CHF incidence, burden expected to climb

The numbers tell it all

Congestive heart failure (CHF) affects about 4.7 million Americans with 400,000 new cases each year. Hospitalization costs pose a considerable financial burden, totaling more than $10.3 billion annually.

The national incidence and associated burden is expected to climb as the population ages and the life expectancy of patients surviving a heart attack increases.

Unnecessary readmissions cost an estimated $600 million a year. Noncompliance with medication, ranging from 20% to 58%, is a key reason for readmissions, and education provides the best opportunity for improvement. A recent study from Yale University in New Haven CT, showed that almost half of all Medicare CHF patients are readmitted within six months of discharge.1 Investigators analyzed readmission rates of Connecticut Medicare patients admitted to 33 hospitals between 1991 and 1994. Of 17,500 survivors, 44% were readmitted at least once six months later. The high rate underscores the insufficiency of current practice patterns.

Total discharges for CHF were 945,307 in 1994, the latest year available for statistics from the Healthcare Cost and Utilization Project (HCUP-3), a federal-state-industry partnership under the Agency for Health Care Policy and Research (AHCPR) of the Department of Health and Human Services in Rockville, MD. This number represents 2.73% of total discharges. Mean length of stay that year was 6.92, and the mean total charge was $11,227. That information is based on data from discharge records from a 20% inpatient sample of community hospitals from 17 states, including all payers.

LVD leads by two routes to CHF

Most primary cardiovascular diseases that damage myocardial cells - coronary artery disease, hypertension, myocarditis, diabetes, cardiomyopathy, valvulopathies, and congenital heart disease - share a common symptomatologic pathway: left ventricular dysfunction (LVD) leading by the following two main routes to congestive heart failure (CHF).2

1. Cardiac remodeling.

This condition occurs when the ventricular chamber progressively enlarges in an attempt to maintain stroke volume and effectively perfuse target organs. This leads to severely decreased left ventricular ejection fractions (LVEF), arrhythmias, pump failure, and death. However, the extent of remodeling does not necessarily correlate with the severity of the symptomatology - a patient with proven LVD may not experience any symptoms of CHF.

2. Activation of noncardiac factors.

These factors are thought responsible for development of symptoms. The symptoms of CHF include shortness of breath, dyspnea on exertion, paroxysmal nocturnal dyspnea, orthopnea, and lower extremity edema. Noncardiac factors work through endocrine, neural, and renal mechanisms to result in sodium and water retention. Not only do noncardiac factors result in symptoms; they also accelerate and potentiate remodeling, resulting in faster progression to severely decreased LVEF and death.

Early diagnosis of CHF is a major goal. Which-ever method is used to monitor progression of disease - LVEF, New York Heart Association functional class, neurohormones, quality of life, or myocardial oxygen consumption - ratings continue to deteriorate with time. With early diagnosis, disease progression may be halted, and the natural history modified.

The goal of therapy is to maintain stroke volumes adequate to perfuse vital organs while avoiding the detrimental compensatory mechanism of remodeling. Maintenance of small chamber size is the best means to effectively improve all these parameters.

Therapeutic modalities can be divided into two groups: those directed to reduce symptomatology and those intended to prevent left ventricular remodeling. These are:

· The first group of therapeutics includes diuretics, vasodilators, and positive inotropes which decrease symptomatology, but may not increase survival. In fact, some experts hold that IV inotropes such as dobutamine and phosphodiesterase inhibitors decrease survival.

However, investigators recently conducted a study to determine whether patients with end-stage CHF could safely tolerate intermittent outpatient inotropic therapy. They demonstrated both symptomatic and functional improvement with the agents.3

The study looked at the effects of low-dose, intermittent home infusions of the inotrope/ vasodilator milrinone and concluded that patients' improvement partly relates to a "training" effect on the heart or peripheral muscles and circulation. Investigators stated that the promising results suggest that, given appropriately, inotropes have an important therapeutic role in the outpatient treatment of end-stage CHF.

· The second group of therapeutics slow disease progression. Among that group, angiotensin-converting enzyme (ACE) inhibitors are the most effective. Beta blockers have also been proven to be effective, and a recent study showed that blockade reduces all-cause mortality, and its benefit is not affected by etiology.4 Nitrates are very effective in inhibiting remodeling, but tolerance to them develops rapidly due to formation of superoxides. Addition of hydralazine blocks this biochemical response. The efficacy of a combination of nitrates and hydralazine, therefore, is well -established.

Exercise has been shown to help some patients - it helps them breathe easier and does not cause further damage to heart muscle.5 While patients were often excluded from rehab programs in the past because it was thought that exercise training might worsen remodeling, physical activity is encouraged today.

(Editor's note: For information about HCUP-3 databases, contact the AHCPR, Healthcare Cost and Utilization Project, 2101 East Jefferson St., Suite 500, Rockville, MD 20852; http://www.ahcpr.gov/data/.)

References

1. Rivas EJ. Congestive Heart Failure: The Interacting Roles of Remodeling and Noncardiac Factors. On-line coverage from the 70th Annual Scientific Sessions of the American Heart Association. Orlando, FL; November 1997.

2. Krumholz HM, Parent EM, Tu N, et al. Readmission after hospitalization for congestive heart failure among medicare beneficiaries. Arch Intern Med 1997; 157:99-104.

3. Cesario D, Clark J, Maisel A. Beneficial effects of intermittent home administration of the inotrope/vasodilator milrinone in patients with end-stage congestive heart failure. Am Heart J 1998; 135:121-129.

4. Heidenreich PA, Lee TT, Massie BM. Effect of beta-blockade on mortality in patients with heart failure. J Am Coll Cardiol 1997; 30:27-34.

5. Paul Dubach P, Myers J, Dziekan G, et al. Effect of exercise training on myocardial remodeling in patients with reduced left ventricular function after myocardial infarction. Circulation 1997; 95:2,060.