versus 2.3%; RR 0.86, 95% CI 0.73 to 1.01; 2 trials, 24,396 participants; ARR 0.4%; moderate-certainty), may result in little to no difference in CHD (RR 0.98, 95% CI 0.86 to 1.11; 2 trials, 24,396 participants; low-certainty), probably reduce heart failure (5.4% versus 2.8%; RR 0.51, 95% CI 0.45 to 0.58; 1 trial, 24,316 participants; ARR 2.6%; moderate-certainty), and may reduce withdrawals due to adverse effects (1.3% versus 0.9%; RR 0.70, 95% CI 0.54 to 0.89; 3 trials, 24,772 participants; ARR 0.4%; low-certainty). For the other drug classes, data were insufficient. No antihypertensive drug class demonstrated any clinically important advantages over first-line thiazides.

AUTHORS' CONCLUSIONS

When used as first-line agents for the treatment of hypertension, thiazides and thiazide-like drugs likely do not change total mortality and likely decrease some morbidity outcomes such as cardiovascular events and withdrawals due to adverse effects, when compared to beta-blockers, calcium channel blockers, ACE inhibitors, and alpha-blockers.

Comparative efficacy of different types of antihypertensive drugs in reversing left ventricular hypertrophy as determined with echocardiography in hypertensive patients: A network meta-analysis of randomized controlled trials

Reversing left ventricular hypertrophy (LVH) can reduce the incidence of adverse cardiovascular events. However, there is no clear superiority-inferiority differentiation between angiotensin-converting enzyme inhibitors (ACEI), angiotensin receptor blockers (ARB), beta-blockers (BB), calcium channel blockers (CCB), and diuretics in reversing LVH in hypertensive patients. To provide further evidence for choosing the optimal antihypertensive drug for improving LVH, we performed a network meta-analysis of randomized controlled trials (RCTs) based on the Cochrane library database, Embase, and Pubmed, and identified 49 studies involving 5402 patients that were eligible for inclusion. It was found that ARB could improve LVH in hypertensive patients more effectively than CCB (MD -4.07, 95%CI -8.03 to -0.24) and BB (MD -4.57, 95%CI -8.07 to -1.12). Matched comparison of renin-angiotensin system inhibitors (RASi) showed that the effect of ACEI in reducing left ventricular mass index (LVMi) was not effective as that of ARB (MD -3.72, 95%CI -7.52 to -0.11). The surface under the cumulative ranking for each intervention indicated that the use of ARB was more effective among the different types of antihypertensive drugs (97%). This network meta-analysis revealed that the use of ARB in antihypertensive therapy could achieve better efficacy in reversing LVH in hypertensive patients.

Hydrochlorothiazide and alternative diuretics versus renin-angiotensin system inhibitors for the regression of left ventricular hypertrophy: a head-to-head meta-analysis

BACKGROUND

Found in 36-41% of hypertension, elevated left ventricular mass (LVM) independently predicts cardiovascular events and total mortality. Conversely, drug-induced regression of LVM predicts improved outcomes. Previous studies have favored renin-angiotensin system inhibitors (RASIs) over other antihypertensives for reducing LVM but ignored differences among thiazide-type diuretics. From evidence regarding potency, cardiovascular events, and electrolytes, we hypothesized a priori that 'CHIP' diuretics [CHlorthalidone, Indapamide and Potassium-sparing Diuretic/hydrochlorothiazide (PSD/HCTZ)] would rival RASIs for reducing LVM.

METHOD AND RESULTS

Systematic review yielded 12 relevant double-blind randomized trials. CHIPs were more closely associated with reduced LVM than HCTZ (P = 0.004), indicating that RASIs must be compared with each diuretic separately. Publication bias favoring RASIs was corrected by cumulative analysis. For reducing LVM, HCTZ tended to be less effective than RASIs. However, the following surpassed RASIs: chlorthalidone Hedge's G: -0.37 (95% CI -0.72 to -0.02), P = 0.036; indapamide -0.20 (-0.39 to -0.01), P = 0.035; all CHIPs combined (with 61% of patients in one trial) -0.25 (-0.41to -0.09), P = 0.002. Statistical significance (P < 0.05) did not depend on any one trial. CHIPs reduction in LVM was 37% greater than that from RASIs. CHIPs superiority tended to increase with trial duration, from a negligible effect at 0.5 year to a maximal effect at 0.9-1.0 years: -0.26 (-0.43 to -0.09), P = 0.003. Fifty-eight percent of patients had information on echocardiographic components of LVM: relative to RASIs, CHIPs significantly reduced end-diastolic LV internal dimension (EDLVID): -0.18 (-0.36 to -0.00), P = 0.046. Strength of evidence favoring CHIPs over RASIs was at least moderate.

CONCLUSION

In these novel results in patients with hypertension, CHIPs surpassed RASIs for reducing LVM and EDLVID.

Uncoupling proteins as a therapeutic target to protect the diabetic heart

Myocardial remodeling and dysfunction caused by accelerated oxidative damage is a widely reported phenomenon within a diabetic state. Altered myocardial substrate preference appears to be the major cause of enhanced oxidative stress-mediated cell injury within a diabetic heart. During this process, exacerbated free fatty acid flux causes an abnormal increase in mitochondrial membrane potential leading to the overproduction of free radical species and subsequent cell damage. Uncoupling proteins (UCPs) are expressed within the myocardium and can protect against free radical damage by modulating mitochondrial respiration, leading to reduced production of reactive oxygen species. Moreover, transgenic animals lacking UCPs have been shown to be more susceptible to oxidative damage and display reduced cardiac function when compared to wild type animals. This suggests that tight regulation of UCPs is necessary for normal cardiac function and in the prevention of diabetes-induced oxidative damage. This review aims to enhance our understanding of the pathophysiological mechanisms relating to the role of UCPs in a diabetic heart, and further discuss known pharmacological compounds and hormones that can protect a diabetic heart through the modulation of UCPs.

Comparative Efficacy of Angiotensin II Antagonists in Essential Hypertension: Systematic Review and Network Meta-Analysis of Randomised Controlled Trials

BACKGROUND

Evidence on the long-term clinical benefits of individual members of angiotensin II receptor blockers is limited given the lack of head-to-head studies. We conducted a network meta-analysis to determine the comparative efficacy of different members within this drug class with respect to outcomes of (i) blood pressure reduction (at 24 and 52 weeks) and (ii) prevention of cardiovascular disease (>104 weeks).

METHODS

A systematic literature review was conducted - Protocol registration: (PROSPERO - CRD42014007067) - to identify relevant literature from the following databases: Cochrane Library, PubMed, Medline and EMBASE; searched from inception to July 2016. Randomised controlled trials (RCTs) were included if they reported long-term effectiveness relating to blood pressure, mortality, myocardial infarction or stroke. Eligible studies included those with placebo or specific active-treatment comparators (either another angiotensin II receptor blockers or hydrochlorothiazide). A Bayesian random-effects network model was used to combine direct within-trial comparisons between treatment groups with indirect evidence from other trials.

RESULTS

Thirty-six studies were identified, representing 28 unique trials. Blood pressure reduction, based on 12 studies (n=807) with fixed dosing regimen, was found to be similar amongst members of the angiotensin receptor blocker drug class at both 24 and 52 weeks. A network meta-analysis of five studies (n=16,716) with a treat-to-target approach found that prevention of all-cause mortality, stroke and myocardial infarction was similar across the angiotensin-receptor blockers therapies initiated.

CONCLUSIONS

Current evidence is insufficient to show differences in any members within the angiotensin II receptor blocker drug class with respect to blood pressuring lowering effects or a reduction in cardiovascular diseases.

Losartan Reduces Left Ventricular Hypertrophy Proportionally to Blood Pressure Reduction in Hypertensives, but Does Not Affect Diastolic Cardiac Function

In contrast to the well-recognized salutary effects of angiotensin-converting enzyme inhibition, the value of angiotensin II type I (ATl)-receptor blockade on left ventricular hypertrophy (LVH) is controversial. In addition, the data on the influence of this therapy on cardiac diastolic function are scarce. Thirty-nine patients with moderate primary hypertension, LVH, and normal systolic function received losartan, 50 to 100 mg daily. Transthoracic echocardiography was performed at baseline and after 6 months of treatment. Thirty-one patients completed and were included in the study (16 males, 61.1 ±1.0 years). The patients were divided into responders if mean blood pressure (BP) decreased >5 mm Hg at the end of the study (20 patients) and non-responders (mean BP decrease ≤5 mm Hg, 11 patients). The BP and the LVH were significantly reduced (systolic BP by 10.0%, diastolic BP 6.5%, mean BP 8.2%, left ventricular mass index [LVMI] 6.2%, interventricular septum 5.8%, posterior wall 3.0%) (p≤0.02), attributed to the reduction of BP and LVH in responders; the LVH in non-responders did not alter with treatment. A significant correlation was noted between changes in BP and LVMI ( r =0.60, p<0.001). The systolic cardiac function remained normal. The Doppler parameters usually used to assess the diastolic function of the LV (early diastolic filling velocity [E wave], late diastolic filling velocity [A wave], ratio of E/A waves, isovolumic relaxation time), which were abnormal at baseline, did not change with treatment. The size of the left atrium increased (p<0.05) at the end of the study. In conclusion, a 6-month course with losartan decreased BP and LVH. However, the LVH regression was rather associated with the reduction of the hemodynamic stimulus per se, than any trophic effect of the drug in the myocardium. The diastolic cardiac function remained abnormal with treatment.

Effect of Intensive Blood Pressure Lowering on Left Ventricular Hypertrophy in Patients With Diabetes Mellitus: Action to Control Cardiovascular Risk in Diabetes Blood Pressure Trial

Left ventricular hypertrophy (LVH), a marker of cardiac end-organ damage, is a common complication of hypertension. Regression of LVH is achievable by sustained lowering of systolic blood pressure (BP). However, it is unknown whether a strategy aimed at lowering BP beyond that recommended would lower the risk of LVH. We examined the effect of intensive (systolic BP<120 mm Hg), compared with standard (systolic BP<140 mm Hg), BP lowering on the risk of LVH in 4331 patients with diabetes mellitus from the Action to Control Cardiovascular Risk in Diabetes (ACCORD) BP trial, a randomized controlled trial. The outcome measures were electrocardiographic LVH defined by Cornell voltage (binary variable) and mean Cornell index (continuous variable). The baseline prevalence of LVH (5.3% versus 5.4%; P=0.91) and the mean Cornell index (1456 versus 1470 µV; P=0.45) were similar in the intensive (n=2154) and standard (n=2177) BP-lowering arms, respectively. However, after median follow-up of 4.4 years, intensive, compared with standard, BP lowering was associated with a 39% lower risk of LVH (odds ratio [95% confidence interval], 0.61[0.43, 0.88]; P=0.008) and a significantly lower adjusted mean Cornell index (1352 versus 1447 µV; P<0.001). The lower risk of LVH associated with intensive BP lowering during follow-up was because of more regression of baseline LVH and lower rate of developing new LVH, compared with standard BP lowering. No interactions by age, sex, or race were observed. These results provide evidence that targeting a systolic BP of <120 mm Hg when compared with <140 mm Hg in patients with hypertension and diabetes mellitus produces a greater reduction in LVH.

CLINICAL TRIAL REGISTRATION

URL: http://www.clinicaltrials.gov. Unique identifier: NCT00000620.

Antihypertensive efficacy of angiotensin receptor blockers as monotherapy as evaluated by ambulatory blood pressure monitoring: a meta-analysis

AIMS

Angiotensin receptor blockers (ARBs) are available in different dosages and it is common clinical practice to uptitrate if blood pressure goal is not achieved with the initial dose. Data on the incremental antihypertensive efficacy with uptitration are scarce. It is also unclear if antihypertensive efficacy of losartan is comparable with other ARBs.

METHODS AND RESULTS

We systematically reviewed PubMed/EMBASE/Cochrane databases for all randomized clinical trials until December 2012 reporting 24 h ambulatory blood pressure (ABP) for most commonly available ARBs in patients with hypertension. Reduction in ABP with ARBs was evaluated at 25% of the maximum (max) dose, 50% of the max dose, and at the max dose. Comparison was made between 24 h BP-lowering effect of losartan 50 and 100 mg and other ARBs at 50% max dose and the max dose, respectively. Sixty-two studies enrolling 15 289 patients (mean age 56 years; 60% men) with a mean duration of 10 weeks were included in the analysis. Overall, the dose-response curve with ARBs was shallow with decrease of 10.3/6.7 (systolic/diastolic), 11.7/7.6, and 13.0/8.3 mmHg with 25% max dose, 50% max dose, and with the max dose of ARBs, respectively. Losartan in the dose of 50 mg lowered ABP less well than other ARBs at 50% max dose by 2.5 mmHg systolic (P < 0.0001) and 1.8 mmHg diastolic (P = 0.0003). Losartan 100 mg lowered ABP less well than other ARBs at max dose by 3.9 mm Hg systolic (P = 0.0002) and 2.2 mmHg diastolic (P = 0.002).

CONCLUSION

In this comprehensive analysis of the antihypertensive efficacy of ARBs by 24 h ABP, we observed a shallow dose-response curve, and uptitration marginally enhanced the antihypertensive efficacy. Blood pressure reduction with losartan at starting dose and at max dose was consistently inferior to the other ARBs.

Effects of combined therapy of Xuezhikang Capsule and Valsartan on hypertensive left ventricular hypertrophy and heart rate turbulence

OBJECTIVE

To observe the effect of combined therapy with Xuezhikang Capsule (XZK) and Valsartan on left ventricular hypertrophy (LVH) and heart rate turbulence (HRT) in hypertensive patients.

METHODS

Ninety primary hypertensive patients with LVH were randomly assigned to three groups. Basic treatment, including aspirin, beta-blockers, calcium antagonists, etc. were administered to all patients. Additionally, Valsartan (VS, 80 mg once a day) was given to the 30 patients in the VS group. Valsartan (in the same dosage) and XZK (600 mg, twice a day) were given to the 32 patients in the Chinese medicine (CM) group, while none was given to the 28 patients in the control group. The therapeutic course lasted for 24 months. Changes in left ventricular mass index (LVMI) measured by cardiac ultrasonic indices, HRT parameters, including the original heart rate (TO) and slope coeffificient (TS), systolic and diastolic blood pressures (SBP and DBP), as well as blood cholesterol level (TC) were measured before and after treatment.

RESULTS

After treatment, TO and LVMI were lowered, while TS increased in both the VS group and the CM group (P<0.01), but changed insignificantly in the control group. Significant differences between the CM group and the control group were shown in terms of TO, LVMI, SBP, DBP and TS (P<0.01); and between the CM group and the VS group in terms of TO, LVMI and TS (P<0.01). Moreover, HRT parameters showed an evident correlation with LVMI (r=0.519-0.635, P<0.01).

CONCLUSION

Combined therapy with XZK and Valsartan can improve hypertensive LVH and HRT parameters, and lessen the damage on the autonomous nervous system.

Regression of Left Ventricular Mass by Antihypertensive Treatment

Blood pressure–lowering therapy reduces left ventricular mass, but the question of whether differences exist among drug classes has not been fully resolved. Our aim was to compare the effects of diuretics, β-blockers, calcium channel blockers, angiotensin-converting enzyme inhibitors, and angiotensin receptor blockers on left ventricular mass regression in patients with hypertension on the basis of prospective, randomized comparative studies. We performed meta-analyses, involving pooled pairwise comparisons of the drug classes and of each class versus other classes statistically combined, and meta-regression analyses to identify the determinants of the regression. The 75 relevant publications involved 84 pairwise comparisons and 6001 patients. Regression of left ventricular mass was significantly less ( P =0.01) with β-blockers (9.8%) than with angiotensin receptor blockers (12.5%), but none of the other analyzable pairwise comparisons between drug classes revealed significant differences ( P >0.10). In addition, β-blockers showed less regression than the other 4 classes statistically combined ( P <0.01), and regression was more pronounced with angiotensin receptor blockers versus the others ( P <0.01). In multivariable meta-regression analysis on all of the treatment arms, β-blocker treatment was a significant and negative predictor of the regression (−3.6%; P <0.01), but this was not the case for the other drug classes, including angiotensin receptor blockers. In conclusion, β-blockers show less regression of left ventricular mass, whereas angiotensin receptor blockers may induce larger regression. The inferiority of β-blockers appears to be more convincing than the superiority of angiotensin receptor blockers.

Left atrial size in 164 hypertensive patients: an echocardiographic and ambulatory blood pressure study

BACKGROUND

Left atrial enlargement (LAE) is associated with an increased risk of death and cardiovascular (CV) hospitalization. Whether or not LAE reflects early structural change from hypertension is unclear.

HYPOTHESIS

The aim of this study was to evaluate the relationship between LA size, 24-h blood pressure measurements, age, body mass index (BMI), and left ventricular mass index (LVMI) in hypertensive patients.

METHODS

We studied 164 outpatients (age range 30-76 years, 73 men and 91 women) with mild to moderate hypertension. Physical examination, electrocardiogram, noninvasive blood pressure monitoring (ABPM), Doppler echocardiogram were performed. Left ventricular mass index and LA dimensions were calculated. The sample was divided by age (< 60 and > or = 60 years).

RESULTS

Left ventricular hypertrophy (LVH) was present in 45% of patients aged < 60 years and in 70% of patients aged > or = 60 years (p = 0.002). Left atrial enlargement (> 4 cm) was present in 35% of elderly and in 24% of young patients (p = 0.31), and in 36% of patients with and 21% of patients without LVH (p = 0.0057). There was no significant difference in the younger patients with and without LVH. The incidence of obesity was low (31%) in the whole sample. The percentage of overweight in the elderly patients with LVH and higher LA size was equally low. Multivariate analysis showed age (p = 0.044) and LVMI (p = 0.002) as the only significant predictors of LA enlargement.

CONCLUSION

Since LAE is associated with a high risk of death and CV hospitalization, we emphasize the importance of development and use of drugs that inhibit LVH.

Studies on left ventricular hypertrophy regression in arterial hypertension: a clear message for the clinician?

BACKGROUND

Evidence-based medicine should provide clear and unbiased information to clinicians. We conducted an analysis on published randomized trials evaluating the effects of antihypertensive therapy on left ventricular (LV) morphology assessed by echocardiography to investigate (i) the consistency of criteria used for definition of LV hypertrophy (LVH) and (ii) the consistency of the way LVH regression and blood pressure (BP) control were reported.

METHODS

Studies identified by a PubMed search were eligible for inclusion in the analysis, if they fulfilled the following criteria: (i) publication in a peer-reviewed journal within the last 12 years; (ii) double blind, randomized, controlled, parallel-group design; (iii) numerosity of at least 50 adult hypertensive subjects; (iv) follow-up duration of at least 6 months; (v) comparison between single-drugs or association regimens; (vi) LV mass (LVM) or wall thickness measured by echocardiography.

RESULTS

Thirty-nine trials, including 9,162 hypertensive subjects of both genders in 78 active treatment arms or in 6 placebo arms were identified. Definition of LVH was provided by 34 studies (87.1%) according to 19 different criteria. All trials evaluated LVH regression as the absolute or relative changes of continuous variables such as LVM index (LVMI) or LV wall thickness. Data concerning prevalence rates of LVM normalization were reported in 12 studies (30.7%). The percentage of patients reaching BP target (<140/90 mm Hg) was reported in 11 studies (28.2%).

CONCLUSIONS

Our findings indicate that (i) definition of hypertensive LVH phenotype is extremely variable, and (ii) no precise information on LVH regression rates or changes in LV geometrical patterns, as well as on target BP, is provided by the majority of papers.

Effects of monotherapy and combination therapy on blood pressure control and target organ damage: a randomized prospective intervention study in a large population of hypertensive patients

This prospective, randomized trial evaluated the effect of monotherapy and different combination therapies on cardiovascular target organ damage and metabolic profile in 520 hypertensive patients. Patients were allocated to a single agent: carvedilol 25 mg, amlodipine 10 mg, enalapril 20 mg, or losartan 50 mg (groups C, A, E, and L, respectively). After 2 months (level 2), nonresponders received a low-dose thiazide diuretic, and after 4 months (level 3), amlodipine (groups E, C, and L) and carvedilol (group A). Twenty-four-hour blood pressure was significantly lowered in all treatment groups. Blood pressure control was more pronounced in patients receiving two or three drugs. At the end of the study, the carotid intima-media thickness decreased in group L (P<.01), left ventricular mass index in groups E and L (P<.05 and P<.001, respectively), with a concomitant reduction in cholesterol in group L (P<.03). Diastolic function improved significantly in group L (P<.05). This study describes the need to control blood pressure with two or more drugs in most hypertensive patients and illustrates good clinical outcomes, independent of blood pressure lowering, using combination therapy with losartan, low-dose thiazide, and amlodipine.

Review of the molecular pharmacology of Losartan and its possible relevance to stroke prevention in patients with hypertension

BACKGROUND

The Losartan Intervention For End-point reduction in hypertension (LIFE) study found that a losartan-based regimen, compared with an atenolol-based regimen, resulted in a significantly lower risk of stroke in hypertensive patients with left ventricular hypertrophy, despite similar reductions in blood pressure.

OBJECTIVE

The purpose of this review was to examine the molecular and pharmacologic mechanisms that may be associated with the different outcomes observed in the LIFE study.

METHODS

A PubMed/MEDLINE search of English-language articles (1990 to February 2006) with the terms angiotensin II antagonists or AIIAs or angiotensin receptor blockers or losartan or atenolol or beta blocker and terms including, but not limited to, atherosclerosis, left ventricular hypertrophy, carotid artery hypertrophy, fatty streaks, atrial fibrillation, arrhythmias, endothelial function, myocyte hypertrophy, myocardial fibrosis, platelet aggregation, tissue factor, plasminogen activator inhibitor-1, PAI-1, anti-inflammatory, uric acid, or oxidative stress.

RESULTS

Losartan's significant effect on stroke may be related to several possible mechanisms that are independent of blood-pressure reductions. These include improvements in endothelial function and vascular structure; decreases in vascular oxidative stress; reductions in left ventricular hypertrophy, reductions in myocardial fibrosis, or both; and modulation of atherosclerotic disease progression. Although some of these effects may be shared by other angiotensin II receptor antagonists (AIIAs), and perhaps other anti-hypertensive classes (eg, angiotensin-converting enzyme inhibitors), the ability of losartan to lower serum uric acid levels-a proposed independent risk factor for cardiovascular disease-appears to be a molecule-specific effect. Alternative explanations of the results of the LIFE study have also been hypothesized, including inappropriate choice of atenolol as an active comparator and differences in central pulse pressures between study groups.

CONCLUSIONS

This review of the literature suggests that losartan (and perhaps other AIIAs) may possess a number of properties, independent of its antihypertensive effects, that may be associated with decreased vulnerability of the plaque, myocardium, and blood.

Blockade of the renin-angiotensin-aldosterone system: a key therapeutic strategy to reduce renal and cardiovascular events in patients with diabetes

Diabetes (particularly type 2 diabetes) represents a global health problem of epidemic proportions. Individuals with diabetes are not only more likely to develop hypertension, dyslipidemia, and obesity, but are also at a significantly higher risk for coronary heart disease, peripheral vascular disease, and stroke. Angiotensin II plays a key pathophysiological role in the progression of diabetic renal disease, and blockade of the renin-angiotensin system with angiotensin-converting enzyme inhibitors (ACEi) or angiotensin II antagonists has therefore become an important therapeutic strategy to reduce renal and cardiovascular events in patients with diabetes. Several studies have demonstrated the effects of angiotensin II antagonists on the reduction of albuminuria and the progression of renal disease from microalbuminuria to macroalbuminuria. More importantly, several endpoint trials have shown that the antiproteinuric effects of losartan and irbesartan translate into cardiovascular and renoprotective benefits beyond blood pressure lowering, thereby delaying the need for dialysis or kidney transplantation by several years. These and other studies indicate that angiotensin II antagonists not only improve survival and quality of life of patients with diabetic nephropathy, but also have the potential to reduce the substantial healthcare burden associated with managing these patients. ACEi also appear to exert similar beneficial effects in diabetic patients, but whether clinically significant differences in renoprotection or mortality exist between angiotensin II antagonists and ACEi in patients with type 2 diabetes remains to be fully investigated in appropriate head-to-head studies.

Blockade of Angiotensin II Type 1 Receptor Improves the Arrhythmia Morbidity in Mice With Left Ventricular Hypertrophy

BACKGROUND

Stimulation of angiotensin II type 1 (AT(1)) receptors has been shown to generate the arrhythmogenic substrate in ventricular hypertrophy. We examined whether candesartan, an AT1 receptor blocker, has antiarrhythmic effects on mouse model of left ventricular hypertrophy created by transverse aorta constriction (TAC).

METHODS AND RESULTS

Forty-eight male mice were divided into 3 groups: TAC, candesartan (TAC plus candesartan) and control groups. Echocardiographic examination was performed before the operation and 2 and 4 weeks after the operation. Four weeks after the operation, electrophysiological studies were conducted by inserting a 1.7 F octapolar electrode catheter through the right external jugular vein into the right ventricle. The effective refractory period of the atrioventricular node (AVNERP) in TAC group was significantly prolonged, and short episodes of ventricular tachycardia (VT) and atrial fibrillation (AF) could be induced in 12 of 16 mice (75%) and 8 of 16 (50%), respectively. In contrast, in candesartan group, the incidence of VT was significantly reduced (12.5%) and no AF was induced. Moreover, the drug produced a significant left ventricular hypertrophy regression and restored the AVNERP to normal.

CONCLUSIONS

Candesartan reduced both ventricular and atrial arrhythmias in the TAC mice, presumably by preventing the electrical remodeling by inhibiting the AT(1) receptor.

Losartan controlled blood pressure and reduced left ventricular hypertrophy but did not alter arrhythmias in hypertensive men with preserved systolic function

The effect of antihypertensive therapy on arrhythmias is controversial. An initial study in patients with chronic heart failure indicated that losartan, an angiotensin II receptor antagonist, may possess antiarrhythmic properties. However, the effect of AT1 receptor antagonists on arrhythmias of subjects with good systolic function has never been evaluated. Thirty-nine men with primary hypertension (18 without left ventricular hypertrophy [LVH], and 21 with LVH, aged 48.2 +/-8.6 and 50.5 +/-6.0 years, respectively), 15 healthy normotensive subjects (47.9 +/-8.5 years), and 14 highly trained athletes (34.1 +/-1.6 years) were studied. Transthoracic echocardiography and 24-hour Holter ambulatory monitoring were performed at baseline (without treatment). Hypertensive patients underwent the same examinations after 8 months of losartan administration. The prevalence and complexity of ventricular arrhythmias, and the frequency of supraventricular arrhythmias were increased in hypertensive patients with LVH compared to normotensive controls and athletes, at baseline. A similar significant reduction of blood pressure (BP) was noted in both groups of patients (p < 0.001). The LVH was reduced in hypertensives with LVH (the left ventricular mass index by 12%, the interventricular septum by 8.1%, the posterior wall by 7%, all p < 0.01). However, the arrhythmias did not change in either group of patients, even if all hypertensives were considered as 1 group. In conclusion, an 8-month course with losartan was effective in lowering BP and reducing LVH. However, the increased arrhythmias, which were registered in hypertensive patients with LVH at baseline, did not change.

Chronobiologically explored effects of Telmisartan

Effects of Micardis (Telmisartan), alone or with low-dose aspirin, on blood pressure and other cardiovascular endpoints are examined in 20 patients with MESOR-hypertension in a crossover, double-blind, randomized study consisting of three stages, each lasting 7 days: I-placebo, II-Micardis, and III-Micardis with low-dose aspirin. Treatment was administered each day at a different circadian stage, upon awakening, and 3, 6, 9, 12, 15 and 18 hr after awakening. During each stage, the following variables were measured at 3-hr intervals during waking: systolic and diastolic blood pressure, heart rate, ejection fraction, intrarenal resistive index, acceleration time, and serum creatinine. Each data series was analyzed by single cosinor. Results were summarized by population-mean least squares spectra. At matched treatment times, the MESOR and circadian amplitude of each variable were compared among the three treatments by paired t-tests. A prominent circadian rhythm characterizes all variables. Micardis was associated not only with a lowering of blood pressure, but also with a reduction of the circadian blood pressure amplitude. The ejection fraction was increased, and the resistive index and acceleration time were decreased, the effect being more pronounced when low-dose aspirin was added to Micardis. Any circadian-stage dependent effect of Micardis, with or without low-dose aspirin, will require monitoring over spans longer than a single day for a given treatment administration time.

Angiotensin converting enzyme inhibition for cardiac hypertrophy in patients with end-stage renal disease: what is the evidence?

Dialysis patients show a high prevalence of cardiovascular complications among which left ventricular hypertrophy is one of the most frequent and is independently predictive of mortality. A recent study indicates that partial regression of left ventricular hypertrophy improves mortality and reduces cardiovascular events in end-stage renal disease (ESRD) patients, suggesting the importance of targeting therapeutic strategies to reduce cardiac hypertrophy and improve the outcome in these patients. The pathogenesis of left ventricular hypertrophy in ESRD patients is multifactorial and includes hypertension, activation of the renin-angiotensin system, increased sympathetic activity, chronic volume overload, chronic anaemia and hyperparathyroidism. In this paper, we review the available experimental and clinical evidence showing the important contribution of the renin-angiotensin system as well as its interaction with the sympathetic nervous system in the pathogenesis of left ventricular hypertrophy in ESRD patients. Furthermore, we summarize the results of currently available clinical studies that examined the effects of angiotensin-converting enzyme inhibition or angiotensin receptor antagonism on left ventricular hypertrophy in ESRD patients, and review evidences that support the use of angiotensin-converting enzyme inhibitors or angiotensin receptor antagonists in the ESRD population.

Regression of left ventricular hypertrophy and improvement of diastolic function in hypertensive patients treated with telmisartan

OBJECTIVES

The study was designed to test whether or not the angiotensin II receptor blocker telmisartan brings about regression of left ventricular (LV) concentric hypertrophy and whether or not these changes are associated with improved diastolic filling.

METHODS

An echocardiographic follow-up study was performed in 85 hypertensive patients (systolic blood pressure [SBP] >140 mmHg, diastolic blood pressure [DBP] >90 mmHg) and mild-to-moderate LV hypertrophy (LV mass index related to body surface area [LVMI] 117-150 g/m2 for men and 105-150 g/m2 for women) treated with telmisartan monotherapy 40-80 mg once daily for 1 year. Blood pressure, LVMI, left atrial (LA) volumes, and diastolic function were determined at baseline and after 3, 6, 9, and 12 months of treatment. Blood pressure was also monitored at all visits. Diastolic function was assessed by examination of transmitral inflow and pulmonary vein flow patterns.

RESULTS

Telmisartan reduced blood pressure; after 12 months, the mean+/-S.D. SBP and DBP were reduced from 144+/-10 to 126+/-8 mmHg (p<0.001) and from 98+/-8 to 86+/-7 mmHg (p<0.001), respectively. The LVMI was decreased from 119+/-7 to 109+/-3 g/m2 (p<0.001) after 12 months' telmisartan treatment. All patients had diastolic dysfunction at baseline. After 12 months' telmisartan treatment, a normal pattern of transmitral inflow was present in 21% of patients. The regression of LV hypertrophy observed after 12 months was associated with increased peak early diastolic velocity/peak late diastolic velocity ratio from 0.60+/-0.18 to 0.83+/-0.20 (p<0.001), shortened isovolumic relaxation time (IVRT) from 110+/-13 to 105+/-13 ms (p<0.001), and decreased deceleration time from 229+/-30 to 215+/-28 ms (p=0.002). Univariate analysis showed that shortened IVRT was related to a reduction in the LVMI and LA maximal and minimal volumes. In the multivariate analysis, the reduction in LVMI and the reduction in LA maximal and minimal volumes were independently associated with IVRT reduction.

CONCLUSIONS

Telmisartan 40-80 mg is effective in LV hypertrophy regression in hypertensive patients. The reduction in LVMI due to telmisartan monotherapy was associated with a significant improvement of diastolic filling parameters and with a significant reduction of LA volumes.

AII antagonists in hypertension, heart failure, and diabetic nephropathy: focus on losartan

The goal of antihypertensive therapy is to prevent cardiovascular complications of hypertension, such as heart failure, stroke, end stage renal disease, and death, not just to normalize blood pressure. Recently, several clinical trials investigated the beneficial effects of angiotensin II antagonists (AIIAs) in patients with hypertension, heart failure or diabetic nephropathy utilizing proven clinical outcomes (e.g., all-cause mortality) rather than surrogate outcomes (e.g., blood pressure or proteinuria). The AIIAs may offer therapeutic advantages with respect to particular outcomes in certain types of patients. Evidence is also emerging that losartan may possess beneficial pharmacological properties such as effects on uric acid, platelets, sexual dysfunction, and cognitive function, that may set it apart from other members of the AIIA class. However, further studies are needed to delineate fully these potential pharmacological differences among the AIIAs and their possible clinical relevance. This paper reviews recent AIIA outcomes studies in patients with hypertension, heart failure, or diabetic nephropathy and also examines data suggesting that molecular differences exist within the AIIA class, differences that may assist in explaining the outcomes achieved in these recent trials.

Effects of losartan and valsartan on left ventricular hypertrophy and function in essential hypertension

This study compared the effect of losartan and valsartan on left ventricular mass (LVM) and function in patients with untreated essential hypertension and concentric left ventricular hypertrophy (LVH). Thirty patients (17 men and 13 women; mean age, 48+/-8 years) with untreated essential hypertension and concentric LVH, as determined by echocardiographic assessment, were randomly assigned in equal numbers and double-blind fashion to receive either losartan 50 to 100 mg/d or valsartan 80 to 160 mg/d. Doppler echocardiograms were obtained from each patient before treatment, at the time of initial blood pressure control, and then after 6 months. A significant reduction (P<.01) in LVM index was observed in both the losartan group (from 57.1+/-7.2 g/m2.7 to 51.5+/-6.1 g/m2.7) and the valsartan group (from 58.1+/-8.4 g/m2.7 to 48.2+/-6.2 g/m27), but the reduction was higher (P<.05) in the valsartan group. The predicted midwall fractional shortening improved significantly in both the losartan group (from 81+/-8% to 89+/-9%, P<.05) and the valsartan group (from 78+/-7% to 91+/-9%, P<.01). Similarly, the early peak/peak atrial velocity ratio improved significantly both in the losartan group (from 0.78+/-0.4 to 0.88+/-0.3, P<.05) and the valsartan group (from 0.84+/-0.3 to 0.94+/-0.4, P<.01). These results indicate that valsartan is more effective than losartan in reducing LVM index in hypertensive patients with concentric LVH. This effect is associated with improvement in midwall systolic performance and left ventricular diastolic function.

Freehand three-dimensional echocardiographic evaluation of the effect of telmisartan compared with hydrochlorothiazide on left ventricular mass in hypertensive patients with mild-to-moderate hypertension: a multicentre study

Antihypertensive efficacy, effects on left ventricular mass index (LVMI) and tolerability of telmisartan, an angiotensin II receptor blocker, were compared with those of hydrochlorothiazide (HCTZ). Adult patients with mild-to-moderate hypertension and an optimal acoustic window by two-dimensional echocardiography were randomised at baseline to 12 months' double-blind, once-daily treatment with telmisartan 80 mg or HCTZ 25 mg. Two-dimensional echocardiography and freehand precordial three-dimensional echocardiography and 24-h ambulatory blood pressure monitoring were performed at baseline and after treatment. Of the 41 telmisartan group patients and 28 HCTZ group patients, 40 and 25, respectively, completed the study. Following treatment, 24-h mean SBP (telmisartan 157 +/- 11 vs 133 +/- 7 mmHg, P<0.001; HCTZ 154 +/- 10 vs 144 +/- 11 mmHg, P<0.003) and DBP (telmisartan 96 +/- 6 vs 83 +/- 5 mmHg, P<0.001; HCTZ 95 +/- 7 vs 87 +/- 8 mmHg, P<0.003) were significantly reduced. Telmisartan produced significantly greater 24-h mean SBP and DBP reductions than HCTZ (P<0.001). LVMI was significantly reduced by telmisartan (141 +/- 16 vs 125 +/- 19 g/m2, P<0.001), but not by HCTZ (139 +/- 20 vs 135 +/- 22 g/m(2)). Incidences of adverse events in both the treatment groups were low; two cases of hypokalaemia occurred with HCTZ. In conclusion, telmisartan 80 mg was well tolerated and significantly reduced SBP, DBP and LVMI after 12 months' treatment compared with HCTZ.

Regression of left ventricular hypertrophy is a key goal of hypertension management

Left ventricular hypertrophy (LVH) in patients with hypertension is associated with an increased risk for many cardiovascular events and predicts a higher mortality rate. The pathogenesis of LVH is complicated. In addition to the hemodynamic burden (pressure or volume overload) and demographic factors, several trophic humoral factors, such as angiotensin II, aldosterone, endothelin, leptin, and catecholamines, may also contribute to the development and progression of LVH. Effective antihypertensive therapy can reverse LVH as well as prevent its development. Regression of LVH decreases subsequent cardiovascular morbidity and mortality. The commonly used drugs have various effects on LVH. Angiotensin receptor blockers and angiotensin-converting enzyme inhibitors seem most effective. Several new agents, including direct antifibrotic drugs, aldosterone blockade, vasopeptidase inhibitors, and endothelin receptor antagonists that more specifically target the underlying pathogenesis of LVH may provide us with innovative approaches to treat LVH.

A meta-analysis of the effects of treatment on left ventricular mass in essential hypertension

PURPOSE

Antihypertensive medications have different effects on left ventricular mass. We conducted a meta-analysis of double-blind trials that measured the effects of antihypertensive therapy on left ventricular mass.

METHODS

Medical databases and review articles were screened for double-blind, randomized controlled trials (through September 2002) that reported the effects of diuretics, beta-blockers, calcium antagonists, angiotensin-converting enzyme (ACE) inhibitors, or angiotensin II receptor antagonists on echocardiographic left ventricular mass in essential hypertension. Treatment arms of the same drug class, weighted for the number of patients, were combined. Analysis of covariance was performed to detect differences among drug classes in effects on left ventricular structure.

RESULTS

Eighty trials with 146 active treatment arms (n = 3767 patients) and 17 placebo arms (n = 346 patients) were identified. Adjusted for treatment duration and change in diastolic blood pressure, there was a significant difference (P = 0.004) among medication classes: left ventricular mass index decreased by 13% with angiotensin II receptor antagonists (95% confidence interval [CI]: 8% to 18%), by 11% with calcium antagonists (95% CI: 9% to 13%), by 10% with ACE inhibitors (95% CI: 8% to 12%), by 8% with diuretics (95% CI: 5% to 10%), and by 6% with beta-blockers (95% CI: 3% to 8%). In pairwise comparisons, angiotensin II receptor antagonists, calcium antagonists, and ACE inhibitors were more effective at reducing left ventricular mass than were beta-blockers (all P <0.05 with Bonferroni correction).

CONCLUSIONS

Antihypertensive drug classes have different effects on left ventricular mass reduction. Whether a greater reduction of left ventricular mass results in better clinical outcomes remains to be determined.

Does the angiotensin II receptor antagonist losartan improve cognitive function?

Newer classes of antihypertensive agents, such as angiotensin II receptor antagonists, may offer benefits to patients in addition to their ability to lower blood pressure. It is accepted that chronic hypertension contributes to the development of cerebrovascular and cardiovascular disease, and several studies have demonstrated a link between hypertension and reduced cognitive function, especially in patients not receiving antihypertensive medication. In an initial clinical trial, the angiotensin II receptor antagonist losartan was shown to improve cognitive function in patients with hypertension, including in those who were elderly (up to 73 years of age). This effect cannot be explained by a reduction in blood pressure alone and is likely to involve interactions with the diverse biological actions of the renin-angiotensin system. Improving or maintaining cognitive function in patients with hypertension may translate into economic benefits beyond those expected due to blood pressure control, and would result in considerable quality-of-life benefits for the aging population.

Effects of losartan and atenolol on left ventricular mass and neurohormonal profile in patients with essential hypertension and left ventricular hypertrophy

OBJECTIVE

To compare the effects of the angiotensin II antagonist, losartan, with those of atenolol on left ventricular hypertrophy (LVH), blood pressure and neurohormone concentrations in hypertensive patients with LVH.

DESIGN

A multinational, randomized, double-blind trial.

SETTING

Hospital.

PATIENTS

Hypertensive patients with an echocardiographically documented left ventricular mass index (LVMI) 120 g/m(2) (men) or 105 g/m(2) (women).

INTERVENTIONS

Patients allocated randomly to groups received either losartan or atenolol 50 mg/day for 36 weeks, with possible titration to 100 mg/day, and addition of hydrochlorothiazide 12.5 or 25 mg/day.

MAIN OUTCOME MEASURES

Changes in LVMI and sitting systolic (SBP) and diastolic (DBP) blood pressures after 36 weeks of treatment (study powered for non-inferiority hypothesis). All echocardiographic data were read in a central laboratory by staff blinded to the treatments and sequence of echocardiographic tapes.

RESULTS

The estimated treatment difference between the losartan and atenolol regimens (mean change from baseline at week 36) in LVMI was -2.5 g/m(2) [95% confidence interval (CI) -7.36 to 2.37 g/m(2) ] in favor of losartan, indicating that losartan was significantly non-inferior ( 0.001, non-inferiority limit 8 g/m(2) ) and numerically superior to atenolol in reducing LVMI. The losartan-based regimen significantly reduced LVMI after 36 weeks compared with baseline (-6.56 g/m(2) , 95% CI -10.24 to -2.88 g/m(2) , P<0.001), whereas the atenolol-based regimen had no significant effect (-3.71 g/m, 95% CI -7.75 to 0.32 g/m(2) , P= NS). In a subset of 82 patients, significant changes in serum concentrations of atrial natriuretic peptide, brain natriuretic peptide and immunoreactive amino-terminal pro-brain natriuretic peptide were recorded in losartan-treated ( 0.01) but not atenolol-treated patients. Losartan and atenolol significantly decreased SBP and DBP from baseline after 6, 12, 24 and 36 weeks. The changes from baseline in DBP were greater in the atenolol group at weeks 6 and 36 [difference -2.6 mmHg ( P= 0.016) at week 36]. However, both treatment regimens achieved similar SBP/DBP values at week 36 (141.1 +/- 12.8/86.8 +/- 8.2 mmHg for losartan and 141.4 +/- 17.2/85.0 +/- 10.1 mmHg for atenolol, respectively). Overall, losartan treatment was associated with significantly fewer drug-related clinical adverse events, compared with atenolol (10 and 22%, respectively, P= 0.028).

CONCLUSIONS

Both losartan- and atenolol-based regimens effectively decreased blood pressure. Losartan was non-inferior and numerically superior to atenolol in regression of LVH. The reduction in hypertrophy with losartan treatment was accompanied by reductions in circulating concentrations of cardiac natriuretic peptides. Losartan, by specifically blocking angiotensin II, may therefore have effects on the heart beyond those expected from the decrease in blood pressure alone. Losartan was better tolerated than atenolol.

[Beyond blood pressure reduction in the treatment of arterial hypertension. Clinical implications of the LIFE study]

To date, blood-pressure lowering has been the main therapeutic objective in patients with arterial hypertension, regardless of the drug used, except for drugs selected for accompanying conditions. The LIFE study, carried out in 9,193 high-risk hypertensive patients (with ECG criteria of left ventricular hypertrophy), has shown that a therapeutic regimen based on losartan combined with a thiazide was accompanied by a significant reduction in the risk of cardiovascular complications in more than 90% of patients compared with atenolol and a thiazide over a mean follow-up period of 4.8 years. The incidence of the primary endpoints (cardiovascular death, stroke, and myocardial infarction) was 11% in the losartan group and 13% in the atenolol group (13% relative risk reduction, p = 0.021). Losartan therapy was associated with more benefits in stroke risk reduction and in the development of new cases of diabetes. In the analysis of the subgroup of 1,195 patients with hypertension and diabetes included in the LIFE study, losartan had a special prognostic benefit. One of the cardiovascular events included as a primary endpoint was observed in 18% of the losartan-treated patients and in 23% of the atenolol-treated patients (24% relative risk reduction, p = 0.031). The LIFE trial showed that losartan produced better cardiovascular protection than atenolol, a similar blood pressure reduction, and was better tolerated. This drug seems to confer extra cardiovascular protection in addition to reducing blood pressure.

Risk-benefit assessment of angiotensin II receptor antagonists

Inhibiting the renin-angiotensin-aldosterone system through the use of angiotensin-converting enzyme (ACE) inhibitors has proven very useful in the treatment of hypertension, congestive heart failure (CHF) and progressive renal failure. More recently, agents that directly block the angiotensin II Type 1 (AT(1)) receptor--angiotensin II receptor antagonists (AIIRAs)--have been developed. These agents are thought to have a more specific mechanism of action since they do not affect other hormone systems as do the ACE inhibitors. Whether such specificity results in a different efficacy profile is still being determined. However, these drugs are extremely well-tolerated and very safe. AIIRAs are effective in the reduction of both systolic and diastolic blood pressure and compare favourably to other classes of agents. Recent results indicate that at least one AIIRA has a favourable effect on stroke in hypertensive patients with left ventricular hypertrophy. Additional studies with other members of the class will provide further information on similar outcomes. In CHF patients, ACE inhibitors remain the drug of choice and AIIRAs are best utilised in patients who cannot tolerate an ACE inhibitor or in those receiving an ACE inhibitor who cannot tolerate a beta-blocker and need additional therapy. AIIRAs are effective in slowing the progression of renal failure in patients with Type II diabetes and may be effective in other proteinuric conditions. Whether they are more or less effective than ACE inhibitors is unknown. Overall, AIIRAs represent an important addition to the armamentarium of cardiovascular therapies with an excellent safety record and an emerging profile of utility in multiple cardiovascular conditions.

Comparison of the effects of losartan and atenolol on common carotid artery intima-media thickness in patients with hypertension: results of a 2-year, double-blind, randomized, controlled study

BACKGROUND

Hypertension induces progressive pathologic changes in the arterial wall. Experimental findings suggest that these changes, which include intima-media thickening, may be mediated, at least in part, by angiotensin II (AII).

OBJECTIVE

The Losartan Vascular Regression Study (LAARS) was a double-blind, parallel-group, randomized, controlled, multicenter study designed to compare the effects of the AII antagonist losartan and the beta-blocker atenolol on ultrasonographically determined intimamedia thickness (IMT) of the common carotid artery (CCA) in patients with mild to moderate essential hypertension.

METHODS

The primary end point of the study was the yearly rate of change (YRC) from baseline of the mean IMT of the CCA (CCA-IMT(mean)) averaged over 2 years of treatment. Secondary end points included IMT of the common femoral artery and sitting systolic and diastolic blood pressures (SiSBP/SiDBP). Safety assessments of losartan and atenolol were made by statistical and clinical review of the incidence of adverse experiences as well as review of vital signs and laboratory values. A total of 414 patients with essential hypertension were screened for study inclusion at 36 study centers in Germany and Brazil. Patients received losartan (50 mg once daily) or atenolol (50 mg once daily) for 24 months. Target blood pressure (SiSBP/SiDBP <140/<90 mm Hg) was achieved by adding hydrochlorothiazide 12.5 mg once daily, doubling the dose of study drug, or adding an open-label calcium channel blocker sequentially, as needed.

RESULTS

Of the original 414 patients screened, 280 hypertension patients (SiDBP 95-115 mm Hg), aged 35 to 65 years, with an IMT of 0.8 to 1.5 mm of the right or left CCA, were randomized to treatment with either losartan (n = 142) or atenolol (n = 138). Both losartan and atenolol therapy produced comparable reductions in CCA-IMTmean over 24 months compared with baseline; the average YRC was -0.038 +/- 0.004 mm/y (P < or = 0.001) for losartan and -0.037 +/- 0.004 mm/y (P < or = 0.001) for atenolol. There were no significant differences between groups. Losartan showed a greater reduction of femoral artery IMT than did atenolol; the average YRC was -0.024 mm/y (P < or = 0.05) for losartan and -0.017 mm/y for atenolol (P = NS), with no significant difference between groups. Both agents produced similar significant reductions in SiSBP and SiDBP and were generally well tolerated. Approximately 7% of losartan patients had drug-related clinical adverse events, compared with 12% of atenolol patients.

CONCLUSIONS

The findings of LAARS, the first large study with an AII antagonist that examined IMT, suggest that AII antagonism reverses the early stages of vascular hypertrophy in patients with hypertension. Further studies are needed to delineate the relative importance of AII antagonism versus blood pressure reduction per se in mediating the beneficial vascular effects of losartan.

Comparative antihypertensive efficacy of olmesartan: comparison with other angiotensin II receptor antagonists

Hypertension is a major risk factor for cardiovascular morbidity and mortality. Effective control of elevated blood pressure (BP) has been shown to reduce this risk. Early studies of risk reduction assumed that the mechanism by which BP was lowered had little impact on the benefit obtained. Recent evidence, however, suggests that agents that inhibit the renin-angiotensin system may be particularly beneficial. The results of the recent Heart Outcomes Prevention Evaluation (HOPE) trial suggest that angiotensin-converting enzyme (ACE) inhibitors have a greater impact on cardiovascular morbidity and mortality than would be anticipated from their antihypertensive effects alone. Angiotensin receptor blockers, the other major class of antihypertensive drugs that inhibit the renin-angiotensin system, have not been widely tested in outcomes trials, but early results suggest that they are beneficial for controlling target organ damage that is related to hypertension. Furthermore, unlike ACE inhibitors, these agents have a side-effect profile that is similar to that of placebo. Based on their efficacy in controlling hypertension and their wider health benefits, together with minimal side effects, angiotensin II (A II) receptor blockers should be considered as first-line agents for the treatment of hypertension, particularly in patients with other cardiovascular risk factors. Preliminary evidence suggests that olmesartan, an A II receptor blocker currently being evaluated for approval for clinical use, may provide antihypertensive efficacy that is superior to other members of the class.

Comparison of angiotensin II receptor antagonists

Nonpeptide orally active angiotensin II type 1 (AT1) receptor antagonists are the most specific means presently available to block the renin-angiotensin enzymatic cascade. Six of these drugs have already been licensed in Europe and in the United States for the treatment of high blood pressure, and additional candidates are in the pipeline. The World Health Organisation has also recently endorsed their use for this condition. Inasmuch as AT1 receptor antagonists have proven themselves the equals of angiotensin converting enzyme inhibitors with respect to antihypertensive efficacy, but demonstrated better safety profiles, this class of drugs may be considered to be a qualitative improvement in the treatment of essential hypertension. Interestingly, the six agents now on the market diverge considerably with respect to their pharmacokinetic and pharmacodynamic properties, although it is not certain whether such differences are clinically relevant. A considerable number of large, multicentre trials are in progress to ascertain the possible longer-term organoprotective effects of these substances on cardiovascular morbidity and mortality. Because of their noteworthy safety record to date, and simple once-a-day dosage regimen, AT1 receptor antagonists have the potential to improve compliance in patients with chronic hypertension.

Angiotensin II and the pathophysiology of cardiovascular remodeling

Hypertension is associated with a number of adverse morphologic and functional changes in the cardiovascular system. These include remodeling of the left ventricle, alterations in the morphology and mechanical properties of the vasculature, and the development of endothelial dysfunction. Recent studies have shown that angiotensin II is capable of mediating these changes via its interaction with the angiotensin II type 1 receptor. These nonhemodynamic effects of angiotensin II are independent of its effect on blood pressure. Thus, elevated levels of angiotensin II may lead directly to many hypertension-associated pathologies. Recent evidence that mechanical strain, oxidized low-density lipoprotein cholesterol, and aldosterone can cause upregulation of angiotensin II type 1 receptors indicates that activation of the renin-angiotensin system is not necessary for the actions of angiotensin II to be amplified. Because the strain on the vessel wall may be increased under conditions of hypertension, increased arterial pressure may amplify the actions of angiotensin II without a discernible increase in plasma angiotensin II levels. In both the myocardium and the peripheral vasculature, fibrosis is a major component of the remodeling that occurs in hypertension. There is substantial evidence that transforming growth factor beta-1 (TGF-beta(1)) mediates angiotensin-II-induced fibrosis in patients with hypertension and in those with a variety of nephropathies. Mechanical strain also induces fibrosis in a mechanism mediated by TGF-beta(1). This cytokine thus represents a common pathway by which angiotensin II and increased arterial pressure may induce cardiovascular fibrosis.

Regression of left ventricular hypertrophy by AT1 receptor blockade in renal transplant recipients

AT1 receptor antagonists control blood pressure (BP) effectively and reduce left ventricular hypertrophy in patients with essential hypertension. Because left ventricular hypertrophy is very common in renal transplant recipients, we examined the cardiovascular effects and the safety profile of the AT1 receptor antagonist losartan in hypertensive renal transplant recipients. In 20 renal transplant recipients with stable renal graft function 50 mg of losartan was added to the preexisting antihypertensive treatment (no angiotensin-converting enzyme inhibitors) at least 6 months after renal transplantation. Twenty-four-hour ambulatory BP, two-dimensional-guided M-mode echocardiography, and duplex sonography, as well as renal function, red blood cell count, cyclosporine A and FK 506 levels, erythropoetin, and angiotensin II concentration were determined at baseline and after 6 months of therapy. With 24-h ambulatory BP measurement, systolic blood pressure (SBP) was reduced by 7.5 +/- 2.4 mm Hg and diastolic blood pressure (DBP) by 4.5 +/- 1.8 mm Hg (P < .01 and P < .05, respectively). Posterior, septal, and relative wall thickness decreased by 0.95 +/- 0.2 mm, 0.91 +/- 0.2 mm and 0.04 +/- 0.01 mm, respectively (all P < .001). Left ventricular mass index decreased by 18.1 +/- 4.7 g/m2 (P < .01). Ejection fraction and midwall fractional fiber shortening as systolic parameters and the relation of passive-to-active diastolic filling of the left ventricle were unaltered. Serum creatinine and cyclosporine A concentration remained stable in all patients. Hemoglobin and hematocrit decreased by 1.0 +/- 0.3 g/dL and 3.6% +/- 0.9%, respectively (P < .002 and P < .001) without a change in serum erythropoetin level. In renal transplant recipients the AT1 receptor antagonist losartan reduces left ventricular hypertrophy without altering systolic or diastolic function. It is safe with regard to renal function and immunosuppression, but slightly decreases hemoglobin level.

Transforming growth factor beta in hypertensives with cardiorenal damage

We investigated whether a relationship exists between circulating transforming growth factor beta -1 (TGF-beta(1)), collagen type I metabolism, microalbuminuria, and left ventricular hypertrophy in essential hypertension and whether the ability of the angiotensin II type 1 receptor antagonist losartan to correct microalbuminuria and regress left ventricular hypertrophy in hypertensives is related to changes in TGF-beta(1) and collagen type I metabolism. The study was performed in 30 normotensive healthy controls and 30 patients with never-treated essential hypertension classified into 2 groups: those with microalbuminuria (urinary albumin excretion >30 and <300 mg/24 h) associated with left ventricular hypertrophy (left ventricular mass index >116 g/m(2) for men and >104 g/m(2) for women) (group B; n=17) and those without microalbuminuria or left ventricular hypertrophy (group A; n=13). The measurements were repeated in all patients after 6 months of treatment with losartan (50 mg once daily). The serum concentration of TGF-beta(1) was measured by a 2-site ELISA method, and the serum concentrations of carboxy-terminal propeptide of procollagen type I (a marker of collagen type I synthesis) and carboxy-terminal telopeptide of collagen type I (a marker of collagen type I degradation) were measured by specific radioimmunoassays. The duration of hypertension and baseline values of blood pressure were similar in the 2 groups of patients. No differences in serum TGF-beta(1), carboxy-terminal propeptide of procollagen type I, and carboxy-terminal telopeptide of collagen type I were found between normotensives and group A of hypertensives. Serum TGF-beta(1), carboxy-terminal propeptide of procollagen type I, and the ratio of carboxy-terminal propeptide of procollagen type I to carboxy-terminal telopeptide of collagen type I were increased (P<0.05) in group B of hypertensives compared with group A of hypertensives and normotensives. No differences in carboxy-terminal telopeptide of collagen type I were found among the 3 groups of subjects. After treatment with losartan, microalbuminuria and left ventricular hypertrophy persisted in 6 patients (then considered nonresponders) and disappeared in 11 patients (then considered responders) from group B. Compared with nonresponders, responders exhibited similar control of blood pressure and higher (P<0.05) blockade of angiotensin II type 1 receptors (as assessed by a higher increase in plasma levels of angiotensin II). Whereas TGF-beta(1), carboxy-terminal propeptide of procollagen type I, and the ratio of carboxy-terminal propeptide of procollagen type I to carboxy-terminal telopeptide of collagen type I decreased (P<0.05) in responders, no changes in these parameters were observed in nonresponders. These findings show that an association exists between an excess of TGF-beta(1), stimulation of collagen type I synthesis, inhibition of collagen type I degradation, and cardiorenal damage in a group of patients with essential hypertension. In addition, our results suggest that the ability of losartan to blunt the synthesis of TGF-beta(1) and normalize collagen type I metabolism may contribute to protect the heart and the kidney in a fraction of patients with essential hypertension.

A multicenter, randomized, double-blind study of the antihypertensive efficacy and tolerability of irbesartan in patients aged > or = 65 years with mild to moderate hypertension

BACKGROUND

Blockade of the renin-angiotensin-aldosterone system (RAAS) is the preferred mechanism of action for controlling hypertension in select groups of patients, including those with diabetic nephropathy and heart failure. Currently, 2 classes of drugs work by blocking the RAAS, albeit by differing mechanisms: angiotensin-converting enzyme (ACE) inhibitors and angiotensin II angiotensin type 1 receptor blockers (ARBs).

OBJECTIVE

The goal of this study was to assess the comparative efficacy and tolerability of the ARB irbesartan and the ACE inhibitor enalapril in patients > or = 65 years of age with mild to moderate hypertension (sitting diastolic blood pressure [DBP], 95 to 110 mm Hg).

METHODS

Elderly (> or = 65 years of age) patients were recruited from 26 Canadian study centers for a randomized, double-blind, 8-week clinical trial. Exclusion criteria included sitting DBP >110 mm Hg or sitting systolic blood pressure (SBP) >200 mm Hg, angina pectoris, myocardial infarction, cardiac procedure, stroke, or transient ischemic attack within 6 months of randomization, as well as other preexisting or present severe medical or psychologic conditions. Patients were randomly assigned to receive a single daily dose of irbesartan 150 mg (n = 70) or enalapril 10 mg (n = 71) with treatment doses of study drugs doubled at week 4 for sitting DBP > or = 90 mm Hg. Reductions from baseline blood pressure measurements at trough (24 +/- 3 hours after the last dose of medication) were assessed for sitting DBP and sitting SBP. Comparative tolerability to study drugs was also assessed.

RESULTS

The intent-to-treat analysis demonstrated similar reductions at week 8 in both DBP and SBP for both groups. For the primary efficacy analysis of sitting DBP, there was a mean reduction from baseline of 9.6 mm Hg and 9.8 mm Hg for the irbesartan and enalapril groups, respectively (P = 0.93). The mean reduction from baseline in sitting SBP was 10.1 mm Hg and 11.6 mm Hg for the irbesartan and enalapril groups, respectively (P = 0.54). Normalization rates (sitting DBP <90 mm Hg) at week 8 did not differ between groups (52.9% in the irbesartan group and 54.9% in the enalapril group; P = 0.81). No statistical difference existed between the 2 groups with respect to serious adverse events or discontinuations due to adverse events. Irbesartan was associated with a significantly lower incidence of cough than was enalapril (4.3% vs 15.5%, respectively; P = 0.046).

CONCLUSIONS

Irbesartan is an effective and well-tolerated antihypertensive for elderly patients with mild to moderate hypertension. This study establishes that irbesartan has better tolerability than enalapril with respect to cough and suggests that irbesartan is as effective at lowering blood pressure but better tolerated than an ACE inhibitor in hypertensive patients > or = 65 years of age.

Optimal antihypertensive therapy for prevention and treatment of left ventricular hypertrophy

Left ventricular hypertrophy (LVH) is considered an adaptation to a pressure load on the left ventricle and is common in hypertensive patients. The condition is a profound risk factor for cardiovascular events, greater than and independent of blood pressure. It is now recognized in hypertension management guidelines as an indication for more stringent blood pressure control. All of the first-line antihypertensive agents have been shown to variably regress LVH, but no definitive evidence yet shows that one agent is superior to others in decreasing risk independent of blood pressure control. Although some evidence suggests that reduction of LVH is associated with improved prognosis independent of blood pressure control, relative efficacy of drug classes in this regard has yet to be demonstrated. At present, recommendations for optimal therapy in hypertensive patients with LVH must rest on the presence of underlying cardiac and noncardiac conditions, with the understanding that the major classes of antihypertensive agents will probably decrease LVH.

Use of ambulatory blood pressure monitoring to compare antihypertensive efficacy and safety of two angiotensin II receptor antagonists, losartan and valsartan. Losartan Trial Investigators

The efficacy and safety of losartan and valsartan were evaluated in a multicenter, double-blind, randomized trial in patients with mild to moderate essential hypertension. Blood pressure responses to once-daily treatment with either losartan 50 mg (n = 93) or valsartan 80 mg (n = 94) for 6 weeks were assessed through measurements taken in the clinic and by 24-hour ambulatory blood pressure monitoring (ABPM). Both drugs significantly reduced clinic sitting systolic (SiSBP) and diastolic blood pressure (SiDBP) at 2, 4, and 6 weeks. Maximum reductions from baseline in SiSBP and SiDBP on 24-hour ABPM were also significant with the two treatments. The reduction in blood pressure was more consistent across patients in the losartan group, as indicated by a numerically smaller variability in change from baseline on all ABPM measures, which achieved significance at peak (P = .017) and during the day (P = .002). In addition, the numerically larger smoothness index with losartan suggested a more homogeneous antihypertensive effect throughout the 24-hour dosing interval. The antihypertensive response rate was 54% with losartan and 46% with valsartan. Three days after discontinuation of therapy, SiDBP remained below baseline in 73% of losartan and 63% of valsartan patients. Both agents were generally well tolerated. Losartan, but not valsartan, significantly decreased serum uric acid an average 0.4 mg/dL at week 6. In conclusion, once-daily losartan 50 mg and valsartan 80 mg had similar antihypertensive effects in patients with mild to moderate essential hypertension. Losartan produced a more consistent blood pressure-lowering response and significantly lowered uric acid, suggesting potentially meaningful differences between these two A II receptor antagonists.