Angiotensin Receptor Blockers versus ACE Inhibitors: Prevention of Death and Myocardial Infarction in High-Risk Populations

One Molecule, Many Faces: Repositioning Cardiovascular Agents for Advanced Wound Healing

Chronic wound treatments pose a challenge for healthcare worldwide, particularly for the people in developed countries. Chronic wounds significantly impair quality of life, especially among the elderly. Current research is devoted to novel approaches to wound care by repositioning cardiovascular agents for topical wound treatment. The emerging field of medicinal products' repurposing, which involves redirecting existing pharmaceuticals to new therapeutic uses, is a promising strategy. Recent studies suggest that medicinal products such as sartans, beta-blockers, and statins have unexplored potential, exhibiting multifaceted pharmacological properties that extend beyond their primary indications. The purpose of this review is to analyze the current state of knowledge on the repositioning of cardiovascular agents' use and their molecular mechanisms in the context of wound healing.

Comparative effectiveness of ACE inhibitors and angiotensin receptor blockers in patients with prior myocardial infarction

Objective

Although ACE inhibitors (ACEIs) and angiotensin receptor blockers (ARBs) are commonly prescribed for patients with coronary artery disease, whether these medications are similarly effective is still a subject of intense debate. Our objective was to compare the clinical effectiveness of ACEIs and ARBs in patients with prior myocardial infarction (MI).

Methods

All residents older than 65 years, alive on 1 April 2012, with a prior MI were included. Propensity weighting was used to balance potentially confounding baseline covariates between the treatment groups. The primary outcome was a composite of cardiovascular death, hospitalisation for MI or unstable angina at 3 years.

Results

Our cohort included 59 353 patients with MI; their mean age was 77 years and 40% were women. In the propensity-weighted cohort, the primary outcome occurred in 6.5% in the ACEI group and 5.7% in the ARB group at 1 year (HR comparing ACEI with ARB 1.14, 95% CI 1.05 to 1.23, p<0.001). At 3 years, the primary outcome occurring in 16.0% with ACEIs and 15.1% with ARBs (HR 1.07; 95% CI 1.02 to 1.12; p<0.001). A significant interaction with sex was observed, with women prescribed ACEIs having a higher hazards (HR 1.17; 95% CI 1.10 to 1.26) compared with ARBs, while no significant difference was seen among men (HR 1.00; 95% CI 0.93 to 1.06, interaction p<0.001).

Conclusions

Despite previous concerns regarding ARBs, we found that they had slightly lower rates of adverse clinical cardiovascular outcomes among older patients with MI compared with ACEIs. The observed difference in clinical outcomes may be related to a sex difference in effectiveness.

How Do Antihypertensive Drugs Work? Insights from Studies of the Renal Regulation of Arterial Blood Pressure

Though antihypertensive drugs have been in use for many decades, the mechanisms by which they act chronically to reduce blood pressure remain unclear. Over long periods, mean arterial blood pressure must match the perfusion pressure necessary for the kidney to achieve its role in eliminating the daily intake of salt and water. It follows that the kidney is the most likely target for the action of most effective antihypertensive agents used chronically in clinical practice today. Here we review the long-term renal actions of antihypertensive agents in human studies and find three different mechanisms of action for the drugs investigated. (i) Selective vasodilatation of the renal afferent arteriole (prazosin, indoramin, clonidine, moxonidine, α-methyldopa, some Ca(++)-channel blockers, angiotensin-receptor blockers, atenolol, metoprolol, bisoprolol, labetolol, hydrochlorothiazide, and furosemide). (ii) Inhibition of tubular solute reabsorption (propranolol, nadolol, oxprenolol, and indapamide). (iii) A combination of these first two mechanisms (amlodipine, nifedipine and ACE-inhibitors). These findings provide insights into the actions of antihypertensive drugs, and challenge misconceptions about the mechanisms underlying the therapeutic efficacy of many of the agents.

Combined Treatment With Angiotensin-Converting Enzyme Inhibitors and Angiotensin II Receptor Blockers: A Review of the Current Evidence

Several studies have shown that angiotensin-converting enzyme inhibitors and angiotensin II receptor blockers are useful in the treatment of hypertension, cardiovascular disease, chronic heart failure, and some types of nephropathy. In this context, dual renin-angiotensin system blockade with both angiotensin-converting enzyme inhibitors and angiotensin II receptor blockers may be more effective than treatment with each agent alone. Many clinical trials have demonstrated the beneficial effect of this combined treatment on proteinuria, hypertension, heart failure, and cardiovascular events. Moreover, these studies demonstrated that dual renin-angiotensin system blockade is generally safe and well tolerated. Long-term studies are under way to confirm these effects and also investigate the effectiveness of dual reninangiotensin system blockade on cerebrovascular disease and prevention of type 2 diabetes mellitus. These studies are expected to define the optimal use of combination treatment in everyday clinical practice. This review considers the most important clinical trials that evaluated the effect of dual renin-angiotensin system blockade on blood pressure, heart failure, and renal function.

Role of the Renin-Angiotensin-Aldosterone System and Its Pharmacological Inhibitors in Cardiovascular Diseases: Complex and Critical Issues

Hypertension is one of the major risk factor able to promote development and progression of several cardiovascular diseases, including left ventricular hypertrophy and dysfunction, myocardial infarction, stroke, and congestive heart failure. Also, it is one of the major driven of high cardiovascular risk profile in patients with metabolic complications, including obesity, metabolic syndrome and diabetes, as well as in those with renal disease. Thus, effective control of hypertension is a key factor for any preventing strategy aimed at reducing the burden of hypertension-related cardiovascular diseases in the clinical practice. Among various regulatory and contra-regulatory systems involved in the pathogenesis of cardiovascular and renal diseases, renin-angiotensin system (RAS) plays a major role. However, despite the identification of renin and the availability of various assays for measuring its plasma activity, the specific pathophysiological role of RAS has not yet fully characterized. In the last years, however, several notions on the RAS have been improved by the results of large, randomized clinical trials, performed in different clinical settings and in different populations treated with RAS inhibiting drugs, including angiotensin converting enzyme (ACE) inhibitors and antagonists of the AT1 receptor for angiotensin II (ARBs). These findings suggest that the RAS should be considered to have a central role in the pathogenesis of different cardiovascular diseases, for both therapeutic and preventive purposes, without having to measure its level of activation in each patient. The present document will discuss the most critical issues of the pathogenesis of different cardiovascular diseases with a specific focus on RAS blocking agents, including ACE inhibitors and ARBs, in the light of the most recent evidence supporting the use of these drugs in the clinical management of hypertension and hypertension-related cardiovascular diseases.

Cardiovascular mortality in hypertensive patients newly prescribed perindopril vs. lisinopril: a 5-year cohort study of 15,622 Chinese subjects

BACKGROUND

Perindopril and lisinopril are two common ACE inhibitors prescribed for management of hypertension. Few studies have evaluated their comparative effectiveness to reduce mortality. This study compared the all-cause and cardiovascular related mortality among patients newly prescribed ACE inhibitors.

METHODS

All adult patients newly prescribed perindopril or lisinopril from 2001 to 2005 in all public clinics or hospitals in Hong Kong were retrospectively evaluated, and followed up until 2010. Patients prescribed the ACE inhibitors for less than a month were excluded. The all-cause mortality and cardiovascular-specific (i.e. coronary heart disease, heart failure and stroke) mortality were compared. Cox proportional hazard regression model was used to assess the mortality, controlling for age, sex, socioeconomic status, patient types, the presence of comorbidities, and medication adherence as measured by the proportion of days covered. An additional model using propensity scores was performed to minimize indication bias.

RESULTS

A total of 15,622 patients were included in this study, in which 6910 were perindopril users and 8712 lisinopril users. The all-cause mortality (22.2% vs. 20.0%, p<0.005) and cardiovascular mortality (6.5% vs. 5.6%, p<0.005) were higher among lisinopril users than perindopril users. From regression analyses, lisinopril users were 1.09-fold (95% C.I. 1.01-1.16) and 1.18-fold (95% C.I. 1.02-1.35) more likely to die from any-cause and cardiovascular diseases, respectively. Age-stratified analysis showed that this significant difference was observed only among patients aged >70 years. The additional models controlled for propensity scores yielded comparable results.

CONCLUSIONS

The long-term all-cause and cardiovascular related mortality rates of lisinopril users was significantly different from those of perindopril users. These findings showed that intra-class variation on mortality exists among ACE inhibitors among those aged 70 years or older. Future studies should consider a longer, large-scale randomized controlled trial to compare the effectiveness between different medications in the ACEI class, especially among the elderly.

Perindopril/indapamide combination in the first-line treatment of hypertension and end-organ protection

This article examines evidence-based findings in the literature on the efficacy of perindopril 2 mg/indapamide 0.625 mg, a first-line, low-dose antihypertensive drug combination. In regulatory Phase II and III trials, perindopril/indapamide significantly lowered blood pressure compared with other first-line therapies (atenolol, losartan and irbesartan). This was also the case in STRAtegies of Treatment in Hypertension: Evaluation, a postregistration study versus current monotherapies and stepped-care therapy with different classes of antihypertensive agents. The efficacy/safety ratio (both clinical and with regard to laboratory parameters) of perindopril/indapamide was good. Perindopril/indapamide provides additional antihypertensive efficacy compared with each component used alone and with current monotherapies, with major efficacy on systolic blood pressure, an important predictor of cardiovascular risk. It also reduces pulse pressure, an independent cardiovascular risk factor, large-vessel arterial stiffness and microcirculatory alterations. The fixed dosage of a once-daily tablet, ensures optimal ease of use and enhances patient compliance. Perindopril/indapamide also reduces target organ damage in patients at high cardiovascular risk, such as patients with cardiac hypertrophy and Type 2 diabetics with albuminuria. These benefits, together with the good efficacy/tolerability ratio, fulfill the requirements of the European Society of Hypertension and of the Seventh Report of the Joint National Committee on Prevention, Detection, Evaluation, and Treatment of High Blood Pressure guidelines for low-dose, first-line combination therapy in hypertension.

Does outcome reporting bias "cause" cancer? Risks associated with hidden data on Angiotensin receptor blockers

Conflicting reports have been published regarding the influence of angiotensin receptor blockers (ARBs) on the incidence of cancer. One meta-analysis reported a 1% absolute increase in the incidence of cancer associated with ARBs over 4 years. Contrasting findings were reported in an industry-sponsored meta-analysis and in another meta-analysis, both of which showed no difference in the incidence of cancer in ARB treatment groups relative to control groups. The US Food and Drug Administration has recently asserted that evidence does not support an association between ARBs and the development of cancer. The current review compares the 3 published meta-analyses assessing the association between ARBs and cancer and shows that outcome reporting bias contributed to the conflicting results. Given the prevalence of this form of bias in the scientific literature, the processes for systematic reviews and meta-analyses are under siege, and there is an important role for health care regulators to play. If all outcome data from clinical trials were to be reported in the public domain, independent analyses could be performed and the results of industry-sponsored trials verified. Furthermore, if regulators were to mandate the publication, in the public domain, of all clinical outcomes collected in clinical trials, outcome reporting bias could be eliminated.

Cardiovascular outcomes in high-risk patients without heart failure treated with ARBs: a systematic review and meta-analysis

BACKGROUND AND OBJECTIVE

Angiotensin II type 1 receptor antagonists (ARBs) are widely used as a substitute for angiotensin-converting enzyme inhibitors (ACEIs) to treat patients without heart failure, but their effect on cardiovascular morbidity and mortality has not been clearly determined. A systematic review and meta-analysis was undertaken to determine the impact of ARBs on cardiovascular outcomes in high-risk patients without heart failure.

METHODS

A computerized literature search was carried out using PubMed, the Cochrane Central Register of Controlled Trials (CENTRAL) in The Cochrane Library, MEDLINE, and EMBASE, from January 1990 to April 2008. The following search terms were used: 'hypertension', 'clinical trial', 'sartan', 'ARB', 'angiotensin receptor antagonist', 'losartan', 'candesartan', 'valsartan', 'irbesartan', 'eprosartan', 'telmisartan', 'olmesartan', 'coronary disease', 'coronary heart disease', 'myocardial infarction', 'cardiovascular disease', 'cerebrovascular disease', and 'stroke'. Criteria for inclusion of clinical trials in our meta-analysis were the use of a randomized control group not receiving an ARB and the availability of outcome data for any one of four endpoints: myocardial infarction (MI), stroke, cardiovascular death, and all-cause death (these were not always pre-specified endpoints in all trials). Out of 45 potentially relevant studies, 37 trials met the inclusion criteria. We tabulated all occurrences of these four adverse outcomes.

RESULTS

Homogenous subgroups were combined by means of a fixed-effects model, while heterogenous subgroups were not combined. In the subgroup without heart failure, ARBs, when compared with the control group, had an odds ratio of 1.09 (95% CI 1.00, 1.18; p = 0.05) for MI. Other endpoints, namely, cardiovascular death and all-cause death, did not reach statistical significance. There was a clear trend for fewer strokes in the ARB group, but these studies were clearly heterogenous, and therefore a pooled risk estimate was not computed.

CONCLUSION

After pooling more than 89 000 patients, there is no evidence to suggest that ARBs confer cardiovascular protection akin to ACEIs, and the results that emerged are not in favor of ARB therapy in terms of its use as a substitute for ACEIs in non-heart failure patients. ARBs may have a small benefit in terms of stroke risk, but the studies are heterogenous, making it very difficult to quantify this effect. Given that ACEIs protect against both stroke and MI, caution is advised in the use of ARBs as a substitute for ACEIs in patients without a heart failure indication, who are tolerant of an ACEI.

Do we need more than just powerful blood pressure reductions? New paradigms in end-organ protection

Antihypertensive therapy can lower the risk of cardiovascular morbidity and mortality. Yet, partly because of inadequate dosing, wrong pharmacological choices, and poor patient adherence, hypertension control remains suboptimal in the majority of hypertensive patients. Achieving greater blood pressure control requires a multifaceted approach that raises awareness of hypertension, uses effective therapies, and improves adherence. Particular classes of antihypertensive therapy have beneficial actions beyond blood pressure and studies have evaluated differences in cardiovascular protection among classes. The LIFE and HOPE studies showed between-class differences that may be due to effects other than blood pressure-lowering. In the ONTARGET study, telmisartan and ramipril provided similar cardiovascular protection but adherence was higher with telmisartan, which was better tolerated. This difference in compliance is likely to be important for long-term therapy. The selection of an agent for cardiovascular protection should depend on an appreciation of its composite properties, including any beneficial effects on tolerability and increased patient adherence, as these are likely to be advantageous for the long-term management of hypertension. This review examines the evidence that the effects beyond blood pressure provided by some antihypertensive agents can also lower the risk of cardiovascular, cerebrovascular, and renal events in patients with hypertension.

Effect on the atherogenic marker plasminogen activator inhibitor type-1 of addition of the ACE inhibitor imidapril to angiotensin II type 1 receptor antagonist therapy in hypertensive patients with abnormal glucose metabolism: a prospective cohort study in primary care

BACKGROUND AND OBJECTIVE

Renin-angiotensin system (RAS) inhibitors, such as angiotensin-converting enzyme (ACE) inhibitors and angiotensin II type 1 receptor antagonists (angiotensin receptor blockers [ARBs]), are recommended by the American Diabetes Association for blood pressure control and prevention or management of cardiovascular disease in patients with diabetes mellitus. However, some investigators have suggested that ARBs may increase the risk of myocardial infarction in hypertensive patients. Activation of the RAS is associated with an increased risk of ischaemic events. Angiotensin II stimulates the production of plasminogen activator inhibitor type-1 (PAI-1), a powerful predictor of cardiovascular disease. ACE inhibitors are reported to reduce PAI-1 levels and activity, while ARBs do not reduce or may even elevate levels of this atherogenic marker. The objective of this study was to determine whether the ACE inhibitor imidapril reduces PAI-1 levels in hypertensive patients already being treated with an ARB.

METHODS

This was a prospective cohort study carried out in primary care with a follow-up period of 6 months. Estimating the alpha error (p-value) at 0.05, the power of the test as 80%, and the difference in PAI-1 levels as 10 + or - 15 ng/mL, the required sample size was calculated to be 40. Participants were hypertensive patients taking ARBs for more than 8 weeks, and having dyslipidaemia, obesity or abnormal glucose metabolism. Imidapril 5-10 mg/day was prescribed for 6 months to reduce blood pressure to <130/80 mmHg. The main outcome measure, PAI-1 level, was measured before and 6 months after the addition of imidapril to ARBs in 21 subjects (13 men, eight women), all with abnormal glucose metabolism, nine with dyslipidaemia, and six who were obese. Bodyweight, body mass index, blood pressure, homeostasis model assessment of insulin resistance, glycosylated haemoglobin, creatinine, potassium, high sensitivity C-reactive protein (hs-CRP), and high molecular weight adiponectin levels were measured as secondary outcomes.

RESULTS

PAI-1 level was not significantly changed overall. Hs-CRP level was also not significantly changed; however, the high molecular weight adiponectin level was significantly increased (p = 0.044), especially in men (p = 0.026). There were no significant changes in the other outcomes measured.

CONCLUSION

The current study showed that imidapril added to ARBs did not decrease PAI-1 levels in hypertensive patients with abnormal glucose metabolism; however, this combination therapy significantly increased high molecular weight adiponectin levels in men.

The association of Medicare drug coverage with use of evidence-based medications in the Veterans Health Administration

BACKGROUND

Veterans with Medicare managed-care plans have access to pharmacy benefits outside the Veterans Health Administration (VA), but how this coverage affects use of medications for specific disease conditions within the VA is unclear.

OBJECTIVE

To examine patterns of pharmacotherapy among patients with diabetes mellitus, ischemic heart disease, and chronic heart failure enrolled in fee-for-service (FFS) or managed-care (HMO) plans and to test whether pharmacy benefit coverage within Medicare is associated with the receipt of evidence-based medications in the VA.

METHODS

A retrospective analysis of veterans dually enrolled in the VA and Medicare healthcare systems was conducted. We used VA and Medicare administrative data from 2002 in multivariable logistic regression analysis to determine the unique association of enrollment in Medicare FFS or managedcare plans on the use of medications, after adjusting for sociodemographic, geographic, and patient clinical factors.

RESULTS

A total of 369,697 enrollees met inclusion criteria for diabetes, ischemic heart disease, or chronic heart failure. Among patients with diabetes, adjusted odds ratios (ORs) of receiving angiotensin-converting enzyme (ACE) inhibitors and oral hypoglycemics in the FFS group were, respectively, 0.86 and 0.80 (p < 0.001). Among patients with ischemic heart disease, FFS patients were generally less likely to receive beta-blockers, antianginals, and statins. Among patients with chronic heart failure, adjusted ORs of receiving ACE inhibitors, angiotensin-receptor blockers, and statins in the FFS group were, respectively, 0.90, 0.78, and 0.79 (all p < 0.05). There were few systematic differences within HMO coverage levels.

CONCLUSIONS

FFS-enrolled veterans were generally less likely to be receiving condition-related medications from the VA, compared with HMO-enrolled veterans with lower levels of prescription drug coverage. Pharmacy prescription coverage within Medicare affects the use of evidence-based medications for specific disease conditions in the VA.

Significance of pulsatility of brachial artery pressure for blood pressure control

Few studies have examined predictors of poor blood pressure (BP) control. The aim of this study was to observe the relationship between the pulsatility of brachial artery pressure characterized as pulse pressure/diastolic pressure (PP/DP), suggesting aortic input impedance, and poor BP control. We obtained office BP measurements for 94 patients aged 40-75 years with either office systolic BP (SBP) >or= 140 mmHg or diastolic BP (DBP) >or= 90 mmHg. Patients were given a single antihypertensive agent or were untreated at baseline. The angiotensin II receptor blocker valsartan (80 mg) was administered to all patients. Patients were treated with 1 to 2 antihypertensive drugs (valsartan only or valsartan + Ca antagonist) for 6 months to achieve an office BP of less than 140/90 mmHg. At follow-up, 32 patients were taking a single drug (valsartan) with good BP control, 24 were receiving two drugs with good BP control, and 38 were on two drugs with poor BP control. SBP and DBP at baseline were similar in the 3 groups. PP/DP at baseline differed in the 3 groups (P<0.01). In multivariate analysis, only PP/DP at baseline correlated with lack of BP control. The pulsatility of brachial artery pressure is associated with achieving adequate BP control.

Dihydropyridine calcium channel antagonists in the management of hypertension

Dihydropyridine calcium channel antagonists have been maligned in recent years because of concerns regarding their cardiovascular and overall safety profile. Specifically, it was widely publicised in the mid-1990s that these agents might increase the risk of myocardial infarction, gastrointestinal bleeding and cancer. Data linking these agents with increased cardiovascular risk were based on nonrandomised studies and implicated short-acting, immediate-release agents. These results were inappropriately extrapolated to longer-acting compounds, extended-release products, and to the non-dihydropyridine class. Fortunately, recent studies have vindicated the class from safety allegations. These studies are reviewed herein. Compared with both diuretics and contemporary agents, amlodipine decreases cardiovascular events to a similar or greater extent without evidence for increased coronary heart disease, gastrointestinal bleeding or cancer. Despite these data, initial concerns have had lasting repercussions, as the use of dihydropyridine calcium channel antagonists appears to lag behind what emerging data would support. Dihydropyridine calcium channel antagonists have several noteworthy attributes that merit consideration in the management of hypertension. The blood pressure response to this class of drugs is less contingent on patient factors such as age and race compared with other antihypertensive agents (e.g. ACE inhibitors). Dihydropyridine calcium channel antagonists may exert effects that protect against stroke that are independent of their blood pressure-lowering mechanism. Unlike diuretics and beta-adrenoceptor anatagonists (beta-blockers), dihydropyridine calcium channel antagonists are lipid neutral and do not disturb glucose homeostasis. Dihydropyridine calcium channel antagonists demonstrate a highly desirable profile when administered as part of combination therapy. Combinations of dihydropyridine calcium channel antagonists and ACE inhibitors or angiotensin receptor antagonists display additive efficacy and an enviable adverse-effect profile. Collectively, the cardiovascular benefit, metabolic neutrality and homogeneous blood pressure response illuminated in recent studies, and reviewed here, represent a reaffirmation of the benefit of long-acting dihydropyridine calcium channel antagonists and should serve to help reinforce the critical importance of these agents in the therapeutic armamentarium against cardiovascular disease.

Molecular mechanism of imidapril for cardiovascular protection via inhibition of MMP-9

To investigate the inhibitory specificity of angiotensin converting enzyme (ACE) inhibitors to matrix metalloproteinase (MMP)-9, we predicted molecular interactions between an ACE inhibitor imidapril and MMP-9 active site based on recent X-ray structural analyses. Two binding modes differing in the orientation of imidapril on the active site were identified, and its hydrophobic group appeared to preferentially interact with the S1 site compared with the S1' site. Compared with the lisinopril-MMP-9 model in our previous study, imidapril was stabilized effectively on the active site with less of molecular distortions. We also measured ACE and MMP-9 inhibitory activities of imidapril and lisinopril after myocardial infarction. Imidapril had a stronger inhibitory activity against MMP-9 than lisinopril. These findings show that imidapril inhibits MMP-9 directly like lisinopril and its hydrophobic interactions with the S1 site of MMP-9 would be important for enhancing inhibitory activity.

Inhibition of matrix metalloproteinase-9 activity by lisinopril after myocardial infarction in hamsters

We measured angiotensin-converting enzyme and matrix metalloproteinase-9 activities after myocardial infarction in hamsters and compared the effects of an angiotensin-converting enzyme inhibitor lisinopril with those of an angiotensin receptor blocker candesartan cilexetil after myocardial infarction. Angiotensin-converting enzyme activity was significantly increased 3 and 7 days, but not 1 day after myocardial infarction. Matrix metalloproteinase-9 activity was significantly increased 1 day after myocardial infarction. Lisinopril significantly inhibited both angiotensin-converting enzyme and matrix metalloproteinase-9 activities, but candesartan cilexetil did not. Angiotensin-converting enzyme inhibitors might directly inhibit matrix metalloproteinase-9 activity.

Effects of zofenopril on myocardial ischemia in post-myocardial infarction patients with preserved left ventricular function: the Survival of Myocardial Infarction Long-term Evaluation (SMILE)-ISCHEMIA study

BACKGROUND

The aim of the study was to investigate the cardioprotective effects of the angiotensin-converting enzyme inhibitor zofenopril in post-myocardial infarction (MI) patients with preserved left ventricular function (LVF).

METHODS

Three hundred forty-nine post-MI patients with preserved LVF (LV ejection fraction >40%) were treated for 6 months with zofenopril 30 to 60 mg (n = 177) or placebo (n = 172) according to a double-blind, randomized study design. The primary end point of the study was the combined occurrence of significant ST-T abnormalities on ambulatory electrocardiography (ECG), ECG abnormalities or symptoms of angina during standard exercise test, recurrence of MI, and need for revascularization procedures for angina.

RESULTS

The primary end point occurred in 20.3% of zofenopril-treated and 35.9% of placebo-treated patients (P = .001), despite no differences in blood pressure control, LVF, and concomitant therapy. ST-T depression during ambulatory ECG occurred in 22.7% of patients treated with placebo and 10.7% of those undergoing ACE-inhibition treatment (P = .027). ST-T depression in response to exercise test occurred in 14.2% and 26.7% of patients treated with zofenopril or placebo, respectively, (P = .024), with a lower proportion of zofenopril-treated patients who complained of anginal pain (4.7 vs 14.3%; P = .017), significant ST depression (14.2 vs 26.7%; P = .024), and major ventricular arrhythmias (3.8 vs 10.5%; P = .048). The rate of major cardiovascular events was reduced in patients treated with ACE inhibitor, with a lower rate of development and progression of congestive heart failure.

CONCLUSIONS

The results of the SMILE-ISCHEMIA study support the cardioprotective role of zofenopril when given to patients with normal LVF after acute MI.

Perindopril versus Angiotensin II Receptor Blockade in Hypertension and Coronary Artery Disease

The renin-angiotensin-aldosterone system (RAAS) is now known to play a key role in the pathogenesis of hypertension and a range of other cardiovascular diseases. Two groups of drugs, the ACE inhibitors and angiotensin II type 1 receptor antagonists (angiotensin receptor blockers [ARBs]) have been developed with the aim of improving clinical outcomes by regulating the RAAS in patients with cardiovascular disease. Initial assumptions were that these two drug types might be interchangeable, but ongoing research has revealed differences between them in terms of pharmacology and outcomes in clinical trials. Although both groups of drugs lower blood pressure, studies of the ACE inhibitor perindopril have revealed preservation of beneficial vascular and endothelial effects mediated by bradykinin and nitric oxide. The selective blockade exerted by ARBs is not associated with these effects. Furthermore, examination of clinical endpoints in major clinical trials has provoked discussion about outcomes comparing ACE inhibitors and ARBs, with recent debate focusing on the incidence of myocardial infarction (MI) in patients receiving these agents. Whether there is an actual difference in protection from MI remains unresolved, although available data confirm the benefit and safety of ACE inhibitors, in particular perindopril, for myocardial protection.

Angiotensin inhibition after myocardial infarction: does drug class matter?

BACKGROUND

Angiotensin converting enzyme-inhibitors (ACEI) and angiotensin-II-receptor blockers (ARB) are equally efficacious in reducing mortality after MI, although the latter are far more costly. Little is known about their relative use after MI in typical care settings, and about their relative effectiveness outside the clinical trial setting.

OBJECTIVES

To assess temporal trends in the relative use of ACEI and ARB after myocardial infarction, and to test for differences in 1-year survival between users of these drug classes.

DESIGN

Retrospective closed cohort study.

PATIENTS

Medicare beneficiaries who survived >90 days after myocardial infarction, had full prescription drug coverage, and who filled a prescription for either ACEI or ARB within 90 days of myocardial infarction.

MEASUREMENTS

Relative use of ACEI versus ARB over time. Adjusted relative 1-year mortality between ACEI and ARB users.

RESULTS

Between 1995 and 2004, 14,190 patients met inclusion criteria. Mean age was 80 years, 75% were female, and 90% were white. Overall, 88% received an ACEI, and 12% an ARB, with the proportion receiving an ARB increasing from 2% (1995) to 25% (2004; P<.001). Multivariate-adjusted 1-year mortality did not differ between ARB and ACEI users (HR: 1.04; 95% confidence interval: 0.88 to 1.22). The findings were similar for new users of ACEI/ARB, and for those with preexisting heart failure.

CONCLUSIONS

ARB users had the same 1-year mortality after myocardial infarction as ACEI users in routine care. Use of more costly ARB has increased dramatically over time, to a quarter of ACEI/ARB users, despite the lack of a therapeutic advantage for most patients.

Emerging drugs for diabetic nephropathy

There is an increasing number of patients with diabetes mellitus in many countries. Diabetic kidney disease, one of its microvascular complications, is also increasing markedly and has become a major cause of end stage renal disease worldwide. Intervention for preventing and delaying the development and progression of diabetic kidney disease is not only a medical concern, but also a social issue. Despite extensive efforts, however, medical interventions thus far are not effective enough to prevent the progression of the disease and the development of end stage renal disease. This justifies attempts to develop novel therapeutic approaches for diabetic nephropathy. Recent insights on its pathogenesis and progression have suggested new targets for the specific treatment of this disease. They include aldosterone, aldose reductase, arachidonic acid metabolites, growth factors, advanced glycosylation end-products, peroxisome proliferator-activated receptors and endothelin. Several other biochemical mediators have been targeted in experimental animal models with the goal to prevent diabetic nephropathy progression, but translation to clinics of these experimental achievements are still limited or lacking.

Targeting the renin-angiotensin system for the reduction of cardiovascular outcomes in hypertension: angiotensin-converting enzyme inhibitors and angiotensin receptor blockers

Agents that counteract the negative impact of the renin-angiotensin-aldosterone system (RAAS) are effective antihypertensives and reduce the risk of developing Type 2 diabetes. Contrary to common perception, angiotensin-converting enzyme inhibitors do not share the apparent benefit of angiotensin II receptor blockers (ARBs) in reducing risk of cardiovascular-disease outcomes, particularly stroke, in randomised clinical trials. RAAS agents, especially ARBs, are well tolerated. Use of ARBs alone or in combination with other classes of antihypertensive agents to lower blood pressure and/or medications to control other conditions (e.g., insulin sensitivity) reduces risk of cardiovascular disease outcomes and Type 2 diabetes with excellent tolerability. Selected issues related to use of RAAS agents as antihypertensive therapies (e.g., Type 2 diabetes, global risk management, multiple drug therapy and coronary heart disease) are addressed.

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

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