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The unique findings from the HOPE (Heart Outcomes Prevention Evaluation) study strongly support extending the use of the angiotensin-converting enzyme (ACE) inhibitor ramipril as a preventive agent for patients at high risk of cardiovascular events with normal left ventricular function. In addition, ramipril provides significant benefit in diabetic patients. These findings will impact on how ramipril is used in primary care, where ACE inhibitors are currently underprescribed. Patients reflecting the inclusion criteria of the HOPE study should be considered as suitable candidates for long-term ramipril therapy as an addition to their existing drug regimen. Screening should include control of kidney function (by serum creatinine), particularly within the first two weeks of treatment, in addition to regular monitoring of serum potassium. However, the HOPE study shows that ramipril is well tolerated at high doses and over a long treatment period. The effectiveness of therapy should also be regularly reviewed and dose adjustments made where necessary. If concern remains, referral to a specialist--a cardiologist or a diabetologist--may ultimately be necessary.

Background: We undertook a prospective systematic overview based on data from individual patients from five long-term randomised trials that assessed inhibitors of angiotensin-converting enzyme (ACE) in patients with left-ventricular dysfunction or heart failure., Methods: Three of the trials enrolled patients within a week after acute myocardial infarction. Data were combined by use of the Peto-Yusuf method., Findings: Overall 12,763 patients were randomly assigned treatment or placebo and followed up for an average of 35 months. In the three post-infarction trials (n=5,966), mortality was lower with ACE inhibitors than with placebo (702/2995 [23.4%] vs 866/2971 [29.1%]; odds ratio 0.74 [95% CI 0.66-0-83]), as were the rates of readmission for heart failure (355 [11.9%] vs 460 [15.5%]; 0.73 [0.63-0.85]), reinfarction (324 [10.8%] vs 391 [13.2%]; 0.80 [0.69-0.94]), or the composite of these events (1049 [35.0%] vs 1244 [41.9%]; 0.75 [0.67-0.83]; all p

Ramipril is a long-acting, lipophylic angiotensin converting enzyme inhibitor, its principle action is to inhibit the conversion of angiotensin I to the active angiotensin II. Ramipril is indicated in the treatment of hypertension, congestive cardiac failure (including that following acute myocardial infarction), nephropathy (with and without diabetes mellitus) and now, following the findings of the HOPE study, in the prevention of cardiovascular events (including myocardial infarction) in high risk individuals. This article concentrates on reviewing the evidence supporting ramipril's use in these indications.

Angiotensin-converting enzyme (ACE) inhibitors are now accepted as part of the routine management of patients with heart failure. Their use has been mandated in all the new major mortality trials to test the efficacy of beta-blockers in heart failure. Morbidity and mortality remain high in those with heart failure even with the benefits proven for both these groups of agents. In spite of the evidence for benefit of ACE inhibitors they are persistently used in lower doses in clinical practice than tested in the large-scale trials. This was so prevalent as to allow the conduct of a substantial study, the ATLAS trial, to compare high and low dose ACE inhibition. Its equivocal findings have allowed different interpretations. Clinical experience would suggest that starting with a low dose is appropriate but the dose should be titrated then without undue delay to the levels used in the trials wherever possible. The evidence for benefit with these drugs had been obtained largely in patients with impaired systolic function. However the AIRE study selected patients with clinical evidence of heart failure after myocardial infarction rather than with impaired systolic function. A substantial and long-term benefit was found from ACE inhibition. A cohort of patients had ventricular function assessed and as anticipated almost one half had preserved systolic function. Whilst the absolute benefit in lives saved was greater in the higher risk/low ejection fraction group, the relative risk reduction was not significantly different between those with preserved or impaired systolic function. The publication of the HOPE trial, although not a study of patients with heart failure, has clarified the situation considerably for those taking day to day care of patients. The HOPE study selected patients on the basis of high cardiovascular risk excluding those with known impaired systolic function. Although not an entry requirement for the study, ejection fraction was measured in a substantial majority and was above 40% indicating preservation of systolic function. The ACE inhibitor ramipril markedly reduced the combined end-point of cardiovascular death, stroke and myocardial infarction. Importantly there was a highly significant 20% risk reduction in the rate of myocardial infarction, a prospectively defined end-point, over the average four and a half year follow-up. Taken together with the retrospectively derived evidence from the heart failure trials there is now compelling evidence that the ACE inhibitors prevent myocardial infarction. The majority of patients with clinical heart failure have underlying ischaemic heart disease. Prevention of myocardial infarction and control of blood pressure are two key factors in the management of these patients irrespective of systolic ventricular function. The ACE inhibitors like the beta-blockers therefore have a pivotal role in their management. A challenge to current clinical trials is to determine whether these properties are shared to the same degree by the angiotensin antagonists or if even further gains in benefit can come from their combination. The neutral findings of the ELITE II study comparing the angiotensin antagonist, losartan, with the ACE inhibitor, captopril, have heightened interest in the on-going trials addressing these issues.

In a cohort of 67 patients from the Acute Infarction Ramipril Efficacy study, we showed that ramipril therapy was associated with a significant reduction in QT dispersion over a 2-month period after acute myocardial infarction. This reduction of ventricular repolarization inhomogeneity indicates an antiarrhythmic effect and may be an important additional mechanism for the reduced all-cause mortality and sudden death incidence achieved with angiotensin-converting enzyme inhibition after acute myocardial infarction.

Objectives: To examine clinical outcomes associated with optional beta blockade in a population of patients with evidence of heart failure after myocardial infarction., Design and Patients: Data from the acute infarction ramipril efficacy (AIRE) study were analysed retrospectively. At baseline 22.3% of the patients were receiving a beta blocker. To minimise confounding, beta blocker and diuretic treatments, presence of clinical signs of heart failure, left ventricular ejection fraction, and 16 other baseline clinical variables were simultaneously entered in a multivariate Cox regression model. In addition, the same analysis was repeated separately within a high and a low risk group of patients, as defined according to the need for diuretic treatment., Results: beta Blocker treatment was an independent predictor of reduced risk of total mortality (hazard ratio 0.66, 95% confidence interval (CI) 0. 48 to 0.90) and progression to severe heart failure (0.58, 95% CI 0.40 to 0.83) for the entire study population. There were similar findings in high risk patients requiring diuretics (0.59, 95% CI 0.40 to 0.86; and 0.58, 95% CI 0.38 to 0.89)., Conclusions: beta Blocker treatment is associated with improved outcomes in patients with clinical evidence of mild to moderate heart failure after myocardial infarction. Most importantly, high risk patients with persistent heart failure appear to benefit at least as much as lower risk patients with transient heart failure.

It is now clear that angiotensin-converting enzyme (ACE) inhibitor treatment after myocardial infarction (MI) reduces mortality and morbidity. However, the benefits of ACE inhibition are not homogeneous and are largely confined to high-risk patients who have subjective or objective evidence of left ventricular (LV) dysfunction. How long treatment should continue is a vexed question, which also arises with other agents, for example beta-blocker use after MI. The AIREX study assessed the long-term magnitude and duration of the survival benefits observed with ramipril in patients after MI who have clinically defined heart failure. The mortality status of all 603 patients recruited from the UK centres involved in the AIRE study was verified at an extended 5-year follow-up (3 years after the AIRE study closed). Ramipril assignation was associated with a 36% relative and a 11% absolute mortality risk reduction. These findings strongly support the view to select patients on the basis of impaired LV function and reinforce the previously reported conclusions of the "selective" ACE inhibition post-MI trials. Using this approach, the survival benefit is not only of large magnitude but also sustained over many years. These results also argue for life-long treatment with an ACE inhibitor, once a decision to treat an individual patient after MI has been made.

The structure and function of subcutaneous small arteries from patients with mild heart failure (n = 27) 6-43 mo after myocardial infarction were compared with vessels from healthy control subjects (n = 10). Patients were randomized to treatment with placebo or the angiotensin-converting enzyme inhibitor ramipril starting 3-10 days after myocardial infarction. Dissected arterial vessels were mounted on a wire myograph for measurement of morphology and isometric tension. Morphology was not different in arteries from the three groups. Responses to norepinephrine, angiotensin II, and electrical field stimulation were similar in arteries from placebo-treated patients with mild heart failure and control subjects. Similarly, endothelium-dependent and -independent relaxation was normal in arteries from patients with mild heart failure. Ramipril therapy was associated with functional alterations: vasoconstrictor responses to norepinephrine and angiotensin II were significantly enhanced compared with placebo (P < 0.001). These data suggest that vascular structure and function are not different in vitro in subcutaneous arteries from placebo-treated patients with mild heart failure. Angiotensin-converting enzyme inhibitor therapy is associated with enhanced vasoconstriction to norepinephrine and angiotensin II, which may reflect upregulation of receptor-mediated events.

We estimated the cost effectiveness of adding the ACE inhibitor ramipril to conventional treatment in patients with heart failure after acute myocardial infarction. These estimates were based on the Acute Infarction Ramipril Efficacy (AIRE) study and on complementary Swedish healthcare resource use data for a subset of patients. The average follow-up period was 15 months (minimum 6 months, maximum 3.8 years). The perspective of the analysis was that of the county councils (third-party payers), and we focused on the cost of drugs and hospitalisation. The marginal cost effectiveness of the treatment was estimated over 3 treatment periods: 1, 2 and 3.8 years. The cost-effectiveness ratios varied between SEK14,148 and SEK33,033 per life-year gained ($US1 = SEK7.70. Pounds 1 = SEK12.40) for the 3 treatment periods. Adding ramipril to conventional treatment for heart failure after acute myocardial infarction is therefore cost effective, and compares favourably with the cost effectiveness of other common medical therapies in the cardiovascular field.

Background: In the Acute Infarction Ramipril Efficacy (AIRE) Study, the effect of angiotensin-converting-enzyme (ACE) inhibition on the survival of patients with clinical heart failure after acute myocardial infarction (AMI), was assessed. At an average follow-up time of 15 months after randomisation, all-cause mortality was reduced from 22.6% (placebo group) to 16.9% (ramipril group) representing an absolute mortality reduction of 5.7% and a relative risk reduction of 27% (95% CI 11-40%; p = 0.002). Our aim in this study was to assess the long-term (3 years after the AIRE Study closed) magnitude, duration, and reliability of the survival benefits observed after treatment with ramipril (target dose 5 mg twice a day) when compared with placebo., Methods: We investigated the mortality status of all 603 patients recruited from the 30 UK centres involved in the AIRE Study. Through government records we were able to confirm the death or survival of all 603 patients exactly 3 years after the close of the AIRE Study. Follow-up was for a minimum of 42 months and a mean of 59 months. The average duration of treatment with masked trial medication was 13.4 months for placebo and 12.4 months for ramipril., Findings: By 0000 h March 1, 1996, death from all causes had occurred in 117 (38.9%) of 301 patients randomly assigned placebo and 83 (27.5%) of 302 patients randomly assigned ramipril, representing a relative risk reduction of 36% (95% CI 15-52%; p = 0.002) and an absolute reduction in mortality of 11.4% (114 additional 5-year survivors per 1000 patients treated for an average of 12.4 months)., Interpretation: Our data provide robust evidence that administration of ramipril to patients with clinically defined heart failure after AMI results in a survival benefit that is not only large in magnitude, but also sustained over many years.

Large randomised clinical trials have shown ACE inhibitors to improve survival after acute myocardial infarction (AMI). The precise mechanism underlying this benefit is not fully established, despite extensive research. There is also controversy with regard to the clinical use of these drugs, particularly the need for selection of patients prior to treatment and the timing of drug initiation and withdrawal for maximum benefit. Animal models of AMI used to assess drug effects are of limited value in understanding the mechanisms of benefit because they involve significantly different pathophysiology from that which occurs in humans. Here we propose that the benefit of ACE inhibitor therapy is largely confined, post-AMI, to those with evidence of left ventricular dysfunction clinically or on investigation, and suggest the continuing importance of treatment distant from the acute event. We argue that the beneficial effects are, at least in part, related to a reduction in the direct toxic effects of angiotensin II and catecholamines on cardiomyocytes resulting from the long term excess stimulation of the renin-angiotensin and sympathetic systems in these patients. Importantly, we believe that for some patients after AMI there is little or no benefit to be gained from treatment and that, in fact, careful analysis of the trials suggests that ACE inhibitors may be associated with adverse outcomes in some individuals. Finally, since ACE inhibitors also potentiate bradykinin and other peptides, their beneficial action may not simply be due to reducing the formation of angiotensin II. The proportion of the benefit that may be via bradykinin is difficult to assess, especially in humans. However, the advent of the angiotensin receptor antagonists has provided the opportunity to investigate this important issue.

Background: The importance of the effects of ACE inhibitors on sudden death, progressive heart failure and recurrent infarction to the reduction in overall mortality in heart failure and after myocardial infarction is disputed., Methods: The AIRE study randomized 2006 patients with clinical or radiological evidence of heart failure within 2-9 days of a myocardial infarction to receive ramipiril 5 mg b.d. or matching placebo. Outcomes were assessed independently by members of an end-points committee blinded to treatment allocation., Results: Fewer patients developed severe resistant heart failure as their first validated end-point on rampril, despite the greater number of at-risk survivors, compared to placebo (n = 143 vs 178; risk reduction 23%; CI 5 to 39%; P = 0.017). Ramipril did not alter the rate of reinfarction or stroke. Irrespective of treatment allocation 182 (46%) patients developed resistant heart failure prior to death. A validated acute or remote myocardial reinfarction occurred in 76 (19%) patients prior to death and chest pain occurred in 90 (23%) patients around the time of death suggesting an ischaemic element to these deaths Eighty deaths occurred on the index admission, 167 during re-admission and 145 out-of-hospital. Sudden death accounted for 54% of all deaths and 93% of out-of-hospital deaths. Ramipril reduced the risk of sudden death by 30% (95% CI: 8-47%; P = 0.011). However, overall, 45% of those patients who died suddenly had severe or worsening heart failure prior to their death. Only 39% of sudden deaths were considered to be due to arrhythmias. Ramipril reduced the risk of death from circulatory failure by 18%, but this did not reach statistical significance (95% CI; 41 to -14%; P = 0.237). The magnitude of the effects on sudden death and death due to circulatory failure were not significantly different. However, 38% of the reduction in overall mortality was from the subgroup with sudden death who had developed prior severe resistant heart failure (placebo n = 35, ramipril n = 15), again emphasizing the marked benefit in preventing failure. Ramipril did not selectively alter the proportion of in- to out-of-hospital deaths., Conclusion: Ramipril reduces mortality and progression to resistant heart failure among patients with evidence of heart failure early after myocardial infarction. Retarding the progression of heart failure appears to be a major factor contributing to the reduction in mortality both by reducing circulatory failure and by reducing sudden death.

Doctors treat patients, not populations. 'Evidence-based' practice is essential but extrapolation to the individual patient is always necessary and this fact is well illustrated by data from trials of ACE inhibitors post-myocardial infarction. In the AIRE (Acute Infarction Ramipril Efficacy) study, 2,006 patients with some evidence of heart failure, even if transient, after a myocardial infarction, were randomised to receive oral ramipril or placebo in addition to standard treatment. Follow-up was for a minimum of six and an average of 15 months. The risk reduction in total mortality was 27% (95% CI 11-40%; p = 0.002); approximately 40 lives might be expected to be saved for every 1000 patients treated for one year. Benefit was apparent within weeks of starting treatment. Additional data from the AIRE study are considered in relation to the findings of other mortality trials. It is argued that ACE inhibitors offer most to those patients with impaired left ventricular function through a mechanism not related to the prevention of myocardial re-infarction.

Angiotensin-converting enzyme (ACE) inhibitors are now established drugs in the treatment of hypertension and heart failure. However, their use in patients after a myocardial infarction has occurred remains controversial. The major clinical question regarding ACE inhibitors is whether they should be given to all patients immediately after thrombolysis or whether their use should be restricted to a particular subgroup. This question has now been addressed in several large-scale trials of mortality after myocardial infarction, and no important new information seems likely to emerge on the issue. Clinicians must therefore decide what their practice will be on the basis of data that are currently available. The authors of the recently published Gruppo italiano per lo Studio delta Sopravvlvenza nell' infarcto Miocardico (GISSI-3) and Fourth International Study of Infarct Survival (ISIS-4) mega-trials advocate a policy of widespread and early use of ACE inhibitors in all patients after myocardial infarction occurs. However, the small mortality benefit observed from use of ACE inhibitors in these studies lacks certainly and may prove difficult to reproduce in the general population of patients who have had an infarct outside the setting of a trial. Although patients were essentially not selected apart from the exclusion of those with marked hypotension, the low 6-month and 1-year mortality figures indicate "selection" compared with the typical population of patients who have had a myocardial infarction. Furthermore, a significant long-term mortality benefit was not observed with the short-term (4- to 6-week) use of ACE inhibitors in these trials. In contrast, in the Survival and Ventricular Enlargement (SAVE), Acute Infarction Ramipril Efficacy (AIRE), and Trandopril Cardiac Evaluation (TRACE) trials, where evidence of impairment of ventricular function was used to select patients, both a marked and certain benefit regarding mortality was apparent from long-term prescription of these drugs. Importantly, the marked benefit observed in these selected patients may have been "diluted out" in the larger scale trials of unselected patients where the majority may have gained little and some may have been harmed by treatment or its withdrawal. In most of the large mortality trials the rationale for use of ACE inhibitors after myocardial infarction was stated to be their likely beneficial effect on "remodeling" of the heart after "Infarct expansion." Because adverse remodeling occurs in only a proportion of patients after a heart attack, the benefits of ACE inhibitor therapy might be predicted to be largely limited to this group, which would favor a selective policy. However, strong claims have been made that ACE inhibitors have other important actions, including prevention of myocardial infarction. If this is confirmed in a number of ongoing large-scale trials. then an even ore widespread use of these agents can be expected.

A series of elegant experimental studies and careful clinical observation over a decade or more have led to the concept of 'infarct expansion' and 'remodelling' of the heart, culminating in a number of major mortality studies indicating the effectiveness of angiotensin-converting enzyme (ACE) inhibitors in patients after myocardial infarction (MI). But has this concept been too narrow in predicting which patients might benefit from treatment with ACE inhibitors? Measurable infarct-expansion with progressive dilatation probably occurs in less than 20% of patients, whereas increase in volume and hypertrophy of the heart as responses to compromised function are likely wherever significant myocardial damage has occurred. Irrespective of infarct expansion, cumulative extensive damage can lead to an inevitable downward spiral with gross ventricular dilatation and death in heart failure. But in the majority of patients after MI a 'new equilibrium' is established in which initial dilatation and subsequently hypertrophy restore adequate function. Is it possible to distinguish patients in whom the cost and inconvenience of long-term therapy with an ACE inhibitor justify the likely benefit from treatment after an MI? The SAVE, AIRE and recent TRACE studies allow a rational approach for the clinician, indicating the effectiveness of these drugs in patients with evidence of impaired ventricular function. However, the prospect that ACE inhibitors prescribed long term might also prevent myocardial reinfarction could justify wider use. Post-MI patients are an easily identifiable high-risk group for a cost-effective programme of secondary prevention. Reinfarction in an already damaged ventricle carries a particularly poor prognosis and its prevention by ACE inhibitors could make a major contribution to the undoubted benefit from these agents. The recently completed TRACE study with its long-term follow-up may help resolve this issue, which is also being investigated in a number of long-term prospective studies in populations at high risk of cardiovascular disease.

The rationale for using angiotensin converting enzyme (ACE) inhibitor therapy after acute myocardial infarction has been largely founded on observations made in experimental situations, and in humans before the routine introduction of reperfusion therapies. An important area of ongoing debate therefore continues to be the role of ACE inhibition as an early adjunct to attempts to achieve and maintain patency of infarct-related coronary arteries. Data from clinical trials indicate a substantial survival benefit in patients with impaired ventricular function, but provide little support for the routine treatment of the remaining majority of patients. An important issue in determining whether these agents should be used in a more general and long-term secondary prevention role, is their potential ability to prevent subsequent reinfarction. However, such a strategy is unlikely to be enhanced by either immediate initiation of treatment or withdrawal after just 1 month of therapy.

A number of major studies have examined the impact of angiotensin-converting enzyme inhibitors on mortality in patients with ischemic heart disease. However, in these studies, selection of patients, choice of agent and timing of treatment after myocardial infarction have differed. In the Second Cooperative North Scandinavian Enalapril Survival Study (CONSENSUS II), all patients, unless hypotensive, were treated immediately after thrombolysis with placebo or intravenous enalaprilat followed by oral therapy. In contrast, in the Survival and Ventricular Enlargement (SAVE) study, patients were selected with a reduced radionuclide ejection fraction and without overt ongoing ischemia. Despite these different approaches, both studies were based on the rationale that angiotensin-converting enzyme inhibition would beneficially affect infarct expansion and subsequent remodeling. The SAVE study reported a significant reduction in mortality rate (19% risk reduction, 95% confidence interval [CI] 3% to 32%) over an average follow-up period of 42 months, but with no observable impact on mortality rate until almost 1 year into treatment. The CONSENSUS II trial closed prematurely, with no benefit (a 10% increase in risk, 95% CI 7% reduction to 29% increase) apparent from enalapril after 6 months of follow-up. The recently reported but unpublished findings of Gruppo Italiano per lo Studio della Sopravvivenza nell'Infarto Miocardico (GISSI-3) and the Fourth International Study of Infarct Survival (ISIS-4) indicate a small benefit from early (within 24 h) short-term (4 to 6 weeks) treatment of all patients, unless hypotensive, after a myocardial infarction.(ABSTRACT TRUNCATED AT 250 WORDS)

Three major trials, in patients with chronic heart failure, have shown that treatment with an ACE inhibitor reduces mortality. However, at the time of writing this review there continue to be strong grounds for uncertainty as to the role of these drugs after acute myocardial infarction in man. This uncertainty is exemplified by the findings of two recently published mortality trials, the CONSENSUS II and the SAVE investigations. Despite virtually identical premises, though widely differing therapeutic approaches, the observations reported in these two papers contrast markedly. In this review we have sought to analyse the possible reasons why the findings of the two trials differ. In our attempt to understand this important issue we have necessarily turned to smaller clinical studies, and also to investigations performed in animals. Furthermore, we review the investigational strategies which have been employed by other, currently unreported, large scale survival studies, as these will certainly hold many of the answers to the questions which the SAVE and CONSENSUS II trials have raised.

Potential benefit or harm of drug therapy in patients with chronic congestive heart failure and those later presenting to hospital after an acute myocardial infarction (AMI) have been studied in a number of large-scale survival studies during the last few decades. Currently available data are reviewed in order to consider both methodology and also the clinical relevance of findings with emphasis on trials with ACE-inhibitors like CONSENSUS-II, the ISIS-4, GISSI-3 and Chinese mega-trials, TRACE, SAVE and AIRE. Results of SAVE and AIRE show a clear survival benefit for the patients. Furthermore, the benefit of both trials was in addition to any other benefit which resulted from aspirin, thrombolytic and beta-blocker therapies. In absolute terms, treatment of 1,000 patients with ramipril (AIRE) for 1 year would be expected to result in the prevention/delay of 40 premature deaths. The beneficial effects of ramipril were clearly apparent by 30 days though additional benefit beyond this point was also present. Furthermore, prespecified subgroup analysis revealed significant benefit for patients at risk like women and the elderly. A selective approach is argued for the treatment of patients with ACE-inhibitors after myocardial infarction.

There is justifiable enthusiasm for the use of angiotensin-converting enzyme (ACE) inhibitors in patients with heart failure. However, early after an acute myocardial infarction, the benefits (or harm) from use of these agents in individual patients may depend on the critical balance between the ischemic problem (the extent of coronary artery narrowing and risk of vessel occlusion) against the need to preserve remaining ventricular function. Patients who are hemodynamically stable without ongoing chest pain but with significantly impaired ventricular function seem likely to gain most from treatment with ACE inhibitors. Extrapolation to the acute infarct situation from the recently published trials in chronic stable heart failure may mislead, and the findings of a number of large ongoing mortality trials in patients with recent myocardial infarction are awaited.

Angiotensin converting enzyme inhibitors are now widely used in the treatment of hypertension and heart failure. They are clearly as effective as other conventional antihypertensive agents in reducing blood pressure and combined with diuretics seem likely to transform current management of chronic heart failure. Myocardial infarction remains the major cause of death in patients with raised blood pressure and current studies should establish whether the attractive features of ACE inhibitors translate into reduction in the rate of infarction or its consequences. Similarly, whilst symptomatic benefit undoubtedly accrues from their use in heart failure it is less clear that they can prolong life particularly when used in the immediate setting of a myocardial infarction. Again a number of ongoing major trials are set to establish whether these drugs reduce death in patients with chronic heart failure (V-HeFT II, SOLVD) and in patients immediately after myocardial infarction (CONSENSUS II, SAVE,. AIRE, GISSI III and ISIS IV). The physician has a wide choice of ACE inhibitors with different pharmacological profiles for clinical use.

The rationale, design, organization, and outcome definitions of the Acute Infarction Ramipril Efficacy (AIRE) Study are described prospectively. A total of 2,000 patients (1,000 per treatment group) will be recruited to this multicenter, multinational, double-blind, randomized, placebo-controlled study investigating the effect of oral treatment with ramipril (2.5 or 5 mg twice daily) on the total mortality of survivors of an acute myocardial infarction (AMI) with early clinical evidence of heart failure. Secondary outcomes of the study include progression to severe/resistant heart failure (at which time the patient will be withdrawn from the study treatment), reinfarction, and stroke. Treatment will be initiated in hospital between day 3 and day 10 following AMI, and follow-up continued for an average of 15 months and a minimum of 6 months. The study data will be analyzed on an intention-to-treat basis: a single formal interim analysis will be conducted after 175 deaths. An Independent Adjudicating Panel will act as the overall ethical supervisory body for the study and will retain the randomization code. An International Steering Committee will be responsible for the clinical definitions of the secondary study outcomes, and will regularly review progress of the study. We believe that early treatment with ramipril may reduce the total mortality of patients surviving an AMI with clinical evidence of heart failure.

Experience with angiotensin converting enzyme (ACE) inhibitor drugs as with other antihypertensive agents, is limited in the elderly. Nevertheless, they appear effective and well tolerated but without evidence to suggest that they have any special role in the elderly compared to a younger age group. Most are excreted through the kidney and dosage should be reduced to match glomerular function. ACE inhibitors seem likely to be used increasingly in the elderly, especially when more traditional agents are contraindicated because of concomitant disease.

Most commonly used drugs reduce blood pressure equally. Reduction in pressure lessens the chance of stroke but appears to have little impact on death from ischaemic heart disease in the majority. Loss of arterial compliance, development of cardiac hypertrophy, impaired coronary blood flow, and dysrhythmias may contribute, at least in part, to the adverse cardiac effects of hypertension. It is speculated that converting enzyme inhibitors could offer beneficial effects in these areas.

Different oral doses (5, 20, 50 mg) of the new orally active nonsulfhydryl-converting enzyme inhibitor, ramipril (HOE498), were given to 12 normotensive healthy males, and the pattern of changes in plasma active and inactive renin concentration was evaluated. Active and inactive renin increased after ramipril, and the magnitude of the response was clearly dose related. Active renin rose markedly by 4 hours and tended to decrease thereafter, although remaining higher than basal at 24 hours. In contrast, inactive renin rose more slowly, and the increase was sustained throughout the 24-hour period. The pattern of these changes is consistent with the hypothesis that circulating inactive renin is a biosynthetic precursor of the active form.

Ramipril is a long-acting non-sulphydryl converting enzyme inhibitor that requires cleavage of its ester group to form the active diacid metabolite, ramiprilat. Renal excretion largely determines the drug's duration of action and the dosage should be reduced in patients with renal impairment. Oral ramipril given daily at dosages of 5 mg or more can control blood pressure over a 24-hour period; lower doses may be effective in patients with heart failure inadequately controlled by diuretics alone. No serious idiosyncratic adverse reactions have been reported. Ramipril is one of the most potent long-acting converting enzyme inhibitors developed; it is effective given once daily in the treatment of all grades of hypertension and of heart failure.

Converting enzyme inhibitors are likely to be prescribed with increasing frequency in elderly patients. The pharmacokinetics of ramipril, a new potent long-acting non-sulphydryl converting enzyme inhibitor, and its effects on blood pressure, plasma renin activity and angiotensin II concentrations were studied in a group of 8 elderly volunteers (mean age 77, range 61 to 84). Circulating concentrations of the active diacid formed from its parent drug were consistently higher in this group despite apparently normal renal function, assessed by serum creatinine and urea concentrations, compared with younger volunteers (age range 21 to 30). The initial dose of ramipril should be lower in older subjects. The study emphasizes the importance of careful extrapolation of data obtained from young volunteers to older subjects.

Angiotensin II appears to have important actions in modulating sympathetic nerve activity; conversely, sympathetic stimulation alters renin release. Drugs that inhibit angiotensin II formation would be expected then not only to offset the direct vasoconstricting and aldosterone releasing actions of this peptide but also to reduce sympathetic nerve activity. Hypertension and cardiac failure are two major conditions in which converting enzyme inhibitors have found important therapeutic roles; both are considered to be associated with increased activity of the renin-angiotensin-aldosterone and sympathetic nervous systems. However, in spite of considerable experimental evidence for a sympatholytic action of converting enzyme inhibitors, direct proof has been difficult to obtain in humans. In part, this results from the lack of any satisfactory way of assessing sympathetic activity in the clinical situation. Nevertheless, our failure to understand the pathophysiology of disease and the precise mechanism of action of drugs has not precluded exploiting the salutatory effects of inhibition of converting enzyme.

Several studies have shown symptomatic and haemodynamic improvement after the introduction of angiotensin converting enzyme inhibitors in patients with heart failure treated with diuretics. The concomitant long term effects of the new orally effective long acting angiotensin converting enzyme inhibitor, enalapril, on symptoms, exercise performance, cardiac function, arrhythmias, hormones, electrolytes, body composition, and renal function have been further assessed in a placebo controlled double blind cross over trial with treatment periods of eight weeks. Twenty patients with New York Heart Association functional class II to IV heart failure who were clinically stable on digoxin and diuretic therapy were studied. Apart from the introduction of enalapril, regular treatment was not changed over the study period; no order or period effects were noted. Enalapril treatment significantly improved functional class, symptom score for breathlessness, and exercise tolerance. Systolic blood pressure was significantly lower on enalapril treatment. Echocardiographic assessment indicated a reduction in left ventricular dimensions and an improvement in systolic time intervals. In response to enalapril, the plasma concentration of angiotensin II was reduced and that of active renin rose; plasma concentrations of aldosterone, vasopressin, and noradrenaline fell. There were significant increases in serum potassium and serum magnesium on enalapril. Glomerular filtration rate measured both by isotopic techniques and by creatinine clearance declined on enalapril while serum urea and creatinine rose and effective renal plasma flow increased. Body weight and total body sodium were unchanged indicating that there was no overall diuresis. There was a statistically insignificant rise in total body potassium, though the increase was related directly to pretreatment plasma renin (r = 0.5). On enalapril the improvement in symptoms, exercise performance, fall in plasma noradrenaline, and rise in serum potassium coincided with a decline in the frequency of ventricular extrasystoles recorded during ambulatory monitoring. Adverse effects were few. In patients with heart failure, enalapril had a beneficial effect on symptoms and functional capacity. The decline in glomerular filtration rate on enalapril may not be beneficial in early heart failure.

An examination of the principal physiological actions of angiotensin II should make it clear why in vivo attempts to inhibit the rate of angiotensin II generation have been an attractive avenue in pursuing control of high blood pressure. The major physiological effect of angiotensin II relates to its direct pressor effect, but there are supplementary blood pressure regulating actions. Therefore, if we limit the rate of angiotensin II generation by inhibiting the angiotensin converting enzyme (ACE) we should expect to control high blood pressure in a number of clinical syndromes. This paper reviews the future of ACE inhibitors in the treatment of conditions such as hypertension associated with unilateral renal artery stenosis, essential hypertension and severe and previously unresponsive hypertension, with respect not only to efficacy but also to the side-effect profile and ancillary properties. Side effects seen with this class of drug are cough, rashes (both morbilliform and urticarial) and, rarely, angio-oedema. Proteinuria, nephrotic syndrome, leukopenia and taste disturbance were previously reported with captopril but only taste disturbance, and that less frequently, is apparent at the lower doses now employed. Several studies have examined the 'quality-of-life' aspects of ACE therapy and have usually but not always reported favourably. There are features of the ACE inhibitors which make them attractive drugs, and while we should be cautious because of limited experience, we should critically and creatively examine their properties over the next years.