Incidence and Epidemiology of Congenital Heart Disease and Pediatric Advanced Heart Disease

The reported prevalence of CHD varies widely, depending on the method of diagnosis and whether the data reflect prenatally detected CHD or live births of children with CHD. In general, the prevalence of CHD is approximately 3 per 1000 for clinically severe defects, 6 per 1000 when including the more moderate defects, and 9 to 20 per 1000 when including smaller septal defects and mild valve stenosis.^1,2 CHD is the leading cause of infant deaths owing to congenital anomalies worldwide.^1,2 Between 1940 and 2002, approximately 2 million infants were born with CHD in the United States.¹ In those same six decades, enormous achievements in medical and surgical care of these infants and children have resulted in improved long-term survival. Despite dramatically improved short- and long-term outcomes, palliated advanced heart disease remains one of the leading causes of non-accidental death in childhood in the United States. During the past 60 years, surgical procedures have been developed to treat most congenital heart defects, including those that were historically uniformly fatal, such as hypoplastic left heart syndrome.⁷ During the same time period, major advances have been achieved in intensive care management, ventilatory support, mechanical support, intra-operative management, long-term medical management, and diagnostic imaging.^7,8 These improvements are forcing reassessment of the outcomes and impact of CHD. For example, prenatal diagnosis has led to earlier detection, more controlled perinatal transition, and earlier surgical repair as well as more educated and prepared parents. The traditional statistics of prevalence and outcomes are, therefore of historic value, but may be less helpful in determining the longer term needs of children with advanced heart disease.

Improved survival rates of children with CHD is reported over the past two decades. A review⁹ of the multiple-cause mortality files compiled by the National Center for Health Statistics of the Centers for Disease Control and Prevention from all death certificates filed in the United States found that from 1979 through 1997, mortality from heart defects for all ages declined 39 percent, from 2.5 to 1.5 per 100,000. In the last two years of the study, heart defects contributed to 5822 deaths per year. Of these deaths, 51% were infants and 7% were children 1 to 4 years old. In this series, age at death increased over the decade for every heart defect, as more palliated infants are surviving into adolescence and adulthood.⁹ Only a small number of children born with CHD will progress to advanced heart disease (Box 40-1). There are no published data on the numbers of children with CHD who meet criteria for advanced heart disease and prognostic indicators to assist with predicting which patients are likely to progress are limited.

Evolution of Palliative Care in Advanced Heart Disease in Children

Because of the previously described advances and improved longevity, pediatric cardiac teams now provide long-term care for children for whom previously the only treatment decision was the location of their death. Early efforts necessarily focused on survival. Over time, the focus expanded to include managing medical morbidity and maximizing the quality of life of children with CHD, including those with advanced heart disease. The evolution of palliative care in children with advanced heart disease has occurred slowly in part due to the perception of heart disease as treatable with the focus on surgical cures. This is similar to the evolution of care in adult advanced heart disease as well.^10,11 It is important to recognize that many interactions between families and the healthcare team revolve around the surgical or interventional procedure to fix the child’s heart. Even in complex situations where palliative surgery is planned, death is rarely an immediate outcome. Aggressive, highly technological options and treatments are available and offered even in the final stages of advanced disease. Ongoing successes encourage caretakers and families to pursue continued therapies. Also, the progression of heart failure in children is largely variable, and the point at which there is no possibility for long-term survival is often unclear. Advanced heart disease is often marked by acute decompensations followed by periods of stability. This unpredictable nature often discourages end of life discussions for children and their families.

Because of the trajectory of acute decompensation alternating with periods of stability, many children with advanced heart disease die in the hospital, most often in an intensive care setting as advanced therapies are used even at the end of life. Little data are available for children with advanced heart disease. Fig. 40-1 shows the data from one large Cardiac Intensive Care Unit with approximately 1000 admissions per year. Overall, the ICU mortality is between 2% and 4% each year, which is approximately 30 to 40 deaths yearly. This percentage may vary between institutions and internationally. Although end of life discussions are happening with these families, there are limited data as to when and where these discussions are occurring.

Fig. 40-1 Overall mortality in a large pediatric cardiac intensive care unit.

(Data provided by the authors.)

Despite ongoing challenges, providing palliative care for children with CHD is a critical need. Key aspects include symptom management, promoting psychosocial health and quality of life, and decision making. Each of these areas will be discussed in the sections that follow.

Symptom management for children with advanced heart disease

Children with advanced heart disease represent a diverse group with complex cardiac issues that result from either palliated complex CHD or from severe forms of cardiomyopathy or post-transplant care. Symptom management includes a variety of complex medical and psychosocial interventions in order to optimize quality of life. As cardiac function deteriorates, traditional symptoms of heart failure can ensue (Fig. 40-2). Symptom management can be complex and side effects of drugs can worsen symptoms. Some guidelines are offered in Table 40-1.

Fig. 40-2 Pathophysiology of cardiac symptoms in children.

TABLE 40-1 Medication Guidelines

Fatigue

The activation of both the renin-angiotensin system and the sympathetic nervous system results in vasoconstriction and poor skeletal muscle perfusion. This often leads to overwhelming fatigue, sometimes out of proportion to the cardiac dysfunction. For patients in the early phases of advanced heart disease, fatigue can be particularly difficult to sort out, as it can often be confused with laziness or depression. Modified physical therapy and cardiac rehabilitation programs can be useful to avoid deconditioning and maintaining muscle tone. In addition, modified exercise programs have been shown to be beneficial to outlook and endurance in patients with CHD.¹² For the more advanced heart disease patients, systemic vasodilators, such as milrinone, can help lower systemic vascular resistance and result in temporary improvement of fatigue. Many children and young adults describe “something lifting off my chest” after a few hours of a milronone infusion. There is some anecdotal evidence that a short infusion holiday of 3 to 5 days can have an improved effect lasting for several weeks. Some patients may benefit from this therapy either intermittently or as a continuous infusion.

Congestion and/or Fluid Overload

Fluid overload is a common symptom for children, adolescents, and young adults with advanced heart disease. Rarely, they will present with the traditional adult heart failure congestion with rales, respiratory distress, and shortness of breath. More commonly in children however, congestion and heart failure result in gastrointestinal symptoms such as nausea, vomiting, and anorexia. Diuretics are the key therapy for congestive symptoms in heart failure in children, and can often improve symptoms rapidly. Often GI symptoms will respond dramatically to diuretic therapy. Many loop diuretics, such as furosemide, have a threshold effect, and if patients with normal renal function are not responding, then doses can be doubled. Fluid restriction for these patients is critical in maintaining homeostasis and decreasing hospital admissions. However, fluid restriction can be very difficult, as the body’s response to lower output is secretion of ADH and subsequent thirst. Discussion about the utility of fluid restriction and the understanding that the thirst response is counter-regulatory may help some patients and families. The maintenance of fluid restriction for many families is endless and futile, and increasing diuretics may be the simplest action. In addition, timing of diuretics is critical in maintaining good sleep hygiene. Diuretics before bedtime will obstruct sleep. Diuretics should not be given within 4 hours of bedtime.

Dizziness and/or Syncope

Syncope can be a result of primary ventricular arrhythmia, secondary to myocyte fibrosis. This can be very frightening for families and patients. It may be worsened by electrolyte abnormalities such as hypomagnesemia and hypokalemia, which should be monitored closely. Dizziness can be very disturbing for patients, as it may remind them of the pre-syncopal state. It may be due to low cardiac output. More often, however, it is a symptom related to side effects of the cardiac medications and can limit quality of life. The use of multiple anithypertensives together in the morning can often lead to dizziness and headache. Awareness of the total medical picture can help improve timing of medications for patient comfort. However, vasodilating medication could be given at bedtime, as dizziness is less likely once the patient is lying down.

Pain

Pain is unusual in the ambulatory advanced heart disease population. However, pain associated with medical procedures, including minor ones, is not unusual. Needle-stick pain is a major source of trauma for children in healthcare settings, including children who require frequent needle sticks. For outpatient procedures, it may be helpful to provide a written prescription for topical anesthetic cream and instructions for application for the parents. Managing inpatient needle sticks with pain prevention protocols, which include distraction techniques and topical anesthetic creams, may reduce the trauma. Pain can also result from excessive fluid overload and edema of neck, abdomen, and extremities.

Although chest pain is rare, it is very frightening and carries multiple meaning for the families. Opioids can improve coronary perfusion, and may have a primary cardiac role in patients with ischemic disease. Discussions about pain control should occur early on. Many families and caretakers worry about the cardiac effects of opioids. Most cardiac ICUs are comfortable with opioids in the post-operative period. They are critical for comfort at end of life, even while life-extending measures are still in play.