Update of ELITE-II, BEST, CHAMP, and IMPRESS clinical trials in heart failure

The ELITE-II, BEST and CHAMP Trials were reported for the first time at the American Heart Association in November 1999. These trials provide valuable new information to guide clinical practice in the management of heart failure and of myocardial infarction, although none mandate a major change from current clinical practice. The IMPRESS trial of the vasopeptidase inhibitor, omapatrilat, indicated a promising new treatment for the management of heart failure.

Progression from hypertension to heart failure. Mechanisms and management

Patients with hypertension are at increased risk of developing heart failure (HF), but the mechanisms by which hypertension leads to HF have not been clarified [although left ventricular hypertrophy (LVH) is clearly a predictor of an increased risk of HF]. Similarly, although antihypertensive therapy has been shown to reduce the risk of HF in hypertensive patients, it is not known how this benefit is produced and, currently, there is no clear evidence that any class of antihypertensive agent is more effective than any other in this respect. On theoretical grounds, beta-blockers would be expected to be ideal agents for the prevention of HF in hypertensive patients. In addition to control of blood pressure and regression of LVH, they have clear benefits on morbidity and mortality after myocardial infarction (MI), which probably plays a major role in the development of HF in hypertensive patients, and on the prognosis of HF itself. A reduction in long-term mortality after MI has been demonstrated only for non-selective beta-blockers. Carvedilol, a non-selective beta-blocker which also has other ancillary properties including alpha-1-receptor blockade and antioxidant effects and a favourable metabolic profile, may be an appropriate choice for the prevention of HF in hypertensive patients. This is reinforced by the salutary benefits of carvedilol for the reduction in the morbidity and mortality of HF itself.

The carvedilol hibernation reversible ischaemia trial, marker of success (CHRISTMAS) study. Methodology of a randomised, placebo controlled, multicentre study of carvedilol in hibernation and heart failure

BACKGROUND

Carvedilol reduces mortality and improves symptoms and ejection fraction in ischemic heart failure, but its mode of action is not well defined and not all patients respond to treatment. The aim of the CHRISTMAS (Carvedilol Hibernation Reversible Ischaemia Trial, Marker of Success) study is to examine whether hibernation may be a significant factor determining this response. This paper describes the methodology and the rationale for the choice of the nuclear cardiology and echocardiography imaging techniques used in the study.

METHODS AND RESULTS

The CHRISTMAS study is a double-blind, randomised, parallel group, multinational study of oral carvedilol versus placebo in patients with chronic stable heart failure due to left ventricular systolic dysfunction from coronary artery disease. The study aims to randomise 400 patients who are on optimal treatment. Two parallel groups will be randomised to carvedilol or placebo, namely 200 with hibernating myocardium at baseline and 200 matched patients without. The presence of hibernation is defined from a mismatch between regional contractile function and regional viability, measured by echocardiography (severe segmental asynergy) and nitrate prepared resting Tc99m-MIBI myocardial perfusion imaging (segmental activity >60%). The primary treatment-related end-point of the study is the comparison of the mean change, from baseline to the final visit, in radionuclide-determined left ventricular ejection fraction in patients on placebo with those on carvedilol, between the groups designated as hibernating and non-hibernating. Other end-points being examined include the prevalence of hibernation in heart failure, the relationship between the volume of hibernating myocardium and the ejection fraction response, the prevalence of reversible ischemia in heart failure, and the comparison of echo with gated SPECT. To date, 303 patients have been screened and 251 patients randomised in the study. The study aims to report in 2000.

CONCLUSIONS

The CHRISTMAS study addresses the issue of whether the presence of hibernation is a predictor of the ejection fraction response to carvedilol in heart failure. It also examines the potential role of medical therapy in hibernation as well as a number of other end-points. The study may potentially lead to an important new role for nuclear cardiology in heart failure, and demonstrates important synergy between cardiac imaging and the pharmaceutical industry.

Beta-blockers for heart failure

This is the protocol for a review and there is no abstract. The objectives are as follows: Our objective is to appraise the effectiveness of beta blockers in patients with heart failure. Our protocol defined main outcome is all cause mortality. The specific a priori defined aims are to examine: the effectiveness of beta blockers in all trials of patients with heart failure, and examine the importance of the presence or absence of ischaemic cardiomyopathy in patients included in trials and vasodilator properties of beta blocking agents used. We will also examine the predictive value of left ventricular function, age, use of angiotensin converting enzyme inhibitors and New York Heart Association Class (NYHA), and the rate of discontinuation of therapy due to treatment. There are a number of important ongoing trials for which data will become available in the next few years. Thus a systematic review which may be updated regularly is required to provide an up to date synthesis of the available data in this increasingly important area.

Comparative effects of low and high doses of the angiotensin-converting enzyme inhibitor, lisinopril, on morbidity and mortality in chronic heart failure. ATLAS Study Group

BACKGROUND

Angiotensin-converting enzyme (ACE) inhibitors are generally prescribed by physicians in doses lower than the large doses that have been shown to reduce morbidity and mortality in patients with heart failure. It is unclear, however, if low doses and high doses of ACE inhibitors have similar benefits.

METHODS AND RESULTS

We randomly assigned 3164 patients with New York Heart Association class II to IV heart failure and an ejection fraction < or = 30% to double-blind treatment with either low doses (2.5 to 5.0 mg daily, n=1596) or high doses (32.5 to 35 mg daily, n=1568) of the ACE inhibitor, lisinopril, for 39 to 58 months, while background therapy for heart failure was continued. When compared with the low-dose group, patients in the high-dose group had a nonsignificant 8% lower risk of death (P=0.128) but a significant 12% lower risk of death or hospitalization for any reason (P=0.002) and 24% fewer hospitalizations for heart failure (P=0.002). Dizziness and renal insufficiency was observed more frequently in the high-dose group, but the 2 groups were similar in the number of patients requiring discontinuation of the study medication. Conclusions-These findings indicate that patients with heart failure should not generally be maintained on very low doses of an ACE inhibitor (unless these are the only doses that can be tolerated) and suggest that the difference in efficacy between intermediate and high doses of an ACE inhibitor (if any) is likely to be very small.

Structural and functional assessment of small arteries in patients with chronic heart failure

The physiological response to a chronically failing heart is the implementation of compensatory mechanisms intended to support blood pressure. These mechanisms, which are not fully understood, increase peripheral vascular tone, thus increasing the strain on the weakened myocardium. This study investigated the structure and function of small arteries from heart failure patients and controls without heart failure in an attempt to identify abnormalities associated with heart failure which may be related to these mechanisms. Small arteries were dissected from gluteal biopsies and studied using wire myography. Arterial morphological parameters were measured and concentration-response curves constructed for a number of vasoconstrictor and vasodilator agonists. Plasma concentrations of neuroendocrine hormones were also measured. There were no morphological differences between small arteries from control subjects and those from patients with chronic heart failure. In heart failure patients, vasoconstrictor responses to endothelin-1 were significantly reduced, although plasma endothelin-1 levels were increased. Arteries from heart failure patients also showed evidence of an impaired neuronal uptake mechanism, since blockade by cocaine had no effect on noradrenaline-induced vasoconstriction in these vessels. These results suggest that small-artery structure is not altered in chronic heart failure and so cannot account for the heightened vascular resistance in this syndrome. However, abnormal neuronal uptake and impaired vasoconstriction in response to endothelin-1 may be associated with the complex compensatory phenomenon involved in heart failure.

Disruption of the relationship between renin and atrial natriuretic peptide early in the course of ventricular dysfunction

BACKGROUND

Plasma renin activity is normal in left ventricular dysfunction in the absence of diuretic therapy. In health there is a reciprocal relationship between renin and atrial natriuretic peptide (ANP) but a positive correlation in advanced heart failure. The relationship between renin and ANP in mild left ventricular dysfunction is unknown.

METHODS AND RESULTS

Patients with left ventricular dysfunction (n = 35, 18 without diuretic therapy) were compared to 20 age-matched healthy subjects. Plasma concentrations of active renin (PARC), ANP and norepinephrine were measured after 20 min rest and 45 min after an infusion of normal saline (10 ml/kg body wt.). Basal plasma ANP was increased in patients with left ventricular dysfunction compared to healthy subjects, whether or not they were receiving diuretics. PARC was similar in healthy controls and patients untreated with diuretics but was increased in diuretic treated patients. After saline loading in healthy subjects PARC fell while ANP rose. Patients with left ventricular dysfunction had a smaller decline in PARC, that did not achieve statistical significance, but had a greater increase in plasma ANP compared to healthy subjects (P<0.05). The close reciprocal relationship between PARC and ANP observed in healthy subjects before and after saline loading (r = 0.8, P<0.001 and r = 0.6, P<0.01) was weakened in those not receiving diuretics (r = 0.4, P<0.05 and r = 0.24, ns) and lost in those receiving diuretics (r = 0.1 and r = 0.08).

CONCLUSIONS

Patients with left ventricular dysfunction have a disturbance of the normal reciprocal relationship between PARC and ANP which antedates diuretic treatment. This should be taken into account when interpreting plasma neuroendocrine measurements in patients with ventricular dysfunction.

Impaired pulmonary diffusion during exercise in patients with chronic heart failure

BACKGROUND

Pulmonary diffusion is impaired at rest in patients with chronic heart failure (CHF) and has been implicated in the generation of symptoms and exercise intolerance. The aim of this study was to determine whether pulmonary diffusion is impaired during exercise in CHF, to examine its relationship to pulmonary blood flow, and to consider its functional significance in relation to metabolic gas exchange.

METHODS AND RESULTS

Carbon monoxide transfer factor (TLCO) and pulmonary blood flow (Q(C)) were measured by a rebreathe technique at rest and during steady-state cycling at 30 W in 24 CHF patients and 10 control subjects. Both patients and control subjects were able to raise TLCO and Q(C) during exercise. However, the patient group had a lower diffusion for a given blood flow (TLCO/Q(C)) both at rest (3.6+/-0.16 and 4.8+/-0.23 mL x L(-1) x mm Hg(-1); P<0.001) and during exercise (2.8+/-0.16 and 3.4+/-0.13 mL x L(-1) x mm Hg(-1) for CHF patients and control subjects, respectively; P<0.05). TLCO/Q(C) was related to the ventilatory equivalent for carbon dioxide (VEVCO(2)) production at 30 W (TLCO/Q(c) versus VEVCO(2), r = -0.58, P<0.01) and to peak exercise oxygen consumption measured during a progressive test (TLCO/Qc versus VO(2peak), r = 0.57, P<0.01) in these patients.

CONCLUSIONS

Patients with CHF are able to recruit reserves of TLCO and Q(C) during exercise. However, the TLCO/Q(C) ratio is consistently impaired in these patients and relates to both exercise hyperpnea and peak exercise oxygen consumption. Whether this impairment in alveolar gas exchange is reversible in CHF and therefore is a potential target for therapy has yet to be determined.

Perindopril for elderly people with chronic heart failure: the PEP-CHF study. The PEP investigators

BACKGROUND

The prevalence of chronic heart failure (CHF) rises with increasing age, from < 1% in those below 65 years of age to > 5% in those over 65 years of age and is a major cause of morbidity and mortality in older people. Recent European guidelines point to a major deficiency in our knowledge of how to treat diastolic chronic heart failure, and a lack of information on treatment for heart failure in the elderly in general.

AIMS

The aims of this trial are to assess the potential benefits of the ACE inhibitor perindopril to treat chronic heart failure in elderly people, in the absence of any major left ventricular systolic dysfunction.

SUBJECTS

One thousand people over the age of 70 years will be recruited into this study. Evidence of chronic heart failure will be confirmed by clinical criteria and echocardiography.

METHODS

Once a diagnosis of chronic heart failure has been confirmed, the patient will receive either perindopril or placebo in addition to their usual treatment. Death, and unplanned heart failure related hospitalisations, are the primary outcomes. Quality of life, as measured by the Guyatt questionnaire will be assessed at the beginning of the study and at 1 year. Sub-studies of this trial include a 6-min walking test and more detailed evaluation of ventricular function (as assessed by echocardiography). Both parameters will be measured at 8 weeks and 1 year, and analysed against baseline data. Cognitive function in this group of patients will also be evaluated at baseline and 1 year. This trial is due to report in the year 2001.

Is the prognosis of heart failure improving?

BACKGROUND AND METHODS": Heart failure is common and effective therapy exists but as yet there is little evidence that the overall prognosis is improving in clinical practice. We sought to determine if mortality, re-admission with heart failure and re-admission for any cause, had changed between cohorts of first-time admissions for heart failure identified in 1984, 1988 and 1992 using linked hospital discharge and mortality data from Scotland (population approximately 5 million).

FINDINGS

The number of first-time admissions for heart failure increased by 30% between 1984 and 1992, from 9716 to 12640. Their mean age was 74 years and 54% were women. Over the same period 3-year mortality declined in patients < 65 years from 53 to 41% (reduction in risk 12% (95% confidence interval 9-15%. Log-rank 70.0; P<0.001) and for patients > or =65 years from 71% to 66% (reduction in risk 5% (95% confidence interval 3-6%. Log-rank 74.5; P<0.0001). Time to death or first re-admission with heart failure also improved but not time to death or first re-admission for any cause. The total number of re-admissions increased between 1984 and 1992 but bed-days occupancy for heart failure and for any cause, adjusted for days alive, declined due to a reduction in length of stay.

INTERPRETATION

These data suggest that the prognosis of patients with a first admission for heart failure is improving. The timing of improvement coincides with the gradual increase in the use of angiotensin converting enzyme inhibitors for heart failure although a causal link cannot be proved from these data.

Heart failure update

The RUSSLAN study, which randomised 504 patients with post-infarction heart failure in whom intravenous inotropic support might be deemed appropriate, was presented for the first time in a hotline session at the annual meeting of the Working Group on Heart Failure of the European Society of Cardiology. The study suggested that levosimendan, a new calcium sensitising agent, could be used safely in patients with post-infarction heart failure in the absence of severe hypotension and that it appeared to improve symptoms and survival. If these results can be confirmed it would render it unique among intravenous inotropic agents.

Area variations in use of modern contraception in rural Bangladesh: a multilevel analysis

This study in Bangladesh found that inter-cluster variation in the use of modern reversible methods of contraception was significantly attributable to the educational levels of the female family planning workers working in the clusters. Women belonging to clusters served by educated workers had a higher probability of being contraceptive users than those whose workers had only completed primary education. At the household level, important determinants of use were socioeconomic status and religion. At the individual level, the woman being the wife of the household head and having some education were positively related to her being a user. The model also found that inter-household variation was significantly greater than inter-cluster variation. Finally, the study concludes that after controlling for various covariates at all three levels, the clusters do not have significantly different levels of use of modern reversible methods of contraception. There are, however, some special areas where contraceptive use is dramatically low, and these contribute significantly to the observed inter-cluster variation.

Update of REACH-1 and MERIT-HF clinical trials in heart failure. Cardio.net Editorial Team

BACKGROUND

This article reviews the design and results of REACH-1 (Research on Endothelin Antagonism in Chronic Heart Failure) and MERIT (Metoprolol controlled and Extended release, Randomised Intervention Trial in congestive Heart Failure), two recently reported clinical trials that investigated, respectively, the role of a non-selective endothelin antagonist (bosentan) and of a beta-selective blocker for the treatment of heart failure.

RESULTS

The REACH-1 trial demonstrated that initiation of bosentan therapy is associated with an increased risk of worsening heart failure. However, long-term therapy with bosentan may have improved symptoms and favourably altered the progression of heart failure. The MERIT-HF clinical trial indicated that beta-blockade using metoprolol confers a significant beneficial effect on total mortality in patients with stable chronic heart failure.

The carvedilol hibernation reversible ischaemia trial; marker of success (CHRISTMAS). The CHRISTMAS Study Steering Committee and Investigators

BACKGROUND

Carvedilol improves left ventricular (LV) function when heart failure is due to LV systolic dysfunction, but the magnitude of the response is heterogeneous among patients with coronary disease, possibly reflecting the presence or volume of hibernating myocardium.

AIMS

The primary objective of the study is to determine whether the presence of hibernating myocardium predicts the magnitude of improvement in LV ejection fraction in response to carvedilol among patients with heart failure and LV systolic dysfunction due to coronary disease.

METHODS

The study is a prospective, randomised, parallel-group, double-blind, multi-centre study comparing carvedilol and placebo over a period of approximately 6 months in the above patient population. The primary end-point is the comparison of the mean change, from baseline to the final visit, in radionuclide-determined LV ejection fraction among patients on placebo with those on carvedilol stratified according to the presence of hibernating myocardium. Hibernating status will be determined by a combination of echocardiographic and myocardial perfusion (technetium-99m sestamibi) imaging.

RESULTS

255 patients have undergone screening tests of which 207 have been randomised so far. The study intends to randomise 400 patients and the first report of results is expected in 2000.

CONCLUSIONS

As far as we are aware this is the first randomised controlled trial to investigate the effects of treatment in patients stratified according to the presence of hibernating myocardium. The study will provide insights into the prevalence of myocardial hibernation, its natural history, and its influence on prognosis as well as the interaction between the presence of hibernating myocardium and the effects of treatment with carvedilol.

Heart failure due to ischaemic heart disease: epidemiology, pathophysiology and progression

Ischaemic heart disease is the most common underlying cause of heart failure in industrialised countries. Its manifestations are protean with myocardial infarction being only one important facet. The prognosis of patients with heart failure due to ischaemic heart disease also appears to be worse than that associated with many other aetiologies. The presence of ischaemic heart disease may influence both the efficacy and choice of treatment. Agents such as digoxin and amlodipine appear less effective in patients with ischaemic heart disease while ACE inhibitors and beta-blockers appear as or more effective in patients with ischaemic heart disease. Many have expressed an opinion about how coronary disease should be managed in the patient with heart failure supported by little or no evidence. There are major theoretical and practical concerns about the use of anti-coagulant, anti-platelet and statin therapy in patients with heart failure as well as major theoretical benefits. Only randomised controlled trials will resolve these issues. The same may be said of revascularisation. Fortunately trials addressing all these areas are under way. This should put the management of coronary disease in patients with heart failure on a firm evidence-based footing.

Endothelin B receptors are functionally important in mediating vasoconstriction in the systemic circulation in patients with left ventricular systolic dysfunction

OBJECTIVES

This study was designed to assess the functional importance of endothelin (ET)B receptors in patients with left ventricular systolic dysfunction (LVSD) by comparing the hemodynamic effects of ET-1, a nonselective ET(A) and ET(B) agonist, with ET-3, a selective ET(B) receptor agonist.

BACKGROUND

Knowledge of the functional importance of ET(B) receptors in mediating vasoconstriction in chronic heart failure will help determine whether antagonists at both ET(A) and ET(B) receptors are required to fully prevent vasoconstriction to endogenously produced ET-1.

METHODS

We infused ET-1 (5 and 15 pmol/min) and ET-3 (5 and 15 pmol/min) into two separate groups of eight patients with LVSD with similar baseline hemodynamic indices. Hemodynamics were measured using a pulmonary thermodilution catheter and an arterial line.

RESULTS

Endothelin-1 infusion led to systemic vasoconstriction, with a rise in mean arterial pressure (mean +/- SEM 100 +/- 3 to 105 +/- 3 mm Hg, p < 0.02) and systemic vascular resistance (1,727 +/- 142 to 2,055 +/- 164 dyn/s/cm(-5), p < 0.001) and a fall in cardiac index (2.44 +/- 0.21 to 2.22 +/- 0.20 liters/min/m , p < 0.01). Endothelin-3 infusion also led to systemic vasoconstriction, with a rise in mean arterial pressure (99 +/- 6 to 105 +/- 6 mm Hg, p < 0.01) and systemic vascular resistance (1,639 +/- 210 to 1,918 +/- 245 dyn/s/cm(-5), p < 0.01) and a fall in cardiac index (2.66 +/- 0.28 to 2.42 +/- 0.24 liters/min/m2, p < 0.05). Pulmonary hemodynamic measurements did not change significantly in either group.

CONCLUSIONS

Both ET-1 and ET-3 infusions led to systemic vasoconstriction; the hemodynamic changes observed were of a similar magnitude at the same molar concentration. This suggests that ET(B) receptors are functionally important in mediating vasoconstriction, at least in the systemic circulation, in patients with LVSD.

Has the survival of the heart failure population changed? Lessons from trials

Heart failure is a common and growing problem with a poor prognosis both in terms of morbidity and mortality. Furthermore, the natural history of heart failure can be modified dramatically by appropriate therapy. The purposes of this article are to (1) describe briefly the epidemiology and current therapy of heart failure; (2) examine potential differences between heart failure as studied in the clinical trials, compared with heart failure in the community; and (3) suggest a number of areas where improvements might be made or further research is required.