Rationale for HF Clinics
The Problem: Heart Failure
Heart failure (HF) is a major health problem in Canada and throughout the world. Presently, HF affects 5 million to 7 million North Americans and another 20 million individuals in Third World countries.1
In Canada, HF affects more than 1% of the population and is responsible for 9% of all deaths. HF is the most common cause of hospitalization of people over 65 years of age.2
The incidence and prevalence of HF will continue to rise as the population ages. As shown in Figure 1.1, it is estimated that HF prevalence will nearly double due to the aging population by the year 2030.3 In some regions of Canada, the rate of HF is increasing by as much as 4% annually.
Despite medical management, recent data suggest that the HF mortality rate may be as high as 40% to 50% two years following treatment.4 In addition, the continual cycles of acute crises associated with HF result in high hospital readmission rates and increased health care costs.
This steady increase in the number of deaths, hospitalizations, and medical costs associated with HF continues to occur at a time when morbidity and mortality rates from other common cardiovascular diseases (such as myocardial infarction) are on the decline.
There is an urgent need for aggressive measures to reduce the mortality and morbidity associated with HF, reduce hospital admissions and readmissions, and improve patient management.
One Solution: HF Clinics
In recent years, a number of HF clinics have been established in Canada and the United States in an effort to improve the quality of life of patients with HF and reduce the economic burden associated with the inpatient management of this patient population.
Preliminary findings from the Cardiology Preeminence Roundtable publication suggest that progress in the management of patients with HF depends on avoiding hospitalization in the first place.3
Figure 1.2 shows several approaches that are being successfully used to manage HF patients in the outpatient setting. 3
“As much as 50% of inpatient care for HF ideally should have occurred elsewhere or been avoided altogether.”
Cardiology Preeminence Roundtable3
As shown in Figure 1.3, heart failure
clinics have the potential to reduce length of stay
and hospital admissions.3
“Outpatient intervention not only reduces HF admissions, but when hospitalization is unavoidable, it reduces the average length of stay.”
Cardiology Preeminence Roundtable3
Heart failure (HF) is a state in which the heart is unable to pump blood at a rate to meet the requirements of metabolizing tissues or can only do so from an elevated filling pressure. Many forms of heart disease may lead to heart failure. Other diseases and treatments can precipitate exacerbations of HF.
Etiology of Heart Failure
- Ischemia/myocardial infarction 65%
- Non-ischemic dilated cardiomyopathy 20%
- Other 15%
Ischemia and/or myocardial infarction contribute to the development of heart failure in up to 65% of cases.5 Myocardial infarction can lead to ventricular remodelling with compensatory dilation and hypertrophy and subsequent systolic and diastolic dysfunction progressing to the clinical syndrome called HF. In patients with ischemia, the major cause of heart failure is systolic dysfunction with some degree of diastolic dysfunction.
In a subgroup of patients, the cause of heart failure is diastolic dysfunction. These individuals have signs and symptoms of heart failure but a normal left ventricular ejection fraction. Appropriate management of these patients is to address the underlying etiology. Unfortunately, there are few clinical trials to direct decisions about the best choice of drug therapy.
Some patients have signs of HF such as cardiomegaly on chest x-ray or left ventricular dysfunction, but no symptoms.
Goals of Heart Failure Treatment
The clinical goals of heart failure treatment are to:
- Improve heart function
- Reduce symptoms
- Prevent hospital readmissions
- Improve survival
- Improve quality of life
Disease Progression in Heart Failure
Most patients with heart failure have only mild symptoms and often respond well to medical therapy. Unfortunately, because of the progressive nature of HF, these patients remain at risk for worsening disease despite the optimal use of current firstline medications. This is because myocardial damage triggers a series of compensatory mechanisms that progressively compromise cardiac function.
In the early stages of myocardial damage, activation of neurohormonal systems, including the renin-angiotensin-aldosterone (RAA) and sympathetic nervous systems, provides initial support for the failing heart. However, the continued neurohormonal activation becomes deleterious with excessive vasoconstriction, volume expansion, and ventricular remodelling leading to continued deterioration in cardiac function.
Ventricular remodelling can be favourably altered by angiotensin-converting enzyme (ACE) inhibitors, agents that have been shown to reduce morbidity and mortality in patients with HF and asymptomatic left ventricular dysfunction.6
Recent clinical findings suggest that beta-blockers can reduce symptoms, improve left ventricular function, and inhibit disease progression in patients with mild to moderate HF on standard therapy consisting of an ACE inhibitor and diuretics, with or without digoxin.7-10
Emerging data on the beneficial effects on outcome in heart failure patients with beta1-selective blockers further support the importance of this therapy.11,12 However, in a meta-analysis of the clinical effects of beta-adrenergic blockade in heart failure, Lechat and colleagues reported that the reduction in mortality risk was greater for nonselective beta-blockers than for beta1–selective agents.10
Diuretics are very successful in reducing symptoms of HF and they probably reduce readmissions for heart failure. However, their influence on survival has not been adequately tested. Digoxin can improve symptoms and will reduce hospital readmissions for heart failure, but has a neutral effect on survival. Some positive inotropic agents will reduce symptoms and hospital readmissions for heart failure, but may worsen the underlying disease process.
- Ackman ML, Harjee KS, Mansell G, et al. Cause-specific noncardiac mortality in patients with chronic heart failure — a contemporary Canadian audit. Can J Cardiol 1996;12:809-813.
- Brophy JM. Epidemiology of chronic heart failure. Canadian data from 1970-1989. Can J Cardiol 1992;8:495-498.
- Cardiology Preeminence Roundtable. Beyond Four Walls: Cost-Effective Management of Chronic Congestive Heart Failure. Washington, D.C.: Advisory Board Company, 1994.
- Johnstone DE, Abdulla A, Arnold JMO, Bernstein V, et al. Diagnosis and management of heart failure. Can J Cardiol 1994;10:613-631.
- Canadian Cardiovascular Society. Report on the 1993 Consensus Conference on the Diagnosis and Treatment of Heart Failure. Toronto: Queen’s Printer for Ontario, 1996.
- The SOLVD Investigators. Effect of enalapril on mortality and the development of heart failure in asymptomatic patients with reduced left ventricular ejection fractions. N Engl J Med 1992;327:685-691.
- Doughty RN, Whalley GA, Gamble G, MacMahon S, Sharpe N. Left ventricular remodeling with carvedilol in patients with chronic heart disease due to ischemic heart disease. J Am Coll Cardiol 1997;29:1060-1066.
- Packer M, Bristow MR, Cohn JN, et al, for the U.S. Carvedilol Heart Failure Study Group. The effect of carvedilol on morbidity and mortality in patients with chronic heart failure. N Engl J Med 1996;334:1349-1355.
- Heidenreich PA, Lee TT, Massie BM. Effect of beta-blockade on mortality in patients with heart failure: a meta-analysis of randomized clinical trials. J Am Coll Cardiol 1997;30:27-34
- Lechat P, Packer M, Chalon S, Cucherat M, Arab T, Boissel J-P. Clinical effects of ß-adrenergic blockade in chronic heart failure. Circulation 1998;98:1184-1191.
- CIBIS Investigators and Committees. A randomized trial of ß-blockade in heart failure: the Cardiac Insufficiency Bisoprolol Study (CIBIS). Circulation 1994;90:1765-1773.
- The International Steering Committee on Behalf of the MERIT-HF Study Group. Metoprolol CR/XL. Randomized Intervention Trial in Heart Failure (MERIT-HF): rationale, design, and organization. Am J Cardiol 1997;80(Suppl 9B):54J-58J.
*Draft changes pending adoption by CHFN