Impact of converting enzyme inhibition on progression of chronic heart failure: results of the Munich Mild Heart Failure Trial

The integrated effects of angiotensin II

In recent years, a prodigious amount of information has been gathered regarding the relationship between vascular biology and the mechanisms underlying cardiovascular disease. Activation of elements of the reninangiotensin system (RAS) appear to play an important role in the development and progression of conditions such as hypertension, coronary artery disease, and heart failure. Indeed, converging lines of evidence indicate that angiotensin-converting enzyme (ACE) regulates a delicate balance among a multitude of factors responsible for vascular tone, cellular growth promotion and inhibition, and pro- and anti-inflammatory effects. Because angiotensin II inhibits fibronectin, stimulates expression of plasminogen activator inhibitors, and degrades bradykinin, thereby impairing production of nitric oxide, ACE and the RAS are also involved in thrombosis and fibrinolysis. The favorable effects of ACE inhibition on endothelial function and, potentially, on cardiovascular morbidity and mortality are believed to result not only from angiotensin II suppression but also its consequent bradykinin preservation and nitric oxide production.

Captopril and norepinephrine-induced hypertrophy and haemodynamics in rats

We wished to determine whether pretreatment with captopril, an angiotension-converting enzyme (ACE) inhibitor, modified the myocardial and haemodynamic consequences of chronic administration of norepinephrine (NE) in rats. Administration of NE (0.15 mg kg(-1) h(-1) by an osmotic minipump implanted subcutaneously for 28 days) resulted in left but not right ventricular hypertrophy. Captopril (250 but not 52 mu g kg(-1) h(1) administered for 28 days) significantly attenuated the development of left ventricular hypertrophy (weight of left ventricle to body weight ratio was 0.46 +/- 0.01 0.57 +/- 0.02, 0.53 +/- 0.02, and 0.51 +/- 0.01 for vehicle, NE, and NE plus low and high dose of captopril, respectively). Chronic administration of NE caused significant increases in systolic arterial blood pressure (BP: 194 +/- 11 vs. 130 +/- 6 mm Hg), systolic left ventricular pressure, heart rate (HR: 458 +/- 13 vs. 389 +/- 15 beats/min) and dP dt(-1)(max) P(-1), an index of myocardial contractility (202 +/- 29 vs. 91 +/- 3 s(-1)). Captopril (250 mu g kg(-1) h(-1) for 28 days) significantly reduced diastolic arterial BP (from 86 +/- 6 to 53 +/- 3 mm Hg). Concomitant administration of this dose of captopril together with NE prevented the NE-induced increase in systolic arterial BP but did not modify the increases in HR or dP dt(-1) max P(-1) (261 +/- 41 and 202 +/- 29 s(-1) in captopril and NE vs. NE-alone groups). Acute administration of NE (0.1-10 mu g kg(-1) intravenously, i.v.) produced less marked increases in cardiac contractility and in arterial BP in rats chronically pretreated with NE or NE plus captopril than in animals receiving vehicle or captopril alone. Chronic administration of NE and/or captopril did not significantly modify the haemodynamic effects of the acute administration of calcium chloride. We conclude that administration of captopril at 250 but not 52 mu g kg(-1) h(-1) for 28 days attenuates NE-induced cardiac hypertrophy and that this effect is associated with a decrease in systolic arterial BP. Captopril did not modify the reduced effects of acutely administered NE in rats treated with NE for a prolonged period.

The pharmacoeconomics of ACE inhibitors in chronic heart failure

Because heart failure is common and disabling, patients with this condition utilise healthcare resources to a considerable extent. In particular, patients with heart failure frequently require hospital admission, and inpatient care is often protracted. Patients with the most advanced stages of heart failure make the greatest demands on the healthcare system. Expenditure related to the consumption of healthcare resources accounts for the 1 to 2% of total healthcare spending related to heart failure. Between two-thirds and three-quarters of this is due to the costs of hospital care. ACE inhibitors reduce progression of heart failure and also reduce the need for hospitalisation by approximately 30%. In so doing, these drugs substantially or totally offset their cost and the cost of extended life. Five independent economic analyses collectively show ACE inhibitors, at worst, to be very cost effective (in comparison to other cardiovascular therapies), cost neutral or to lead to overall cost savings when used to treat heart failure.

The Economics of Cardiac Failure

Quality assurance and inclusion of prospective evaluation of costs of treatment in phase 3 and 4 pharmaceutical trials are becoming increasingly important. Not only high technology applications have to be investigated, but also relatively cheap but very common strategies for diagnostic work up and therapy. This may yield major savings. We are at the beginning of an era in which waste of resources may be reduced by scientific analysis with improvement in patient care and teaching achieved as a result.

Current guidelines for the treatment of congestive heart failure

Overt congestive heart failure (CHF) has a prevalence of 1% of the population. The predominant symptoms of patients with CHF are fatigue and dyspnoea. Fatigue is thought to result from changes in peripheral muscle metabolism secondary to decrease vasodilative capacity and physical inactivity. An increase of peripheral perfusion by vasodilator therapy and physical activity are therefore recommended. Beside overt decompensation, where dyspnoea results from acute pulmonary congestion due to backward failure, increased physiological dead space ventilation caused by pulmonary ventilation/perfusion mismatch accounts, to a large degree, for dyspnoea, and can be improved by vasodilator therapy. According to the pathophysiology of CHF, normalisation of loading conditions and myocardial inotropy are the parameters addressed by various pharmacological agents in order to alleviate symptoms and slow progression of the disease. Diuretics are rapidly acting and effective agents to improve congestion and decrease filling pressures. Digitalis improves haemodynamics and symptomatology by increasing inotropy and slowing resting heart rate in atrial fibrillation; however, prognostic effects have yet to be proved. The introduction of vasodilators has significantly improved the prognosis of the disease, and the administration of ACE inhibitors in particular has been shown to slow progression of CHF. This results in a substantial decrease in morbidity and mortality. The present article appraises the role of the currently used drugs in the treatment of CHF, considering effects on pathophysiology and clinical outcome and provides an approach to a differential drug regimen.

Improving survival for patients with advanced heart failure: a study of 737 consecutive patients

OBJECTIVES

This study sought to determine whether survival and risk of sudden death have improved for patients with advanced heart failure referred for consideration for heart transplantation as advances in medical therapy were systematically implemented over an 8-year period.

BACKGROUND

Recent survival trials in patients with mild to moderate heart failure and patients after a myocardial infarction have shown that angiotensin-converting enzyme inhibitors are beneficial, type I antiarrhythmic drugs can be detrimental, and amiodarone may be beneficial in some groups. The impact of advances in therapy may be enhanced or blunted when applied to severe heart failure.

METHODS

One-year mortality and sudden death were determined in relation to time, baseline variables and therapeutics for 737 consecutive patients referred for heart transplantation and discharged home on medical therapy from 1986 to 1988, 1989 to 1990 and 1991 to 1993. Medical care was directed by a single team of physicians with policies established by consensus. From 1986 to 1990, the hydralazine/isosorbide dinitrate combination or angiotensin-converting enzyme inhibitors were the initial vasodilators, and class I antiarrhythmic drugs were allowed. After 1990, captopril was the initial vasodilator, given to 86% of patients compared with 46% of patients before 1989. After mid-1989, class I agents were routinely withdrawn, and amiodarone was used for frequent ventricular ectopic beats or atrial fibrillation (53% of patients after 1990 vs. 10% before 1989).

RESULTS

The total 1-year mortality rate decreased from 33% before 1989 to 16% after 1990 (p = 0.0001), and sudden death decreased from 20% to 8% (p = 0.0006). Adjusted for clinical and hemodynamic variables in multivariate proportional hazards models, total mortality and sudden death were lower after 1990.

CONCLUSIONS

The large reduction in mortality, particularly in sudden death, from advanced heart failure since 1990 may reflect an enhanced impact of therapeutic advances shown in large randomized trials when they are incorporated into a comprehensive approach in this population. This improved survival supports the growing practice of maintaining potential heart transplant candidates on optimal medical therapy until clinical decompensation mandates transplantation.

Effects of 12 weeks of ramipril treatment on the quality of life in patients with moderate congestive heart failure: results of a placebo-controlled trial. Ramipril Study Group

The assessment of quality of life (QoL) has become recognized as an important tool for evaluating heart failure therapy. The angiotensin-converting enzyme inhibitor ramipril (mean dose 8 mg) was evaluated in 223 patients with moderate chronic congestive heart failure at 24 centers in 4 Nordic countries following a randomized, double-blind, placebo-controlled, parallel group design. The follow-up period was 12 weeks. QoL was evaluated using a questionnaire with 47 items, including the disease-specific Severe Heart Failure Questionnaire, the Sleep Dysfunction Scale, and the Psychological General Well-Being Index. In both treatment groups the total score increased from baseline to 12 weeks for both the Severe Heart Failure Questionnaire and for the Psychological Well-Being Index, reflecting relief of symptoms and improved well-being. However, no significant differences between the placebo and ramipril groups could be detected. Only a trend toward improvement in sleep on ramipril compared with placebo therapy was observed. In conclusion, in this placebo-controlled trial no significant effects of 12-week ramipril treatment of QoL could be demonstrated in patients with moderate congestive heart failure.

Indications for immediate angiotensin-converting enzyme inhibition in patients with acute myocardial infarction

When initiated a few days after myocardial infarction, angiotensin-converting enzyme inhibition exerts beneficial effects on survival and morbidity in patients with asymptomatic left ventricular systolic dysfunction or symptomatic heart failure. During the acute phase of a myocardial infarction, angiotensin-converting enzyme inhibition appears to be well tolerated, to prevent the development of heart failure in patients with asymptomatic left ventricular systolic dysfunction and to improve the hemodynamic and clinical variables of heart failure when present. Accordingly, early angiotensin-converting enzyme inhibition is clearly indicated in patients with acute myocardial infarction associated with asymptomatic left ventricular dysfunction or clinical evidence of heart failure. Angiotensin-converting enzyme inhibition may also be beneficial when thrombolytic agents fail to restore coronary patency in patients with acute myocardial infarction.

Identifying the patient with heart failure

Heart failure is becoming an increasing concern to healthcare worldwide, and of particular concern in the Western world where the age of the population continues to rise. Furthermore, it has now become clear that, if heart failure is identified and treated in the earliest stages of ventricular dysfunction, the possibility of recovery from or substantial delay in progression to complete heart failure is extremely good and will give the patient a considerably improved quality of life. Certain signs and symptoms found on routine examination, coupled with knowledge of patient history, can indicate early heart failure. Patients will normally present to their family practitioner, who is likely to have long term, firsthand knowledge of the patient's medical and family history. Consequently, the general practitioner has a key role in identifying individuals with early heart failure. It is essential that the general practitioner is aware of the signs and symptoms of early heart failure, can interpret them correctly and knows what follow-up tests are necessary to confirm the diagnosis. Guidelines are presented here to assist the general practitioner in this task.

Progression of mild untreated heart failure during six months follow-up and clinical and neurohumoral effects of ibopamine and digoxin as monotherapy. DIMT Study Group. Dutch Ibopamine Multicenter Trial

There is increasing evidence that clinical deterioration in manifest chronic heart failure is related to both hemodynamic and neurohumoral factors. Only few data are available, however, on the progression of disease in its early stages, when treatment has not yet been initiated. The aim of this study was therefore to examine the changes in clinical and neurohumoral variables that occur over 6 months in patients with clinically stable and untreated heart failure, and to evaluate the influence of drugs that may affect these variables. Accordingly, we studied 64 patients with heart failure who were in New York Heart Association functional class II (88%) and III (12%). They were randomized to double-blind treatment with the oral dopamine agonist ibopamine (100 mg 3 times daily; n = 22), digoxin (0.25 mg once daily; n = 22) or placebo (n = 20). Their age (mean +/- SD) was 60 +/- 8 years, and left ventricular ejection fraction (mean +/- SD) was 0.33 +/- 0.08. Of the 64 patients, 56 (88%) completed the 6-month study period (p = NS between groups). Exercise time decreased in patients treated with placebo after 6 months (median -62 seconds; p < 0.05 vs baseline), but it increased with ibopamine (+48 seconds), and digoxin (+17 seconds; both p < 0.05 vs placebo). Plasma norepinephrine increased in the placebo group after 6 months (median + 31 pg/ml, p < 0.05 vs baseline), but decreased in patients receiving active drug treatment (ibopamine: -24 pg/ml, digoxin: -98 pg/ml, both p < 0.05 vs placebo). Plasma renin and aldosterone levels were unchanged after 6 months in the placebo group, but digoxin therapy slightly reduced plasma renin concentration (-5 microU/ml; p < 0.05 vs placebo).(ABSTRACT TRUNCATED AT 250 WORDS)

Interobserver discordance in the classification of mechanisms of death in studies of heart failure

Studies of the mechanism of death in heart failure are dependent on the reliability and validity of classification of deaths as pump failure or arrhythmias (sudden). Two recent trials differed in that the Vasodilator Heart Failure Trial II (V-HeFT II) reported a higher incidence of sudden death than the Studies of Left Ventricular Dysfunction Treatment Trial (SOLVD) and an effect of enalapril on sudden death was not observed in SOLVD. A similar classification system was used in the two studies, but deaths in V-HeFT were classified centrally from a narrative summary, whereas deaths in SOLVD were classified in the field by individual investigators. To examine reliability, 10 narratives used to classify V-HeFT deaths were independently classified by 21 SOLVD investigators. In only 5 of 10 cases did 75% of SOLVD investigators agree with the V-HeFT classification. In no deaths were all SOLVD investigators in agreement on classification. Although V-HeFT classified 5 of 10 cases as sudden death, 16 of 21 SOLVD investigators classified less than 5 deaths as sudden and 1 classified none as sudden. The kappa statistic for interobserver agreement of 0.22 (P < or = .01) indicated interobserver agreement only slightly better than chance agreement. Therefore, the incidence of sudden death in heart failure is critically dependent on the bias of the investigator. Central classification will minimize inconsistencies, but it does not solve the problem that the mechanism of death is difficult to assign. Total mortality may be the only reliable endpoint in heart failure trials.

Optimizing the treatment of heart failure

The introduction of new drugs, and a re-evaluation of older drugs, have radically changed the pharmacological management of heart failure. Angiotensin converting enzyme (ACE) inhibitors, digitalis, diuretics and the combination of nitrates and hydralazine are now used. The first Cooperative North Scandinavian Enalapril Survival Study (CONSENSUS I) and the second Vasodilator therapy in Heart Failure Trial (V-HeFT II) have demonstrated that patients with severe or advanced heart failure should be treated with ACE inhibitors, digitalis and diuretics (other vasodilators can be used if ACE inhibitors are contraindicated) to improve symptoms and duration of life. The Studies Of Left Ventricular Dysfunction (SOLVD) and the Munich Heart Failure trial have shown that patients with mild heart failure should be treated with ACE inhibitors. However, data from several large clinical registries suggest that only 40% of patients with heart failure are being given ACE inhibitors perhaps through fear of serious renal damage or hypotension; these fears are unfounded. Patients with anterior myocardial infarcts and reduced left ventricular function also benefit from ACE inhibitors. The fourth International Study of Infarct Survival (ISIS 4) and results from the Gruppo Italiano per Io Studio della Sopravvivenza nell'Infarto miocardico 3 (GISSI 3) have indicated that patients with acute myocardial infarction benefit from early ACE inhibitor therapy and that survival is increased. Heart failure treatment can be optimized by establishing a disease etiology and stressing the need to restrict dietary sodium. ACE inhibitors should be used for depressed left systolic ventricular function, including patients in New York Heart Association class I heart failure.(ABSTRACT TRUNCATED AT 250 WORDS)

Prognosis in congestive heart failure

Prognostic variables such as the ejection fraction and peak oxygen consumption can be used to place patients with heart failure in risk strata. Some vasodilators have been shown to improve survival at all stages of heart failure with the probability of benefit increasing as the prognosis worsens. Quantitative estimates of survival among groups defined by prognostic variables and treatments should be used to make more informed benefit-to-risk assessments.

Postinfarct heart failure: role of diuretic therapy

There can be no doubt that ACE inhibitors prolong survival in patients with a low ejection fraction. There is no evidence whether or not diuretics have the same effect. The pathophysiology of asymptomatic patients with poor left ventricular function differs from that of patients with the clinical syndrome of heart failure, and different treatments may well be needed. Diuretics still have a crucial role in the relief of symptoms.

Acute and chronic effects of flosequinan on resting and exercise haemodynamics in congestive heart failure

1 The acute and chronic (8 weeks) haemodynamic responses to oral flosequinan have been investigated in 12 male patients of mean age 58.9 years with congestive heart failure of N.Y.H.A. classes II and III. 2 Flosequinan 125 mg orally significantly reduced right atrial pressure, pulmonary artery pressure and pulmonary wedge pressure prior to and following 8 weeks chronic treatment (125 mg daily). A significant decrease in systemic pressure and an increase in heart rate were also observed with acute flosequinan prior to chronic treatment. A reduction in systemic vascular resistance and an increase in cardiac index reached significance in response to flosequinan 125 mg orally following 8 weeks of therapy. 3 In the erect position, flosequinan reduced pulmonary wedge pressure and tended to reduce systemic vascular resistance, without decreasing mean arterial pressure. 4 Following chronic treatment, there was a trend towards a reduction in pulmonary wedge pressure and an increase in cardiac index, otherwise resting and exercise haemodynamics were unchanged. 5 The response to flosequinan was similar at week 1 and after 8 weeks of treatment for all of the haemodynamic parameters. 6 Flosequinan increased bicycle exercise times and attenuated exercise-induced increases in pulmonary arterial and systemic pressures. There was a trend towards an increase in treadmill exercise time. 7 Sublingual glyceryl trinitrate (0.5 mg) and oral flosequinan (125 mg) had similar effects on right atrial pressure, pulmonary arterial and pulmonary wedge pressures at 5 min and 2 h respectively post-dosing. A small additive effect on pulmonary arterial and wedge pressures was observed.

Concurrent neutral endopeptidase and ACE inhibition in experimental heart failure: renal and hormonal effects

Neutral endopeptidase (NEP) inhibitors have been shown to strengthen the effects of endogenous atrial natriuretic peptide (ANP). It has been well documented that angiotensin I-converting enzyme (ACE) inhibitors act beneficially in chronic congestive heart failure (CHF). In the present study, renal and hormonal effects of SCH 34826, an orally active NEP inhibitor, were studied in a coronary-ligation model of experimental CHF in the rat. The effects were compared to those of captopril. The drugs were also administered in combination. In anaesthetized rats with CHF, SCH 34826 (90 mg kg-1 sc) elevated plasma ANP from 382 +/- 85 to 658 +/- 120 ng l-1 compared with vehicle (p = 0.002). In sham-operated control rats, plasma ANP also increased slightly from 52 +/- 6 to 70 +/- 9 ng l-1 (p = 0.05). Plasma renin activity did not change in either group. When given orally for 36 h (90 mg kg-1 b.i.d.), SCH 34826 enhanced natriuresis in controls but not in rats with CHF. Captopril (0.2 mg ml-1 in drinking water) enhanced natriuresis in CHF rats and both natriuresis and kaliuresis in controls. When SCH 34826 and captopril were combined, natriuresis was potentiated in control rats as compared with captopril alone; in rats with CHF, however, a brisk kaliuresis was seen. The excretion of cyclic guanosine monophosphate was enhanced in CHF rats by 52% during treatment with SCH 34826 but not with captopril or combination of the two drugs. Moreover, captopril suppressed aldosterone excretion both in CHF rats and controls when administered alone but not when combined with SCH 34826.(ABSTRACT TRUNCATED AT 250 WORDS)

Ibopamine. A review of its pharmacodynamic and pharmacokinetic properties, and therapeutic use in congestive heart failure

Ibopamine is an orally administered dopamine agonist which is rapidly converted to its active metabolite epinine by esterase hydrolysis. Ibopamine acts predominantly as a vasodilator and inhibitor of neuroendocrine activation in congestive heart failure, but also has mild positive inotropic effects at higher doses. The beneficial effects on cardiac and systemic haemodynamic parameters seen in short term studies have been maintained in predominantly noncomparative trials for up to 1 year, and improvements in New York Heart Association (NYHA) functional class and clinical symptoms have been observed in patients with congestive heart failure of varying severity. In double-blind studies conducted in small numbers of patients, the efficacy of ibopamine was comparable to that of digoxin, captopril, enalapril and hydrochlorothiazide. Ibopamine can successfully replace treatment with intravenous dopamine in patients with severe heart failure, and is effective and well tolerated when administered in combination with digoxin, diuretics and/or angiotensin converting enzyme (ACE) inhibitors. Ibopamine has shown no detrimental effects on renal function, few adverse effects on neurohormonal parameters and has demonstrated no significant proarrhythmic properties at therapeutic doses in patients with congestive heart failure. No adverse metabolic effects were observed during ibopamine therapy in patients with diabetes mellitus, nor did ibopamine have detrimental effects in patients with chronic obstructive pulmonary disease. While reliable evidence is required concerning effects on mortality before the role of ibopamine can be clearly defined, the drug appears to be a useful agent for combination with conventional therapies in treating patients with mild to severe congestive heart failure.

Relation of pathophysiologic mechanisms to outcome in heart failure

Advances in the treatment of heart failure with angiotensin-converting enzyme inhibitors have been accompanied by an improved understanding of the pathophysiology of heart failure. The inability of the heart to act as a pump is determined in some patients by alterations to the architecture of the heart and changes in the extracellular space, particularly fibrosis. The degree to which the failure of the heart as a pump can be attributed to a reduced ability of the myocyte to contract is contentious. The origin of symptoms is still uncertain but does relate to identified changes in the lung, increased peripheral resistance and atrophy of skeletal muscle. The mechanisms of action of angiotensin-converting enzyme inhibitors are numerous and do not yet account easily for the clinical benefits. Further epidemiologic studies are needed to ascertain the proportion of patients who manifest progressive heart failure rather than deterioration due to further cardiac events. Understanding the pathophysiology of heart failure will allow therapy to be tailored to the requirements of the individual patient.

The treatment of heart failure--what next?

1. Despite demonstrable benefits in terms of symptomatic relief and improvement in prognosis, even the best treatments of heart failure currently available fall short of being ideal. We review the basis for newer approaches to the treatment of heart failure and discuss some of the agents which capitalize on current understanding of the underlying patho-physiology. 2. Several drugs, old and new, are presently being investigated by major clinical trials. We also consider some of the difficulties related to the design and conduct of such trials and suggest how drugs might be better assessed in the future.

Angiotensin-converting enzyme inhibitors, left ventricular dysfunction, and early heart failure

A study was undertaken to examine the effects of the angiotensin-converting enzyme inhibitor lisinopril on exercise performance in 18 patients with major impairment of left ventricular systolic function. The study was a randomized, double-blind, crossover design, and patients received treatment with either once-daily lisinopril (2.5-10 mg) or placebo for a period of 6 weeks. A total of 15 patients completed the study. Compared with placebo, lisinopril had no significant effect on supine or standing blood pressure or heart rate. Although lisinopril had no effect on exercise duration during a low-intensity exercise protocol, in patients undergoing a high-intensity exercise protocol, there was a trend toward improved exercise time and peak oxygen consumption improved significantly. In addition, treatment with lisinopril resulted in an increase in renal blood flow and a reduction in glomerular filtration rate. Moreover, administration of once-daily lisinopril 10 mg resulted in a decrease in plasma concentrations of angiotensin II, aldosterone, and atrial natriuretic peptide, and an increase in plasma concentrations of active renin.