Left ventricular hypertrophy as an independent predictor of acute cerebrovascular events in essential hypertension

Potential mechanisms of stroke benefit favoring losartan in the Losartan Intervention For Endpoint reduction in hypertension (LIFE) study

INTRODUCTION

The Losartan Intervention For Endpoint reduction in hypertension (LIFE) study is the first, and, so far, the only endpoint trial in patients with hypertension and left ventricular hypertrophy (LVH) to show a divergent therapeutic outcome of one treatment modality over another with equivalent blood pressure control. The purpose of this article is to review post hoc sub-analyses of LIFE study data and other clinical studies that offer some insight into possible treatment-related differences contributing to the superior stroke outcome of losartan versus atenolol beyond blood pressure reduction.

METHODS

Relevant randomized clinical trials and review articles were identified through a MEDLINE search of English-language articles published between 1990 and 2006 using the search terms losartan, atenolol, LIFE, hypertension, and LVH. Articles describing major clinical studies, new data, or mechanisms pertinent to the LIFE study were selected for review.

RESULTS

Differences in blood pressure or in the distribution of add-on medications were not evident between study groups in the LIFE study. Thus, the observed outcomes benefits favoring losartan may involve other possible mechanisms, including differential effects of losartan and atenolol on LVH regression, left atrial diameter, atrial fibrillation, brain natriuretic peptide, vascular structure, thrombus formation/platelet aggregation, serum uric acid, albuminuria, new-onset diabetes, and lipid metabolism. Alternative explanations for the LIFE study findings have also been put forward, including the choice of atenolol as an appropriate active comparator and differential effects between treatment groups on central pulse pressure. Additional clinical trials are needed to determine if the beneficial effects of losartan seen in LIFE are shared by other inhibitors of the renin-angiotensin system.

CONCLUSION

Sub-analyses of the LIFE study data suggest that losartan's stroke benefit may arise from a mosaic of mechanisms rather than a single action. Further studies are expected to continue to delineate the mechanisms of differential responses to treatments in LIFE.

Impact of blood pressure vs. glycemic factors on target organ damage in patients with type 2 diabetes mellitus

The hypothesis that three measures of target organ damage in type 2 diabetics would be more closely related to blood pressure (BP) than to glycemic factors was tested by recording 24-hour ambulatory BP and glycosylated hemoglobin. The prevalence of silent cerebral infarcts with brain magnetic resonance imaging, left ventricular mass index with cardiac ultrasonography, and albuminuria in 244 asymptomatic diabetics (mean age, 65.4+/-9 years; 122 men and 122 women; hypertension, 73%) were evaluated. Multivariate analysis showed that age (standard partial regression coefficient: b=0.299; p<0.001), duration of hypertension (b=0.176; p=0.007), and 24-hour systolic BP (b=0.195; p=0.004) were significantly associated with the number of silent cerebral infarcts, but glycosylated hemoglobin (b=0.104; p=0.109) and duration of diabetes were not. Left ventricular mass index was associated with 24-hour systolic BP (b=0.377; p<0.001) and male sex (b=0.172; p=0.019). Presence of albuminuria was significantly associated with 24-hour systolic BP (b=0.209; p=0.003), duration of diabetes (b=0.154; p=0.022), cholesterol (b=0.132; p=0.042), and insulin use (b=0.150; p=0.026). In conclusion, all three measures of target organ damage were related to 24-hour BP, but only albuminuria was related to glycosylated hemoglobin in type 2 diabetics. BP may be more important than glycemic factors for predicting future cardiovascular complications.

Site specific differential activation of ras/raf/ERK signaling in rabbit isoproterenol-induced left ventricular hypertrophy

To understand better the mediating role of ras/raf/ERK signaling pathway in development of cardiac hypertrophy and cerebrovascular events in vivo, the molecular mechanism of the pathway in heart and cerebral arteries after isoproterenol (ISO) induced beta-adrenergic receptor (betaAR) stimulation was examined in rabbit as animal model. Compared with the heart, our findings indicate that ISO-stimulation results in increase in mRNA levels of ras, raf, and immediate-early genes in the cerebral arteries. Conversely, the ras and raf protein expression levels (determined by Western blot) and the ras-GTP level (determined by pull-down assay) in the heart, but not the cerebral arteries, are markedly elevated after treatment. In addition, despite constant ERK1/2 abundance, phosphorylated ERK (pERK) activity was elevated at both sites with prominent effect on heart following stimulation. Opposing to the PKA and PKC, as upstream contributors in the pathway, which seem to be similarly affected at both sites following ISO-stimulation, the results imply that the downstream candidates ras and raf, as well as immediate-early genes, have different responses at both sites post-stimulation. The results provide an evidence of site-dependent differential response of ras/raf/ERK pathway after cardiac hypertrophy-induced by ISO-stimulation. This varied response may account for underlying mechanisms of development of cardiac hypertrophy and cerebrovascular events in heart and cerebral arteries, respectively.

Left ventricular hypertrophy and cardiovascular risk stratification: impact and cost-effectiveness of echocardiography in recently diagnosed essential hypertensives

BACKGROUND

Echocardiography is more accurate than electrocardiography in the assessment of cardiac target organ damage related to hypertension, thus leading to a more precise stratification of total cardiovascular risk. However, ultrasound examination of the heart on a routine basis remains a matter of debate.

OBJECTIVE

To evaluate the impact and cost-effectiveness of echocardiographic examination on global risk stratification in low and medium-risk hypertensive patients in relation to age and sex.

METHODS

A total of 580 untreated hypertensive individuals (355 men and 225 women, mean age 47.8 +/- 11.4 years), classified at low to medium risk, according to routine clinical work-up suggested by the 2003 European Society of Hypertension/European Society of Cardiology guidelines, were included in the study. Total risk was reassessed by adding the results of ultrasound examination of the heart. Left ventricular hypertrophy (LVH) was defined as a left ventricular mass index of 125 g/m2 or more in men and 110 g/m2 or more in women. The impact of LVH in stratifying risk was assessed according to age (< 50 and > or = 50 years) and sex.

RESULTS

According to routine classification, 16.3% (n = 93) of the 580 patients were considered to be at low added risk and 83.7% (n = 487) at medium added risk. In the whole population, echocardiographic LVH was found in 86 patients (14.8%) who were then reclassified in the high-risk stratum. The prevalence rates of patients reclassified in the high-risk class as a consequence of LVH detection, according to age and sex, were as follows: 8.9% in men under 50 years, 12.3% in women under 50 years, 26.7% in men aged 50 years and over and 15.3% in women aged 50 years and over. The cost per detected case of LVH was 595 euros in patients under 50 years of age and 290 euros in those 50 years of age and older.

CONCLUSIONS

Our findings indicate that the prevalence of LVH, and consequently the probability of upgrading the total cardiovascular risk profile, is highest in the group of old hypertensive men; echocardiography has a limited impact on the risk reclassification in younger patients and an unfavourable cost-effectiveness profile. Our data thus do not support the systematic ultrasound assessment of the heart in all uncomplicated hypertensive individuals.

Prospects for the prevention of stroke

We are currently fighting a battle against a stroke epidemic. Implementation of new treatment strategies could save many patients in the future. The control of blood pressure is a major objective; however, choosing specific antihypertensive therapy (e.g. an agent blocking the renin-angiotensin system) is also important. The Losartan Intervention For Endpoint reduction in hypertension (LIFE) study demonstrates potential benefits beyond blood pressure reduction of prescribing an angiotensin II receptor blocker (ARB) compared with more established therapy in patients with left ventricular hypertrophy (LVH). Losartan-based therapy brought about regression of LVH and reduced incidences of fatal and non-fatal stroke by 25%, new-onset diabetes by 25% and atrial fibrillation by 30% more than atenolol-based therapy for a similar blood pressure control and better tolerability. The Study on COgnition and Prognosis in the Elderly (SCOPE) study, although difficult to interpret, does not contradict an ARB benefit beyond blood pressure lowering in primary prevention linked to targeting the angiotensin type 1 receptor. The findings of the MOrbidity and mortality after Stroke, Eprosartan compared with nitrendipine in Secondary prevention (MOSES) trial suggest clear-cut ARB benefits independent of blood pressure lowering in secondary stroke prevention. Experimental findings and other clinical evidence further support the benefits of ARBs in stroke prevention. Telmisartan is an ARB with a particularly interesting profile for stroke; given the 24-hour efficacy with more pronounced protection against the morning blood pressure surge and peroxisome proliferator-activated receptor-gamma activity at clinical doses. The unique properties of telmisartan for secondary stroke prevention are being tested in the Prevention Regimen For Effectively avoiding Second Strokes (PRoFESS) study.

From Left Ventricular Hypertrophy to Congestive Heart Failure: Management of Hypertensive Heart Disease

Other than age, left ventricular hypertrophy (LVH) is the most potent predictor of adverse cardiovascular outcomes in the hypertensive population, and is an independent risk factor for coronary heart disease, sudden death, heart failure and stroke. Although directly related to systolic blood pressure, other factors including age, sex, race, body mass index and stimulation of the renin-angiotensin-aldosterone and sympathetic nervous systems play an important role in the pathogenesis of LVH. LVH involves changes in myocardial tissue architecture consisting of perivascular and myocardial fibrosis and medial thickening of intramyocardial coronary arteries, in addition to myocyte hypertrophy. The physiologic alterations which occur as a result of these anatomical changes include disturbances of myocardial blood flow, the development of an arrhythmogenic myocardial substrate and diastolic dysfunction. The latter is directly related to the degree of myocardial fibrosis and is the hemodynamic hallmark of hypertensive heart disease. When diastolic dysfunction is present, left ventricular end-diastolic pressure increases out-of-proportion to volume and may be elevated at rest or with exertion leading to clinical heart failure. At least one third of heart failure patients in the United States can be considered to have heart failure related to diastolic dysfunction. Compared to heart failure patients with systolic dysfunction, diastolic heart failure patients are more likely to be older, female, and to be hypertensive at the time of presentation. Although it has been assumed that LVH may lead to systolic dysfunction, evidence is lacking that LVH resulting from hypertension is a major risk factor for systolic heart failure independent of coronary artery disease. Treatment of hypertension greatly attenuates the development of LVH and significantly decreases the incidence of heart failure. In patients with established LVH, regression is both possible and desirable and results in a significant reduction in adverse clinical endpoints.

The Role of Angiotensin II Type 1 Receptor Antagonists in Elderly Patients with Hypertension

Hypertension is a major risk factor for stroke and coronary events in elderly people and clinical trials have shown that treatment of hypertension with various drugs can result in a substantial reduction in cerebrovascular and cardiovascular events. The angiotensin II type 1 (AT1) receptor antagonists are the newest class of antihypertensive agents to be used widely in clinical practice. AT1 receptor antagonists can generally be given once-daily. They are also extremely well tolerated with minimal first-dose hypotension and an incidence of adverse effects similar to that seen with placebo. Adverse event rates are significantly lower than with other classes of antihypertensive drugs including ACE inhibitors. These factors result in improved compliance and increased rates of continuance on therapy. AT1 receptor antagonists show similar efficacy in lowering blood pressure to other classes of antihypertensive agents and their antihypertensive effect is potentiated when they are given concomitantly with low-dose thiazide diuretics. AT1 receptor antagonists are eliminated predominantly by the hepatic route but most are not subject to extensive metabolism and interactions with other drugs are uncommon. This is an advantage in the elderly, who are often receiving multiple medications which increases the risk for adverse drug interactions. Dose adjustments are not usually required in the elderly unless there is plasma volume depletion. Although plasma AT1 receptor antagonist concentrations are generally higher in the elderly than in younger subjects, this pharmacokinetic difference may be balanced by decreased activation of the circulating renin-angiotensin-aldosterone system in the elderly. Recent clinical studies in high-risk hypertensive patients with left ventricular hypertrophy or in patients with diabetic nephropathy or heart failure have demonstrated that AT1 receptor antagonists can improve clinical outcomes to a similar or sometimes greater extent than other antihypertensive agents. Many of these studies have included large numbers of older patients and have confirmed the excellent tolerability profile of these drugs. Thus, AT1 receptor antagonists should be considered as a possible first-line treatment or as a component of combination therapy in patients with type 2 diabetes mellitus and microalbuminuria or nephropathy and as an alternative or additional treatment to ACE inhibitors in patients with heart failure or left ventricular dysfunction. AT1 receptor antagonists also appear to reduce the onset of new diabetes compared with some other antihypertensive drugs. The benefits in terms of organ protection have mainly been seen in studies using higher doses of particular AT1 receptor antagonists and it is not certain at present whether these results can be extrapolated to other members of the class. As the elderly are more likely to have developed organ damage related to hypertension or to have heart failure or diabetes as concomitant conditions, AT1 receptor antagonists represent an appropriate option for many elderly patients. The main disadvantage of these drugs is the cost of the medication but this may be offset by their improved tolerability with fewer adverse reactions and thus increased compliance, resulting in better blood pressure control and fewer clinical events. Overall, AT1 receptor antagonists are well tolerated and efficacious for blood pressure-lowering when given as a single daily dose in elderly patients and have many potential benefits in high-risk hypertensive subjects.

[Cardiac protection as priority strategy of cardiovascular prevention in high blood pressure]

Cardiac complications are the main cause of morbidity and mortality related with HBP in our setting and entail first magnitude human and social-health care consequences. Although the incidence of ACVA has decreased in recent decades, this has not occurred with the same intensity for cardiac complications, probably due to their multifactorial origin. Left ventricular hypertrophy, main etiologic responsible factor of hypertensive heart disease that includes heart failure, ischemic heart disease, arrhythmias and sudden death are found as nuclear element of the cardiac disease. Consequently, the magnitude, etiological diversity, vulnerability and social-health care implications grant the intervention on cardiac protection a priority role in the management of HBP and its complications.

Evaluación del riesgo de un primer ictus en la población hipertensa española en atención primaria. Estudio ERIC-HTA

BACKGROUND AND OBJECTIVE

Stroke is a major cause of morbidity and mortality in hypertensive population. The aim of this study is to estimate the 10-year risk of a first stroke in Spanish hypertensive population using the Framingham scale.

PATIENTS AND METHOD

Cross-sectional multicenter study in primary care environment, on hypertensive patients aged 55 or more (10 consecutive patients each physician). Blood pressure (BP) was measured according to standardized rules. Stroke and coronary risk were estimated using the Framingham scale.

RESULTS

16,129 patients (mean age 67.7 years; 57.1% women; 30.4% with diabetes mellitus; 26.6% with previous history of cardiovascular disease) were analyzed. 20.3% showed electrocardiographic left ventricular hypertrophy (more prevalent in males, diabetics, with systolic BP > or = 140 mmHg; p < 0.001). The goal of BP control was reached in 30.1% of non-diabetic patients and only in 5.9% of diabetics. The estimated 10-year risk of a first stroke (standard deviation) was estimated to be 19.9% (16.8), and the coronary risk 19.2% (14.0). While males had an estimated risk of coronary disease above the stroke risk, women had an estimated risk of a first stroke greater than the estimated risk of coronary disease.

CONCLUSIONS

The estimated risk of stroke among Spanish hypertensive population is high, and the main risk factors (age, systolic BP, diabetes and left ventricular hypertrophy) tend to aggregate. In women estimated risk of stroke in greater than estimated coronary risk. The risk of stroke must be taken into account in the assessment and treatment of hypertensive patients.

Prostacyclin protects against elevated blood pressure and cardiac fibrosis

Specific inhibitors of COX-2 have been associated with increased risk for cardiovascular complications. These agents reduce prostacyclin (PGI2) without affecting production of thromboxane (Tx) A2. While this abnormal pattern of eicosanoid generation has been implicated in the development of vascular disease associated with COX-2 inhibition, its role in the development of hypertension, the most common cardiovascular complication associated with COX-2 inhibition, is not known. We report here that mice lacking the receptor for PGI2 (IPKOs) develop salt-sensitive hypertension, cardiac hypertrophy, and severe cardiac fibrosis. Coincidental deletion of the TxA2 (TP) receptor does not prevent the development of hypertension, but cardiac hypertrophy is ameliorated and fibrosis is prevented in IPTP double knockouts (DKOs). Thus, deletion of the IP receptor removes a constraint revealing adverse cardiovascular consequences of TxA2. Our data suggest that adjuvant therapy that blocks unrestrained Tx actions might protect against end-organ damage without affecting blood pressure in patients taking COX-2 inhibitors.

Update on the drug treatment of hypertension in patients with cardiovascular disease

The management of the high-risk patient with hypertension has become more challenging in recent years. Drug therapy should be initiated earlier and at lower blood pressure levels in patients with coexisting cardiovascular or kidney diseases. The blood pressure goals of drug therapy are substantially lower when patients have concomitant heart or kidney disease or diabetes mellitus. Numerous clinical trials in tens of thousands of hypertensive patients with increased cardiovascular risk have demonstrated that the calcium antagonists are as effective and safe as diuretics, beta-adrenergic blockers, and renin-angiotensin blocking agents to prevent heart attack and stroke but not heart failure. Several recent studies also demonstrate that angiotensin-converting enzyme inhibitors and angiotensin-receptor blockers are effective in preventing stroke, progressive renal insufficiency, and heart failure in higher risk patients with hypertension. To achieve the aggressive blood pressure goals in patients with cardiovascular disease, thoughtful combinations of additive or synergistic agents improve efficacy and tolerability and have become an integral part of the modern management of hypertensive patients with coexisting cardiovascular disease.

The effects of losartan compared to atenolol on stroke in patients with isolated systolic hypertension and left ventricular hypertrophy. The LIFE study

The Losartan Intervention For Endpoint reduction in hypertension (LIFE) study reported that a losartan-based antihypertensive regimen reduced cardiovascular morbidity and mortality (composite of cardiovascular death, stroke, and myocardial infarction) more than therapy based on atenolol in patients with left ventricular hypertrophy and isolated systolic hypertension (ISH). Patients aged 55-80 years with blood pressures 160-200/<90 mm Hg were followed for a mean of 4.7 years. Blood pressure was similarly reduced in the losartan (n=660) and atenolol (n=666) ISH groups. There were 88 (6.6%) patients who experienced a stroke, 18 of which were fatal. Of patients experiencing strokes, 72.7% had an ischemic stroke. ISH patients in LIFE compared to the non-ISH group had a higher incidence of any stroke and embolic stroke, and similar incidences of fatal, atherosclerotic, and hemorrhagic/other strokes. The incidence of any stroke (40% risk reduction [RR], p=0.02), fatal stroke (70% RR, p=0.035), and atherothrombotic stroke (45% RR, p=0.022) was significantly lower in losartan-treated compared to the atenolol-treated patients. The 36% RR for embolic strokes in the losartan group was not statistically significantly (p=0.33) different from the atenolol group. These data suggest that losartan-based treatment is more effective than an atenolol-based treatment for patients with ISH and a high risk for stroke.

Influence of dietary sodium on the renin-angiotensin-aldosterone system and prevalence of left ventricular hypertrophy by EKG criteria

We investigated the interplay of dietary sodium and renin-angiotensin-aldosterone system (RAAS) activity with the prevalence of left ventricular hypertrophy (LVH) in essential hypertension. Electrocardiograms (EKG) were reviewed for the presence of LVH in 160 hypertensive patients. We then compared the rate of LVH to levels of plasma renin activity (PRA) and serum aldosterone under high and low sodium diet conditions. On high sodium diet, serum aldosterone was significantly higher (7.7+/-0.93 vs 5.7+/-0.35 ng/dl, P=0.02) in participants with LVH. With low sodium diet and upright posture, PRA was significantly lower in subjects with LVH vs those without (5.6+/-1.1 vs 7.6+/-0.56 ng/ml/h, P=0.026). Aldosterone levels on low sodium diet were not different between those with and those without LVH. PRA was then dichotomized at the lowest quartile under low sodium/upright posture conditions to define a 'low renin' group. In a multivariate logistic regression containing renin status (low renin vs normal/high renin), aldosterone on a high sodium diet, age, body mass index, gender, race, duration of hypertension, systolic and diastolic blood pressure and salt-sensitivity only low-renin status on a low sodium diet (P=0.019) and serum aldosterone on a high sodium diet (P=0.04) were significant predictors of LVH. Thus, reduced modulation of renin activity in response to sodium restriction and an increased aldosterone on a high sodium diet appear to identify characteristics of hypertensive patients predisposed to abnormal cardiac remodelling.

Left ventricular hypertrophy as a predictor of cardiovascular risk

Left ventricular hypertrophy (LVH) is a potent, independent predictor of cardiovascular events, particularly in hypertension, in which it dramatically increases the risk of stroke, coronary heart disease and heart failure. LVH is predominantly a surrogate marker for the effects of other risk factors integrated over time, but it may also contribute directly to cardiovascular disease through pathological changes in cardiac structure. The influence of blood pressure is central to LVH pathology, with 24-h blood pressure being more predictive of LVH than single clinic measurements. Blood pressure variation throughout the day is also emerging as an important correlate of LVH, and a strong association has been found between the early morning blood pressure rise and increased left ventricular mass. Antihypertensive treatment can reverse LVH, and preliminary studies suggest that this improves cardiovascular outcome and long-term prognosis. Most classes of antihypertensive agent show some effect on LVH regression, with the notable exceptions of minoxidil and hydralazine. However, many of the data regarding LVH regression come from small, poor-quality trials or from meta-analyses of these studies. In the few well-conducted studies that are available, certain classes of antihypertensive drugs are more effective than others. Those that target angiotensin II, such as the angiotensin II receptor blockers, appear to have a specific action on LVH that is independent of blood pressure reduction. Further high-quality studies are needed to define how LVH predicts cardiovascular risk, which agents are most effective at eliciting LVH regression and how such reversal can affect cardiovascular outcome.

Do angiotensin II antagonists provide benefits beyond blood pressure reduction?

Hypertension is a powerful risk factor for cardiovascular (CV) morbidity and mortality; therefore, blood pressure (BP) lowering plays a central role in reducing the cardiovascular complications of hypertension, including stroke. Recent outcomes studies--Losartan Intervention For Endpoint reduction in hypertension, Reduction of Endpoints in Non-insulin-dependent Diabetes Mellitus with the Angiotensin II Antagonist Losartan, and the Irbesartan Type 2 Diabetic Nephropathy Trial--suggest that some angiotensin II antagonists are associated with CV and renal effects beyond their ability to lower BP in patients with hypertension or diabetic nephropathy and may play a role in the prevention of new-onset type 2 diabetes. Angiotensin II antagonists are associated with a wide variety of vascular, cardiac, and renal effects, as well as molecule-specific effects independent of those induced by the angiotensin-I receptor. These actions may offer a mechanistic explanation for the outcome benefits observed in patients with hypertension or diabetic nephropathy. Angiotensin-converting enzyme inhibitors and calcium-channel blockers may also have effects that are not completely explained by differences in the antihypertensive response to these agents, but the evidence is less robust. Collectively, these findings suggest that management of patients with hypertension, with or without diabetes or renal disease, should no longer be viewed as simply a matter of correcting elevated BP. Antihypertensive agents that possess CV benefits beyond their BP-reducing effects should be used to prevent the development of end-organ damage.

Additional impact of electrocardiographic over echocardiographic diagnosis of left ventricular hypertrophy for predicting the risk of ischemic stroke

BACKGROUND

Patients with left ventricular hypertrophy (LVH) have an increased risk of ischemic stroke. Although echocardiography is commonly used for the diagnosis of LVH, there is little information about the potential role of electrocardiography in providing additional prognostic information. The purpose of this study is to determine if electrocardiographically derived criteria for LVH provide additional prognostic value over echocardiography for predicting ischemic stroke in a multiethnic population.

METHODS

A population-based, case-control study was conducted in 177 patients who had had a first ischemic stroke and in 246 control patients matched for age, gender, and race or ethnicity. Left ventricular mass was measured by using 2-dimensional transthoracic echocardiography. Logistic regression analysis was performed to assess the risk of stroke associated with the presence of LVH diagnosed by electrocardiography (defined by 4 established criteria) after adjustment for the presence of other stroke risk factors and for echocardiographically determined LVH.

RESULTS

After adjustment for the presence of other established stroke risk factors, ECG-LVH was associated with ischemic stroke, using Sokolow-Lyon (odds ratio [OR] 2.12, 95% CI 1.05-4.30), Cornell voltage (OR 2.06, 95% CI, 1.26-3.35), and Cornell product criteria (OR 2.12, 95% CI, 1.13-3.97). Cornell voltage criterion (men, >2.8 mV; women, >2.0 mV) was associated with ischemic stroke even after adjustment for echocardiographically determined LVH (OR 1.73, 95% CI, 1.04-2.88). The combination of echo-LVH and a positive Cornell voltage criterion was associated with a 3.5-fold increase in stroke risk.

CONCLUSIONS

Our study indicates that the presence of ECG-LVH is associated with an increased risk of ischemic stroke after adjustment for other stroke risk factors. For Cornell voltage criteria, this relationship persisted even after adjustment for echocardiographic LVH. Electrocardiographic results can provide independent information for left ventricular myocardial changes and should be considered together with echocardiographic results to fully assess the risk of ischemic stroke.

11β-Hydroxysteroid dehydrogenase type 2 activity is associated with left ventricular mass in essential hypertension

AIMS

Left ventricular mass (LVM) is under the control of aldosterone and angiotensin II in experimental hypertension, but the effect of aldosterone on LVM is controversial in essential hypertension (EH). Some EH patients show a mild impairment of 11beta-hydroxysteroid dehydrogenase type 2 (11beta-HSD2) activity without clinical features of the syndrome of apparent mineralocorticoid excess, where the incomplete cortisol-to-cortisone conversion leads to glucocorticoid-mediated mineralocorticoid effects. The mineralocorticoid receptor and 11beta-HSD2 are co-expressed in human heart. We investigated whether LVM may be regulated by glucocorticoids in EH patients.

METHODS AND RESULTS

The ratio between 24 h urinary tetrahydro derivatives of cortisol and cortisone (THFs/THE), plasma renin activity, 24 h urinary aldosterone, blood pressure, and LVM indexed for height(2.7) (LVMh(2.7)) were analysed in 493 never-treated hypertensives and 98 normotensives. THFs/THE was associated with LVMh(2.7) in hypertensives and normotensives (r=0.32, P<0.001, and r=0.17, P=0.04, respectively) and persisted after adjusting for confounders (multiple regression analysis). Body mass index, sex, recumbent plasma renin activity, and THFs/THE accounted for 26.1% of LVMh(2.7) variation. Urinary aldosterone was not correlated with LVMh(2.7).

CONCLUSION

We suggest that glucocorticoids may take part in the regulation of LVM in EH patients as a function of 11beta-HSD2 activity, and contribute to the target organ damage associated with essential hypertension.

Muscle ring finger protein-1 inhibits PKC{epsilon} activation and prevents cardiomyocyte hypertrophy

Much effort has focused on characterizing the signal transduction cascades that are associated with cardiac hypertrophy. In spite of this, we still know little about the mechanisms that inhibit hypertrophic growth. We define a novel anti-hypertrophic signaling pathway regulated by muscle ring finger protein-1 (MURF1) that inhibits the agonist-stimulated PKC-mediated signaling response in neonatal rat ventricular myocytes. MURF1 interacts with receptor for activated protein kinase C (RACK1) and colocalizes with RACK1 after activation with phenylephrine or PMA. Coincident with this agonist-stimulated interaction, MURF1 blocks PKCε translocation to focal adhesions, which is a critical event in the hypertrophic signaling cascade. MURF1 inhibits focal adhesion formation, and the activity of downstream effector ERK1/2 is also inhibited in the presence of MURF1. MURF1 inhibits phenylephrine-induced (but not IGF-1–induced) increases in cell size. These findings establish that MURF1 is a key regulator of the PKC-dependent hypertrophic response and can blunt cardiomyocyte hypertrophy, which may have important implications in the pathophysiology of clinical cardiac hypertrophy.

The use of selective aldosterone antagonists

Mineralocorticoid hormones, specifically aldosterone, have been shown to be increasingly important in the development and maintenance of cardiovascular disorders, particularly hypertension and congestive heart failure. The use of the mineralocorticoid receptor blocker, spironolactone, has been fraught with side effects, largely related to the poor specificity of this agent. Eplerenone, a new and more specific mineralocorticoid receptor blocker with little effect on sex-hormone receptors, has offered an alternative approach. Many studies in hypertension as well as a major and compelling study in congestive heart failure have documented the efficacy and specificity of eplerenone with a minimum of side effects. The major findings with this new agent are presented herein.

Prognostic significance of isolated, non-specific left ventricular repolarization abnormalities in hypertension

OBJECTIVE

Clinicians are often confronted with the incidental finding of isolated minor, non-specific repolarization changes on the electrocardiogram (ECG) in hypertensive patients. The aim of this study was to investigate the prognostic significance of such changes.

DESIGN

Prospective, observational study.

METHODS

A total of 1970 hypertensive patients without prevalent cardiovascular disease were followed for up to 9.1 years (mean 4.7 years). Patients with ECG abnormalities including ischaemia, previous infarction, bundle branch block, atrial fibrillation and ventricular pre-excitation were excluded. Patients were divided into three groups: normal left ventricular (LV) repolarization (n = 1355); minor repolarization changes (n = 504); and typical LV strain (n = 111).

RESULTS

During follow-up, 78 patients developed new-onset ischaemic heart disease. The event rates were 0.50, 1.28 and 3.08 per 100 patient-years in the groups with normal repolarization, minor changes, and typical LV strain, respectively (P < 0.001). After adjustment for the effect of age, sex, diabetes, serum cholesterol, smoking, LV hypertrophy and 24-h pulse pressure, the risk for developing coronary events was higher in patients with minor repolarization changes (hazard ratio 2.07, 95% confidence interval 1.23-3.47; P < 0.01) or LV strain (hazard ratio 4.00, 95% confidence interval 2.09-7.65; P < 0.001) than in patients with normal repolarization (reference category). Population-attributable risks were 21 and 14%, respectively. Minor ST-T changes also retained an adverse prognostic value among patients without LV hypertrophy (hazard ratio 1.90, 95% confidence interval 1.08-3.33; P = 0.026).

CONCLUSION

We have identified minor, non-specific LV repolarization changes as a novel, independent risk factor for ischaemic heart disease in patients with uncomplicated hypertension.

Greater Change of Orthostatic Blood Pressure Is Related to Silent Cerebral Infarct and Cardiac Overload in Hypertensive Subjects

Greater change of postural blood pressure (BP) is often seen in elderly hypertensives and is recognized as a risk factor for cognitive decline and poorer cerebrovascular outcome, but its clinical significance still remains to be clarified. We performed a head-up tilting test, ambulatory BP monitoring, and brain MRI in 59 hypertensives and 27 normotensive subjects. We measured plasma atrial natriuretic peptide (ANP) and brain natriuretic peptide (BNP) levels at rest to assess cardiac burden. The 59 hypertensive patients were classified into 3 groups: an orthostatic hypertension (OHT) group with orthostatic increase in systolic BP (SBP) > or = 10 mmHg (n=16); an orthostatic hypotension (OHYPO) group with orthostatic SBP decrease < or = -10 mmHg (n=18); and an orthostatic normotension (ONT) group with neither of these two patterns (n=25). A group of 27 normotensive subjects (NT) was also included as a control. Plasma BNP (72 +/- 92 vs. 29 +/- 24 pg/ml, p < 0.05) and BNP/ANP ratio (4.6 +/- 3.3 vs. 2.4 +/- 1.5, p < 0.05) were significantly higher in the OHYPO than in the NT group. The BNP/ANP ratio was also higher in the OHT than in the NT group (5.1 +/- 3.9 vs. 2.4 +/- 1.5, p < 0.01). The number of silent cerebral infarct (SCI), prevalence of SCI and number of multiple SCIs was the highest in the OHT group, followed in order by the OHYPO, ONT and NT groups. Blood pressure and left ventricular mass index were not significantly different among the 3 hypertensive groups. In conclusion, hypertensive patients with greater change of postural BP (OHT and OHYPO) were shown to have increased risk of advanced silent brain lesions and greater cardiac burden.

Use of Calcium Channel Antagonists for the Treatment of Hypertension in the Elderly

Systolic blood pressure and pulse pressure increase continuously throughout adult life and the prevalence of arterial hypertension rises accordingly, reaching 53-78% among those aged 65-74 years. Estimates of the prevalence of isolated systolic hypertension in the elderly range from 34-65%, with more women than men affected. It has been shown that within all age groups a difference in usual systolic blood pressure of 20 mm Hg or a difference in usual diastolic blood pressure of 10 mm Hg is associated with an approximately 2-fold difference in the risk of dying from stroke or ischaemic heart disease. Intervention trials using predominantly diuretics and/or beta-adrenoceptor antagonists have proven the efficacy and tolerability of antihypertensive treatment in elderly patients. For many years there have been ongoing discussions about the safety of calcium channel antagonists, especially in patients with diabetes mellitus. However, according to a recently published large prospective, randomised, double-blind, controlled clinical trial with more than 33,000 patients enrolled, no indications for increased total mortality, cancer rate or gastrointestinal bleeding for participants on amlodipine, a long-acting dihydropyridine calcium channel antagonist, were found. With calcium channel antagonists, protective effects against cardiovascular disease have been proven in large trials with elderly patients, particularly against stroke. There is good evidence to suggest that calcium channel antagonists may be superior to other antihypertensive agents in diabetic patients with isolated systolic hypertension. These agents are well tolerated and probably delay the progression of dementia. The lack of adverse metabolic effects that, in the case of a diuretic-based regimen, may have important long-term implications concerning cardiovascular risk, make calcium channel antagonists an attractive choice when antihypertensive treatment decisions need to be made in a predominantly overweight or obese elderly population.

Reversal of left ventricular hypertrophy: what have recent trials taught us?

Regression of left ventricular hypertrophy (LVH) is an important intermediate target for antihypertensive therapy. Thus, several trials and meta-analyses have attempted to compare the effects of different antihypertensive agents on LVH, but flawed study designs and methodologic problems have limited the utility of these studies. PRESERVE (Prospective Randomized Enalapril Study Evaluating Regression of Ventricular Enlargement), LIVE (LVH: Indapamide Sustained Release Versus Enalapril) and LIFE (Losartan Intervention For Endpoint reduction in hypertension) represent a new generation of large well designed trials with the power to compare different antihypertensive drugs. These studies have shown that treatment regimens based on enalapril and a nifedipine gastrointestinal therapeutic system are of similar efficacy (PRESERVE), that indapamide sustained release (SR) is superior to enalapril (LIVE), and that a regimen based on losartan is superior to a regimen based on atenolol (LIFE) in reversing hypertensive LVH. LIVE incorporated on-treatment echocardiographic quality control, with centralized readers blinded for both treatment and sequence of recording. The findings of these rigorous studies, to some extent in disagreement with results of previous meta-analyses, support the notion that antihypertensive drugs need to be judged on their individual effects on important intermediate endpoints such as LVH in well designed and adequately sized studies. However, extrapolation of the results of these studies in terms of class effects could be misleading and should be made with caution.

Cardiac remodeling in systemic hypertension

Experimental and clinical studies provide evidence that hypertension is causally related to adverse cardiac structural changes, such as LA enlargement, LV hypertrophy and myocardial fibrosis, and functional changes inclusive of LV systolic and diastolic dysfunction. These changes are induced by both hemodynamic and nonhemodynamic factors. There is accumulating evidence from several small and large clinical trials that various classes of antihypertensive therapy prevent and regress LVH and myocardial fibrosis. Prevention and reversal of LVH are associated with an improvement in cardiac function and with a decline in risk of adverse cardiovascular outcomes. Prevention of LVH should be a priority in subjects with hypertension. In patients with hypertensive heart disease, the components of therapy must comprise optimization of BP and regression of LVH. Future targets of therapy in hypertensive heart disease may include regression of myocardial fibrosis, normalization of LA size, and improvement in LV diastolic function.

Risk Factors for Incident Stroke among Patients with End-Stage Renal Disease

ABSTRACT. Although patients with ESRD experience markedly higher rates of stroke, no studies in the US have identified risk factors associated with stroke in this population. It was hypothesized that black race, malnutrition, and elevated BP would be associated with the risk of stroke among patients with ESRD. Data from the United States Renal Data Systems were used. Adult Medicare-insured hemodialysis and peritoneal dialysis patients without a history of stroke or transient ischemic attack (TIA) were considered for analysis. The primary outcome was hospitalized or fatal stroke. Cox proportional hazards models were used to determine the associations between the primary predictor variables and stroke. The rate of incident stroke was 33/1,000 person-years in the study sample. After adjustment for age and other patient characteristics, three markers of malnutrition were associated with the risk of stroke—serum albumin (per 1 g/dl decrease, hazard ratio [HR] = 1.43), height-adjusted body weight (per 25% decrease, HR = 1.09), and a subjective assessment of undernourishment (HR = 1.27)—as was higher mean BP (per 10 mmHg, HR = 1.11). The association between black race varied by cardiac disease status, with blacks estimated to be at lower risk than whites among individuals with cardiac disease (HR = 0.74), but at higher risk among individuals without cardiac disease (HR = 1.24). This study confirms the extraordinarily high rates of stroke in ESRD patients on dialysis and identifies high mean BP and malnutrition as potentially modifiable risk factors. The association between black race and stroke differs by cardiac disease status; the reasons for this differing effect of race deserve further investigation. E-mail: seliger@u.washington.edu

Physical activity in relation to indices of endothelial function and angiogenesis factors in hypertension: a substudy of the Anglo-Scandinavian Cardiac Outcomes Trial (ASCOT)

BACKGROUND

Hypertension is an important risk factor for cardiovascular disease. The latest guidelines recommend regular physical exercise as initial step or adjunct in the treatment of hypertension. We investigated the association between physical activity and the degree of hypertension, as well as the relation to indices of endothelial damage/dysfunction and angiogenesis.

METHODS

We studied 234 patients with hypertension (198 males; mean age 64 years; mean blood pressure 166/90 mmHg), who were compared with 60 age and sex-matched healthy normotensive controls. We assessed the patient's physical activity using the validated Baecke physical activity questionnaire and measured flow-mediated dilatation (FMD) of the brachial artery and von Willebrand factor (vWf) as indices of endothelial damage/dysfunction, whilst angiogenesis was assessed by measurement of plasma vascular endothelial growth factor (VEGF) and its soluble receptor (sFlt-1) both by ELISA.

RESULTS

When hypertensive patients were compared with the controls, there was no statistically significant difference in total physical activity score using the Baecke questionnaire although plasma VEGF and vWf levels were higher, but sFlt-1 levels and FMD lower (all P < 0.001). Patients with high physical activity were younger, and had lower mean diastolic blood pressure and 10-year Framingham stroke risk, when compared with those with low physical activity; but indices of endothelial damage/dysfunction and angiogenesis were not significantly different.

CONCLUSION

Physical activity scores in hypertensive patients are not significantly different from healthy normotensive controls, and there appears to be no relation to the abnormal processes of endothelial damage/dysfunction and angiogenesis seen in hypertensives.

The Losartan Intervention for Endpoint Reduction (LIFE) trial-have angiotensin-receptor blockers come of age?

The Losartan Intervention for Endpoint Reduction trial is one of several end-point trials that are now available with angiotensin-receptor blockers. This trial compared two regimens-losartan-based therapy to atenolol-based therapy-in 9193 hypertensive patients with electrocardiographic evidence of left ventricular hypertrophy. In the instance of each of these therapeutic groups, hydrochlorothiazide add-on therapy was permitted as per protocol. Although blood pressures were comparably reduced in both the losartan and the atenolol-based treatment groups, stroke rate was notably less in the losartan-treatment group. The 1195 patient diabetic cohort in this trial also experienced a substantial reduction in total and cardiovascular mortality favoring losartan. An additional finding in this trial was that new-onset diabetes developed 25% less frequently in the losartan-treated group. The results of this trial are both interesting and relevant to what is an expanding use of angiotensin-receptor blockers in the hypertensive population.

Cardiovascular morbidity and mortality in the Losartan Intervention For Endpoint reduction in hypertension study (LIFE): a randomised trial against atenolol

BACKGROUND

Blood pressure reduction achieved with beta-blockers and diuretics is the best recorded intervention to date for prevention of cardiovascular morbidity and death in patients with hypertension. Left ventricular hypertrophy (LVH) is a strong independent indicator of risk of cardiovascular morbidity and death. We aimed to establish whether selective blocking of angiotensin II improves LVH beyond reducing blood pressure and, consequently, reduces cardiovascular morbidity and death.

METHODS

We did a double-masked, randomised, parallel-group trial in 9193 participants aged 55-80 years with essential hypertension (sitting blood pressure 160-200/95-115 mm Hg) and LVH ascertained by electrocardiography (ECG). We assigned participants once daily losartan-based or atenolol-based antihypertensive treatment for at least 4 years and until 1040 patients had a primary cardiovascular event (death, myocardial infarction, or stroke). We used Cox regression analysis to compare regimens.

FINDINGS

Blood pressure fell by 30.2/16.6 (SD 18.5/10.1) and 29.1/16.8 mm Hg (19.2/10.1) in the losartan and atenolol groups, respectively. The primary composite endpoint occurred in 508 losartan (23.8 per 1000 patient-years) and 588 atenolol patients (27.9 per 1000 patient-years; relative risk 0.87, 95% CI 0.77-0.98, p=0.021). 204 losartan and 234 atenolol patients died from cardiovascular disease (0.89, 0.73-1.07, p=0.206); 232 and 309, respectively, had fatal or non-fatal stroke (0.75, 0.63-0.89, p=0.001); and myocardial infarction (non-fatal and fatal) occurred in 198 and 188, respectively (1.07, 0.88-1.31, p=0.491). New-onset diabetes was less frequent with losartan. Interpretation Losartan prevents more cardiovascular morbidity and death than atenolol for a similar reduction in blood pressure and is better tolerated. Losartan seems to confer benefits beyond reduction in blood pressure.