BETHESDA, MD—The American College of Cardiology (ACC) and the American Heart Association (AHA) have updated their clinical guidelines for evaluating and managing heart failure (HF).[1] The guidelines, which were developed in collaboration with the International Society for Heart and Lung Transplantation and endorsed by the Heart Failure Society of America, include a new, four-stage classification system and recommendations for patients with comorbid conditions, notably pulmonary disease, that may complicate the diagnosis and management of HF.

The ACC/AHA guidelines for HF management were first issued in 1995. Since that time, data supporting the use of angiotensin-converting enzyme (ACE) inhibitors and ß-blockers have continued to evolve. “Now we have a great deal more evidence documenting their utility in treating HF,” noted Sharon A. Hunt, MD, Professor of Medicine in the Division of Cardiovascular Medicine at Stanford University School of Medicine in Stanford, California, and chair of the guidelines writing committee.

HF currently affects nearly five million persons in the United States and is rapidly becoming a public health problem of epidemic proportions.[2] Each year, HF is diagnosed for the first time in an additional 500,000 adults, and—because HF is primarily a disease of the elderly—this number is expected to increase as the US population continues to age.

STAGING HF

The staging system proposed in the guidelines recognizes the evolution and progression of HF. It is meant to complement, not replace, the widely used New York Heart Association (NYHA) functional classification, which categorizes HF patients by the severity of their symptoms. “The NYHA classifications still stand and always will,” explained Dr. Hunt. “The classification or staging that we have suggested has to do with the stage of patients’ disease in terms of its progression.” The guidelines identify four stages:

• Stage A denotes patients who are at high risk for developing HF because of a predisposing condition (eg, hypertension, coronary artery disease, or diabetes mellitus) but who have no structural cardiac abnormalities.

• Stage B refers to patients who have a structural cardiac abnormality but who have never had any symptoms of HF.

• Stage C includes patients who have had or who currently have HF symptoms associated with underlying structural heart disease.

• Stage D encompasses patients with end-stage HF who require specialized interventions.

The NYHA functional classification essentially categorizes HF patients who are in Stage C or Stage D. The new staging system presented by the guidelines “is basically meant to highlight the fact that there are preclinical stages of heart failure during which prevention is extremely important,” Dr. Hunt noted. The stage-by-stage approach to HF prevention and management is summarized in Table 1.

RECOGNIZING HF

Another hallmark of the new guidelines is the recognition of the clinical variability of HF. The disorder (which can result from any structural or functional cardiac abnormality that impairs ventricular filling or ejection) is marked by dyspnea, fatigue, and fluid retention, which can lead to pulmonary congestion and peripheral edema. However, the various manifestations of HF are not present at the same time in all patients. Furthermore, some patients with HF do not have volume overload at presentation or during subsequent evaluations. Thus, the guidelines prefer the term heart failure over the older designation, congestive heart failure.

Patients with HF typically present to their physicians in one of the following ways:

• With decreased exercise tolerance (eg, due to dyspnea or fatigue).

• With fluid retention (eg, leg or abdominal swelling may be the primary or the only symptom).

• With no symptoms or symptoms of another cardiac disorder (ie, left ventricular dysfunction is incidentally discovered).

The guidelines stress that HF remains a clinical diagnosis, based on a thorough history and physical examination. Baseline laboratory testing should include a complete blood cell count, urinalysis, serum electrolyte measurements, a lipid profile, and tests of renal, hepatic, and thyroid function. The guidelines recommend a two-dimensional echocardiogram with Doppler flow studies as the single most useful test for evaluating a structural cardiac component in HF. It can be used to assess the pericardium, myocardium, and cardiac valves and to determine whether any myocardial dysfunction is diastolic or systolic in origin.

DIFFERENTIATING CARDIAC FROM PULMONARY SYMPTOMS

The key to diagnosing HF in patients with comorbid pulmonary disease is differentiating symptoms with a cardiac origin from those with a pulmonary cause. “The main thing to remember,” explained Dr. Hunt, “is that both diseases cause shortness of breath. It is very important to sort out what component is pulmonary and what component is cardiac.”

Although a chest film may be helpful as part of the initial evaluation (eg, for estimating the degree of pulmonary congestion and detecting pulmonary disease), the guidelines suggest exercise testing with simultaneous gas exchange or blood gas measurements to assess the extent to which pulmonary disease is contributing to the patient’s disability. This approach may be used in conjunction with right heart catheterization.[3]

Pulmonary disease may also complicate the management of HF because drugs used to treat HF can worsen pulmonary symptoms. Cough is a common side effect of ACE inhibitor therapy. An ACE inhibitor–induced cough may be mistaken for a symptom of respiratory infection. Conversely, a cough of pulmonary origin may cause ACE inhibitor therapy to be discontinued inappropriately. In addition, ß-blockers can aggravate bronchospasm in patients who have asthma or who have chronic obstructive pulmonary disease with a bronchospastic component. Thus, the guidelines recommend:

• Seeking a pulmonary cause in all HF patients who complain of coughing. A cough should be attributed to ACE inhibitor therapy only if respiratory disorders have been excluded and if the cough ceases with the termination of the ACE inhibitor and recurs when the treatment is reinstituted.

• Avoiding ß-blocker therapy in all HF patients with coexisting bronchospastic pulmonary disease.

—Christine M. Olsen, PhD