Abstract
Complex forms of congenital heart disease (CHD) often require early and or emergent medical, surgical, or catheterization–based interventions in the first days to weeks of postnatal life. CHD lesions with inadequate aortic or pulmonary outflow can usually be stabilized in the neonatal period with medical therapy, using prostaglandin E1 to maintain ductal patency, prior to intervention. More critical forms of CHD have an additional element of instability during perinatal transition and may need emergent neonatal intervention in the first hours after delivery. These include lesions such as obstructed total anomalous pulmonary venous return and hypoplastic left heart syndrome with restrictive atrial septum, which lack adequate pulmonary egress, d-transposition of the great arteries with restrictive atrial septum resulting in limited intracardiac mixing, and severe Ebstein anomaly and tetralogy of Fallot with absent pulmonary valve associated with airway anomaly, which compromises the caregivers’ ability to ventilate, and congenital complete heart block with inadequate cardiac output due to severe fetal bradycardia. These critical forms of CHD can be predicted with fetal echocardiography, which then allows for careful planning of maternal care to optimize the delivery and provide targeted postnatal care. Many cardiac centers are now using highly coordinated perinatal action plans that are lesion-specific to guide neonatal stabilization and, if appropriate, immediate transfer to the cardiac care team. Active perinatal strategies and delivery room protocols based on the anticipated postnatal acuity level, complexity, and need for emergent intervention hold the promise of improving outcomes for neonates with complex CHD. In the future, innovative fetal therapies may also alter outcomes of critical CHD and allow for improved transition from fetal to postnatal life.
Keywords
congenital heart disease, fetal cardiology, fetal echocardiography, neonatal intensive care, neonatal management, prenatal diagnosis
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Most prenatally diagnosed congenital heart disease (CHD) does not require emergent neonatal care.
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Critical forms of CHD require emergent stabilization and intervention in the first hours after delivery.
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Critical forms of CHD can benefit most from active perinatal and delivery room management.
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Risk stratification strategies for CHD can help guide neonatal management in cases of complex CHD.
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Fetal echocardiography can be used to determine which critical CHD lesions will need emergent neonatal intervention.
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Current areas of research include evaluation of fetal echocardiographic markers used for assessing CHD severity and fetal interventions to improve postnatal outcomes.
Introduction to Prenatal Evaluation of Congenital Heart Disease and the Definition of Critical Congenital Heart Disease
The incidence of congenital heart disease (CHD) is estimated at about 8 per 1000 live births, while more severe forms of CHD affect about 3 out of 1000 live births. Severe forms of CHD include those which require early medical, surgical, or catheterization based interventions in the first postnatal days to weeks, generally in concert with multidisciplinary subspecialty care including pediatric cardiologists, cardiothoracic surgeons, neonatologists, and pediatric cardiac intensivists. Since the first reports of using ultrasound to prenatally diagnose CHD more than 3 decades ago, there have been remarkable advances in ultrasound technology allowing for high-resolution assessment of fetal cardiac anatomy, function, and rhythm.
Transition at birth from fetal to postnatal circulation involves lung expansion and a drop in pulmonary vascular resistance, loss of the low-resistance placenta from the circulation with a resultant increase in systemic vascular resistance, loss of the fetal intracardiac shunts, and shift to reliance on oxygenation by the lungs rather than the placenta. CHD lesion types with inadequate aortic or pulmonary outflow are termed “ductal dependent,” given the need for flow through the ductus arteriosus to provide or augment either pulmonary or systemic blood flow. Postnatally, medical therapy with prostaglandin E1 (PGE1) is needed to maintain ductal patency, with the eventual need for surgical- or catheter-based intervention to provide a more stable source of pulmonary or systemic blood flow (see Chapter 32 ). The most critical forms of CHD have an additional element of instability with the perinatal transition. These can be grouped into four categories, including (1) lack of adequate pulmonary egress, found in obstructed total anomalous pulmonary venous return (TAPVR) and subtypes of hypoplastic left heart syndrome (HLHS) with intact or restrictive atrial septum; (2) inadequate intracardiac mixing of oxygenated blood to the systemic circulation in some cases of d-transposition of the great arteries (d-TGA) with restrictive atrial shunting; (3) an associated anomaly of the airway which compromises the ability to ventilate such as severe cases of Ebstein anomaly and tetralogy of Fallot (TOF) with absent pulmonary valve (APV); and (4) inadequate cardiac output in cases of severe fetal arrhythmias or diminished cardiac function either in isolation or in combination with CHD. These critical forms of CHD can be predicted with fetal echocardiographic findings, which then allows for careful planning of maternal care to optimize the delivery and provide targeted postnatal care.
Perinatal Management Strategies to Optimize Postnatal Transition
The goals of active prenatal planning and perinatal management for neonates with CHD are a well-coordinated transition from fetal life to postnatal care, minimizing mortality and morbidity, and ensuring a stable preoperative clinical status. Additional benefits include adequate time for parental education, expanded prenatal evaluation, and mobilization of psychosocial support systems. Action plans must take into account the underlying cardiac anatomy, anticipated physiologic changes during the transition from fetal to postnatal life, the speed at which patients may become critically unstable, and the need for emergent neonatal intervention. Risk stratification systems are designed for multiple levels of CHD severity and are used to select the appropriate medical center for delivery, mode of delivery (MOD), level of perinatology and neonatology services available, and capability for immediate access to cardiology and cardiothoracic surgery care. The transportation of infants with critical CHD to a higher-level cardiac care center for delivery and postnatal care has been shown to improve outcomes and is associated with lower overall health care costs. Of note is that it is not recommended to deliver patients with CHD prematurely, as prematurity and low birth weight can have a significant negative impact on outcomes. Given this data, the current recommendations are to deliver these patients at 39 weeks’ gestation. A prenatal diagnosis of CHD may alter the chosen MOD and has been shown to result in elevated rates of elective C-section for many forms of CHD. However, there is little evidence to show that altering MOD improves outcomes for CHD patients and studies have shown that vaginal birth is well tolerated in this population. Thus, changes in delivery timing and MOD should only be made in order to provide rapid postnatal stabilization and intervention in the most critical of cases.
Active perinatal management of critical CHD is now practiced by many centers across the United States and Europe using similar risk stratifying schemes with recommended care plans. These classification systems are based on regional practice patterns and designed to identify patients that require specialized treatment in the delivery room (DR) and cardiac intervention in the first hours after delivery ( Table 31.1 and 31.2 ). The cardiovascular disease severity scales are based on the anatomic severity of CHD, need for postnatal intervention, complexity of intervention, and overall prognosis. The level of care (LOC) is typically assigned first by the cardiologist, according to the CHD severity, and is then reviewed and agreed upon with the entire maternal fetal medicine team. Each LOC is linked with a specific coordinated action plan and detailed perinatal recommendations for delivery and DR management such as need for PGE, transport, and intervention. Risk stratification and management systems using LOC for neonates prenatally diagnosed with CHD have been shown to be highly accurate at predicting the postnatal care and need for emergent intervention at birth. These classification strategies have been highly reproducible, with the exception of d-TGA, due to the difficulty determining the risk for postnatal atrial level restriction and the result was to upgrade all d-TGA cases to LOC 4 status. Table 31.3 shows a comparison of various published CHD risk stratification systems, while Table 31.4 depicts an example of one of the classification systems, which we have termed “Emergent Neonatal Cardiac Intervention” (ENCI) risk categories (see Table 31.4 ).
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LEVEL ONE, Low Risk: The lowest LOC is for CHD that does not cause hemodynamic instability in the newborn and is not expected to require specialized care or intervention in the newborn period. These patients can deliver at a hospital capable of providing care for babies with mild forms of CHD. MOD is not an issue and no special care is needed in the DR. Examples include atrial septal defect (ASD), ventricular septal defect (VSD), and mild valve abnormalities.
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LEVEL TWO, Intermediate Risk: These newborns have potential for hemodynamic instability and need for postnatal evaluation by subspecialists, but low risk for neonatal intervention. These patients should deliver at a facility with access to subspecialty consultation if needed and neonatology involvement at birth as needed. Thus delivery should occur in a facility in close proximity to a center with pediatric cardiology support and a Level III neonatal intensive care unit (NICU) with a regional transfer agreement with a children’s hospital. MOD may be an issue if signs of congestive heart failure or hydrops are present. Examples include complete atrioventricular septal defect, aortic arch obstruction, moderate valve abnormality, truncus arteriosus, and TOF with expected mild to moderate level of pulmonary stenosis.
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LEVEL THREE, Moderate Risk: These patients require neonatal intervention in the first days to weeks after delivery and include all ductal dependent lesions. These deliveries should be highly coordinated and occur at or nearby tertiary care centers with a high level of neonatal and cardiac expertise. If early intervention is likely or there is increased risk for high acuity at birth, delivery by induction or scheduled C-section should be considered to provide a window of anticipated delivery. MOD must also take in to account any evidence of congestive heart failure or hydrops. The cardiac intensive care unit (ICU), cardiology, and cardiothoracic surgery should be made aware of the patient well in advance. The transport team should be notified and on standby, to expedite the transfer. Examples include d-TGA with VSD, HLHS without restrictive atrial septum (RAS), severe aortic or pulmonary valve abnormalities (including single ventricles), unobstructed TAPVR, TOF with APV without lobar emphysema, Ebstein anomaly without hydrops, and complete heart block (CHB) with adequate heart rate (HR) (>60 bpm).
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LEVEL FOUR, High Risk: The highest level is reserved for patients requiring immediate or emergent intervention, within hours after birth, and in whom severe instability is anticipated. The perinatal care should be highly coordinated in order for all resources to be available at the time of birth. These patients should deliver via scheduled C-section to minimize time to treatment with the necessary subspecialists on standby to care for the newborn. Ideally the delivery could occur in a highly specialized labor and delivery unit in a children’s hospital for immediate intervention. However, few programs have this capability and most still rely on transfer of the newborn from a connected or nearby maternity hospital. If transfer is needed, the transport team should also be on standby at the delivery institution. The baby must be adequately stabilized and monitored for transport, but performance of procedures in the delivery room must be balanced with the need to get the baby to intervention with minimal delay. Cardiac ICU, cardiology, and cardiothoracic surgery should be notified again immediately upon confirmation of birth. The operating room and/or cardiac catheterization laboratory should be on standby. Examples include obstructed TAPVR, HLHS with RAS, d-TGA with RAS, TOF/APV with lobar emphysema, severe Ebstein anomaly with hydrops or uncontrolled arrhythmia and unstable CHB with very low ventricular rate (<50 bpm), decreased myocardial function, or hydrops fetalis.
| LOC | Definition | Example CHD | Prenatal Planning | Delivery | DR Recommendations |
|---|---|---|---|---|---|
| 1 | CHD without physiologic instability in first weeks of life |
| Arrange outpatient cardiology evaluation | Spontaneous vaginal delivery | Routine DR management |
| 2 | CHD with physiologic stability in DR but requiring postnatal intervention/surgery before discharge |
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| Create plan of care for DR stabilization and neonatal management by local hospital with transport to pediatric cardiac center | Spontaneous vaginal delivery versus induction near term | Neonatologist in DR; initiate PGE at low dose for ductal-dependent lesions | ||
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| 3 | CHD with expected instability requiring immediate specialty care in DR before anticipated stabilizing intervention/surgery |
| Create plan of care to include specialized pediatric cardiology team in DR and interventional/surgical team on standby | Planned induction usually at 39 weeks with “bailout” C/S if necessary for care coordination | Neonatologist and pediatric cardiology specialists in DR; stabilizing medications predetermined by care plan |
| 4 | CHD with expected instability requiring immediate specialty care and urgent intervention/surgery in DR to improve chance of survival |
| Create multidisciplinary plan of care to include delivery at medical center with high-level obstetrical and pediatric cardiac services available and with specialized care team in DR and interventional/surgical team ready | Planned C/S at a medical center with high-level obstetrical and pediatric cardiac and other pediatric subspecialty services available usually at 38–39 weeks or sooner if there is evidence of fetal distress or hydrops; maternal risk determined by obstetrician (delivery of such cases at medical centers with high-level adult and complex pediatric services) | Specialized care team in DR Stabilizing medications/equipment predetermined by care plan |
| LOC | Definition | Example CHD | Delivery Recommendations | DR Recommendations |
|---|---|---|---|---|
| P | CHD in which palliative care is planned | CHD with severe/fatal chromosome abnormality or multisystem disease | Arrange for family support/palliative care services Normal delivery at local hospital | |
| 1 | CHD without predicted risk of hemodynamic instability in the DR or first days of life | VSD, AVSD. mild TOF | Arrange cardiology consultation or outpatient evaluation Normal delivery at local hospital | Routine DR care Neonatal evaluation |
| 2 | CHD with minimal risk of hemodynamic instability in DR but requiring postnatal catheterization/surgery | Ductal-dependent lesions, including HLHS, critical coarctation, severe AS, IAA, PA/IVS, severe TOF | Consider planned induction usually near term Delivery at hospital with neonatologist and accessible cardiology consultation | Neonatologist in DR Routine DR care, initiate PGE if indicated Transport for catheterization/surgery |
| 3 | CHD with likely hemodynamic instability in DR requiring immediate specialty care for stabilization | d-TGA with concerning atrial septum primum (note: it is reasonable to consider all d-TGA fetuses without an ASD at risk) Uncontrolled arrhythmias CHB with heart failure | Planned induction at 38–39 weeks; consider C/S if necessary to coordinate services Delivery at hospital that can execute rapid care, including necessary stabilizing/lifesaving procedures | Neonatologist and cardiac specialist in DR, including all necessary equipment Plan for intervention as indicated by diagnosis Plan for urgent transport if indicated |
| 4 | CHD with expected hemodynamic instability with placental separation requiring immediate catheterization/surgery in DR to improve chance of survival | HLHS/severely RFO or IAS d-TGA/severely RFO or IAS and abnormal DA Obstructed TAPVR Ebstein anomaly with hydrops TOF with APV and severe airway obstruction Uncontrolled arrhythmias with hydrops CHB with low ventricular rate, EFE, and/or hydrops | C/S in cardiac facility with necessary specialists in the DR usually at 38–39 weeks | Specialized cardiac care team in DR Plan for intervention as indicated by diagnosis; may include catheterization, surgery, or ECMO |
| 5 | CHD in which cardiac transplantation is planned | HLHS/IAS; CHD including severe Ebstein anomaly; CHD, or cardiomyopathy with severe ventricular dysfunction | List after 35 weeks of gestation C/S when heart is available | Specialized cardiac care team in DR |
| Characteristics of Various CHD Severity Scales and Coordinating Care Plans | Donofrio et al., 2004 | Berkley et al., 2009 | Davey et al., a 2014 | Pruetz et al., 2014 | Slodki et al., 2016 | AHA Statement Donofrio et al., 2014 |
|---|---|---|---|---|---|---|
| Level description | LOC 1–4 | Care plans 1–5 | LOC 1–7 | ENCI Level 1–4 | Severest, severe, urgent, planned | LOC 1–5, palliative care (P) |
| Palliative care | N | Y | Y | N | N | Y |
| Delivery site | Y | Y | N | Y | N | Y |
| Mode of delivery | Y | Y | N | Y | Y | Y |
| Prostaglandin E1 | Y | Y | Y | Y | Y | Y |
| Neonatology care | Y | Y | Y | Y | Y | Y |
| Multispecialty care team | Y | Y | Y | Y | Y | Y |
| Level of instability | Y | N | N | Y | Y | Y |
| Need for emergent intervention | Y | Y | N | Y | Y | Y |
| Need for transport/transfer | N | N | N | N | N | Y |
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