Effects of an angiotensin-converting-enzyme inhibitor, ramipril, on cardiovascular events in high-risk patients

Type-II error rates (beta errors) of randomized trials in orthopaedic trauma

BACKGROUND

Although an investigator may limit bias through randomization, concealment of patient allocation, and blinding, the results of randomized trials may be less convincing when the sample size is not sufficiently large to reveal a true difference between treatment groups. When the sample size is small, randomized trials are subject to beta errors (type-II errors)--that is, the probability of concluding that no difference between treatment groups exists when, in fact, there is a difference. The purpose of this study of randomized trials involving fracture care published between 1968 and 1999 was twofold: (1) to evaluate type-II error rates and study power (1 - beta) for the primary outcomes and (2) to identify whether investigators clearly identified the primary and secondary outcomes.

METHODS

To be eligible, studies were required to (1) be published in English, (2) be described as a randomized trial, (3) involve the care of adult patients with fractures, treated either operatively or nonoperatively, and (4) contain sufficient outcome information to enable study power to be calculated. Computer database searches were performed independently by two investigators to identify all potentially relevant study titles. Additional strategies to identify articles included (1) hand searches of selected orthopaedic journals from 1989 to 1999, (2) searches of the bibliographies of potentially relevant articles, and (3) review by content experts to identify missing studies. For each study, a standard power calculation was performed on the primary and secondary outcomes. For those studies in which the primary outcome was not explicitly reported, the most clinically relevant measure was chosen by consensus. Acceptable study power was agreed a priori to be > or = 80% (type-I error of < or = 0.20).

RESULTS

We identified 620 potentially relevant citations from MEDLINE, of which only 187 were potentially eligible. We identified nine more articles with other searches, and application of the eligibility criteria to the 196 articles eliminated seventy-nine. Thus, we analyzed 117 studies in which a total of 19,942 patients with orthopaedic trauma had been randomized. Sample sizes ranged from ten to 662 patients (mean and standard deviation, 95 79 patients). The majority (34%) of trials involved the treatment of hip fractures. The mean overall study power among the 117 trials was 24.65% (range, 2% to 99%). The type-II error rate for primary outcomes was 90.52%.

CONCLUSIONS

Mean type-II error rates in the orthopaedic trauma trials that we analyzed exceeded accepted standards. Investigators can reduce type-II error rates by performing power and sample-size calculations prior to conducting a trial.

Potentiation of bradykinin-induced tissue plasminogen activator release by angiotensin-converting enzyme inhibition

OBJECTIVES

The aim of the present study was to determine the effect of angiotensin-converting enzyme (ACE) inhibition on the local stimulated release of tissue plasminogen activator (t-PA) from the endothelium.

BACKGROUND

Angiotensin-converting enzyme inhibitor therapy may exert a beneficial effect on the endogenous fibrinolytic balance.

METHODS

Blood flow and plasma fibrinolytic factors were measured in both forearms of eight healthy males who received unilateral brachial artery infusions of the endothelium-dependent vasodilators substance P (2 to 8 pmol/min) and bradykinin (100 to 1,000 pmol/min), and the endothelium-independent vasodilator sodium nitroprusside (2 to 8 microg/min). These measurements were performed on each of three occasions following one week of matched placebo, quinapril 40 mg or losartan 50 mg daily administered in a double-blind randomized crossover design.

RESULTS

Sodium nitroprusside, substance P and bradykinin produced dose-dependent increases in the blood flow of infused forearm (analysis of variance [ANOVA], p < 0.001 for all). Although sodium nitroprusside did not affect plasma t-PA concentrations, they were increased dose-dependently in the infused forearm by substance P and bradykinin infusion (ANOVA, p < 0.001 for both). Bradykinin-induced release of active t-PA was more than doubled during treatment with quinapril in comparison to placebo or losartan (two-way ANOVA: p < 0.003 for treatment group, p < 0.001 for t-PA response and p = ns for interaction), whereas the substance P response was unaffected.

CONCLUSIONS

We have shown a selective and marked augmentation of bradykinin-induced t-PA release during ACE inhibition. These findings suggest that the beneficial clinical and vascular effects of ACE inhibition may, in part, be mediated through local augmentation of bradykinin-induced t-PA release.

Vitamin E supplementation in the prevention of coronary heart disease

Vitamin E consists of a number of compounds, tocopherols and tocotrienols, that function as lipid-soluble antioxidants. A hypothesis is that vitamin E may slow the progression of atherosclerosis by blocking the oxidative modification of low-density lipoprotein cholesterol and thus decrease its uptake into the arterial lumen. Basic science and animal studies have generally supported this hypothesis. Observational studies have primarily assessed patients with no established coronary heart disease (CHD), and results have generally supported a protective role of vitamin E in CHD. Early primary and secondary prevention clinical trials (Alpha-Tocopherol, Beta-Carotene Cancer Protection study and Cambridge Heart Antioxidant Study) showed mixed results. Despite years of encouraging evidence from basic science and observational studies, 3 large randomized clinical trials (Gruppo Italiano per lo Studio della Sopravvivenza nell'Infarto miocardico, Heart Outcomes Prevention Evaluation, and Primary Prevention Project) with a combined total of more than 25,000 patients failed to show a significant benefit with vitamin E taken as a dietary supplement for the prevention of CHD. Four large randomized primary prevention trials currently under way should add to our knowledge. The American Heart Association has recommended consumption of a balanced diet with emphasis on antioxidant-rich fruits and vegetables but has made no recommendations regarding vitamin E supplementation for the general population. Although vitamin E supplementation seems to be safe for most people, recommendations from health care professionals should reflect the uncertainty of established benefit as demonstrated in clinical trials.

Statistical significance versus clinical relevance in cardiovascular medicine

Evidence-based medicine is the foundation of everyday clinical practices and large clinical trials investigating the effects of various interventions on morbidity and survival and generally provide the most robust evidence. Cardiovascular medicine is considered one of the most evidence-based disciplines of medicine. However, there are a number of limitations to the general applicability of clinical trial results in cardiovascular medicine. Although generally useful to the clinician, clinical trials have often been suboptimally designed from 1 or several points of view. As a consequence of flaws in the design and the execution of the trials, statistical significance is quite often not equal to clinical relevance. This article outlines some of the shortcomings of designing and carrying out clinical trials, as well as inadequacies concerning the publication, interpretation, and implementation of the trial results. Evidence-based medicine is obviously not always as solid as one might think.

Initial antihypertensive therapy. What are the current drugs of choice?

The goal of antihypertensive treatment, in addition to lowering blood pressure, is to reduce the risk of cardiovascular events. Until recently, however, only conventional treatment with diuretics and beta-blockers had been studied in terms of cardiovascular end points. In this article, Dr Yeun reviews the results of recent trials comparing these agents with other classes of antihypertensive drugs. She examines the confounding elements in the trials, provides an interpretation of study results, and suggests a practical approach to initial treatment of uncomplicated hypertension.

Cholesterol: an important but relatively overemphasized risk factor for ischemic heart disease

Educational messages directed at the public to prevent ischemic heart disease (IHD) are generally based on cholesterol-reduction. However, IHD has multiple risk factors, and a study was performed to help determine whether or not the allocation of educational messages among risk factors is appropriate: The severity of high cholesterol was compared with the severity of multiple other major risk factors for IHD, and the beneficial effects of cholesterol-reduction was compared with the benefits of multiple other major preventative factors for IHD. It was found that high cholesterol levels, and multiple other risk factors, generally give a risk of around 2.0 for developing IHD. Cholesterol-reduction by statins, and multiple other factors which prevent IHD, generally reduce the risk of IHD by about 30-40%. It was concluded that the allocation of educational messages to reduce the incidence of IHD should significantly increase discussions of non-cholesterol risk and preventative factors.

The clinical implication of tissue renin angiotensin systems

The presence, and in many cases the regulated synthesis, of components of the renin-angiotensin system have been demonstrated in multiple tissues, indicating the existence of tissue angiotensin-generating systems. These vary with respect to which renin-angiotensin system components are synthesized locally and which are taken up from plasma. Enzymes unrelated to the classical renin-angiotensin system may also contribute to tissue angiotensin synthesis. However, based on the available data, the prevailing opinion that kidney-derived renin is in all cases the only physiologically relevant renin in tissues must be revised. Also there is evidence indicating a role for tissue angiotensin systems in the pathogenesis of cardiovascular disease and in cardiovascular structural remodeling. The angiotensin-regulated synthesis of aldosterone in cardiac tissue has been described, suggesting the possibility that a renin-angiotensin-aldosterone system exists in the heart. In addition, intracellular (intracrine) sites of angiotensin action have been reported. Some of these findings have implications for therapeutics and, in particular, for the use of angiotensin converting-enzyme inhibitors and angiotensin receptor blockers. Finally, tissue angiotensin systems outside the cardiovascular system also appear to be physiologically relevant.

Polypharmacy of heart failure. Creating a rational pharmacotherapeutic protocol

In the management of chronic heart failure, polypharmacy is common, necessary, and often overlooked. The increasing costs of care, noncompliance, and frequent adverse drug interactions have led to diminishing benefits by simply adding additional drugs to the already complex regimen. This review outlines a rational pharmacotherapeutic protocol based on establishing overall therapeutic goals and confirming treatment targets, tailoring therapy to individual patients by balancing beneficial and adverse drug effects, and paying particular attention to patient education and other nonpharmacologic support.

Episodes of ST-segment depression is related to changes in ambulatory blood pressure and heart rate in intermittent claudication

OBJECTIVE

To study the prevalence and circadian distribution of ischaemic ST-segment depression detected with ambulatory electrocardiographic monitoring (AECG) in patients with intermittent claudication (IC) as well as to study ambulatory blood pressure (ABP) and the relation of ischaemic episodes to variations in ABP and heart rate.

DESIGN

A total of 40 patients with a history of IC and an ankle/brachial-index (ABI) <0.9 performed: (i) 24-h AECG recordings, (ii) simultaneous 24 h recordings of ABP every 15 min (Spacelabs 90207), (iii) an exercise treadmill test (ETT). An ischaemic episode was defined as a transient ischaemic ST-segment deviation > or =1 mm lasting >1 min. Eleven patients were excluded from ECG analysis because of uninterpretable ECG caused by treatment with digoxin or technical problems.

RESULTS

Out of 29 patients, eight experienced a total of 15 episodes of ST-depression on AECG. The mean duration was 21+/-31 min. The majority of episodes (11 of 15) occurred between 6 and 12 a.m. In eight patients with ST-segment depression three had a history of ischaemic heart disease (IHD), four were hypertensives and four had signs of myocardial ischaemia on ETT. There were no significant differences between patients with and without ST-segment depression in ABP, walking performance or ABI. During ST-depression episodes systolic and diastolic blood pressure and heart rate were higher than day mean values; 178+/-41 vs. 166+/-30 mmHg (P= 0.09); 96+/-9 vs. 90+/-4 mmHg (P = 0.01) and 103+/-9 vs. 87+/-5 beats min(-1) (P < 0.01).

CONCLUSION

Silent myocardial ischemia occurred in about a third of patients with IC. Episodes of ischaemia were associated with an increased ABP and heart rate. Whether treatment of high blood pressure may reduce silent ischaemia and if this favourably influences outcome is a matter of further research.

Early recognition and treatment of glucose abnormalities to prevent type 2 diabetes mellitus and coronary heart disease

Striking parallels exist in both risk and protective factors between coronary heart disease and type 2 diabetes mellitus. Patients with insulin resistance are more likely to develop diabetes and coronary heart disease. Better treatment of diabetes may result in less coronary heart disease, although this has not yet been established. Reliance on fasting glucose determinations alone will overlook a substantial number of patients at risk for diabetes and subsequent coronary heart disease. Measurement of glycosylated hemoglobin should be a routine part of screening for patients at risk for diabetes. Patients with glycosylated hemoglobin levels in the high-normal range should be treated more aggressively with diet, exercise, and medication because evidence is good that diabetes can be prevented (or its onset delayed). Patients with borderline elevations of low-density lipoprotein cholesterol concentrations and with high-normal glycosylated hemoglobin levels should be considered for statin therapy, and patients with hypertension with high-normal glycosylated hemoglobin levels should be treated with angiotensin-converting enzyme inhibitors as first-line agents. Studies to determine whether metformin is useful in this population are ongoing.

Diagnosis and management of myocardial ischemia (angina) in the elderly patient

Coronary artery disease is a major problem in the elderly population. Approximately 60% of all acute myocardial infarctions in the United States occur in people 65 years or older, and 30% occur in persons older than 75 years. Morbidity and mortality are high in elderly patients who sustain a myocardial infarction. Due to the atypical presentation of myocardial ischemia and absence of classic symptoms, coronary artery disease may not be diagnosed in many of these patients until an acute myocardial infarction occurs. Early diagnosis of coronary artery disease and reduction of all coronary risk factors are beneficial in reducing future coronary events in older as well as in younger patients. Many studies have shown that anti-ischemic and acute myocardial infarction therapies have been underutilized in the elderly population. The principles of drug therapy for myocardial ischemia are the same as those for younger patients. Aggressive therapy, including early coronary angiography and revascularization, has been found to be as beneficial in high-risk, unstable older patients as in younger patients. Therapy should be individualized according to the patient's clinical condition. On the basis of current knowledge, elderly, high-risk patients with acute coronary syndromes may be treated with a combination of intensive medical therapy and early coronary angiography with revascularization.

Molecular interactions of vasoactive systems in cardiovascular damage

The renin-angiotensin system (RAS) and the kallikrein-kinin system (KKS) are important in the aetiology of hypertension and the pathogenesis of cardiac and renal damage associated with elevated blood pressure. While angiotensin II acts by increasing blood pressure and supporting end-organ damage, kinins have an opposite protective effect. The two systems interact on many levels. Angiotensin-converting enzyme (ACE) activates angiotensins and inactivates kinins. ACE inhibitors therefore exert their organ-protective action via both systems, as they block the deleterious RAS and potentiate the protective KKS. Furthermore, ACE may directly interact with the kinin B2 receptor and ACE inhibitors, thereby eliciting a resensitization of this receptor following agonist-induced desensitization. Recently, a functional heterodimer of AT1 and B2 receptors has also been demonstrated. Moreover, kallikreins may be involved in the activation of prorenin and in the signalling pathway of angiotensin AT2 receptors. Because of the multitude of interactions, any therapeutic intervention into one of the two peptide systems will automatically lead to an alteration in the other. This double action is utilized by drugs such as ACE inhibitors to provide unprecedented effectiveness in hypertension and associated cardiac and renal damage.

Cardiovascular protection and blood pressure reduction: a meta-analysis

BACKGROUND

Whether antihypertensive drugs offer cardiovascular protection beyond blood pressure lowering has not been established. We aimed to investigate whether pharmacological properties of antihypertensive drugs or reduction of systolic pressure accounted for cardiovascular outcome in hypertensive or high-risk patients.

METHODS

In a meta-analysis we extracted summary statistics from published reports, and calculated pooled odds ratios for experimental versus reference treatment. We correlated across-trials odd ratios for differences in systolic pressure between groups.

FINDINGS

We analysed nine randomised trials comparing treatments in 62605 hypertensive patients. Compared with old drugs (diuretics and b-blockers), calcium-channel blockers and angiotensin converting-enzyme inhibitors offered similar overall cardiovascular protection, but calcium-channel blockers provided more reduction in the risk of stroke (13.5%, 95% CI 1.3-24.2, p=0.03) and less reduction in the risk of myocardial infarction (19.2%, 3.5-37.3, p=0.01). Heterogeneity was significant between trials because of high risk of cardiovascular events on doxazosin in one trial, and high risk of stroke on captopril in another; but systolic pressure differed between groups in these two trials by 2-3 mm Hg. Similar systolic differences occurred in a trial of diltiazem versus old drugs, and in three trials of converting-enzyme inhibitor against placebo in high-risk patients. Meta-regression across 27 trials (136124 patients) showed that odds ratios could be explained by achieved differences in systolic pressure.

INTERPRETATION

Our findings emphasise that blood pressure control is important. All antihypertensive drugs have similar long-term efficacy and safety. Calcium-channel blockers might be especially effective in stroke prevention. We did not find that converting-enzyme inhibitors or a-blockers affect cardiovascular prognosis beyond their antihypertensive effects.

Inflammatory pathways in atherosclerosis and acute coronary syndromes

Evidence from a broad range of studies demonstrates that atherosclerosis is a chronic disease that, from its origins to its ultimate complications, involves inflammatory cells (T cells, monocytes, macrophages), inflammatory proteins (cytokines, chemokines), and inflammatory responses from vascular cells (endothelial cell expression of adhesion molecules). Investigators have identified a variety of proteins whose levels might predict cardiovascular risk. Of these candidates, C-reactive protein, tumor necrosis factor-alpha, and interleukin-6 have been most widely studied. There is also the prospect of inflammation as a therapeutic target, with investigators currently debating to what extent the decrease in cardiovascular risk seen with statins, angiotensin-converting enzyme inhibitors, and peroxisome proliferator-activated receptor ligands derives from changes in inflammatory parameters. These advances in basic and clinical science have placed us on a threshold of a new era in cardiovascular medicine.

Why vascular biology matters

Cardiovascular disease has been the leading cause of death for men and women in this country since 1921 and is currently the leading cause of death in the world. Adding to the sense of urgency about disease prevention is the recent finding that the initial lesions of atherosclerotic vascular disease may begin within the first year of life-or even earlier, during fetal growth. However, the pathobiology of atherosclerosis (and in particular, the key role of low-density lipoprotein cholesterol) is now well understood. Activation of 3 major oxidative systems as well as the renin-angiotensin system-all located in the vascular wall-is an early step. In fact, the effects of statins and angiotensin-converting enzyme inhibitors on the vascular wall (improved endothelial function, inhibition of platelet aggregation, and plaque stabilization) are an important mechanism of benefit, independent of their systemic effects. Several very positive trials with these agents have been completed. However, if this information is not incorporated into clinical practice in a timely manner, cardiovascular disease will continue to present a major cause of morbidity and mortality worldwide.

Vasopeptidase inhibitors: a new therapeutic concept in cardiovascular disease?

The cardiovascular system is regulated by hemodynamic and neurohumoral mechanisms. These regulatory systems play a key role in modulating cardiac function, vascular tone, and structure. Although neurohumoral systems are essential in vascular homeostasis, they become maladaptive in disease states such as hypertension, coronary disease, and heart failure. The clinical success of ACE inhibitors has led to efforts to block other humoral systems. Neutral endopeptidase (NEP) is an endothelial cell surface zinc metallopeptidase with similar structure and catalytic site. NEP is the major enzymatic pathway for degradation of natriuretic peptides, a secondary enzymatic pathway for degradation of kinins, and adrenomedullin. The natriuretic peptides can be viewed as endogenous inhibitors of the renin angiotensin system. Inhibition of NEP increases levels of atrial natriuretic peptide (ANP), brain natriuretic peptide (BNP) of myocardial cell origin, and C-type natriuretic peptide (CNP) of endothelial cell origin as well as bradykinin and adrenomedullin. By simultaneously inhibiting the renin-angiotensin-aldosterone system and potentiating the natriuretic peptide and kinin systems, vasopeptidase inhibitors reduce vasoconstriction, enhance vasodilation, improve sodium/water balance, and, in turn, decrease peripheral vascular resistance and blood pressure and improve local blood flow. Within the blood vessel wall, this leads to a reduction of vasoconstrictor and proliferative mediators such as angiotensin II and increased local levels of bradykinin (and, in turn, nitric oxide) and natriuretic peptides. Preliminary clinical experiences with vasopeptidase inhibitors are encouraging. Thus, the combined inhibition of ACE and neutral endopeptidase is a new and promising approach to treat patients with hypertension, atherosclerosis, or heart failure.

Contemporary management of chronic stable angina

Chronic stable angina is a common condition with a prognosis that is less benign than is generally appreciated. The optimal treatment strategy of this disorder is unclear, and few anti-ischaemic agents have been rigorously tested in prospectively randomised mortality studies. The evidence base for the anti-ischaemic therapy of chronic angina draws upon data 'borrowed' from studies in acute coronary syndromes, and from studies in chronic angina using surrogate endpoints such as ambulatory silent ischaemia. Such evidence leads us to believe that anti-ischaemic therapy with beta-blockers offers a mortality benefit in chronic angina. In contrast, the mortality benefit of lipid lowering therapy and antiplatelet agents is well proven. Angioplasty offers no mortality benefit in the treatment of chronic angina, although it is more effective than medical therapy alone for the relief of symptoms. In a few patients with high order proximal coronary disease, coronary bypass surgery offers a distinct mortality advantage compared with medical treatment alone. Most patients, however, do not warrant such an approach, and only require surgery for when they remain symptomatic despite adequate medical therapy. Alternative strategies such as cardiac transplantation, transmyocardial laser revascularisation and spinal cord stimulation are now accepted in a subgroup of patients for the treatment of chronic angina refractory to standard therapy.

Reduction of cardiovascular risk by regression of electrocardiographic markers of left ventricular hypertrophy by the angiotensin-converting enzyme inhibitor ramipril

BACKGROUND

Electrocardiographic markers of left ventricular hypertrophy (LVH) predict poor prognosis. We determined whether the ACE inhibitor ramipril prevents the development and causes regression of ECG-LVH and whether these changes are associated with improved prognosis independent of blood pressure reduction.

METHODS AND RESULTS

In the Heart Outcomes Prevention Evaluation (HOPE) study, patients at high risk were randomly assigned to ramipril or placebo and followed for 4.5years. ECGs were recorded at baseline and at study end. We compared prevention/regression and development/persistence of ECG-LVH in the two groups and related these changes to outcomes. At baseline, 676 patients had LVH (321 in the ramipril group and 355 in the placebo group) and 7605 patients did not have LVH (3814 in the ramipril group and 3791 in the placebo group). By study end, 336 patients in the ramipril group (8.1%) compared with 406 in the placebo group (9.8%) had development/persistence of LVH; in contrast, 3799 patients in the ramipril group (91.9%) compared with 3740 in the placebo group (90.2%) had regression/prevention of LVH (P=0.007). The effect of ramipril on LVH was independent of blood pressure changes. Patients who had regression/prevention of LVH had a lower risk of the predefined primary outcome (cardiovascular death, myocardial infarction, or stroke) compared with those who had development/persistence of LVH (12.3% versus 15.8%, P=0.006) and of congestive heart failure (9.3% versus 15.4%, P<0.0001).

CONCLUSIONS

The ACE inhibitor ramipril decreases the development and causes regression of ECG-LVH independent of blood pressure reduction, and these changes are associated with reduced risk of death, myocardial infarction, stroke, and congestive heart failure.

Elevated levels of plasma von Willebrand factor and the risk of macro- and microvascular disease in type 2 diabetic patients with microalbuminuria

BACKGROUND

The purpose of this study was to examine the concept suggesting that microalbuminuria in combination with high levels of plasma von Willebrand factor is a stronger predictor for cardiovascular disease and microvascular complications than microalbuminuria alone in type 2 diabetic patients.

METHODS

One hundred and sixty patients with type 2 diabetes mellitus and persistent microalbuminuria were followed for an average of 3.8 (SD 0.3) years. 70% of the patients were treated with angiotensin converting enzyme (ACE)-inhibitors. Patients in this subanalysis were divided into two groups according to baseline plasma von Willebrand factor levels below or above the median. The main outcome was cardiovascular disease (cardiovascular mortality, non-fatal stroke, non-fatal myocardial infarction, coronary artery bypass graft and revascularization or amputation of legs), progression to diabetic nephropathy or progression in diabetic retinopathy.

RESULTS

At baseline the two groups were comparable for HbA(1c), fasting levels of s-total-cholesterol, s-HDL-cholesterol and s-triglycerides, systolic and diastolic blood pressure, gender, known diabetes duration, smoking habits, previous cardiovascular disease and antihypertensive therapy as well as retinopathy. Odds ratio for cardiovascular disease was 1.11 (95% CI 0.45-2.73, P=0.82) (multiple logistic regression), odds ratio for progression to nephropathy was 1.08 (0.41-2.85, P=0.87) and odds ratio for progression in retinopathy was 0.96 (0.46-2.00, P=0.92), all with plasma von Willebrand factor levels above the median.

CONCLUSIONS

Our results do not support the suggestion that the combination of high plasma levels of von Willebrand factor and microalbuminuria is a stronger predictor for cardiovascular disease, progression to diabetic nephropathy or progression in diabetic retinopathy than microalbuminuria alone in patients with type 2 diabetes and persistent microalbuminuria.

Proteinuria and cardiovascular disease

In the last few decades, clinical and experimental data have established microalbuminuria/proteinuria as an independent risk factor for renal disease and for progression of renal disease in patients with diabetes and in those with essential hypertension. Reduction of proteinuria with the use of angiotensin-converting enzyme inhibitors has been shown in clinical trials to delay or stabilize the rate of progression of renal disease. This effect appears to be independent of any effect on blood pressure control. In conjunction with other therapeutic interventions such as dietary modification and control of serum lipids, it appears that for at least a subgroup of patients, it is possible to delay or prevent progression of kidney failure. More recently, evidence has accumulated that establishes microalbuminuria/proteinuria as an independent risk factor for cardiovascular morbidity and mortality even in those without other clinical evidence of kidney disease. There is frequently a clustering of risk factors in these individuals that includes insulin resistance, salt-sensitivity, hypertension, and dyslipidemia. The mechanism of this relationship of proteinuria and cardiovascular disease is unclear, but the presence of proteinuria as a marker for cardiovascular disease has important implications for the identification and treatment of individuals at risk.

The urgent call of albuminuria/proteinuria. Heeding its significance in early detection of kidney disease

Microalbuminuria, one of the earliest indicators of kidney injury, could be a harbinger of progressive kidney failure. Similarly, it can also be one of the early signs that a patient at risk for cardiovascular disease is in fact developing the disease. If so, the patient's therapy is failing. Discussion of specific appropriate interventions are beyond the scope of this article. However, publications referred to in this work have recently discussed such interventions in substantial practical detail. Ample evidence shows that factors that are kidney-protective are also cardiovascular-protective.

Prospective evaluation of a method for estimating ascending aortic pressure from the radial artery pressure waveform

Pressure wave reflection in the upper limb causes amplification of the arterial pulse so that radial systolic and pulse pressures are greater than in the ascending aorta. Wave transmission properties in the upper limbs (in contrast to the descending aorta and lower limbs) change little with age, disease, and drug therapy in adult humans. Such consistency has led to use of a generalized transfer function to synthesize the ascending aortic pressure pulse from the radial pulse. Validity of this approach was tested for estimation of aortic systolic, diastolic, pulse, and mean pressures from the radial pressure waveform. Ascending aortic and radial pressure waveforms were recorded simultaneously at cardiac surgery, before initiation of cardiopulmonary bypass, with matched, fluid-filled manometer systems in 62 patients under control conditions and during nitroglycerin infusion. Aortic pressure pulse waves, generated from the radial pulse, showed agreement with the measured aortic pulse waves with respect to systolic, diastolic, pulse, and mean pressures, with mean differences <1 mm Hg. Control differences in Bland-Altman plots for mean+/-SD in mm Hg were systolic, 0.0+/-4.4; diastolic, 0.6+/-1.7; pulse, -0.7+/-4.2; and mean pressure, -0.5+/-2.0. For nitroglycerin infusion, differences respectively were systolic, -0.2+/-4.3; diastolic, 0.6+/-1.7; pulse, -0.8+/-4.1; and mean pressure, -0.4+/-1.8. Differences were within specified limits of the Association for the Advancement of Medical Instrumentation SP10 criteria. In contrast, differences between recorded radial and aortic systolic and pulse pressures were well outside the criteria (respectively, 15.7+/-8.4 and 16.3+/-8.5 for control and 14.5+/-7.3 and 15.1+/-7.3 mm Hg for nitroglycerin). Use of a generalized transfer function to synthesize radial artery pressure waveforms can provide substantially equivalent values of aortic systolic, pulse, mean, and diastolic pressures.

SELECT: the next prostate cancer prevention trial. Selenum and Vitamin E Cancer Prevention Trial

PURPOSE

Growing evidence implies that selenium and vitamin E may decrease the risk of prostate cancer. The Selenium and Vitamin E Cancer Prevention Trial (SELECT) is a randomized prospective double-blind study designed to determine whether selenium and vitamin E decrease the risk of prostate cancer in healthy men.

MATERIALS AND METHODS

The preclinical and epidemiological evidence regarding chemoprevention with selenium and vitamin E were reviewed. Secondary analyses from randomized trials of the 2 agents were included in the current analysis. Data from these analyses as well as evidence from the Prostate Cancer Prevention Trial were used to develop the SELECT schema.

RESULTS

Preclinical, epidemiological and phase III data imply that selenium and vitamin E have potential efficacy for prostate cancer prevention. The experience of the Prostate Cancer Prevention Trial shows the interest and dedication of healthy men to long-term studies of cancer prevention. A total of 32,400 men are planned to be randomized in SELECT.

CONCLUSIONS

SELECT is the second large-scale study of chemoprevention for prostate cancer. Enrollment in the study is planned to begin in 2001 with final results anticipated in 2013.

Design and baseline characteristics for the ACE Inhibitor After Anthracycline (AAA) study of cardiac dysfunction in long-term pediatric cancer survivors

PURPOSE

The ACE Inhibitor After Anthracycline (AAA) study is a randomized, double-blind, controlled clinical trial comparing enalapril with placebo to determine whether treatment can slow the progression of cardiac decline in patients who screen positive for anthracycline cardiotoxicity.

METHODS

The primary outcome measure is the rate of decline, over time, in maximal cardiac index (in liters per minute per meters squared) at peak exercise; the secondary outcome measure is the rate of increase in left ventricular end systolic wall stress (in grams per centimeters squared). Patients >2 years off therapy and <4 years from diagnosis, aged 8 years and older, were eligible if they had received anthracyclines and had at least one cardiac abnormality identified at any time after anthracycline exposure.

RESULTS

A total of 135 patients were randomized to enalapril or placebo. Baseline characteristics were similar across treatment groups.

CONCLUSIONS

The AAA study will provide important information concerning the efficacy of using angiotensin-converting enzyme inhibitors to offset the effects of late anthracycline cardiotoxicity.

What is the optimal strategy to intensify blood pressure control and prevent progression of renal failure?

Recent clinical trials clearly demonstrate that patients with diabetes and hypertension, and patients with renal disease and hypertension, should have their blood pressure lowered intensively. A recent analysis of long-term clinical trials over the past 8 years clearly demonstrates that the lower the blood pressure over a range of values, the greater the preservation of renal function. It is also readily apparent that monotherapy does not suffice in attaining these more intensified goals. A review of five clinical trials in the recent National Kidney Foundation consensus report demonstrates that patients randomized to the lower level of blood pressure required an average of 3.2 different antihypertensive medications taken daily. Consequently, it is evident that the question is no longer what the initial preferred monotherapy should be, but rather what should be the optimal drug to add to an angiotensin converting enzyme inhibitor or angiotensin receptor blocker. In this paper we review data from several recent studies clearly indicating that to achieve goal blood pressure in the clinical setting of metabolic disarray and hyperglycemia, long-acting calcium antagonists constitute an excellent add-on agent for enhancing efficacy. We anticipate that the data that will accrue from the IDNT and RENAAL studies will further delineate the renal effects of dihydropyridine calcium antagonists.

Quantifying the interaction between angiotensin-converting enzyme inhibitors and aspirin: are we using the right method?

Angiotensin-converting enzyme (ACE) inhibitors reduce mortality in patients with heart failure and coronary artery disease. Recently, there has been growing concern about the possible interaction between ACE inhibitors and aspirin. Numerous investigators have addressed this issue; however, results are equivocal. Most researchers used a statistical test of interaction, but the use of this method has been criticized. To assess the interaction between ACE inhibitors and aspirin properly, an additive model-more specifically, the Rothman Synergy Index-should be used. Further investigation with this model, however, is needed.

Improvement in blood pressure, arterial stiffness and wave reflections with a very-low-dose perindopril/indapamide combination in hypertensive patient: a comparison with atenolol

International guidelines recommend that antihypertensive drug therapy should normalize not only diastolic (DBP) but also systolic blood pressure (SBP). Therapeutic trials based on cardiovascular mortality have recently shown that SBP reduction requires normalization of both large artery stiffness and wave reflections. The aim of the present study was to compare the antihypertensive effects of the very-low-dose combination indapamide (0.625 mg) and perindopril (2 mg) (Per/Ind) with the beta-blocking agent atenolol (50 mg) to determine whether Per/Ind decreases SBP and pulse pressure (PP) more than does atenolol and, if so, whether this decrease is predominantly due to reduction of aortic pulse wave velocity (PWV) (automatic measurements) and reduction of wave reflections (pulse wave analysis, applanation tonometry). In a double-blind randomized study, 471 patients with essential hypertension were followed for 12 months. For the same DBP reduction, Per/Ind decreased brachial SBP (-6.02 mm Hg; 95% confidence interval, -8.90 to -3.14) and PP (-5.57; 95% confidence interval, -7.70 to -3.44) significantly more than did atenolol. This difference was significantly more pronounced for the carotid artery than for the brachial artery. Whereas the 2 antihypertensive agents decreased PWV to a similar degree, only Per/Ind significantly attenuated carotid wave reflections, resulting in a selective decrease in SBP and PP. The very-low-dose combination Per/Ind normalizes SBP, PP, and arterial function to a significantly larger extent than does atenolol, a hemodynamic profile that is known to improve survival in hypertensive populations with high cardiovascular risk.

[Cerebral complications of hypertension in the elderly]

PURPOSE

This review focuses on cerebral complications of hypertension, which include stroke, impairment of cognitive function, dementia, and possibly depression and anxiety. These conditions are major causes of morbidity and mortality in the elderly.

CURRENT KNOWLEDGE AND KEY POINTS

Not only elevated diastolic blood pressure, but also isolated systolic hypertension and elevated pulse pressure play an important role in the development of brain complications. Randomised placebo-controlled trials have provided evidence that reduction of hypertension decreases safely and effectively morbidity and mortality rates in the elderly. The new classes of drugs, in particular calcium-channels blockers and angiotensin-converting enzyme inhibitors, have been shown to be as effective as the originally used diuretics and beta-blockers.

FUTURE PROSPECTS AND PROJECTS

Several trials are currently in progress and should provide more information on the benefit of antihypertensive treatment in very elderly persons (Hypertension in the Very Elderly Trial, HYVET) and secondary prevention of stroke (PROGRESS). The importance of assessing new dosages of the presently used antihypertensive drugs as well as the benefit of new classes of drugs is emphasised. Further trials specifically focusing on the prevention of dementia by antihypertensive drugs are needed to confirm the results of the Syst-Eur Vascular Dementia Project. The benefit of calcium antagonists in the prevention of dementia in elderly hypertensive patients should be assessed in the Dementia Prevention in Hypertension trial (DEPHY).

Evaluation of the use of evidence-based angiotensin-converting enzyme inhibitor criteria for the treatment of congestive heart failure: opportunities for pharmacists to improve patient outcomes

BACKGROUND

The under-utilization and under-dosing of angiotensin-converting enzyme inhibitors (ACEIs) in patients with congestive heart failure (CHF) continues to be a problem observed in clinical practice.

OBJECTIVE

To develop and implement drug use evaluation (DUE) criteria for the use of ACEIs in patients with CHF which could be used by pharmacists to ensure that all eligible patients receive an ACEI at an appropriate dose.

METHODS

A retrospective chart review of all patients discharged from the study institution with a diagnosis of CHF during the period of March 1 to July 31, 1998 was conducted using the DUE criteria developed.

RESULTS

Of the 138 patients evaluated, only 68.6% were discharged on ACEI therapy. Additionally, only 40% of those discharged on an ACEI achieved target dose. Multiple regression analysis revealed that males were 2.43 times more likely to be discharged on an ACEI than females, while those on concomitant diuretics or digoxin were less likely to be discharged on an ACEI (25% and 18%, respectively).

CONCLUSIONS

The application of these DUE criteria by pharmacists in hospital and community practice has the potential to improve utilization and dosing of this important class of medications for the management of the symptoms and progression of CHF.

Acute myocardial infarction: patent or die?

The treatment of acute myocardial infarction (AMI) has changed dramatically over the past 15 years. In this issue (p. 617), Dr Gershlick presents an excellent review of strategies available to promote coronary artery patency in AMI, highlighting the limitations of thrombolytic therapy. In particular, he criticizes the preoccupation with door to needle or pain to needle time. Is there really more to optimizing myocardial salvage than timely thrombolysis?

Hypertension in menopausal women--a special case, for special treatment?

After the menopause the consequences of hypertension in women change. Their risks of myocardial infarction and stroke rise steeply, a rise that has been blamed in part on the loss of estrogen and the onset of menopausal metabolic syndrome, with endothelial dysfunction, hyperlipidemia, insulin resistance and derangement in coagulation. Hypertensive menopausal women have not had optimum treatment. They have poorer prognoses than men of the same age. Their antihypertensive management therefore merits special attention. Hormone replacement, aspirin prophylaxis and lipid-lowering drugs have their place. The antihypertensive drug chosen should not worsen the metabolic syndrome: angiotensin-II converting enzyme (ACE) inhibitors are therefore among the first-line drugs. Few drugs have been specifically aimed at menopausal hypertension and these are reviewed here.

Drugs for cardiovascular risk reduction in the diabetic patient

The diabetic patient is at increased risk for cardiac events. Lowering hemoglobin A1c levels even within the normal range is associated with less cardiac risk. Oral agents for diabetes that reduce insulin resistance and its associated cardiac risk factors in addition to lowering glucose should be used. Energetic reduction of blood pressure with an emphasis on the use of angiotensin-converting enzyme inhibitors and beta blockers will further reduce cardiac risk. Reduction of low-density lipoprotein and triglyceride levels and elevation of high-density lipoprotein levels through judicious use of statins and other anti-lipid agents is essential and will lower the rate of cardiac events in the diabetic patients even more than in the nondiabetic patients. In addition, aspirin and folic acid supplementation should be utilized. Use of a multiple risk factor management strategy with these drugs will lower morbidity and mortality, improve quality of life, and save cost for the diabetic patient.

Randomised trial of a perindopril-based blood-pressure-lowering regimen among 6,105 individuals with previous stroke or transient ischaemic attack

BACKGROUND

Blood pressure is a determinant of the risk of stroke among both hypertensive and non-hypertensive individuals with cerebrovascular disease. However, there is uncertainty about the efficacy and safety of blood-pressure-lowering treatments for many such patients. The perindopril protection against recurrent stroke study (PROGRESS) was designed to determine the effects of a blood-pressure-lowering regimen in hypertensive and non-hypertensive patients with a history of stroke or transient ischaemic attack.

METHODS

6105 individuals from 172 centres in Asia, Australasia, and Europe were randomly assigned active treatment (n=3051) or placebo (n=3054). Active treatment comprised a flexible regimen based on the angiotensin- converting-enzyme inhibitor perindopril (4 mg daily), with the addition of the diuretic indapamide at the discretion of treating physicians. The primary outcome was total stroke (fatal or non-fatal). Analysis was by intention to treat.

FINDINGS

Over 4 years of follow up, active treatment reduced blood pressure by 9/4 mm Hg. 307 (10%) individuals assigned active treatment suffered a stroke, compared with 420 (14%) assigned placebo (relative risk reduction 28% [95% CI 17-38], p<0.0001). Active treatment also reduced the risk of total major vascular events (26% [16-34]). There were similar reductions in the risk of stroke in hypertensive and non-hypertensive subgroups (all p<0.01). Combination therapy with perindopril plus indapamide reduced blood pressure by 12/5 mm Hg and stroke risk by 43% (30-54). Single-drug therapy reduced blood pressure by 5/3 mm Hg and produced no discernable reduction in the risk of stroke.

INTERPRETATION

This blood-pressure-lowering regimen reduced the risk of stroke among both hypertensive and non-hypertensive individuals with a history of stroke or transient ischaemic attack. Combination therapy with perindopril and indapamide produced larger blood pressure reductions and larger risk reductions than did single drug therapy with perindopril alone. Treatment with these two agents should now be considered routinely for patients with a history of stroke or transient ischaemic attack, irrespective of their blood pressure.

Renoprotective effect of the angiotensin-receptor antagonist irbesartan in patients with nephropathy due to type 2 diabetes

BACKGROUND

It is unknown whether either the angiotensin-II-receptor blocker irbesartan or the calcium-channel blocker amlodipine slows the progression of nephropathy in patients with type 2 diabetes independently of its capacity to lower the systemic blood pressure.

METHODS

We randomly assigned 1715 hypertensive patients with nephropathy due to type 2 diabetes to treatment with irbesartan (300 mg daily), amlodipine (10 mg daily), or placebo. The target blood pressure was 135/85 mm Hg or less in all groups. We compared the groups with regard to the time to the primary composite end point of a doubling of the base-line serum creatinine concentration, the development of end-stage renal disease, or death from any cause. We also compared them with regard to the time to a secondary, cardiovascular composite end point.

RESULTS

The mean duration of follow-up was 2.6 years. Treatment with irbesartan was associated with a risk of the primary composite end point that was 20 percent lower than that in the placebo group (P=0.02) and 23 percent lower than that in the amlodipine group (P=0.006). The risk of a doubling of the serum creatinine concentration was 33 percent lower in the irbesartan group than in the placebo group (P=0.003) and 37 percent lower in the irbesartan group than in the amlodipine group (P<0.001). Treatment with irbesartan was associated with a relative risk of end-stage renal disease that was 23 percent lower than that in both other groups (P=0.07 for both comparisons). These differences were not explained by differences in the blood pressures that were achieved. The serum creatinine concentration increased 24 percent more slowly in the irbesartan group than in the placebo group (P=0.008) and 21 percent more slowly than in the amlodipine group (P=0.02). There were no significant differences in the rates of death from any cause or in the cardiovascular composite end point.

CONCLUSIONS

The angiotensin-II-receptor blocker irbesartan is effective in protecting against the progression of nephropathy due to type 2 diabetes. This protection is independent of the reduction in blood pressure it causes.

Effects of losartan on renal and cardiovascular outcomes in patients with type 2 diabetes and nephropathy

BACKGROUND

Diabetic nephropathy is the leading cause of end-stage renal disease. Interruption of the renin-angiotensin system slows the progression of renal disease in patients with type 1 diabetes, but similar data are not available for patients with type 2, the most common form of diabetes. We assessed the role of the angiotensin-II-receptor antagonist losartan in patients with type 2 diabetes and nephropathy.

METHODS

A total of 1513 patients were enrolled in this randomized, double-blind study comparing losartan (50 to 100 mg once daily) with placebo, both taken in addition to conventional antihypertensive treatment (calcium-channel antagonists, diuretics, alpha-blockers, beta-blockers, and centrally acting agents), for a mean of 3.4 years. The primary outcome was the composite of a doubling of the base-line serum creatinine concentration, end-stage renal disease, or death. Secondary end points included a composite of morbidity and mortality from cardiovascular causes, proteinuria, and the rate of progression of renal disease.

RESULTS

A total of 327 patients in the losartan group reached the primary end point, as compared with 359 in the placebo group (risk reduction, 16 percent; P=0.02). Losartan reduced the incidence of a doubling of the serum creatinine concentration (risk reduction, 25 percent; P=0.006) and end-stage renal disease (risk reduction, 28 percent; P=0.002) but had no effect on the rate of death. The benefit exceeded that attributable to changes in blood pressure. The composite of morbidity and mortality from cardiovascular causes was similar in the two groups, although the rate of first hospitalization for heart failure was significantly lower with losartan (risk reduction, 32 percent; P=0.005). The level of proteinuria declined by 35 percent with losartan (P<0.001 for the comparison with placebo).

CONCLUSIONS

Losartan conferred significant renal benefits in patients with type 2 diabetes and nephropathy, and it was generally well tolerated.

Attenuated myocardial vasodilator response in patients with hypertensive hypertrophy revealed by oxygenation-dependent magnetic resonance imaging

BACKGROUND

Oxygen (O(2)) homeostasis is central to myocardial tissue functioning, and increased O(2) demand is thought to be satisfied by a vasodilatory mechanism that results in increased blood and O(2) delivery. We applied blood oxygenation level-dependent (BOLD) MRI in conjunction with vasodilatory stress to index the ability to augment intramyocardial oxygenation in hypertensive hypertrophy, the primary cause of heart failure.

METHODS AND RESULTS

Nine healthy controls and 10 hypertensive subjects with moderate-to-severe hypertrophy underwent imaging on a 1.5 T clinical scanner. The dipyridamole-induced change in the apparent transverse relaxation rate, R2*, which correlates with hemoglobin oxygenation, was -5.4+/-2.2 s(-1) (95% CI, -4.0 to -6.8 s(-1)) in controls compared with -1.7+/-1.4 s(-1) (95% CI, -0.8 to -2.6 s(-1)) in hypertensive patients (P=0.0003).

CONCLUSIONS

Patients with hypertensive hypertrophy demonstrate an impaired ability to increase intramyocardial oxygenation during vasodilatory stress, as indexed by BOLD MRI. The capacity to image vascular function with BOLD MRI may advance the understanding of the development of ventricular dysfunction in hypertension.

Perioperative cardiac complications

Although infrequent, perioperative cardiac complications are a source of major morbidity and mortality. As the population ages, the prevalence of cardiovascular disease is increasing. For physicians who refer patients for surgery as well as for clinicians directly involved in perioperative medical care, an understanding of perioperative cardiac complications, reduction of such complications, and treatment of complications is essential. This article summarizes the approach to perioperative hypertension, hypotension, myocardial ischemia, myocardial infarction, and congestive heart failure.

Pathophysiology and treatment of the dyslipidemia of insulin resistance

Insulin resistance, and the compensatory hyperinsulinemia that results, has been linked to a host of defects including glucose intolerance, diabetes, hypertension, dyslipidemia, endothelial dysfunction, impaired fibrinolysis, and subclinical inflammation. Patients with this metabolic syndrome have a markedly increased risk for the development of atherothrombotic cardiovascular disease. The characteristic dyslipidemia of insulin resistance consists of elevated triglyceride and triglyceride-rich lipoprotein levels, low levels of high-density lipoprotein cholesterol, and increased concentrations of small, dense low-density lipoprotein cholesterol. Management of this dyslipidemia typically involves a dual approach. Lifestyle modification is an essential component of any successful treatment plan, but alone is usually insufficient to correct these lipoprotein abnormalities. Medications that diminish insulin resistance and directly alter lipoproteins are also necessary in the majority of cases. Combinations of therapeutic agents are often required to optimize attainment of treatment goals.