Valsartan in acute myocardial infarction trial (VALIANT): rationale and design

Angiotensin II type 1 receptor blocker attenuates exacerbated left ventricular remodeling and failure in diabetes-associated myocardial infarction

Diabetes mellitus adversely affects the outcomes in patients with myocardial infarction (MI), due in part to the exacerbation of left ventricular (LV) remodeling. Although angiotensin II type 1 receptor blocker (ARB) has been demonstrated to be effective in the treatment of heart failure, information about the potential benefits of ARB on advanced LV failure associated with diabetes is lacking. To induce diabetes, male mice were injected intraperitoneally with streptozotocin (200 mg/kg). At 2 weeks, anterior MI was created by ligating the left coronary artery. These animals received treatment with olmesartan (0.1 mg/kg/day; n = 50) or vehicle (n = 51) for 4 weeks. Diabetes worsened the survival and exaggerated echocardiographic LV dilatation and dysfunction in MI. Treatment of diabetic MI mice with olmesartan significantly improved the survival rate (42% versus 27%, P < 0.05) without affecting blood glucose, arterial blood pressure, or infarct size. It also attenuated LV dysfunction in diabetic MI. Likewise, olmesartan attenuated myocyte hypertrophy, interstitial fibrosis, and the number of apoptotic cells in the noninfarcted LV from diabetic MI. Post-MI LV remodeling and failure in diabetes were ameliorated by ARB, providing further evidence that angiotensin II plays a pivotal role in the exacerbated heart failure after diabetic MI.

Predictors of stroke in high-risk patients after acute myocardial infarction: insights from the VALIANT trial

AIMS

We sought to determine risk models for predicting early and late stroke in a large cohort of high-risk post-myocardial infarction (MI) patients.

METHODS AND RESULTS

We prospectively analysed data from 14 703 patients in the VALIANT trial with acute MI complicated by heart failure, left ventricular (LV) systolic dysfunction, or both. Patients were randomized 0.5-10 days after acute MI to valsartan, captopril, or their combination. We evaluated risk factors for early (<45 days) and late (>45 days) stroke by using multivariable Cox proportional hazards regression analyses with stepwise variable selection techniques applied to 92 pre-specified potential predictor variables. After randomization, 463 (3.2%) patients had fatal (n = 124) or non-fatal (n = 339) strokes, with 134 strokes occurring in the first 45 days. The strokes were classified as ischaemic (348), haemorrhagic (40), or of indeterminate cause (75). Estimated glomerular filtration rate and heart rate when in sinus rhythm were the most powerful predictors of early stroke (<45 days after MI), whereas diastolic blood pressure (DBP) >90 mmHg, prior stroke, and atrial fibrillation (AF) were the most powerful predictors of stroke overall. Ejection fraction and sex were not predictive of stroke in this cohort.

CONCLUSION

Among high-risk patients presenting with MI but without initial neurological symptoms, the risk of stroke 6 weeks thereafter is 0.94% (95% CI 0.78-1.09). Of the most powerful baseline predictors of stroke, DBP and AF are amenable to therapeutic interventions and thus merit special attention in these patients.

Geographic variation in the treatment of acute myocardial infarction in the VALsartan In Acute myocardial iNfarcTion (VALIANT) trial

BACKGROUND

The VALIANT trial compared the efficacy and safety of captopril, valsartan, and their combination in patients with left ventricular systolic dysfunction, heart failure, or both after acute myocardial infarction (MI). By examining this international trial population of high-risk patients, we sought to determine geographic variations in the use of 3 key treatments for MI.

METHODS

We analyzed data from 14,512 high-risk patients with MI in the VALIANT trial from the 20 countries that had enrolled >100 patients. International variation in the proportion of patients receiving (1) reperfusion therapy (thrombolysis or primary percutaneous coronary intervention), (2) beta-blockers, or (3) aspirin at the time of MI was measured by using adjusted W scores. These scores correspond to the number of additional or fewer patients who received each of the therapies compared with the number expected, as estimated from multivariable regression models that account for patients' baseline characteristics.

RESULTS

There was marked variation between countries in the use of reperfusion therapy (equivalent to a difference of up to 36/100 potentially eligible patients) and beta-blockers (41/100), whereas there was much less variation in the use of aspirin (13/100).

CONCLUSIONS

Marked geographic variation persists in the use of standard evidence-based therapy advocated by international guidelines. Our findings have implications not only for care of patients but also for the conduct of international trials.

Extent of coronary artery disease as a predictor of outcomes in acute myocardial infarction complicated by heart failure, left ventricular dysfunction, or both

BACKGROUND

Left ventricular systolic dysfunction (LVSD) and heart failure (HF) are powerful predictors of poor outcome after acute myocardial infarction (MI). It is not known, however, whether the extent of coronary artery disease (CAD) independently influences cardiovascular (CV) outcomes in these high-risk patients.

METHODS

In the VALIANT, 14703 patients were randomly assigned to receive either captopril monotherapy, valsartan monotherapy, or a valsartan and captopril combination between 0.5 and 10 days after acute MI complicated by LVSD, HF, or both. Cox proportional hazards models were used to evaluate the relation between the extent of CAD (the number of diseased vessels as assessed by angiography) and a range of CV outcomes and all-cause mortality.

RESULTS

Coronary angiography data were available on 5742 (40%) of the 14703 randomized patients. Single-vessel disease was reported in 1955 patients (34%), 2-vessel disease in 1598 (28%), and 3-vessel disease in 2189 (38%). For all CV outcomes, the risk increased with the severity of CAD (P for trend < .002). A comparison of single-, 2-, and 3-vessel disease showed that, after adjusting for all known covariates, including revascularization and ejection fraction, 2-vessel disease was associated with a 40% increased hazard (P = .008) and 3-vessel disease was associated with an 85% increased hazard (P < .001) for all-cause mortality. The fully adjusted hazard ratios for death and other CV outcomes increased significantly with increasing extent of CAD.

CONCLUSIONS

Increasing extent of CAD, as detected by angiography, is a significant and independent risk factor for adverse CV outcomes after MI complicated by HF, LVSD, or both. The observed risk was apparent even after excluding patients who had undergone revascularization.

Previously known and newly diagnosed atrial fibrillation: a major risk indicator after a myocardial infarction complicated by heart failure or left ventricular dysfunction

AIMS

To characterize the relationship between known and newly diagnosed atrial fibrillation (AF) and the risk of death and major cardiovascular (CV) events in patients with acute myocardial infarction (MI) complicated by heart failure (HF) and/or left ventricular systolic dysfunction (LVSD).

METHODS

The VALIANT trial enrolled 14,703 individuals with acute MI complicated by HF and/or LVSD. AF was assessed at presentation and at randomization (median 4.9 days after symptom onset). Primary outcomes were risk of death and major CV events 3 years following acute MI.

RESULTS

A total of 1812 with current AF (AF between presentation and randomization), 339 patients with prior AF (history of AF without current AF), and 12,509 without AF were enrolled. Patients with AF were older; had more prior HF, angina, and MI, and received beta-blockers and thrombolytics less often than those without AF. Three-year mortality estimates were 20% in those without AF, 37% with current AF, and 38% with prior AF. Compared with patients without AF, the multivariable adjusted HR of death was 1.25 (1.03-1.52; p=0.03) for prior AF and 1.32 (1.20-1.45; p<0.0001) for current AF. HR for major CV events was 1.15 (0.98-1.35; p=0.08) and 1.21 (1.12-1.31; p<0.0001).

CONCLUSION

AF is associated with greater long-term mortality and adverse CV events with acute MI complicated by HF or LVSD.

Choice of delta: requirements and reality--results of a systematic review

An essential problem in planning clinical non-inferiority or equivalence studies is the specification of the 'irrelevant difference' (irrelevance margin; delta). This quantifies the amount of non-inferiority or difference, respectively, between a new test therapy and an established standard treatment which is to be considered as tolerable. In the past, most recommendations and guidelines for clinical non-inferiority and equivalence studies contained only general statements and formulations concerning the specification of delta. The current unsatisfactory situation was the reason for performing a systematic review of published clinical non-inferiority and equivalence studies. It was the aim to gain an overview on the irrelevance margins used in such studies, and on reasons for choosing the particular margins. For the sake of comparability, the irrelevance margins were converted into standardized differences and odds ratios. Overall, there were 332 non-inferiority or equivalence trials obtained by means of an extensive literature search. The results of the systematic review show that current requirements on the choice of delta and the reality of recent clinical non-inferiority and equivalence trials differ substantially. In about one half of the trials a difference of 0.5 standard deviations or more was regarded as 'irrelevant' explicitly or implicitly. Estimates of standard-placebo differences formed the basis of the irrelevance margin in less than every tenth trial. Reasons for this very low proportion might be (1) the possibly resulting very small irrelevance margins, and (2) unsolved problems of the requirements themselves. Overall, it seems that a more global definition of 'irrelevance' might be warranted.

The effect of valsartan, captopril, or both on atherosclerotic events after acute myocardial infarction: an analysis of the Valsartan in Acute Myocardial Infarction Trial (VALIANT)

OBJECTIVES

We attempted to compare the effect of an angiotensin-converting enzyme (ACE) inhibitor and angiotensin receptor blocker (ARB) on atherosclerotic events.

BACKGROUND

Angiotensin-converting enzyme inhibitors and ARBs interrupt the renin-angiotensin system by distinct mechanisms. It is not clear whether ARBs reduce atherosclerotic events such as myocardial infarction (MI) like ACE inhibitors. This evidence gap may reflect the nature of the studies conducted, to date. Placebo-controlled studies enrolled cohorts at low risk of atherosclerotic events (e.g., patients with chronic heart failure, most treated with an ACE inhibitor). One of the main active controlled trials was confounded by a blood pressure difference between treatments.

METHODS

We compared the effects of captopril, valsartan, and their combination on atherosclerotic events in 14,703 patients randomized in the Valsartan in Acute Myocardial Infarction Trial (VALIANT).

RESULTS

The number of individuals adjudicated as having a fatal or non-fatal MI in the captopril group was 559 (total investigator reported events 798), 587 (796) in the valsartan group, and 554 (756) in the combination group; valsartan versus captopril, p = 0.651 (0.965); combination versus captopril, p = 0.187 (0.350). Overall, all atherosclerotic events examined occurred at a similar frequency in the captopril and valsartan groups.

CONCLUSIONS

Angiotensin receptor blockers appear to be as effective as ACE inhibitors in reducing atherosclerotic events, even when used in addition to other secondary preventive treatments. These data, although not conclusive, also support the hypothesis that adding an ARB to an ACE inhibitor may have a small additional anti-infarction effect, a possibility that needs to be prospectively tested.

Proposed New Score to Rate the Strength of Evidence and Its Application to Large-Scale Clinical Trials of Angiotensin-Receptor Blockers

BACKGROUND

Many large-scale clinical studies appear to be interpreted with bias and with hindsight. To select the best treatment, accurate evaluation of randomized controlled trials (RCTs) and fair comparison of the results using the concept of evidence-based medicine are critical. A scoring system has been developed to rate the scientific strength of evidence and thereby provide guidance for best clinical practice and for large-scale RCTs of angiotensin-receptor blockers (ARBs).

METHOD AND RESULTS

Positive evidence scores (ESs) were given based on whether specified study endpoints were proven and whether treatments tested made significant progress over current usual therapy. Retrospective ad hoc analyses data were not counted, in order to simplify the system and to avoid hindsight interpretations, even in cases that were medically significant. In fact, in more than half of the large-scale trials with ARBs examined, ad-hoc analyses had been retroactively performed. When such post-hoc analyses were not used, the ESs were positive with candesartan and valsartan for treatment of heart failure, irbesartan and losartan for nephropathy and losartan for hypertension. Applying the ES system, losartan was judged to be an ARB with the strongest evidence covering a wide range of clinical relevance.

CONCLUSION

ES is useful for quantifying and comparing the strength of evidence obtained in large-scale RCTs of ARBs. Several problems related to rating the evidence obtained from clinical trials were recognized in this study.

Mortality and morbidity remain high despite captopril and/or Valsartan therapy in elderly patients with left ventricular systolic dysfunction, heart failure, or both after acute myocardial infarction: results from the Valsartan in Acute Myocardial Infarction Trial (VALIANT)

BACKGROUND

The elderly constitute an increasing proportion of acute myocardial infarction patients and have disproportionately high mortality and morbidity. Those with heart failure or impaired left ventricular left ventricular function after acute myocardial infarction have high complication and mortality rates. Little is known about outcomes with contemporary therapies in these patients.

METHODS AND RESULTS

The Valsartan in Acute Myocardial Infarction Trial (VALIANT) randomized 14,703 patients with heart failure and/or left ventricular ejection fraction <40% to receive captopril, valsartan, or both. Mortality and a composite end point, including cardiovascular mortality, readmission for heart failure, reinfarction, stroke, and resuscitated cardiac arrest, were compared for the age groups of <65 (n=6988), 65 to 74 (n=4555), 75 to 84 (n=2777), and > or =85 (n=383) years. With increasing age, 3-year mortality almost quadrupled (13.4%, 26.3%, 36.0%, and 52.1%, respectively), composite end-point events more than doubled (25.2%, 41.0%, 52.3%, and 66.8%), and hospital admissions for heart failure almost tripled (12.0%, 23.1%, 31.3%, and 35.4%). Outcomes did not differ between the 3 study treatments in any age group. Adverse events associated with captopril and valsartan were more common in the elderly and in patients receiving combination therapy. With increasing age, use of aspirin, beta-blockers, and statins declined, and use of digoxin, calcium-channel blockers, and non-potassium-sparing diuretics increased. On 3-year multivariable analysis, each 10-year age increase was associated with a hazard ratio of 1.49 (95% CI, 1.426 to 1.557; P<0.0001) for mortality and an odds ratio of 1.38 (95% CI, 1.31 to 1.46; P<0.0001) for readmission with heart failure.

CONCLUSIONS

Outcomes remained poor in elderly patients with heart failure and/or impaired left ventricular systolic function after acute myocardial infarction, although most received beta-blockers and all received an ACE inhibitor and/or an angiotensin receptor blocker. Better therapies and increased use of aspirin, beta-blockers, and statins are needed in this important and increasing patient group.

Protective Effects of Angiotensin II Interruption: Evidence for Antiinflammatory Actions

Angiotensin II, the major effector molecule produced from the renin-angiotensin-aldosterone axis, is a vasoconstrictor contributing to hypertension. Evidence indicates, however, that angiotensin II also is a potent proinflammatory mediator with growth and remodeling effects. In vitro and in vivo studies have shown that angiotensin II blockade significantly reduces concentrations of proinflammatory mediators and oxidative stress products in numerous inflammatory models. Interruption of angiotensin II activity with angiotensin-converting enzyme inhibitors and angiotensin II receptor blockers has been beneficial for patients with inflammatory diseases. Much of this benefit occurs independent of the antihypertensive effect of angiotensin II interruption, suggesting a distinctive protective mechanism. Angiotensin II receptor blockers may represent a novel class of antiinflammatory drugs with indications far beyond cardiovascular diseases.

Resource use, costs, and quality of life among patients in the multinational Valsartan in Acute Myocardial Infarction Trial (VALIANT)

BACKGROUND

In a multinational clinical trial, valsartan was statistically not inferior to captopril in reducing mortality and cardiovascular morbidity after myocardial infarction (MI) in patients with signs of heart failure and/or left ventricular dysfunction. We conducted a prospective economic evaluation to compare within-trial resource use, costs, and quality of life in patients receiving valsartan, captopril, or both after MI.

METHODS

We assigned country-specific unit costs to resource use data for 14703 patients and measured health-related quality of life in a subset of 4524 patients. We used the nonparametric bootstrap method to compare rates of resource use and costs, and a piecewise linear mixed-effects regression analysis to compare longitudinal measures of quality of life.

RESULTS

There were no significant differences in rates of resource use between the valsartan and captopril groups. During an average follow-up of 2 years, total costs for patients receiving valsartan were significantly higher than for patients receiving captopril (USD 14103 vs USD 13038; 95% CI USD 369-USD 1875). The cost differential was caused primarily by the cost of the study medications (USD 1056 for valsartan vs USD 165 for captopril; 95% CI USD 867 to USD 912). Quality of life did not differ significantly between groups.

CONCLUSIONS

For most patients at high risk after MI, the availability of generic captopril confers a cost advantage over valsartan because of lower medication costs. The difference will be smaller or nonexistent in settings where brand-name ACE inhibitors are prescribed.

Practical Implementation of the Guidelines for Unstable Angina/Non–ST-Segment Elevation Myocardial Infarction in the Emergency Department

In the United States each year, >5.3 million patients present to emergency departments with chest discomfort and related symptoms. Ultimately, >1.4 million individuals are hospitalized for unstable angina and non-ST-segment elevation myocardial infarction. For emergency physicians and cardiologists alike, these patients represent an enormous challenge to accurately diagnose and appropriately treat. This update of the 2002 American College of Cardiology/American Heart Association Guidelines for the Management of Patients with Unstable Angina and Non-ST-Segment Elevation Myocardial Infarction (UA/NSTEMI) provides an evidence-based approach to the diagnosis and treatment of these patients in the emergency department, in-hospital, and after hospital discharge. Despite publication of the guidelines several years ago, many patients with UA/NSTEMI still do not receive guidelines-indicated therapy.

Cardiac regeneration by progenitor cells--bedside before bench?

Recent experimental and clinical trials give rise to the hope that progenitor cells could replace scar tissue after myocardial infarction with healthy functional myocardium. However, while a significant increase in left ventricular ejection fraction has been described after progenitor cell transplantation in several clinical trials, long-term results are lacking, and the mechanisms underlying the improvement of ejection fraction are unclear. Therefore, the efficacy of progenitor cell transplantation after myocardial infarction has not been established, and potential problems may have been underestimated. In-depth laboratory and animal studies are needed to determine the best cell type, optimal amount of cells, and time point for transplantation. Treatment of patients with progenitor cells outside well controlled prospective trials should be avoided.

Practical Implementation of the Guidelines for Unstable Angina/Non–ST-Segment Elevation Myocardial Infarction in the Emergency Department

In the United States each year, >5.3 million patients present to emergency departments with chest discomfort and related symptoms. Ultimately, >1.4 million individuals are hospitalized for unstable angina and non–ST-segment elevation myocardial infarction. For emergency physicians and cardiologists alike, these patients represent an enormous challenge to accurately diagnose and appropriately treat. This update of the 2002 American College of Cardiology/American Heart Association Guidelines for the Management of Patients with Unstable Angina and Non–ST-Segment Elevation Myocardial Infarction (UA/NSTEMI) provides an evidence-based approach to the diagnosis and treatment of these patients in the emergency department, in-hospital, and after hospital discharge. Despite publication of the guidelines several years ago, many patients with UA/NSTEMI still do not receive guidelines-indicated therapy.

VALIANT (VALsartan In Acute myocardial iNfarcTion) trial

Angiotensin-converting enzyme inhibitors (ACE-Is) are an evidence-based treatment for patients who after myocardial infarction (MI) present with either heart failure (HF) or left ventricular systolic dysfunction, or both. An alternative could be a more complete inhibition of the renin-angiotensin system through the blockade of the angiotensin type 1 receptors. The effect of valsartan or captopril, or the combination of the two in post-MI HF or systolic dysfunction or both, has been evaluated in the VALIANT (VALsartan In Acute myocardial iNfarcTion) trial. Total mortality and the combined secondary end point of cardiovascular death, MI or HF were not significantly different in the three groups after 24.7 months of follow-up. Valsartan was not inferior to captopril in terms of total mortality and cardiovascular death, MI and HF. Valsartan can be considered an alternative treatment to ACE-I in these patients.

Novel pharmacological treatments for heart failure

Pharmacological therapies remain the primary strategy for treating patients with acute and chronic heart failure. Several novel neurohormonal antagonists, inotropic agents, immune modulators, and metabolic and replacement therapies are currently in development to meet the demands of an increasing number of patients with heart failure. The success in drug development in this field will require a better understanding of the effects of heart failure on drug dosing, better integration of novel and existing drug therapies, the development of more reliable surrogate markers to effectively tailor medical therapy to individual needs and the ability to detect and treat patients at risk before the onset of heart failure.

Cellular mechanisms for the treatment of chronic heart failure: the nitric oxide- and adenosine-dependent pathways

Accumulated evidence suggests that several drugs proven to improve survival in patients with chronic heart failure (CHF) enhance endogenous nitric oxide (NO)- and/or adenosine-dependent pathways. Indeed, we and others have demonstrated that: i) antagonists of either renin-angiotensin-aldosterone or beta-adrenergic systems enhance NO-dependent pathways; ii) although carvedilol and amlodipine belong to different drug classes, both of them can increase cardiac adenosine levels; iii) increased adenosine levels by dipyridamole are associated with the improvement of CHF. Interestingly, both NO and adenosine have multifactorial beneficial actions in cardiovascular systems. First of all, both of them induce vasodilation and decrease myocardial hypercontractility, which may contribute to a reduction in the severity of myocardial ischaemia. Both adenosine and NO are also involved in cardioprotection attributable to acute and late phases of ischaemic preconditioning, respectively. Secondly, they can modulate the neurohormonal systems that contribute to the progression of CHF. Thus, we propose that enhancement of endogenous NO and/or adenosine as potential therapeutic targets in a new strategy for the treatment for CHF.

Effects of Candesartan on Cardiovascular Outcomes in Japanese Hypertensive Patients

In recent years, angiotensin receptor blockers (ARBs) have begun to represent a markedly larger percentage of the antihypertensive agents used in Japan. However, it remains uncertain whether ARBs are effective for protecting against hypertension-related organ damage in the general Japanese population. In the present report, we describe the results of a single blind, randomized, prospective study conducted in 1999-2002 and employing a total of 2,048 essential hypertensive subjects (sitting blood pressure 140-180/90-110 mmHg) aged 35-79 years. Subjects were randomly assigned to receive the ARB candesartan, 2 to 12 mg daily, or conventional antihypertensive drugs other than angiotensin converting enzyme inhibitors or ARBs. We used Cox regression analysis to compare the two regimens. The primary outcome was assessed by hospitalization due to stroke, myocardial infarction, and congestive heart failure. Blood pressure was reduced from 162.1/91.1 to 140.1/78.9 mmHg in the candesartan group and from 165.9/95.9 to 138.4/81.1 mmHg in the conventional therapy group. The main outcomes were as follows: there was a 39% reduction in hospitalization for stroke (5.8 vs. 9.4 cases: relative risk [RR]: 0.61; 95% confidence interval [CI]: 0.41-0.84; p<0.05) and a 57% reduction in hospitalization for myocardial infarction (RR: 0.44; CI: 0.21-0.84; p<0.05) with the candesartan-based treatment compared with the conventional treatment. In spite of a significant difference in the total incidence of both stroke and myocardial infarction, there was no significant reduction in the incidence of congestive heart failure (15% reduction: 4.3 vs. 5.0; RR: 0.85; CI: 0.57-1.26). Further analysis in stratifying the subjects with or without a past history of cardiovascular diseases including stroke and myocardial infarction revealed that candesartan reduced the incidence of stroke (61% reduction; RR: 0.39; CI: 0.15-0.43; p<0.01) and congestive heart failure (49% reduction; RR: 0.51; CI: 0.23-0.92; p<0.05) but not myocardial infarction (RR: 0.74; CI: 0.36-1.48; p=0.1) in hypertensive patients with a past history. However, conventional treatment was superior to candesartan-based treatment in reducing the incidence of stroke in the patients without a past history of cardiovascular diseases (66% reduction; RR: 0.34; CI: 0.16-0.69; p<0.05). This is the first demonstration that an ARB-based antihypertensive treatment was superior to the conventional treatment for reducing the risk of stroke and myocardial infarction in Japanese hypertensive patients, especially in the patients with a past history of cardiovascular diseases.

Newly Diagnosed and Previously Known Diabetes Mellitus and 1-Year Outcomes of Acute Myocardial Infarction

BACKGROUND

A prior diagnosis of diabetes mellitus is associated with adverse outcomes after acute myocardial infarction (MI), but the risk associated with a new diagnosis of diabetes in this setting has not been well defined.

METHODS AND RESULTS

We assessed the risk of death and major cardiovascular events associated with previously known and newly diagnosed diabetes by studying 14,703 patients with acute MI enrolled in the VALsartan In Acute myocardial iNfarcTion (VALIANT) trial. Patients were grouped by diabetic status: previously known diabetes (insulin use or diagnosis of diabetes before MI, n=3400, 23%); newly diagnosed diabetes (use of diabetic therapy or diabetes diagnosed at randomization [median 4.9 d after infarction], but no known diabetes at presentation, n=580, 4%); or no diabetes (n=10,719). Patients with newly diagnosed diabetes were younger and had fewer comorbid conditions than did patients with previously known diabetes. At 1 year after enrollment, patients with previously known and newly diagnosed diabetes had similarly increased adjusted risks of mortality (hazard ratio [HR] 1.43; 95% confidence interval [CI], 1.29 to 1.59 and HR, 1.50; 95% CI, 1.21 to 1.85, respectively) and cardiovascular events (HR, 1.37; 95% CI, 1.27 to 1.48 and HR, 1.34; 95% CI, 1.14 to 1.56).

CONCLUSIONS

Diabetes mellitus, whether newly diagnosed or previously known, is associated with poorer long-term outcomes after MI in high-risk patients. The poor prognosis of patients with newly diagnosed diabetes, despite having baseline characteristics similar to those of patients without diabetes, supports the idea that metabolic abnormalities contribute to their adverse outcomes.

Valsartan, captopril, or both in myocardial infarction complicated by heart failure, left ventricular dysfunction, or both

BACKGROUND

Angiotensin-converting-enzyme (ACE) inhibitors such as captopril reduce mortality and cardiovascular morbidity among patients with myocardial infarction complicated by left ventricular systolic dysfunction, heart failure, or both. In a double-blind trial, we compared the effect of the angiotensin-receptor blocker valsartan, the ACE inhibitor captopril, and the combination of the two on mortality in this population of patients.

METHODS

Patients receiving conventional therapy were randomly assigned, 0.5 to 10 days after acute myocardial infarction, to additional therapy with valsartan (4909 patients), valsartan plus captopril (4885 patients), or captopril (4909 patients). The primary end point was death from any cause.

RESULTS

During a median follow-up of 24.7 months, 979 patients in the valsartan group died, as did 941 patients in the valsartan-and-captopril group and 958 patients in the captopril group (hazard ratio in the valsartan group as compared with the captopril group, 1.00; 97.5 percent confidence interval, 0.90 to 1.11; P=0.98; hazard ratio in the valsartan-and-captopril group as compared with the captopril group, 0.98; 97.5 percent confidence interval, 0.89 to 1.09; P=0.73). The upper limit of the one-sided 97.5 percent confidence interval for the comparison of the valsartan group with the captopril group was within the prespecified margin for noninferiority with regard to mortality (P=0.004) and with regard to the composite end point of fatal and nonfatal cardiovascular events (P<0.001). The valsartan-and-captopril group had the most drug-related adverse events. With monotherapy, hypotension and renal dysfunction were more common in the valsartan group, and cough, rash, and taste disturbance were more common in the captopril group.

CONCLUSIONS

Valsartan is as effective as captopril in patients who are at high risk for cardiovascular events after myocardial infarction. Combining valsartan with captopril increased the rate of adverse events without improving survival.

Angiotensin AT2 receptors: cardiovascular hope or hype?

British Journal of Pharmacology (2003) 140, 809–824. doi:10.1038/sj.bjp.0705448

Update on therapy for heart failure

The success of angiotensin-converting enzyme (ACE) inhibitors in reducing morbidity and mortality in patients with heart failure has led to investigations of other inhibitors of the renin-angiotensin-aldosterone system. Although ACE inhibitors remain first-line drugs in the treatment of heart failure and left ventricular dysfunction, clinical evidence suggests that a newer class of agents--angiotensin II receptor blockers--may provide additional benefit by blocking the adverse effects of angiotensin II more completely. An improved adverse-effect profile also makes angiotensin II receptor blockers appropriate in patients who cannot tolerate ACE inhibitors. Clinical trials have demonstrated the beneficial effects of angiotensin II receptor blockers on the combined endpoints of morbidity and mortality in patients with heart failure. Aldosterone antagonism with spironolactone has additive benefits in patients receiving an ACE inhibitor. The most recent treatment guidelines for heart failure recommend the use of angiotensin II receptor blockers and spironolactone in selected patients.

VALsartan In Acute myocardial iNfarcTion (VALIANT) trial: baseline characteristics in context

BACKGROUND

The VALsartan In Acute myocardial iNfarcTion (VALIANT) trial compared outcomes with: (1) angiotensin-converting enzyme inhibition (ACEI) with the reference agent captopril; (2) angiotensin-receptor blockade (ARB) with valsartan; or (3) both in patients with heart failure (HF) and/or left ventricular systolic dysfunction (LVSD) after myocardial infarction (MI).

AIMS

a goal of this active-control trial was to simulate conditions that would lead current practitioners to use ACEIs. Thus, we compared characteristics of VALIANT patients with those of patients in placebo-controlled trials that established ACEIs as standard treatment.

METHODS AND RESULTS

We collected demographic, clinical, medication and imaging information from 14703 patients in 24 countries. This high-risk population was a median 65.8 years old, and 31.1% were female. Most (51.8%) showed imaging evidence of LVSD at enrollment. Most (72%) had Killip class>/=II HF. Patients received evidence-based therapies at rates similar to those of contemporary MI trials and at an improved rate compared with prior placebo-controlled ACEI trials.

CONCLUSION

VALIANT represents the largest globally representative cohort enrolled with HF and/or LVSD after MI. Patients were similar to those in placebo-controlled ACEI trials while reflecting improvements in evidence-based care. With enrollment complete, VALIANT is poised to define the optimal strategy for renin-angiotensin system blockade after MI to improve cardiovascular outcomes.

Cardiovascular risk in dialysis patients: A comparison of risk factors and cardioprotective therapy between 1996 and 2001

Cardiovascular disease (CVD) is the major cause of mortality in dialysis patients. Aspirin, beta-blockers, statins, and angiotensin-converting enzyme (ACE) inhibitors reduce CVD mortality in the general population, as may angiotensin II receptor antagonists. The prevalence of cardiovascular risk factors and usage rates of cardioprotective agents in end-stage renal failure are unknown. A retrospective, cross-sectional study of dialysis patients was performed to compare: (i) prevalence of cardiovascular risk factors (age, hypertension, hyperlipidaemia, diabetes mellitus, and smoking); (ii) use of cardioprotective agents; and (iii) prevalence of cardiovascular disease between the time-points: 1996 (n = 262) versus 2001 (n = 369). We found an increase in the risk factors of age (53.6 +/- 14.9 years in 1996 vs 58.4 +/- 14.3 in 2001; P < 0.001) and hyperlipidaemia (45 vs 51.8%; P < 0.001) between the two time-points, with a reduction in the prevalence of smoking (14.5 vs 8.1%; P = 0.016). There was no difference in the prevalence of cardiovascular disease (37.4 vs 40.7%; P = 0.44). Cardioprotective agents were underutilized, with improvement in prescribing practice between 1996 and in 2001, especially in the usage of statins (21.4 vs 38.7% in 2001; P = 0.019). In conclusion, CVD is the primary cause of mortality in our dialysis patients. Although traditional cardiovascular risk factors affect the majority of the dialysis population, underutilization of cardioprotective agents is common. Proof of efficacy of these agents in this population of enormous risk is urgently required.

Why not prescribe the best drugs for hypertension now?

As Westernised societies have become more affluent, the attitudes of the population have become more risk-aware. People are now intolerant of small risks as well as the physical or mental discomforts from drug side effects. Safety and tolerability are now major forces driving the development of new medicines for the treatment of chronic illnesses and the prevention of increasingly rare events. For example, over the past decades, lower and lower treatment thresholds have been recommended in hypertension. Public perception of risk strongly influences the acceptability of lifetime treatment, especially for mild hypertension. This era has also witnessed great advances in the development of antihypertensive drugs that combine efficacy with unsurpassed tolerability. However, the philosophy of Scottish teachers of Materia medica still appears to be followed-'never be the first or the last to prescribe a new drug'. Angiotensin-converting enzyme (ACE) inhibitors and angiotensin II receptor antagonists are as safe and as efficacious as other antihypertensive medications and better tolerated. Large trials (HOT, HOPE, UKPDS and PROGRESS) point to the need for rigorous control of blood pressure particularly in high-risk individuals. Antihypertensive drugs that act on the renin-angiotensin system will probably impact significantly on achieving optimal blood pressure levels. Should it not now be accepted that high-risk patients should have ACE inhibitors and angiotensin II receptor antagonists prescribed as first-line agents? We review the evidence for the use of ACE inhibitors and angiotensin II receptor antagonists as antihypertensive agents.

Trends and Treatment of Heart Failure Developing After Acute Myocardial Infarction

The development of heart failure and/or left ventricular systolic dysfunction following acute myocardial infarction remains prevalent despite improvements in the diagnosis and management over the past decades. Although transient in some cases, the majority of these patients continue to carry a substantially higher mortality risk. New data on the benefits of eplerenone and carvedilol from large clinical trials have added to the complexity of polypharmacy in this patient subgroup, although aggressive medical strategies to prevent or reverse infarct-related left ventricular remodeling remains the most effective method to save lives and prevent disabilities.

Adding angiotensin II type 1 receptor blockade to angiotensin-converting enzyme inhibition limits myocyte remodeling after myocardial infarction

BACKGROUND

Adding angiotensin II type 1 receptor blockade (ARB) to angiotensin-converting enzyme inhibition (ACEI) further attenuates left ventricular (LV) remodeling in an ovine model of myocardial infarction (MI). We hypothesized that combined therapy with ACEI and ARB (CT) would be additive in the limitation of the myocyte hypertrophy and dysfunction that occurs in untreated adjacent noninfarcted regions during remodeling.

METHODS AND RESULTS

Nineteen sheep underwent coronary ligation to create a moderate-sized anteroapical infarction. Post-MI day 2, sheep were randomized to therapy with ramipril (ACEI, n = 5) or ramipril plus losartan (CT, n = 6) or none (untreated, n = 8). Infarct size was similar between groups. At 8 weeks post-MI, myocytes were isolated from regions adjacent to and remote from the infarct to measure morphometric indices (cell volume, length, cross-sectional area, width) and parameters of contraction (% shortening and -dL/dt, rate of shortening) and relaxation (+dL/dt [rate of relengthening] and TR 70% [time for 70% relengthening]). Volume % collagen was measured from adjacent and remote regions. Adjacent myocyte volume was different between groups (2.5 +/- 0.1 x 10(4) microm(3) in CT, 3.0 +/- 0.4 x 10(4) microm(3) in ACEI, 3.5 +/- 0.2 x 10(4) microm(3) in untreated, analysis of variance [ANOVA] P =.001) as was length (158 +/- 4 microm, 161 +/- 9 microm, 189 +/- 8 microm, respectively, ANOVA P <.001). Adjacent cell volume and length in CT were lower than untreated (P <.05). Percent shortening and -dL/dt of isolated adjacent myocytes were improved with both ACEI (7.9 +/- 0.3%, -131 +/- 6 microm/sec, P <.05) and CT (7.7 +/- 0.3%, -144 +/- 8 microm/sec, P <.05) compared with no therapy (6.4 +/- 0.4%, -104 +/- 7 microm/sec), as was both +dL/dt and TR 70%. No between-group difference in volume % collagen was found in adjacent or remote regions.

CONCLUSION

Compared with ACEI alone, the addition of ARB further limits adjacent noninfarcted myocyte hypertrophy during post-MI LV remodeling. Both ACEI alone and CT preserve isolated unloaded myocyte function, but neither significantly reduce interstitial collagen. The additional benefit of ARB on regional and global function in vivo may also be due to other factors including regional load.

Angiotensin II receptor blockers and cardiovascular outcomes: what does the future hold?

The ability of angiotensin-converting enzyme (ACE) inhibitors and angiotensin II receptor blockers (ARBs) to lower blood pressure (BP) is well established. ACE inhibitors (ACE-Is) have also been shown to improve the prognosis of a broad range of patients at high cardiovascular risk, including those with heart failure, post-myocardial infarction (MI), and nephropathy. These benefits suggest that interrupting the renin-angiotensin-aldosterone system (RAAS) with ACE-Is has a widespread vasculoprotective effect, provided that BP is also adequately controlled. Evidence that RAAS blockade by ARBs also improves long-term clinical outcomes in patients with cardiovascular disease has started to accumulate, and will be tested further during the coming years as a number of large-scale, prospective trials are completed. These trials are investigating the long-term protective effects of ARBs on morbidity and mortality in patients with hypertension, heart failure, diabetes mellitus, acute MI, or established vascular disease. The results should establish the extent to which ARBs exhibit the vasculoprotective properties demonstrated by ACE-Is in patients at high cardiovascular risk. If ARBs are found to provide benefits that are similar to, or even greater than ACE-Is, it may have important implications for drug selection, given the excellent tolerability of ARBs. Some studies are also investigating whether more extensive RAAS blockade using a combination of an ARB and an ACE-I will offer even greater protection than either agent alone.

Prospective evaluation comparing the effects of enalapril and losartan in left ventricular remodeling after acute myocardial infarction

BACKGROUND

Previous studies have compared angiotensin receptor blockers and angiotensin-converting enzyme inhibitors in patients with heart failure, but there are few data about the effect of these drugs regarding left ventricular remodeling after myocardial infarction.

METHODS

Fifty-two consecutive patients with first anterior wall myocardial infarction within 24 hours of evolution were randomized to receive enalapril (as much as 20 mg; mean, 14.6 mg), or losartan (as much as 50 mg; mean, 48 mg). Left ventricular ejection fraction and ventricular volumes were analyzed in 2 serial radionuclide ventriculograpies, carried out within 4 days after the infarction (mean, 97.4 +/- 114.2 hours) and after 6 months (mean, 177.7 +/- 16.7 days). Ventriculographies were analyzed by a single blinded observer. Mainly because of the unexpected large SD values obtained, the power of the study to demonstrate equivalence between the groups was only 15.7%.

RESULTS

The differences obtained between the first and the second ventriculographies, for the enalapril and losartan groups, were: for left ventricular ejection fraction, -0.4% +/- 6.6% versus -1.1% +/- 5.9% (P =. 67; 95% CI, 2.77-4.23); for final systolic volume, 0.07 +/- 7.7 mL/m(2) versus -0.2 +/- 6.1mL/m(2) (P =. 85; 95% CI, -3.57-4.26); for final diastolic volume -0.7 +/- 12.1 mL/m(2) versus -3.6 - 9.9 mL/m(2) (P =. 34; 95% CI, -3.22-9.17).

CONCLUSION

This study, although underpowered, suggests that neither enalapril nor losartan was superior as compared with each other for left ventricular remodeling after myocardial infarction; however, powerful evidence of equivalence was not provided.

Pharmacologic therapy for patients with chronic heart failure and reduced systolic function: review of trials and practical considerations

Heart failure (HF) is a complex clinical syndrome resulting from any structural or functional cardiac disorder impairing the ability of the ventricles to fill with or eject blood. The approach to pharmacologic treatment has become a combined preventive and symptomatic management strategy. Ideally, treatment should be initiated in patients at risk, preventing disease progression. In patients who have progressed to symptomatic left ventricular dysfunction, certain therapies have been demonstrated to improve survival, decrease hospitalizations, and reduce symptoms. The mainstay therapies are angiotensin-converting enzyme (ACE) inhibitors and beta-blockers (bisoprolol, carvedilol, and metoprolol XL/CR), with diuretics to control fluid balance. In patients who cannot tolerate ACE inhibitors because of angioedema or severe cough, valsartan can be substituted. Valsartan should not be added in patients already taking an ACE inhibitor and a beta-blocker. Spironolactone is recommended in patients who have New York Heart Association (NYHA) class III to IV symptoms despite maximal therapies with ACE inhibitors, beta-blockers, diuretics, and digoxin. Low-dose digoxin, yielding a serum concentration <1 ng/mL can be added to improve symptoms and, possibly, mortality. The combination of hydralazine and isosorbide dinitrate might be useful in patients (especially in African Americans) who cannot tolerate ACE inhibitors or valsartan because of hypotension or renal dysfunction. Calcium antagonists, with the exception of amlodipine, oral or intravenous inotropes, and vasodilators, should be avoided in HF with reduced systolic function. Amiodarone should be used only if patients have a history of sudden death, or a history of ventricular fibrillation or sustained ventricular tachycardia, and should be used in conjunction with an implantable defibrillator [corrected]. Finally, anticoagulation is recommended only in patients who have concomitant atrial fibrillation or a previous history of cerebral or systemic emboli.

New developments in the pharmacological treatment of chronic heart failure

In recent years, rapid growth in the understanding of the pathophysiology of chronic heart failure has allowed for insights into many potential new therapeutic strategies. Yet until now, despite sound biological basis for efficacy and success in early-Phase studies, novel agents have not stood up to the scrutiny of late-Phase clinical trials. Indeed, remarkably negative results have been observed for vasopeptidase inhibitors, endothelin receptor antagonists and agents which block immune activation. However, efficacy data from other novel agents are still awaited, including the selective aldosterone receptor antagonist eplerenone, arginine vasopressin inhibitors, erythropoietin and hydroxy-methyl-glutaryl coenzyme A reductase inhibitors. Other classes of drugs which may enter clinical development include cardiac metabolic agents, matrix metalloproteinase inhibitors and advanced glycation end product antagonists. That the mortality and morbidity of patients with chronic heart failure remain unacceptably high makes the ongoing commitment to exploration of new drug therapies for the condition critical.

Therapeutic role of angiotensin II receptor blockers in the treatment of heart failure

Angiotensin II type 1 receptor blockers (ARBs) are generally as effective as angiotensin-converting enzyme (ACE) inhibitors in patients with hypertension. However, inhibition of angiotensin is not achieved completely through the blocking effects of ACE inhibitors, and the possibility of a non-ACE pathway for generation of angiotensin II has important implications for treating cardiovascular disease. The selective quality of ARBs for the angiotensin II type 1 (AT1) receptor may confer an advantage. In a recently reported trial, the ARB valsartan substantially improved patients' New York Heart Association class, clinical signs and symptoms, and quality of life and provided morbidity and mortality benefits in selected patients. Valsartan was recently approved to treat heart failure in patients who cannot be maintained on an ACE inhibitor. As a class, ARBs are well tolerated and have a good safety profile.

Clinical trials evaluating angiotensin-converting enzyme inhibitors and angiotensin receptor blockers in the setting of acute myocardial infarction

There is strong evidence from controlled clinical trials that in the setting of acute myocardial infarction complicated by heart failure or isolated left ventricular dysfunction, angiotensin-converting enzyme inhibitors started late during hospitalisation and continued in the long term, significantly reduced mortality and improved the prognosis. On the other hand, administration of angiotensin-converting enzyme inhibitors during the first 24 h in unselected patients with acute myocardial infarction provided only a slight benefit in terms of mortality. Angiotensin-II receptor blockers have and are being examined in the setting of acute myocardial infarction with left ventricular dysfunction and can provide an alternative for patients who cannot tolerate angiotensin-converting enzyme inhibitors. In this article, an evidence-based review of these major trials and suggestions for clinical application are presented.

Angiotensin II receptor blockers in heart failure

Heart failure remains a significant cause of morbidity and mortality, despite major advances in therapy. Angiotensin II, the principal mediator of the renin-angiotensin system, exerts both short-term (e.g., hemodynamic, renal) and long-term (e.g., inflammation, cardiac remodeling) effects in the pathophysiology of cardiovascular disease. The effects of angiotensin II appear to be more completely inhibited by angiotensin II receptor blockers (ARBs), which act at the subtype 1 receptor level, than by angiotensin-converting enzyme (ACE) inhibitors because pathways other than that of ACE contribute to the generation of angiotensin II. Evidence demonstrates that ARBs, when added to conventional treatment for patients with heart failure, are associated with a reduction in morbidity and mortality as well as an improvement in quality of life. Clinical trials of ARB therapy indicate that these agents are generally well tolerated, both alone and in combination with other neurohormonal inhibitors. The current role of ARBs in heart failure is as an alternative for patients who cannot tolerate therapy with an ACE inhibitor. A number of ongoing clinical studies are likely to further define or expand the role of ARBs in the treatment of cardiovascular disease.

[Preclinical and clinical profile of Valsartan, a selective angiotensin II type-1 receptor blocker]

Valsartan (Diovan) is a potent, orally active, specific, and highly selective blocker for the AT1-receptor subtype. The antihypertensive effects of oral treatment with valsartan were preclinically demonstrated in the sodium-depleted marmosets, renal hypertensive rats (2K1C), spontaneous hypertensive rats (SHR) and stroke-prone SHR. Moreover, valsartan had protective effects against hypertensive end-organ damage such as cardiac hypertrophy and renal disease. In an investigation of pharmacokinetics and pharmacodynamics in normotensive male volunteers, valsartan was rapidly absorbed with the maximal plasma concentration occurring 2-3 h after oral administration. The elimination half-life was about 4-6 h, valsartan was poorly metabolized, and most of the drug was excreted via feces. Valsartan produced persistent reductions of blood pressure in patients with mild to moderate essential hypertension and had a good safety profile with a wide therapeutic window between the effective pharmacological doses and the toxic doses. Therefore, valsartan is expected to be a safe and effective antihypertensive agent for the treatment of essential and severe hypertension.

Ongoing trials involving angiotensin-converting enzyme inhibitors

Angiotensin-converting enzyme inhibitors (ACEIs) are an important class of drugs in cardiovascular disease. As their name suggests, they act by blocking angiotensin converting enzyme, thereby limiting the production of angiotensin II, the most active component of the renin-angiotensin- aldosterone system. This system plays an important role in maintenance of blood pressure and electrolyte and fluid balance. Therefore, by blocking this system, the ACEIs have wide ranging effects. Recent trials have reaffirmed their place in the management of hypertension, congestive cardiac failure, in the prevention of renal complications in diabetes and the prevention of strokes in 'at risk' patients. There are still many ongoing trials using the ACEIs. These trials are mainly aimed at comparing their efficacy with 'older' drugs (such as betablockers) and 'newer' drugs such as the angiotensin receptor blockers and calcium antagonists in different indications, such as heart failure and diabetic nephropathy. The impact of these drugs on the prevention of macro- and micro vascular complications in diabetes is also being investigated. The results of all these trials, when available, are expected to reaffirm the important role of this class of drugs in our modern day medical armamentarium. In this review, the ongoing clinical trials involving ACEIs, the rationale behind these trials and what impact they hope to have on our current understanding of the role of this important class of drug in medical practice, will be discussed.

Vascular and cardiac benefits of angiotensin receptor blockers

Angiotensin II not only is a vasoconstrictor, but it also affects cell growth and apoptosis, inflammation, fibrosis, and coagulation. Blockade of the renin-angiotensin system, either with inhibitors of the generation of angiotensin (angiotensin-converting enzyme [ACE] inhibitors) or with blockers of angiotensin receptors, reduces blood pressure and inhibits other pathophysiological actions. These other effects provide benefits in coronary heart disease, heart failure, diabetic nephropathy, and stroke beyond blood pressure reduction. These benefits were first demonstrated with ACE inhibitors. However, the mechanism of action of angiotensin receptor blockers, which block angiotensin II stimulation at the angiotensin type 1 receptor but not at the type 2 receptor, may have advantages, particularly for endothelial dysfunction and vascular remodeling, as well as cardiac and renal protection. Recent multicenter trials suggest that ACE inhibitors and angiotensin receptor blockers may reduce morbidity and mortality associated with cardiovascular and renal disease beyond blood pressure reduction. Several studies with different angiotensin receptor blockers, including comparisons with ACE inhibitors, are under way, and should provide further guidance for their clinical use.

Effects of losartan and captopril on mortality and morbidity in high-risk patients after acute myocardial infarction: the OPTIMAAL randomised trial. Optimal Trial in Myocardial Infarction with Angiotensin II Antagonist Losartan

BACKGROUND

ACE inhibitors attenuate the detrimental effects of angiotensin II, and improve survival and reduce morbidity in patients with acute myocardial infarction and evidence of heart failure or left-ventricular dysfunction. Selective antagonism of the angiotensin type 1 receptor represents an alternative approach to inhibition of the renin-angiotensin system. We did a multicentre, randomised trial to test the hypothesis that the angiotensin II antagonist losartan would be superior or non-inferior to the ACE inhibitor captopril in decreasing all-cause mortality in high-risk patients after acute myocardial infarction.

METHODS

5477 patients 50 years of age or older (mean age 67.4 years [SD 9.8]), with confirmed acute myocardial infarction and heart failure during the acute phase or a new Q-wave anterior infarction or reinfarction, were recruited from 329 centres in seven European countries. Patients were randomly assigned and titrated to a target dose of losartan (50 mg once daily) or captopril (50 mg three times daily) as tolerated. The primary endpoint was all-cause mortality. Analysis was by intention to treat.

FINDINGS

There were 946 deaths during a mean follow-up of 2.7 (0.9) years: 499 (18%) in the losartan group and 447 (16%) in the captopril group (relative risk 1.13 [95% CI 0.99-1.28], p=0.07). The results for the secondary and tertiary endpoints were as follows: sudden cardiac death or resuscitated cardiac arrest 239 (9%) versus 203 (7%), 1.19 (0.98-1.43), p=0.07, and fatal or non-fatal reinfarction 384 (14%) versus 379 (14%), 1.03 (0.89-1.18), p=0.72. The all-cause hospital admission rates were 1806 (66%) versus 1774 (65%), 1.03 (0.97-1.10), p=0.37. Losartan was significantly better tolerated than captopril, with fewer patients discontinuing study medication (458 [17%] vs 624 [23%], 0.70 [0.62-0.79], p<0.0001).

INTERPRETATION

Since we saw a non-significant difference in total mortality in favour of captopril, ACE inhibitors should remain first-choice treatment in patients after complicated acute myocardial infarction. Losartan cannot be generally recommended in this population. However, it was better tolerated than captopril, and was associated with significantly fewer discontinuations. Although the role of losartan in patients intolerant of ACE inhibition is not clearly defined, it can be considered in such patients.

Role of valsartan and other angiotensin receptor blocking agents in the management of cardiovascular disease

Blockade of the renin-angiotensin system by angiotensin converting enzyme (ACE) inhibitors reduces mortality and morbidity in patients post-myocardial infarction as well as in chronic heart failure and hypertension. ACE inhibitors also have a well-established place in the treatment of diabetic nephropathy. Angiotensin receptor blockers (ARBs) have been developed to produce a more complete blockade of the actions of angiotensin II as compared to other drug classes, as well as an improved side effect profile. This article provides an overview of the place of ARBs in general and of the ARB valsartan in particular, and draws comparisons to ACE inhibitors in the treatment of cardiovascular diseases.

Angiotensin II receptor antagonists in chronic heart failure: where do they fit?

Heart failure is a common and disabling condition with a dismal prognosis. Inhibition of the renin-angiotensin-aldosterone system (RAAS) with angiotensin converting enzyme (ACE) inhibitors has proven to be a valuable therapeutic strategy in this condition, with well-proven morbidity and mortality benefits. Nonetheless, ACE inhibitors provide incomplete blockade of the RAAS and also inhibit the degradation of bradykinin. Although increased levels of bradykinin may have haemodynamic advantages by contributing to vasodilatation, they may also be largely responsible for some of the adverse effects of ACE inhibitors. Angiotensin II (Ang II) receptor antagonists offer more complete blockade of the RAAS without the potentiation of bradykinin, and it was therefore hoped that they would provide even greater benefits for patients with heart failure. So far, much of the initial promise of the Ang II receptor antagonists in heart failure has not been realised. There has been no conclusive demonstration of their superiority to ACE inhibitors in their effects on morbidity and mortality, and their equivalence to ACE inhibitors has not been proven. The Ang II receptor antagonists have, however, proven to be better tolerated than ACE inhibitors and they are therefore likely to be a reasonable alternative for those patients with heart failure who cannot tolerate ACE inhibition. Recent evidence has indicated that the Ang II type 1 receptor antagonist valsartan is of value when used in patients already receiving either an ACE inhibitor or a beta-blocker, but has also suggested that giving all three drugs together is deleterious. Further evidence about the value of Ang II receptor antagonists in heart failure may be provided by further studies, of which several are currently ongoing.

The Use of Angiotensin-II Receptor Blockers in Heart Failure

Angiotensin-II receptor blockers (ARBs) have recently been evaluated in large trials to determine their role in the treatment of heart failure. It is clear that angiotensin-converting enzyme inhibitors (ACE-Is) prevent the effects of an overactive renin-angiotensin aldosterone system and therefore prevent disease progression. Despite this evidence, intolerance (eg, cough) limits the use of ACE-Is in heart failure patients. Improved tolerability makes ARBs attractive alternatives in patients intolerant to ACE-Is. ARBs are also hypothesized to have additional benefits when used in combination with ACE-Is through more complete inhibition of angiotensin-II. However, studies of ARBs in patients with heart failure have not confirmed this hypothesis. This article describes the rationale and evaluates the literature for the use of ARBs in heart failure.

The practical aspects of combination therapy with angiotensin receptor blockers and angiotensin-converting enzyme inhibitors

Angiotensin-converting enzyme (ACE) inhibitors and/or angiotensin receptor blockers (ARBs) are widely prescribed for the management of hypertension. ACE inhibitors (ACE-I) and, more recently, ARBs have an established track record of success in the treatment of congestive heart failure (CHF), proteinuric renal disease and most recently the hypertensive patient with a high cardiac-risk profile. The individual success of each of these drug classes has fuelled speculation that given together the overall effect of both would exceed that of either given alone. This premise, although biologically plausible, has yet to be proven in a convincing enough fashion to support the routine use of these two drug classes in combination. Additional clarifying studies are needed to establish whether specific patient subsets exist that might benefit from such combination therapy.

Renin-angiotensin system antagonism and lipid-lowering therapy in cardiovascular risk management

The renin-angiotensin system (RAS) and dyslipidaemia have been shown to be involved in the genesis and progression of atherosclerosis. Manipulation of the RAS has been effective in modifying human coronary artery disease progression. Similarly, the 3-hydroxy-3-methylglutaryl coenzyme A (HMG CoA) reductase inhibitors or statins have been shown to reduce cholesterol and lower cardiovascular events in primary and secondary prevention trials in coronary artery disease. In addition to their primary mode of action, statins and blockers of the RAS possess common additional properties that include restoration of endothelial activity and inhibition of cellular proliferation. This article reviews the current data on the common properties of these classes of drugs in which the beneficial effects extend beyond their antihypertensive and lipid-lowering properties.

Angiotensin II Type 1 receptor antagonists in chronic heart failure

Angiotensin II Type 1 receptor antagonists share most but not all of their pharmacological actions with angiotensin-converting enzyme inhibitors. The latter belong to standard heart failure therapy, with proven benefit in terms of morbidity and mortality. Promising data have been provided for angiotensin II Type 1 receptor antagonists in experimental models of heart failure. In patients with hypertension and those with diabetic nephropathy, favourable results have been observed with regards to blood pressure control, reversibility of structural changes or prevention of progression of disease. The currently available clinical trials in heart failure patients with angiotensin II Type 1 receptor antagonists suggest that they may be equivalent to angiotensin-converting enzyme inhibitors, but superiority has not been proven. There is no doubt about their effectiveness with regards to symptoms; however, their effect on hospitalisation and mortality is not unequivocally demonstrated. Further trials are warranted, particularly to define their role in comparison with and in addition to angiotensin-converting enzyme inhibitors and to further characterise heart failure patient populations who derive benefit from angiotensin II Type 1 receptor blockers above and beyond angiotensin-converting enzyme inhibitors, beta-blockers and spironolactone.

The Evolving Role of Angiotensin Receptor Blockers in Heart Failure

This continuing feature will update readers on recent developments in cardiovascular pharmacotherapy. Cardiovascular disease remains the number one killer in the US, and more clinical outcome trials have been conducted in cardiology than in any other field of medicine. Given this rapidly expanding knowledge base, pharmacists can have a significant impact on the prevention and treatment of cardiovascular disease—if they keep current with developments in drug therapy.