Heart failure: The importance of precision


The diagnosis and treatment of heart failure have progressed rapidly over the past several years, and for coding purposes, it is no longer enough to say that patients have “CHF” or “congestive heart failure.” Since not all heart failure is “congestive,” the term is misleading and needs qualification.

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First, the medical record should clearly indicate whether a patient's heart failure is “chronic” (“stable,” “baseline”), even if asymptomatic, or if an acute exacerbation has occurred. Also, to manage patients correctly and select the most effective medications, a physician needs to know whether the failure is systolic or diastolic failure—or both. This can sometimes be clinically determined, but the best test is an echocardiogram.

Systolic or diastolic

Systolic heart failure is characterized by:

  • dilated, weak heart and/or thin ventricular wall,
  • decreased outflow of blood from the heart (impaired ventricular pumping function), and
  • ejection fraction (EF) less than 40%.

Systolic heart failure is more common than diastolic failure, and the usual cause is ischemic coronary artery disease. If at all possible, these patients must be treated with an angiotensin-converting enzyme inhibitor (ACEI) or angiotensin II receptor blocker (ARB), as these drugs prolong life, reduce complications and lower hospitalization rates for patients with any component of systolic heart failure.

Diastolic heart failure is characterized by:

  • thickened myocardium/hypertrophic ventricle,
  • low-capacity ventricular chamber,
  • an improperly relaxing ventricle,
  • impaired filling with blood (during diastole),
  • strong ventricular contraction, and
  • normal (55% to 70%) or elevated (“preserved”) ejection fraction.

Common causes of diastolic heart failure are aortic stenosis, uncontrolled hypertension and end-stage renal disease. ACEIs or ARBs may be prescribed, but they do not have the same benefits in patients with pure diastolic heart failure as in patients who have any component of systolic failure.

Treatment

To eliminate or reduce fluid retention, physicians often give loop diuretics like furosemide (Lasix) before giving thiazides. If a patient is already taking stable doses of ACEI and digoxin (Lanoxin), spironolactone (Aldactone) should be prescribed to reduce mortality risk in patients with New York Heart Association (NYHA) class III or IV heart failure (i.e., moderate or severe heart failure).

Beta-blockers slow the heart rate, lower blood pressure, reduce cardiac oxygen consumption and lessen the cardiac workload. They are generally prescribed for most patients with heart failure, but are typically first-line therapy for diastolic failure. Three beta-blockers have been shown to improve survival in heart failure: carvedilol (Coreg), metoprolol (Lopressor, Toprol-XL) and bisoprolol (Zebeta).

Nitrates are venous and coronary artery vasodilators that reduce cardiac work, increase coronary blood flow and improve cardiac performance. Digoxin (Lanoxin) is used for rate control when a patient has atrial fibrillation, and improves cardiac function when a patient has symptomatic left ventricular systolic dysfunction despite treatment with an ACEI and diuretic. It does not, however, benefit diastolic heart failure.