The clinical spectrum of decompensated heart failure ranges from the outpatient who is seen in clinic with subtle signs such as worsening peripheral edema to the child presenting to the emergency department in life-threatening cardiogenic shock. Despite optimization of standard medical therapy, some children with chronic heart failure will deteriorate clinically to a point that they require hospitalization for inpatient monitoring and treatment with intravenous therapies. Once the condition is recognized, the fundamental therapeutic goals are the same when managing patients with this very challenging clinical syndrome: reverse hemodynamic derangements, correct metabolic abnormalities, and provide symptomatic relief.

Achievement of these goals requires individualized care and a familiarity with the risks and benefits of particular therapies. Treatment options for decompensated heart failure are limited and almost all are untested in children. Most of the data relied upon for managing patients with advanced heart failure have been derived from studies in adults, the majority of whom have an ischemic etiology for their myocardial dysfunction. Because data are lacking for the treatment of advanced heart failure in children, we must heed the findings of adult trials, reflect on reliable anecdotal experience, and respect the principle that we should first do no harm when we venture to care for this vulnerable population.

Intravenous loop diuretics are considered first-line therapy for decompensated heart failure (HF). Frequently, patients will require a combination of diuretic and intravenous afterload reduction (e.g., nitroprusside, nitroglycerin, or milrinone) to lower filling pressures and achieve symptomatic relief. Patients with decompensated heart failure and reduced blood pressure with normal or low systemic vascular resistance may not benefit from vasodilators and should therefore be considered for inotropic therapy. In these patients, inotropic agents may be necessary to maintain circulatory function, relieve symptoms and improve end-organ function. The ACC/AHA HF treatment guidelines state that patients presenting with low output syndrome or combined low output and congestion may be considered for intravenous inotropes such as dopamine, dobutamine, or milrinone (1).

Despite optimal medical therapy, some children progress to refractory end-stage HF and low cardiac output syndrome. Mechanical circulatory support (MCS) may be the only therapeutic option remaining for those patients who in most cases are considered good candidates for heart transplantation.

Appropriate application of MCS in children requires an understanding of the unique pathologic features of pediatric heart failure as compared to adult heart failure. For example, pediatric patients in systemic ventricular failure have a much higher incidence of concomitant right ventricular failure and pulmonary hypertension. The etiology of right heart failure in children may be similar to that which is seen in the adult experience, secondary to left heart failure, but may also be attributed to intrinsic or anatomic causes. Another challenge in pediatric MCS of patients with congenital heart disease (CHD) relate to the technical aspects of cannulation. One must consider how the patient can be cannulated, not only in regard to what vessels or chambers to use, but how the cannulae, which at times are on opposite sides than normal (i.e., patients with situs inversus), can be attached to the assist devices. Further consideration of the internal cardiac anatomy with respect to septal defects, hypoplastic chambers, anomalous systemic and venous connections, and extracardiac anatomy (i.e., aortic interruption or coarctation) must be taken into account (2). The identification and management of systemic-to-pulmonary shunts, both surgically created (i.e., Blalock–Thomas–Taussig (BTT) shunt) and pathologic (i.e., aortopulmonary collateral arteries) is another necessary and often difficult step in the MCS of patients with CHD.

Although it is important to consider each patient individually, extreme prematurity, very low birth weight (<1.5 kg), severe neurologic injury, a constellation of congenital anomalies with poor prognosis, and/or chromosomal aberrations are widely accepted as contraindications for MCS. Other considerations are multisystem organ failure, sepsis, and severe lung disease, although successful support has been demonstrated in all of these scenarios (22,23). Reversal of multisystem organ failure has been demonstrated in the adult population on VAD support many times with the reversal of liver and renal dysfunction (24,25,26,27). In regard to pulmonary insufficiency, the etiology of the insufficiency will help determine the suitability of MCS and type of support. Severe lung disease resulting in respiratory failure should prompt consideration for ECMO, whereas cardiogenic shock induced pulmonary edema can at times be treated with VAD support. Entertaining the use of MCS in patients with certain congenital heart diagnoses such as single ventricle physiology and pulmonary atresia, VSD, and major aortopulmonary collaterals should include careful consideration for whether the patients are eventual candidates for surgical correction, transplant, or are even capable of benefiting from MCS. As the field of MCS matures, the use of terminology such as absolute and relative contraindications has begun to fade as experience, data driven medical management, and the consideration of medical feasibility, resource allocation, and ethical issues have begun to guide the utilization of MCS in challenging clinical situations.

It should be emphasized that improved results are only possible if application of MCS is early, that is, before the patient is in extremis or end-organ dysfunction is significant. That being said, appropriate timing for institution of support is particularly challenging in this group because it is often governed by which devices are available for supporting pediatric patients and institutional experience. Careful consideration must be given to cases on an individual basis prior to committing to long-term support as our surgical and postoperative management experience with these patients and devices is still in its infancy.

Although no standardized candidate selection criteria have been established for MCS in children, it should be considered in children with end-stage heart failure if the overall benefits of MCS outweigh the risks. The challenge is determining the appropriate time to intervene with MCS in children, as there are consequences to initiating MCS “too early” or “too late.” In the adult population, the utilization of The Interagency registry for Mechanically Assisted Circulatory Support (INTERMACS) scoring system has generated a shift from VAD implantation in critically ill, or “crash and burn,” patients to those in whom a VAD may be implanted electively or semiurgently implanted (Table 25.1) (28,29,30). Other adult studies have shown that several preoperative clinical variables predict a higher postimplant mortality, such as renal function, hypoalbuminemia, coagulopathy, and VAD implant center volume (31,32). The pediatric data are limited in identifying determinants for the post VAD implant outcomes. A recent analysis of children supported with the Berlin EXCOR device identified lower weight, need for a biventricular assist device (BIVAD), and elevated bilirubin as risk factors for early mortality after implantation (33). Another study by Fan et al. identified an elevated C-reactive protein and central venous pressure as predictors of increased in-hospital mortality in children, with 95% of the children supported with the Berlin Heart EXCOR in that study. Our institutional experience has found that among children who are hospitalized with decompensated heart failure, worsening renal function, as defined as a rise in serum creatinine by 0.3 mg/dL, and the need for mechanical ventilation was associated with death or requirement of MCS (34). Based on these data and anecdotal experience, the authors have created candidate selection guidelines for bridging children to transplant with MCS. Patients who are considered acceptable transplant candidates and who have demonstrated inotrope dependency are monitored closely for end-organ injury. The authors will consider instituting MCS in these patients if they demonstrate any of the following: requirement for mechanical ventilation, inability to ambulate due to heart failure symptoms, worsening or impending renal and hepatic function, and the inability to tolerate enteral feeds. Additionally, any patient with cardiogenic shock or impending shock also is considered for MCS.

In the event of an acute decompensation of a child’s myocardial function, be it new onset or in the setting of a chronic condition,
short-term MCS is a viable option in instances when there may be hope of myocardial recovery or as a bridge to bridge/decision. Most centers will institute emergent ECMO in this setting as this mode of support is well established in many pediatric centers and can be rapidly instituted.