Heart failure: a coding classification quandary


According to the American Heart Association (AHA), over 5 million Americans have heart failure and about 58,000 deaths per year have heart failure as the primary cause. Heart failure results from functional or structural abnormalities that impair diastolic filling or systolic ejection of blood.

The diagnosis of heart failure is, first and foremost, clinical, based on history and physical examination supplemented by diagnostic testing. Patients may present with fatigue, dyspnea (with or without exertion), and/or evidence of fluid retention. Because some patients do not have evidence of fluid accumulation (congestion), the American College of Cardiology (ACC) recommends the diagnostic term “heart failure” now be used in preference to “congestive heart failure (CHF).”

Photo from Thinkstock
Photo from Thinkstock.

Heart failure may be classified on the basis of functional status, stage, etiology, or pathophysiologic mechanism. The New York Heart Association (NYHA) functional classification is based on the degree of physical activity limitation (see Table 1). The ACC/AHA also recognize 4 stages of heart failure (see Table 2) based on symptoms and the clinical progression of structural changes in the heart. Heart failure may also be clinically classified based on etiology, including conditions such as those listed in Table 3. Heart failure is pathophysiologically based on systolic and/or diastolic dysfunction.

The documentation dilemma for correct coding to accurately reflect severity of illness arises from the fact that official coding guidelines rely heavily on the pathophysiologic classification of systolic or diastolic dysfunction. The guidelines do acknowledge etiologic distinctions, but these codes rarely capture the severity of illness of hospitalized patients unless systolic and/or diastolic dysfunction and its acuity are also identified. Stage and NYHA classification are not recognized, as there are no codes provided to describe them.

Echocardiogram is the usual method for identifying systolic and diastolic heart failure based on ejection fraction. Normal ejection fraction (EF) is 55% to 70%. If patients with heart failure have an EF below normal, their heart failure is systolic; if EF is normal or elevated, it is diastolic heart failure. Diastolic dysfunction may also be detected by specific echocardiographic measurements irrespective of ejection fraction. Some patients exhibit a combination of diastolic dysfunction and low EF, indicative of combined systolic/diastolic heart failure.

For correct coding and accurate representation of severity of illness, heart failure must be characterized as systolic, diastolic, or combined systolic/diastolic for every patient. Acuity should also be specified. Obviously an acute exacerbation or decompensation is a more serious situation than chronic heart failure, but even stable, asymptomatic chronic systolic or diastolic heart failure contributes to severity classification.

In summary, heart failure should no longer be characterized as “congestive” or “CHF.” Clinical classifications based on NYHA criteria, stage, and etiology rarely result in the correct codes to express the patient's actual condition and severity of illness. While these descriptions have great clinical utility and significance, for correct coding, the pathophysiologic classification of systolic and/or diastolic heart failure must also be specifically documented, as well as its acuity. Heart failure associated with a low EF is systolic, normal or elevated EF indicates diastolic failure, and the two can coexist in some patients.