Two complementary systems are used to classify heart failure stages.
The New York Heart Association (NYHA) classification divides patients into groups according to impairment in ability to carry out physical activity. It is a subjective assessment made by the physician, and it represents a patient’s condition at the time of evaluation. A patient’s NYHA class may change between visits as treatments take effect or the disease progresses.
The American College of Cardiology (ACC) and the American Heart Association (AHA) classify heart failure based on the evolution and progression of the disease, rather than on functional capacity. Once a patient advances to the next stage, he or she is unlikely to move backward. The ACC/AHA system links heart failure stages to recommended treatments.
The ACC/AHA classification broadens the scope to include patients who are at risk for developing heart failure and those who have structural heart disease, but no symptoms. This is an important distinction, because these patients should be advised and treated accordingly. Only ACC/AHA stages B, C and D are comparable to the NYHA classification system; there is no NYHA class for stage A.
New York Heart Association Functional Classification of Heart Failure
Class I (No Impairment)
Patients with cardiac disease but without resulting limitation of physical activity. Ordinary physical activity does not cause undue fatigue, palpitation, dyspnea, or anginal pain.
Class II (Mild To Moderate)
Patients with cardiac disease resulting in slight limitation of physical activity. They are comfortable at rest. Ordinary physical activity results in fatigue, palpitation, dyspnea, or anginal pain.
Class III (Moderate)
Patients with cardiac disease resulting in marked limitation of physical activity. They are comfortable at rest. Less than ordinary physical activity results in fatigue, palpitation, dyspnea, or anginal pain.
Class IV (Severe)
Patients with cardiac disease resulting in inability to carry on any physical activity. Symptoms of heart failure or the anginal syndrome may be present even at rest. If any physical activity is undertaken, symptoms are increased.
American College of Cardiology/American Heart Association Heart Failure Stages
Patients at high risk for developing heart failure who have no structural disorder of the heart.
Patients with a structural disorder of the heart who have never developed symptoms of heart failure.
Patients with past or current symptoms of heart failure associated with underlying structural heart disease.
Patients with end-stage disease who require specialized treatment strategies such as mechanical circulatory support, continuous inotropic infusions, cardiac transplantation, or hospice care.
Treatment for Early Heart Failure Stages Means Fewer Complications
When treatment is started before the symptoms of heart failure appear (ACC/AHA stages A and B), it reduces the risk of complications or death. Therefore, it is important to identify and treat patients in these earlier stages to prevent heart failure from progressing. Unfortunately, many people who have no symptoms do not feel compelled to make lifestyle changes that might prevent heart failure from developing.
As heart failure worsens, treatment becomes more complex, and surgery may be advised. The following is a guideline of treatment strategies for each heart failure stage based on the ACC/AHA classification system.
Treatments by ACC/AHA Class Heart Failure Stages
Patients are considered at high risk of developing heart failure, but don’t have symptoms. Treatment focuses on eliminating risk factors through lifestyle modifications such as weight loss, exercise, and avoidance of tobacco, illicit drugs, and excessive alcohol. Patients with diabetes and/or confirmed coronary artery disease should be prescribed ACE inhibitors or ARBs, statins (cholesterol-lowering drugs), and/or low-dose aspirin.
Patients have no apparent symptoms of heart failure, but have confirmed structural heart disease. Many have had a heart attack; others have cardiomyopathy or valve disease. In addition to the lifestyle modifications and medications listed for stage A, most patients should take an ACE inhibitor (or ARB) and beta-blocker. An implantable cardioverter defibrillator (ICD) may be advised in patients with a low ejection fraction.
Patients have structural heart disease and symptoms of heart failure, such as shortness of breath, fatigue, and reduced exercise tolerance. In addition to all measures appropriate for stages A and B, these individuals should restrict salt intake, use a diuretic, and take an ACE inhibitor or an ARB, plus a beta-blocker. In some, digoxin may be recommended. An aldosterone antagonist may be prescribed for left ventricular (LV) dysfunction and mild-to-severe heart failure symptoms or after a heart attack. Surgical intervention could be considered in select patients. An ICD is recommended for the majority of patients with a left ventricular ejection fraction of less than 35 percent and symptoms of heart failure. Some patients may be eligible for cardiac resynchronization therapy.
Patients are severely ill and require special medical and/or surgical intervention. Intravenous diuretics and vasodilators may be appropriate for hospitalized patients. Some patients may be considered for a heart transplant, ventricular assist device (VAD), and/or investigational surgery or drugs. End-stage patients who are not eligible for any of these extraordinary procedures may be referred for hospice care.
Balancing medications in heart failure is a difficult job. Between 17 and 22 percent of patients with mildly symptomatic heart failure develop anemia, due to iron deficiency or the inability of their kidneys to produce enough of the hormone erythropoietin. As heart failure progresses, anemia becomes more common, affecting up to 70 percent of patients in NYHA class IV. Anemia, which is associated with poor survival, can be caused or aggravated by sodium and water retention, kidney disease, and other processes associated with heart failure. When appropriate, treatment with erythropoietic agents may help. However, these drugs may increase the risk of blood clots and are tricky to administer. They are also expensive. In people who are iron deficient, oral or intravenous iron supplementation can boost hemoglobin, the oxygen-carrying protein found in red blood cells. Iron replacement therapy has been shown to improve exercise tolerance, NYHA class, and quality of life.