Pediatric Congestive Heart Failure Treatment & Management

The management of congestive heart failure (CHF) is difficult and sometimes dangerous without knowledge of the underlying cause. Consequently, the first priority is acquiring a good understanding of the etiology. The goals of medical therapy for congestive heart failure include the following:

• Reducing the preload

• Enhancing cardiac contractility

• Reducing the afterload

• Improving oxygen delivery

• Enhancing nutrition

As previously discussed, the causes of congestive heart failure vary, and they appear in different patients to variable degrees. Thus, the medical management of congestive heart failure in children should be tailored to the specific details of each case.

Preload reduction can be achieved with oral (PO) or intravenous (IV) diuretics (eg, furosemide, thiazides, metolazone). Venous dilators (eg, nitroglycerin) can be administered, but their use is less common in pediatric practice. Contractility can be supported with IV agents (eg, dopamine) or mixed agents (eg, dobutamine, inamrinone, milrinone). Digoxin appears to have some benefit in congestive heart failure, but the exact mechanism is unclear. Ivabradine may be considered to lower heart rate in stable symptomatic heart failure owing to dilated cardiomyopathy.

Afterload reduction is obtained orally through administration of angiotensin-converting enzyme (ACE) inhibitors or intravenously through administration of other agents, such as hydralazine, nitroprusside, and alprostadil. Pharmaceutical agents used in the treatment of congestive heart failure are summarized in the Table below.

Table. Pharmaceutical Agents Used in the Treatment of Congestive Heart Failure (Open Table in a new window)

Acute presentation of the ill newborn or infant with congestive heart failure warrants immediate concern regarding potential sepsis or ductal-dependent congenital heart disease. The evaluation and treatment of these patients are often best performed in the neonatal or pediatric intensive care unit (ICU).

The initial management involves the usual assessment of the patient's airway, breathing, and circulation (ABCs); achieving IV access; laboratory testing, including a blood culture; and empiric antibiotic therapy. Management of low cardiac output can be initiated by using a dopamine infusion of 5-10 mcg/kg/min; acidosis can be corrected with the administration of fluid and/or bicarbonate.

Calcium should be administered when hypocalcemia is documented. Because ductal-dependent structural heart disease is a common cause of congestive heart failure in early infancy, echocardiography should be considered early in the evaluation if a diagnosis is not immediately forthcoming.

Anatomic lesions that may appear early and that should be considered include the following:

• Coarctation or interruption of the aortic arch

• Total anomalous pulmonary venous return

• Hypoplastic left heart syndrome (or variants, including severe mitral valve stenosis and/or aortic valve stenosis or atresia)

• Truncus arteriosus

• Pulmonary atresia

• Transposition of the great arteries

Conditions to consider in young infants with a more protracted congestive heart failure course include those producing significant left-to-right shunts, including large ventricular septal defects, aortopulmonary shunts, and arteriovenous malformations.

Prostaglandin

An alprostadil (PGE₁) infusion is indicated when ductal-dependent cardiac lesions are diagnosed or when they cannot be ruled out in a timely fashion. Absent femoral pulses or the inability to increase the systemic PaO₂ to above 150mm Hg with a fraction of inspired oxygen (FiO₂) of 1 suggests a ductal-dependent lesion, and treatment with PGE₁ is warranted.

PGE₁ may theoretically aggravate the condition in some children with total anomalous pulmonary venous connection and obstruction or in children with other etiologies of congestive heart failure, such as sepsis. Whenever possible, echocardiography should be performed before PGE₁ treatment is begun. On the other hand, when critical heart disease is present and echocardiography is not immediately available, prostaglandin infusion can be lifesaving.

Nonstructural problems

Nonstructural cardiac problems that occur during this stage include tachyarrhythmias (usually supraventricular tachyarrhythmia [SVT]) and complete heart block. Prompt pharmacologic or electrical cardioversion is warranted in any patient with a tachyarrhythmia who presents with congestive heart failure. Primary cardiomyopathy or myopathic disease secondary to inborn errors of metabolism should be considered in the absence of structural cardiac disease or arrhythmia when cardiac dysfunction is present.

Long-standing but unrecognized congestive heart failure may present acutely; similarly, an acute presentation may represent an acute onset of acquired cardiac disease (myocarditis or arrhythmia). Management of acute decompensation involves treatment of presenting symptoms and adjustment or initiation of long-term therapy.

In older children with acute congestive heart failure, admit to the ICU for diuresis with IV furosemide. For patients with significant hypotension, IV dopamine (5-10 mcg/kg/min) or milrinone (0.3-1 mcg/kg/min) infusion is appropriate until stabilization is achieved. Older children may require the placement of a central venous or pulmonary artery catheter to monitor venous pressure and cardiac output during stabilization.

Nitrates (nitroprusside, nitroglycerin) or nesiritide may be useful in patients with elevated pulmonary capillary wedge pressure and pulmonary congestion due to their venous dilating effects. Nesiritide carries the additional theoretical benefits of reversing deleterious neurohumoral responses and increasing natriuresis. Small studies have been conducted to measure hemodynamic effects of nesiritide in children with dilated cardiomyopathy. ^{[8, 9]} However, nesiritide has demonstrated no mortality advantage compared with nitroglycerin for acute decompensated heart failure in a large adult trial. ^[10]

If the underlying cause of the congestive heart failure cannot be immediately corrected in a patient who is hemodynamically stable, outpatient management can be initiated by using several agents. Afterload reduction using an ACE inhibitor is indicated in the presence of left ventricular (LV) dysfunction, regardless of symptoms.

Afterload reduction is indicated in patients who have large left-to-right shunts at the ventricular or arterial level (ventricular septal defect or patent ductus arteriosus), left-sided regurgitant lesions (aortic insufficiency or mitral regurgitation), or poor systolic function (myocarditis or dilated cardiomyopathy). ACE inhibitors are the medications of choice. Alternatively, an angiotensin receptor blocker (ARB), such as losartan, may be used in patients in whom ACE adverse effects (particularly cough) may be unacceptable. ^[11]

In addition to afterload reduction (ACE inhibitor), low-dose furosemide (1 mg/kg/dose PO bid) may be initiated, with or without the addition of another agent for inotropic effect (digoxin), or beta-blockade (carvedilol) to treat mild symptoms of congestive heart failure. ^[12] The dose of digoxin (0.005-0.010 mg/kg/day PO divided twice daily, not to exceed 0.125-0.250 mg PO qd) is almost never increased, either for effect or according to digoxin levels, which are notoriously unreliable. However, the dose may be decreased in the presence of signs of toxicity. The suspicion of digoxin toxicity should increase if an infant is uninterested in feedings, gags, or vomits frequently. These symptoms are typically due to an overdose or renal failure.

For more severe congestive heart failure, diuretic therapy with oral furosemide may be increased to 2 mg/kg/dose orally 3 times daily or a second agent, such as hydrochlorothiazide or metolazone, can be added. To be most effective, hydrochlorothiazide and metolazone are best administered simultaneously with furosemide to achieve their synergistic effect.

Aldosterone antagonists

Aldosterone antagonists are potassium-sparing diuretics. Spironolactone or eplerinone have class I indication for use in heart failure in adults, including any patient with a left ventricular ejection fraction (LVEF) of less than 40% in the presence of even minimal symptoms. ^{[13, 14, 15]} Their mechanism of action in heart failure is unknown. Pediatric studies have not been performed, but these agents have been used in children for a variety of indications, including diuretic-induced hypokalemia. The usual dosage for children is spironolactone 1-3.3 mg/kg/day in single or divided doses.

Potassium

For patients taking more than 1 mg/kg of oral furosemide twice daily without ACE inhibitors, spironolactone should be added for its potassium-sparing effect and theoretical beneficial effects on cardiac remodeling. Adult studies have suggested that it prolongs survival in chronic heart failure. ^[16] Alternatively, serum potassium levels may be monitored, and appropriate supplementation should be provided. Supplemental potassium chloride may be required when high doses of diuretics are used, but most children are extremely averse to the taste of most preparations. Alternatively, aldosterone antagonists may be administered to treat chronic diuretic-induced hypokalemia.

Because ACE inhibitors and aldosterone antagonists cause potassium retention, supplemental potassium should be avoided except in the presence of documented hypokalemia in patients taking these medications.

Sodium

Hyponatremia often accompanies congestive heart failure and is caused by water retention in response to vasopressin (antidiuretic hormone), which is produced as a result of renin-angiotensin activation but may be exacerbated by the use of diuretics and by salt wasting by the kidney.

Sodium supplementation is almost never indicated in infants or children with congestive heart failure except in emergency situations. Severe hyponatremia is generally best managed by reducing the dose of diuretics or by restricting fluid intake, although the latter has little use in small children. In any child taking more than 2 mg/kg/d of furosemide, electrolyte levels should be checked every few months, as they should be in any child taking furosemide in conjunction with other diuretics or ACE inhibitors.

Beta blockers

Experience with beta-blocker therapy in pediatric patients has increased. The selective beta1-blocker metoprolol and the nonselective beta1-blocker and beta2-blocker carvedilol, used primarily in adults, have generally shown encouraging results in select patients with cardiomyopathy and mild or moderate chronic congestive heart failure. Adults using these beta blockers (carvedilol) have demonstrated an increased stroke volume and stroke work index during exercise, along with a decreased heart rate and LV chamber size. ^{[17, 18]}

In addition, carvedilol has been shown to decrease pulmonary artery mean and wedge pressures, decrease cardiac norepinephrine levels, and increase peripheral vasodilation by means of alpha1 blockade. For these reasons, in part, use of carvedilol has increased, particularly in cardiomyopathies.

However, a double-blind, randomized trial (carvedilol vs placebo) in pediatric patients with mild to moderate congestive heart failure failed to demonstrate a benefit in reduction of symptoms or mortality. The power of the study was affected by an unexpectedly high rate of improvement among all patients, including those who received placebo. ^[19] Thus, the exact indications and benefits of carvedilol therapy in children with heart failure remain somewhat unclear. ^[7]

I(f) current inhibitor

Ivabradine was approved by the FDA in April 2019 for children aged 6 months or older with stable symptomatic heart failure caused by dilated cardiomyopathy who are in sinus rhythm with an elevated heart rate. Ivabradine blocks the hyperpolarization-activated cyclic nucleotide-gated (HCN) channel responsible for the cardiac pacemaker I(f) ‘funny’ current, which regulates heart rate.

The primary endpoint or 20% or greater reduction of heart rate from baseline without producing bradycardia or symptoms was reached by 51 of 73 children taking ivabradine (70%) compared with 5 of 41 taking placebo (12%) at varying doses (odds ratio: 17.24; p < 0.0001). Between baseline and 12 months, there was a greater increase in left ventricular ejection fraction in patients taking ivabradine than placebo (13.5% vs. 6.9%; p = 0.024). New York Heart Association functional class or Ross class improved more with ivabradine at 12 months than placebo (38% vs. 25%; p = 0.24). ^[25]

Anemia

Often overlooked in the management of chronic congestive heart failure is the role of the oxygen-carrying capacity of the blood. Anemia aggravates congestive heart failure by increasing the demands for cardiac output, and careful attention to iron stores or the administration of red cell transfusions often results in a significant improvement.

Nutrition

Nutrition is crucial in the management of chronic congestive heart failure. Particularly during infancy, congestive heart failure increases the metabolic demands while making feeding itself more difficult. Enhanced caloric content feedings and, in some cases, nasogastric or gastrostomy feedings may be necessary to maintain the patient's growth.

Growth

The success of medical therapy of congestive heart failure in infants and small children is judged according to the child's growth. The failure to gain weight in the setting of marked congestive heart failure signifies that the current regimen is not sufficient. A failure to thrive is an indication for increased medical management or, when the option is available, surgical repair of structural heart disease.

Cardiac resynchronization therapy

Cardiac resynchronization therapy (CRT) has emerged as a useful therapy in the treatment of chronic congestive heart failure. CRT involves the use of biventricular pacemakers to improve ventricular function by electrically adjusting the timing of right and left ventricular contraction to optimize wall motion and increase filling time. In addition to increasing stroke volume, CRT may allow for reverse remodeling to delay disease progression. Clinical trials in adults with moderate to severe heart failure have demonstrated beneficial effects of CRT use, including reduction of symptoms, increased exercise capacity, and decreased morbidity and mortality. ^[20]

In pediatric practice, resynchronization therapy has been limited; the initial studies described the results for this modality instituted in children with chronic heart failure who required pacemakers for treatment of rhythm disorders. Use of this therapy is more difficult to institute in children, whose small size requires the use of surgically placed epicardial pacemakers rather than percutaneously placed pacemakers. As more registry and retrospective data have accumulated, use of this therapy has increased, and indications based on echocardiographic and electrocardiographic parameters continue to be refined. ^{[21, 22]}

Mechanical support

Mechanical support may be used in the treatment of acute heart failure (ie, myocarditis or postcardiotomy syndrome) or in chronic heart failure as a bridge to recovery or to a heart transplant. The choice of support therapy depends on the expected duration of use.

Extracorporeal membrane oxygenation (ECMO) therapy may be quickly initiated in unstable patients. Generally, its duration of use is limited to days or weeks because of complications related to infection or anticoagulation. ECMO is used to provide acute temporary support as a bridge to recovery or transplantation.

In a study of ECMO use in 108 patients (73 adults and 35 children), most of whom were suffering from postcardiotomy cardiac low output, Beiras-Fernandez et al found that pediatric patients who had undergone congenital heart surgery were among the patients who demonstrated the best results from ECMO. ^[23]

Ventricular assist devices (VADs; eg, Berlin Heart, EXCOR Pediatric System, Thoratec VAD) may be used to provide long-term ventricular support. The EXCOR Pediatric System is the first pulsatile mechanical circulatory support device specifically designed for children and was approved by the FDA in December 2011. The device consists of 1 or 2 external pneumatic blood pumps to support the left ventricle alone or both the left and right ventricles. EXCOR is available in graduated sizes to fit children from newborns to adolescents. ^[24] Also see FDA approves mechanical cardiac assist device for children with heart failure. Other devices, such as Thoratec HeartMate II, have not received approval for pediatric use but have been used in selected cases for appropriately sized patients. Currently, VADs are not approved forpermanent(destination) therapy in pediatric patients and should be considered only as a bridge to transplantation in appropriate candidates. ^[12]