Neuroregulatory proteins appear to have cardiac and neural effects. The neuregulin GGF2 protein (cimaglermin) has been shown to benefit cardiac function in several animal models of heart failure. Drugs used in type 2 diabetes have been of concern because of the association of this condition with cardiac events. Therefore, it is of interest that some of these agents appear to benefit patients with both heart failure and type 2 diabetes. Liraglutide, a GLP-1 agonist (see Chapter 41), has been shown in some studies to nonsignificantly reduce deaths from cardiovascular causes as well as the rates of myocardial infarction, nonfatal stroke, and hospitalization for heart failure. Empagliflozin, an SGLT2 inhibitor, has also been shown to reduce hospitalizations for heart failure.
Detailed guidelines are issued by US and European expert groups (see References). The American College of Cardiology/American Heart Association (ACC/AHA) guidelines for management of chronic heart failure specify four stages in the development of heart failure (Table 13–3). Patients in stage A are at high risk because of other disease but have no signs or symptoms of heart failure. Stage B patients have evidence of structural heart disease but no symptoms of heart failure. Stage C patients have structural heart disease and symptoms of failure, and symptoms are responsive to ordinary therapy. Patients in stage C must often be hospitalized for acute decompensation, and after discharge, they often decompensate again, requiring rehospitalization. Stage D patients have heart failure refractory to ordinary therapy, and special interventions (eg, resynchronization therapy, transplant) are required.
Once stage C is reached, the severity of heart failure is usually described according to a scale devised by the New York Heart Association. Class I failure is associated with no limitations on ordinary activities and symptoms that occur only with greater than ordinary exercise. Class II failure is characterized by slight limitation of activities and results in fatigue and palpitations with ordinary physical activity. Class III failure results in fatigue, shortness of breath, and tachycardia with less than ordinary physical activity, but no symptoms at rest. Class IV failure is associated with symptoms even when the patient is at rest.
The major steps in the management of patients with chronic heart failure are outlined in Tables 13–3 and 13–4. Updates to the ACC/AHA guidelines suggest that treatment of patients at high risk (stages A and B) should be focused on control of hypertension, arrhythmias, hyperlipidemia, and diabetes, if present. Once symptoms and signs of failure are present, stage C has been entered, and active treatment of failure must be initiated.
Sodium removal—by dietary salt restriction and a diuretic—is the mainstay in management of symptomatic heart failure, especially if edema is present. The use of diuretics is discussed in greater detail in Chapter 15. In very mild failure, a thiazide diuretic may be tried, but a loop agent such as furosemide is usually required. Sodium loss causes secondary loss of potassium, which is
TABLE 13–3 Classification and treatment of chronic heart failure.
1American College of Cardiology/American Heart Association classification. 2New York Heart Association classification. 3Risk factors include hypertension, myocardial infarct, diabetes. 4For selected populations, eg, African Americans. ACC, American College of Cardiology; ACEI, angiotensin-converting enzyme inhibitor; AHA, American Heart Association; ARB, angiotensin receptor blocker; ARNI, angiotensin receptor inhibitor plus neprilysin inhibitor; CRT, cardiac resynchronization therapy; LVAD, left ventricular assist device; NYHA, New York Heart Association.
TABLE 13–4 Differences between systolic and diastolic heart failure.
1Avoid excessive reduction of filling pressures.
2Limited to certain β blockers (see text).
3Benefit, if any, may be due to BP reduction.
4Useful combined with hydralazine in selected patients, especially African Americans.