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

Obtaining event status at the close of the Treatment of Mild Hypertension Study: methods and implication for other trials

The Treatment of Mild Hypertension Trial was a randomized, double-blind clinical trial conducted from 1986 to 1992 comparing the efficacy of six antihypertensive treatment regimens in 902 participants with stage I hypertension. To satisfy a secondary objective of the study, follow-up information on mortality and cardiovascular morbidity was collected. For this objective the aim was to ascertain the vital and cardiovascular event status as of the last day of the trial. This was accomplished by inviting each participant to attend a closeout visit shortly after the closeout date. In addition to serving as verification of vital status, this visit allowed data collection on nonfatal events that occurred between the last clinic visit and the closeout date. During this visit the patient was unblinded to study medication and given a medical summary of their participation during the trial, as well as a bottle of open-label medication. The advantages of a closeout visit are discussed along with a call for studies to provide clearer definitions of lost to follow-up and censoring times used in life-table analyses, especially when the primary event includes both fatal and nonfatal events. Control Clin Trials 2001;22:56-61

Hypothesis: Beta-adrenergic receptor blockers and weight gain: A systematic analysis

One of the arguments put forward against the primary use of beta-blockers has been concern about adverse metabolic effects, such as unfavorable effects on lipids or insulin sensitivity. Another less-appreciated potential drawback is their propensity to cause weight gain in some patients. In 8 evaluable prospective randomized controlled trials that lasted >/=6 months, body weight was higher in the beta-blocker than in the control group at the end of the study. The median difference in body weight was 1.2 kg (range -0.4 to 3.5 kg). A regression analysis suggested that beta-blockers were associated with an initial weight gain during the first few months. Thereafter, no further weight gain compared with controls was apparent. There was no relationship between demographic characteristics and changes in body weight. Based on these observations, the first-line use of beta-blockers in obese hypertensive patients should be reviewed. Obesity management in overweight hypertensive patients may be more difficult in the face of beta-blocker treatment.

Workshop: mechanisms and cardiovascular damage in hypertension

Angiotensin (Ang) II is considered a regulatory hormone stimulating vascular smooth muscle cell constriction, aldosterone release from the adrenal gland, and sodium reabsorption in the renal tubule. Furthermore, Ang II may be formed and act locally as a chemokine, inducing tyrosine phosphorylation, cell growth, hypertrophy, and differentiation. In addition, evidence has recently accrued showing that Ang II is important in stimulating the production of reactive oxygen species and the activation of ancient inflammatory mechanisms. The transcription factor nuclear factor kappa-B is pivotal to these processes. Nuclear factor kappa-B activation stimulates the expression of a gene menagerie important to chemoattraction, surface adhesion molecule expression, coagulation, and inflammation. Anti-inflammatory interventions may have therapeutic utility.

Angiotensin II induces migration and Pyk2/paxillin phosphorylation of human monocytes

Angiotensin (Ang) II has been shown to enhance the development of atherosclerotic lesions. Migration of monocytes is an early critical step in the atherosclerotic process. To elucidate mechanisms by which Ang II promotes atherogenesis, we investigated its effects on human monocyte migration. Ang II induced migration of human peripheral blood monocytes (HPBM) and human THP-1 monocytes at concentrations between 0.01 and 1 micromol/L, with a 3.6+/-0.6-fold induction in HPBM and a 4.8+/-0.9-fold induction in THP-1 cells at 1 micromol/L Ang II (both P<0.01 versus unstimulated cells). Addition of the Ang II receptor type 1 (AT1-R) antagonist losartan (1 to 100 micromol/L) suppressed Ang II-induced migration of HPBM and THP-1 monocytes in a dose-dependent manner, demonstrating an AT1-R-mediated mechanism. Ang II-directed migration was also blocked by the Src kinase inhibitor PP2 (10 micromol/L), by the extracellular-regulated protein kinase (ERK 1/2) inhibitor PD98059 (30 micromol/L), and by the p38-MAPK inhibitor SB203580 (10 micromol/L), indicating that Src, ERK 1/2, and p38 are all involved in Ang II-induced migration of HPBM and human THP-1 monocytes. The proline-rich tyrosine kinase 2 (Pyk2) and paxillin are 2 cytoskeleton-associated proteins involved in cell movement, phosphorylated by Ang II in other cell types, and abundantly expressed in monocytes. Ang II (1 micromol/L) induced Pyk2 and paxillin phosphorylation in human THP-1 monocytes, peaking after 10 minutes for Pyk2 with a 6.7+/-0.9-fold induction and after 2 minutes for paxillin with a 3.2+/-0.4-fold induction. Ang II-induced phosphorylation of both proteins was suppressed by losartan and the Src inhibitor PP2, whereas no effect was observed with PD98059 and SB203580. This study demonstrates a novel proatherogenic action of Ang II on human monocytes by stimulating their migration, through an AT1-R-dependent process, involving signaling through Src, ERK 1/2, and p38. Furthermore, the promigratory actions of Ang II in human monocytes are associated with the phosphorylation of 2 cytoskeleton-associated proteins, Pyk2 and paxillin.

Antioxidants and endothelial dysfunction in hyperlipidemia

Endothelial function is abnormal in a variety of diseased states such as hypercholesterolemia and atherosclerosis. This may be secondary to decreased synthesis of nitric oxide (NO) and/or increased degradation of NO due to interaction with superoxide anions. More recent experimental observations demonstrate increased production of superoxide in hyperlipidemia, suggesting that endothelial dysfunction in these states is in part secondary to increased NO metabolism. Enzymes proposed to be involved in increased superoxide production may include xanthine oxidase, the NO synthase, and the NAD(P)H oxidase. Superoxide rapidly reacts with NO to form peroxynitrite (ONOO-), a highly reactive intermediate with cytotoxic properties. Despite experimental evidence for the oxidative stress concept in causing endothelial dysfunction, the results of recent randomized trials to test the influence of antioxidants on coronary event rates and prognosis in patients with coronary artery disease were very disappointing. In all of these studies the use of vitamins such as vitamin E failed to improve the prognosis. In contrast, treatment with angiotensin converting enzyme inhibitors or cholesterol- lowering drugs improved endothelial dysfunction, prevented the activation of superoxide-producing enzymes in cholesterol-fed animals, reduced coronary event rates, and improved prognosis in patients with coronary artery disease. Therefore, inhibition of superoxide production at the enzymatic level rather than symptomatic superoxide scavenging may be the better choice of treatment.

Coronary Artery Disease in Postmenopausal Women

Many important developments recently have been made in the treatment and prevention of coronary artery disease (CAD) in postmenopausal women. Substantial evidence supports focusing on comprehensive risk factor modification based on the "ABCs" of CAD management from the American College of Cardiology, the American Heart Association, and the American College of Physicians-American Society of Internal Medicine guidelines on chronic stable angina. This approach emphasizes cardiovascular risk factor interventions that include antiplatelet agents, angiotensin-converting enzyme (ACE) inhibitors, beta-blockers, cholesterol-lowering medications, diabetes control, and counseling on diet and exercise. Despite the expanding available literature, many questions on CAD in postmenopausal women remain unanswered and await the publication of ongoing and future research. The unexpected findings from the HERS (Heart and Estrogen/progestin Replacement Study) failed to show a benefit of hormone replacement therapy (HRT) in reducing the risk of subsequent events in postmenopausal women with CAD, and instead reported an early increase in CAD events. Based on the data available so far, we advise against starting HRT in postmenopausal women with a recent coronary event for the sole purpose of CAD prevention. For women with acute coronary syndromes, prompt angiography and revascularization should be considered.

[Drug prospects in the treatment of heart insufficiency]

Pharmacological and validated treatment of chronic heart failure (HF) includes successively angiotensin converting enzyme inhibitors (ACEi), beta-blockers and antialdosterone, which is associated with diuretics. The effectiveness of this manner in which to block more and more hormonal systems demonstrate the validity of the "hormonal" paradigm to explain heart failure. Therefore broader educational means are required to increase the prescription of these drugs for HF. Several questions about these drugs remain unresolved: HF with preserved systolic function and elderly patients, class effect, and the role of antagonists of angiotensin II receptors (as an alternative or associated with ACEi). Other short- and mid-term pharmacological perspectives target target hormonal systems and cytokines: endothelin-receptor antagonists, inhibition of natriuretic peptide degradation (via neutral endopeptidase), and newer drugs acting against TNF such as etanercept. Moreover, recent knowledge about molecular mechanisms of myocardium remodeling allows new drug strategies with target more specifically remodeling such as metalloproteinases. Finally, these perspectives should be largely modified by on-going research in the field of genomics.

Paradoxical regulation of short promoter human renin transgene by angiotensin ii

We previously reported the generation of transgenic mice containing the entire human renin gene with a 900-bp promoter. To determine whether all the required elements for angiotensin II-mediated suppression of human renin are present in these mice, angiotensin II was chronically infused by means of osmotic minipump at both low and high doses, 200 and 1000 ng/kg per minute, respectively. Blood pressure was measured by tail-cuff, and kidney renin mRNA levels were quantitated using ribonuclease protection assays. Blood pressure was unchanged in mice receiving either vehicle or low-dose angiotensin II infusion but was increased by approximately 40 mm Hg with the higher dose of angiotensin II. Mouse renin mRNA decreased by >60% during both pressor and nonpressor angiotensin II infusion. Human renin mRNA was not suppressed by nonpressor angiotensin II and was paradoxically increased 1.9-fold by pressor angiotensin II. The lack of upregulation during nonpressor angiotensin II suggested that the increase might be pressure-mediated. To test this, the angiotensin II-induced increase in blood pressure was prevented by coadministration of the vasodilator, hydralazine (15 mg/kg per day). Hydralazine alone decreased blood pressure (-27+/-3 mm Hg) and increased mouse renin mRNA 2.4-fold. Human renin mRNA was unresponsive to this vasodilator-induced fall in pressure and despite the normalization of blood pressure by hydralazine, high-dose angiotensin II still caused a 2.1-fold increase in human renin mRNA. Thus, the first 900 bp of the human renin promoter does not contain all the elements required for appropriate angiotensin II-mediated suppression of human renin mRNA.

Heart failure in the 21st century: a cardiogeriatric syndrome

Chronic heart failure (CHF) is principally a cardiogeriatric syndrome, and it has become a major public health problem in the 21st century due largely to the aging population. Age-related changes throughout the cardiovascular system in combination with the high prevalence of cardiovascular diseases at older age predispose older adults to the development of CHF. Features that distinguish CHF at advanced age from CHF occurring during middle age include an increasing proportion of women, a shift from coronary heart disease to hypertension as the most common etiology, and the high percentage of cases that occur in the setting of preserved left ventricular systolic function. Although the pharmacotherapy of CHF is similar in older and younger patients, the presence of multiple comorbidities in older patients mandates a multidisciplinary approach to care. Manifest CHF is associated with a poor prognosis, especially in elderly persons, and there is an urgent need to develop more effective strategies for the prevention and treatment of this increasingly common disorder to reduce the individual and societal burden of this devastating illness in the decades ahead.

Left ventricle and arteries: structure, function, hormones, and disease

The observation in the 1970s that the performance of the dysfunctional left ventricle was under the influence of aortic impedance led us to exploration of the role of the renin-angiotensin system and other hormonal systems in the progression of heart failure. The apparent efficacy of vasodilator drugs led to the first randomized, controlled trial in heart failure that demonstrated that all impedance-lowering drugs did not exert the same long-term benefit. Differences on the structural remodeling process in the myocardium and arterial vasculature were shown to account for the differential long-term response. We now recognize that the remodeling process in the left ventricle may be inhibited by nitrates, converting enzyme inhibitors, and beta-blockers, and this growth process leads to adverse outcomes. The impedance load on the left ventricle is influenced by vascular remodeling that also may be inhibited by drugs such as converting enzyme inhibitors. Thus, progression of cardiovascular disease is largely a consequence of structural changes that are hormonally mediated and may be inhibited by drug therapy.

Angiotensin, inflammation, hypertension, and cardiovascular disease

We are used to thinking of angiotensin (Ang) II as a regulatory hormone that stimulates constriction of vascular smooth muscle cells, aldosterone release from the adrenal gland, and sodium reabsorption in the renal tubule. We have also become accustomed to understanding that Ang II may be formed and may act locally as a chemokine that induces tyrosine phosphorylation, cell growth, hypertrophy, and differentiation. Viewing Ang II as an inflammatory molecule is stranger still. Nevertheless, recent evidence shows that Ang II is important in stimulating the production of reactive oxygen species and the activation of ancient inflammatory mechanisms. The nuclear factor kappaB (NF-kappaB) is pivotal to these processes. Activation of NF-kappaB stimulates the expression of a gene menagerie that is important to chemoattraction, expression of surface adhesion molecules, coagulation, and inflammation. In addition, Ang II has been shown to regulate cellular immune responses. It stimulates the proliferation of lymphocytes and contributes to their activation via calcineurin-related pathways. Knowledge of these mechanisms may provide additional therapeutic avenues.

Angiotensin II-induced hypertension accelerates the development of atherosclerosis in apoE-deficient mice

BACKGROUND

Angiotensin II may contribute to the development and progression of atherosclerotic lesions because of its growth and proinflammatory effects. We sought to determine whether angiotensin II-induced hypertension would augment and accelerate the development of atherosclerotic lesions in apoE-deficient mice.

METHODS AND RESULTS

Angiotensin II (0.7 mg x kg(-1) x d(-1) SC) was administered to apoE-deficient mice via osmotic minipumps. The animals were placed on either standard chow or an atherogenic diet. After 8 weeks, the mean atherosclerotic lesion area in the descending thoracic and abdominal aortas of animals on a standard chow diet was 0.4+/-0.1% compared with 5.2+/-1.2% in those animals maintained on an atherogenic diet (P:<0.0001). In angiotensin II-treated animals on standard chow, the mean lesion area was increased to 11.0+/-2.3%, which was further increased to 69.9+/-9.4% (P:<0.0001) in angiotensin II-treated animals on an atherogenic diet. Similar findings were obtained when tissues from the ascending aorta were analyzed. At 8 weeks in mice receiving a standard chow diet, angiotensin II dramatically increased the atherosclerotic lesion area by 840+/-83 microm(2) (P:<0.0001). Animals on a high-fat diet had a similar marked increase in lesion area in response to angiotensin II (217+/-19 microm(2), P:<0.0001). In contrast, when hypertension was induced with norepinephrine, only a modest effect on the atherosclerotic lesion area was observed.

CONCLUSIONS

Angiotensin II-induced hypertension specifically increased the development of atherosclerosis in apoE knockout mice. This response was seen in animals receiving either standard chow or an atherogenic diet. These studies demonstrate the profound effect of angiotensin II on the development of atherosclerosis.

Interaction between Aspirin and ACE Inhibitors in Patients with Heart Failure

Both aspirin (acetylsalicylic acid) and ACE inhibitors are often used concomitantly, especially in patients with both heart failure and ischaemic heart disease, which is the most common underlying cause of heart failure. The safety of the association has been questioned because both drugs affect a related prostaglandin-mediated pathway. Thanks to their vasodilating properties, prostaglandins play an important role in heart failure where peripheral vasoconstriction occurs. Some of the beneficial effects of ACE inhibitors might be related to reduced degradation of bradykinin that enhances the synthesis of prostaglandins, while aspirin, through inhibiting the enzyme cyclo-oxygenase, inhibits the production of prostaglandins. To date no prospective study has been conducted to investigate the effect of long term aspirin treatment in the postinfarction period allowing the possible impact of the interaction between aspirin and ACE inhibitors upon survival to be confirmed or negated. However, the practitioner needs to know how to optimise the treatment of his or her patients. In order to stimulate arguments for and against the use of aspirin in patients with heart failure receiving ACE inhibitors, we searched MEDLINE from 1960 to 2000 using the key words heart failure, aspirin, and ACE inhibitors for English language articles and conducted a review of the available data. We report on the potential mechanisms of the interaction and the results of experimental studies on haemodynamic parameters. Results of retrospective clinical studies, subgroup analysis that were undertaken to evaluate the overall action upon haemodynamic parameters and survival of the association are summarised. Conflicting conclusions have been reported in the literature. Many explanations can be advanced to try to understand these conflicting conclusions: differences in study design (results of retrospective trials have to be interpreted with caution); differences in the choice of the evaluation parameter (problem of the clinical relevance of haemodynamic parameters); differences in the characteristics of the patient (different underlying cardiopathy, e.g. heart failure, hypertension or ischaemic cardiopathy); and differences in the type and the dosage of each treatment (especially ACE inhibitors and aspirin since an interaction might occur more often with dosage of aspirin greater than 250mg).

Vascular Effects of ACE Inhibition Independent of the Renin-Angiotensin System in Hypertensive Renovascular Disease : A Randomized, Double-Blind, Crossover Trial

-To evaluate whether ACE inhibition and angiotensin II type 1 blockade exert beneficial effects on NO availability independent of their blood pressure-lowering effect, we used a double-blind crossover design to study vascular function in 18 patients with hypertensive renovascular disease during 6 weeks of therapy with enalapril (Ena) and valsartan (Val) compared with non-renin-angiotensin system-mediated treatment with the alpha(1)-blocker doxazosin (Dox). Control measurements were performed in 13 age-matched volunteers. Forearm blood flow was assessed with venous occlusion plethysmography, and serotonin and nitroprusside were used as endothelium-dependent and -independent vasodilators, respectively. Blood pressure was similar during all treatment periods. Serotonin-induced vasodilation was decreased in patients during Dox treatment (n=12) compared with control subjects (n=13) (increase 42+/-20% versus 107+/-65%, P:<0.05). Crossover from Dox to Val (n=6) had no effect on serotonin response (increase 50+/-14%), but crossover to Ena (n=6) caused a significant improvement (increase 79+/-39%, P:<0.05 versus Dox). In an assessment of all patients, serotonin-induced vasodilation during Ena (n=12, increase 75+/-31%) was increased compared with both Val and Dox (43+/-14% and 42+/-20%, respectively; both P:<0.05 versus Ena). The nitroprusside response remained unaltered during all treatment periods. In conclusion, ACE inhibition improves the impaired endothelium-dependent vascular function in patients with hypertensive renovascular disease. This effect is unrelated to blood pressure-lowering or angiotensin II-mediated effects.

Kinins, receptors, kininases and inhibitors--where did they lead us?

Based on studies presented here and other published experiments performed with surviving tissue preparations, with transfected cells and with cells that constitutively express the human angiotensin I converting enzyme ACE and B2 receptors, we concluded the following: ACE inhibitors and other endogenous peptides that react with the active site of ACE potentiate the effect of bradykinin and its ACE resistant peptide congeners on the B2 receptor. They also resensitize receptors which had been desensitized by the agonist. ACE and bradykinin receptors have to be sterically close, possibly forming a heterodimer, for the ACE inhibitors to induce an allosteric modification on the receptor. When ACE inhibitors augment bradykinin effects, they reduce the phosphorylation of the B2 receptor. The primary actions of bradykinin on the receptor are not affected by protein kinase C or phosphatase inhibitors, but the potentiation of bradykinin or the resensitization of the receptor by ACE inhibitors are abolished by the same inhibitors. The results with protein kinase C and phosphatase inhibitors indicate that another intermediate protein may be involved in the processes of signaling induced by ACE inhibitors, and that ACE inhibitors affect the signal transduction pathway triggered by bradykinin on the B2 receptor.

Diabetes in elderly adults

Diabetes is common in the elderly population. By the age of 75, approximately 20% of the population are afflicted with this illness. Diabetes in elderly adults is metabolically distinct from diabetes in younger patient populations, and the approach to therapy needs to be different in this age group. Diabetes is associated with substantial morbidity from macro- and microvascular complications. Several lines of evidence suggest that optimal glycemic control and risk factor modification can substantially reduce the risk of complications in elderly patients. In the past, treatment options were limited. However, recent studies have delineated several new and exciting therapeutic opportunities for elderly patients with diabetes.

Debate: does it matter how you lower blood pressure?

The evidence base for drug treatment of hypertension is strong. Early trials using thiazide diuretics suggested a shortfall in prevention of coronary heart disease. The superiority of newer drugs has been widely advocated but trial evidence does not support an advantage of beta-blockers, angiotensin converting enzyme inhibitors, calcium channel blockers or alpha-blockers for this outcome. Even meta-analyses have failed to clarify matters. If this issue is to be settled, bigger and better trials of longer duration in high-risk patients are needed. Meanwhile, the importance of rigorous blood pressure control using multiple drugs has been established. This should be the focus of our attention rather than agonising over differences in cause-specific outcomes that may not be generalisable to all patient populations.

What is the optimal medical management of ischaemic heart failure?

Ischaemic heart disease is probably the most important cause of heart failure. All patients with heart failure may benefit from treatment designed to retard progressive ventricular dysfunction and arrhythmias. Patients with heart failure due to ischaemic heart disease may also, theoretically, benefit from treatments designed to relieve ischaemia and prevent coronary occlusion and from revascularisation. However, there is little evidence to show that effective treatments, such as angiotensin converting enzyme (ACE) inhibitors and beta-blockers, exert different effects in patients with heart failure with or without coronary disease. Moreover, there is no evidence that treatment directed specifically at myocardial ischaemia, whether or not symptomatic, or coronary disease alters outcome in patients with heart failure. Some agents, such as aspirin, designed to reduce the risk of coronary occlusion appear ineffective or harmful in patients with heart failure. There is no evidence, yet, that revascularisation improves prognosis in patients with heart failure, even in patients who are demonstrated to have extensive myocardial hibernation. On current evidence, revascularisation should be reserved for the relief of angina. Large-scale, randomised controlled trials are currently underway investigating the role of specific treatments targeted at coronary syndromes in patients who have heart failure. The CHRISTMAS study is investigating the effects of carvedilol in a large cohort of patients with and without hibernating myocardium. The WATCH study is comparing the efficacy of aspirin, clopidogrel and warfarin. The HEART-UK study is assessing the effect of revascularisation on mortality in patients with heart failure and myocardial hibernation. Smaller scale studies are currently assessing the safety and efficacy of statin therapy in patients with heart failure. Only when the results of these and other studies are known will it be possible to come to firm conclusions about whether patients with heart failure and coronary disease should be treated differently from other patients with heart failure due to left ventricular systolic dysfunction.

Anticoagulation and heart failure

There are no clear data regarding whether to use warfarin, aspirin, or no therapy in patients with left ventricular systolic dysfunction. Aspirin use is widespread in patients with vascular disease but it can decrease renal blood flow in low output states. Warfarin may be used in patients with advancing heart failure due to the perceived risk of in situ thromboembolism. However, we know that ejection fraction and symptom class do not always match and that the regulation of warfarin dosing is more difficult in worsening heart failure. Drug use must be individualized, based on knowledge of underlying heart failure etiology, functional class, drug side effects, and renal function. We await ongoing studies to elucidate the differential effects of these drugs on global outcome as well as on the mechanisms by which they achieve their results.

What is the optimal blood pressure in patients with diabetes mellitus?

Cardiovascular disease is the number one cause of death in patients with type 2 diabetes mellitus. This condition leads to an increased risk of premature mortality in patients with ischemic heart disease and stroke. Many risk factors besides hyperglycemia in itself contribute to this increased risk, acting in a synergistic fashion. One of the most important risk factors is hypertension. Several recent clinical trials have shown the benefits of reducing high blood pressure in patients with diabetes mellitus to lower levels than have previously been recommended in clinical guidelines. In both the United Kingdom Prospective Diabetes Study (UKPDS) and the Hypertension Optimal Treatment (HOT) study a significant trend for increased benefits associated with lower diastolic blood pressure levels was shown. Therefore, clinicians should be encouraged to do more to treat hypertension in patients with type 2 diabetes mellitus and increase the proportion of patients in whom acceptable blood pressure control is achieved. For example, in Sweden, acceptable blood pressure control is currently only achieved in about 20 to 25% of patients with type 2 diabetes mellitus. Recent evidence also points to the primary importance of a tight blood pressure control. This implies drug combination treatment for the majority of patients. Therefore, the clinician must be able to use a broad variety of antihypertensive drugs, and from these drugs choose alternative combinations with pharmacological synergism.

Baseline Characteristics of Participants in the Antihypertensive and Lipid Lowering Treatment to Prevent Heart Attack Trial (ALLHAT)

-Diuretics and ss-blockers have been shown to reduce the risk of cardiovascular morbidity and mortality in people with hypertension in long-term clinical trials. No study has compared newer more costly antihypertensive agents (calcium antagonists, ACE inhibitors, and alpha-adrenergic blockers) with diuretics for reducing the incidence of cardiovascular disease in an ethnically diverse group of middle-aged and elderly hypertensive patients. The study is a randomized, double-blind, active-controlled clinical trial designed to determine whether the incidence of the primary outcome, fatal coronary heart disease or nonfatal myocardial infarction, differs between treatment initiation with a diuretic versus each of 3 other antihypertensive drugs. Men and women aged >/=55 years with at least 1 other cardiovascular disease risk factor were randomly assigned to chlorthalidone (12.5 to 25 mg/d), amlodipine (2.5 to 10 mg/d), lisinopril (10 to 40 mg/d), or doxazosin (2 to 8 mg/d) for planned follow-up of 4 to 8 years. This report describes the baseline characteristics of the Antihypertensive and Lipid Lowering Treatment to Prevent Heart Attack Trial (ALLHAT) participants. A total of 42 448 participants were randomized from 625 sites in the United States, Canada, Puerto Rico, and the US Virgin Islands. The mean age was 67 years, with 35% aged >/=70 years. Among those randomized, 36% were black, 19% were Hispanic, and 47% were women. The sample includes a high proportion of people with diabetes (36%), patients with existing cardiovascular disease (47%), and smokers (22%). There were no important differences between the randomized treatment groups at baseline. ALLHAT will add greatly to our understanding of the management of hypertension by providing an answer to the following question: are newer antihypertensive agents similar, superior, or inferior to traditional treatment with diuretics?

No effects on myocardial ischaemia in patients with stable ischaemic heart disease after treatment with ramipril for 6 months

OBJECTIVE: To assess the effects of a 6-month angiotensin-converting enzyme (ACE) inhibitor intervention on myocardial ischaemia. METHOD: We randomized 389 patients with stable coronary artery disease to double-blind treatment with ramipril 5 mg/day (n = 133), ramipril 1.25 mg/day (n = 133), or placebo (n = 123). Forty-eight-hour ambulatory electrocardiography was performed at baseline, and after 1 and 6 months. RESULTS: Relevant baseline variables were similar in all groups. Changes over 6 months in duration of >/= 1 mm ST-segment depression (STD), total ischaemic burden and maximum STD did not differ significantly between the treatment groups. There was no difference in the frequency of adverse events between the groups. CONCLUSION: ACE inhibitor treatment has little impact on incidence and severity of myocardial ischaemia in patients with stable ischaemic heart disease.

Heart failure therapy at the turn of the century

Major changes in the treatment of heart failure have occurred in the last fifty years that have had a dramatic effect on its morbidity and mortality. Over two hundred years have passed since the demonstration of the benefit of digitalis in heart failure to the development of potent loop diuretics. The observation that vasodilators could improve both cardiac function and mortality led to the investigation of the Angiotensin Converting Enzyme Inhibitors (ACEI). Although these agents had significant vasodilator properties, their major benefit appears to be related to their ability to effect remodeling of the failing left ventricle. The most recent randomized clinical trials demonstrate that Beta Adrenergic Blocking agents can provide an incremental effect on both mortality and morbidity when added to therapy with ACEI. Although these agents have improved the outlook for the heart failure patient, they have had very little effect on the improvement of left ventricular function. Future research must be directed at methods to deal with this issue by either changing the contractile properties of the cardiomyocyte by pharmacologic or electrical therapy or by transplanting functional cells that can increase the number of functioning contractile units.

The kidney in diabetes: how to control renal and related cardiovascular complications

The clear-cut and detailed pathogenesis of diabetic renal disease is not yet elucidated, but it is clear that both initiation and progression of renal disease in diabetes is related to glycemic control and blood pressure (BP) regulation, also seen in intervention studies. Consequently, optimal control of glycemia and antihypertensive treatment have become the cornerstones in the management of patients with diabetes. Naturally, modulating factors need to be discussed in further detail. The genetics of diabetes and its renal complications are still very complex issues that need to be explored further. Few and inconclusive data are available with respect to clinical management, for which genotyping is not required. Dietary protein content has long been an interesting avenue for possible treatment, but to date, data from patients with nondiabetic renal disease and with diabetes are not totally convincing, although further results may be published very soon. The issue is also complex because a low-protein diet may increase BP according to new studies, rendering the issue of low-protein content in the diet still more complex and controversial. Metabolic issues remain a key question, specifically with regard to glycemic control, in which data have accumulated over the past decade from epidemiological and interventional studies. There is no doubt that optimal glycemic control is crucial, but issues regarding specific glucose-related mechanisms and protein and lipid metabolism are still under investigation. The renin-angiotensin system has emerged as a key issue in diabetes, especially with regard to its inhibition by angiotensin-converting enzyme (ACE) inhibition and angiotensin-receptor blockade. New studies suggest that more complete inhibition of this system by dual blockade may be an avenue for further study according to positive results in patients with microalbuminuric type 2 diabetes, who are at great risk. Antihypertensive treatment still remains a fundamental component, although the metabolic effects of some antihypertensive agents may be important, especially with respect to diuretics, ss-blockers, and possibly alpha-blockers. The situation becomes complex with the frequent combination of various agents in the treatment of hypertension in patients with diabetes. Conversely, ACE inhibitors may have some diabetes-protective effect, but further studies are needed.

Should an angiotensin-converting enzyme inhibitor be standard therapy for patients with atherosclerotic disease?

Angiotensin-converting enzyme (ACE) inhibitors appear to possess unique cardioprotective benefits, even when used in patients without high blood pressure or left ventricular dysfunction (the traditional indications for ACE inhibitor therapy). The ACE inhibitors improve endothelial function and regress both left ventricular hypertrophy and arterial mass better than other antihypertensive agents that lower blood pressure equally as well. These agents promote collateral vessel development and improve prognosis in patients who have had a coronary revascularization procedure (i.e., percutaneous transluminal coronary angioplasty and coronary artery bypass graft surgery). Insulin resistance, present not only in type 2 diabetes but also commonly in patients with hypertension or coronary artery disease, or both, sensitizes the vasculature to the trophic effects of angiotensin II and aldosterone. This may partly explain the improvement in prognosis noted when patients who have atherosclerosis or diabetes are treated with an ACE inhibitor. Therapy with ACE inhibitors has also been shown, in two large, randomized trials, to reduce the incidence of new-onset type 2 diabetes through largely unknown mechanisms. The ACE inhibitors are safe, well tolerated and affordable medications. The data suggest that most people with atherosclerosis should be considered candidates for ACE inhibitor therapy, unless they are intolerant to the medication, or have systolic blood pressures consistently <100 mm Hg. Patients who show evidence of insulin resistance (with or without overt type 2 diabetes) should also be considered as candidates for prophylactic ACE inhibitor therapy. Although angiotensin receptor blockers should not be considered equivalent to ACE inhibitors for this indication, they may be a reasonable alternative for patients intolerant of ACE inhibitors.

Comments on ALLHAT and doxazosin

This commentary has two purposes: to summarize the rationale, design and initial results of the Antihypertensive and Lipid Lowering Treatment to Prevent Heart Attack Trial (ALLHAT) trial; and to provide a history of the response to ALLHAT that led to a civil action and a Citizens Petition that was the basis for a public hearing by the US Food and Drug Administration, in May 2001. The author concludes that the results of ALLHAT should be widely disseminated. All clinicians must be warned that initial therapy with doxazosin (and possibly other alpha1 blockers) is definitely inferior to low dose diuretic treatment for patients at high risk for cardiovascular disease, such as those enrolled in ALLHAT.

Diuretics: again the first step in the treatment of most patients with hypertension

The results and interpretations of the most recent controlled clinical trials on antihypertensive drugs have fuelled the debate about the drug that should be used to begin treatment for hypertension. Every comparison of diuretics with other drugs has shown that the benefits of diuretics are equivalent to, or better than, other options. These findings, together with other practical reasons, such as left ventricular mass reducing effect, easy administration, few side effects and low cost, suggest that diuretics should regain their primacy as the first step in drug management of hypertension.

The impact of heart failure on prognosis of diabetic and non-diabetic patients with myocardial infarction: a 15-year follow-up study

BACKGROUND

Information about the occurrence of heart failure in the acute phase of myocardial infarction (MI) in diabetic patients and its impact on prognosis are sparse.

AIM

The purpose of the present study was to describe how MI patients with diabetes mellitus (DM) differed from MI patients without DM with respect to the occurrence of heart failure and with respect to the influence of heart failure on mortality during follow-up 30 days extending to 15 years.

METHODS

The study is a retrospective long-term follow-up of prospectively recorded data concerning 1954 consecutive cases of MI admitted to one coronary care unit (CCU) between 1979 and 1983. DM was diagnosed in 10% (n=194), with 17% (n=33) on insulin therapy. Patients with DM comprised of a higher proportion of women (DM 36% vs. no DM 26%, P<0.001) compared with non-diabetic patients. Baseline risk factors were more prevalent in the patients with DM. The cumulative incidence of heart failure was higher among patients with than without DM (DM 54% vs. no DM 34%, P<0.001). The incidence of life-threatening arrhythmias were similar in both groups. Only 2% of patients with DM and heart failure survived 10 years of follow-up compared with 15% of the non-diabetic patients with heart failure (P<0.001). In multivariate analysis DM was not independently associated with 30 days mortality. During long-term follow-up DM was an important risk factor for mortality independent on the presence of heart failure.

CONCLUSION

DM disposes to the development of heart failure. In acute myocardial infarction diabetic patients with heart failure have a worse prognosis than non-diabetic patients with heart failure.

Coronary capillary remodeling in non-insulin-dependent diabetic rats: amelioration by inhibition of angiotensin converting enzyme and its potential clinical implications

Using Otsuka Long Evans Tokushima Fatty (OLETF) rats, a model of human non-insulin-dependent diabetes mellitus (NIDDM) that exhibits hypertension, obesity, hyperglycemia and hyperlipidemia, the role of local angiotensin II in cardiovascular complications at early stages of NIDDM was characterized. OLETF rats were given an angiotensin converting enzyme (ACE) inhibitor, cilazapril (10 mg/kg/day) or vehicle from the age of 5 weeks to 20 weeks. Arteriolar, intermediate and venular capillary proportions were determined by the double-staining method and levels of collagen and non-collagenous proteins were determined by the selective dye-binding method in heart tissues. In OLETF rats at 20 weeks of age, capillary network remodeling (i.e., an increase in arteriolar portions and a decrease in venular portions) and an increase in collagen content were detected. Cilazapril not only exerted favorable effects on markers of diabetes, but also prevented capillary network remodeling and ameliorated the increase in collagen content. These results suggest that 1) capillary network remodeling and increase in extracellular matrix protein levels precede the onset of overt NIDDM in OLETF rats, and 2) angiotensin II may be involved in the pathogenesis of cardiac complications in the early stages of NIDDM.

Diabetes

The causes of accelerated atherogenesis in diabetes are unclear but the consequences in terms of cardiovascular morbidity and mortality are profound. Thus diabetes not only increases the risk of coronary heart disease but also increases the case fatality rate, ensuring that the majority of patients die of cardiovascular causes, often before the age of 50 years. The problem is compounded by autonomic neuropathy which alters the perception of cardiac pain, attenuating symptoms which are often atypical or absent. This may delay presentation or lead to inappropriate triage decisions such that access to defibrillators and specific treatment is denied. Central to the cardiovascular management of diabetes is vigorous risk factor modification although clear evidence that this leads to extra protection against coronary heart disease beyond that achieved in non-diabetic individuals has not been forthcoming. In other respects too, the management of diabetic patients with heart disease is underpinned by the same evidence-base as applies to non-diabetic patients, and it is noteworthy that 15-20% of the patients in most of the landmark clinical trials have been diabetic. Recently, however, trials such as the United Kingdom Prospective Diabetes Study (UKPDS), the Heart Outcomes Prevention Evaluation (HOPE) study, and the Diabetes Mellitus, Insulin Glucose Infusion in Acute Myocardial Infarction (DIGAMI) study have identified novel strategies for reducing cardiovascular risk in diabetes. These trials have already had a major impact on cardiological practice, emphasising the prime importance of blood pressure control and converting enzyme inhibition for reducing cardiovascular risk in diabetes as well as the value of insulin therapy for reducing mortality in diabetic myocardial infarction. Additional trials, already in progress, are expected to refine further the cardiovascular management of patients with diabetes in order to provide an effective challenge for a problem that shows no signs of going away.

Antiatherosclerotic effects of ACE inhibitors: where are we now?

ACE inhibitors have been used extensively in the management of patients with hypertension and heart failure. Over the past decade, a large body of evidence has emerged indicating that ACE inhibition also favorably affects the vasculature, and that these effects are associated with improved patient outcomes. Such evidence is provided by several sources: (i) experimental studies, which demonstrate that in addition to blood pressure lowering, ACE inhibitors improve endothelial function and have a host of other beneficial effects on the arterial wall; (ii) epidemiologic studies, which link the renin-angiotensin-aldosterone system to increased risk for myocardial infarction, and (iii) clinical trials, which demonstrate that treatment with these agents reduces the risk for acute ischemic events, improves the function of the arterial endothelium and can retard the progression of the anatomic extent of atherosclerosis.

Antioxidant vitamins and enzymatic and synthetic oxygen-derived free radical scavengers in the prevention and treatment of cardiovascular disease

Oxygen-derived free radical formation can lead to cellular injury and death. Under normal situations, the human body has a free radical scavenger system (catalase, superoxide dismutase) that can detoxify free radicals. Antioxidant vitamins and enzymatic and synthetic oxygen-derived free radical scavengers have been used clinically to prevent the formation of oxidized LDL and to prevent reperfusion injury, which is often caused by free radicals. In this article, the pathogenesis of free radical production and cell injury are discussed, and therapeutic approaches for disease prevention are presented.

How long should angiotensin-converting enzyme inhibitors be given to patients following myocardial infarction: implications of the HOPE trial

Long-term treatment with angiotensin-converting enzyme inhibitors reduces post-infarction morbidity and mortality in patients with left ventricular (LV) systolic dysfunction or symptomatic heart failure. Until recently, the effect of such treatment in patients with preserved LV function has not been known. The results from the Heart Outcome Prevention Evaluation trial have indicated that long-term treatment with ramipril leads to a significant reduction in cardiovascular events in patients with atherosclerotic disease, including those with prior myocardial infarction and preserved LV function. These results suggest that long-term angiotensin-converting enzyme inhibition should also be considered in post-infarction patients with normal cardiac function.