Congenital Heart Disease and Neurodevelopment

Understanding and Improving Outcomes

Christopher McCusker, Frank Casey, Christopher McCusker, Frank Casey

• Publisher: Academic Press
• Year: 2016
• ISBN:
  9780128017920
• Topic: Biological Sciences
• Subtopic: Neuroscience
• Index: Biological Sciences

Congenital Heart Disease and Neurodevelopment: Understanding and Improving Outcomes brings together the work of leading researchers from the U.K., Europe, and the U.S. to provide a comprehensive examination of the causes, risks, and neurodevelopmental and psychological outcomes in children with congenital heart disease. The book includes longitudinal studies which have tracked outcomes from birth through late childhood and explores the emergent phenotype and etiologies, risk, and protective factors that strengthen proposed models.

Medical and surgical advances have meant that greater numbers of children with even the most severe congenital heart disease (CHD) now survive well into adulthood. Studies over the past 20 years have suggested certain neurodevelopmental and psychological features are common, with clinical interventions being internationally articulated. The U.K. Belfast Center has developed and evaluated unique early intervention programs to circumvent the common problems discerned and promote optimal adjustment and outcomes. The first edition of Congenital Heart Disease and Neurodevelopment: Understanding and Improving Outcomes describes these programs in detail and outlines promising results obtained by researchers worldwide. Such interventions, together with the U.S. consensus statement (Circulation, 2012) on neurodevelopmental screening, hold great promise for clinical interventions.

• Features input from leading research experts in the field
• Describes cutting-edge research on longitudinal studies that link neurodevelopmental phenotypes with cutting-edge neuroimaging studies
• Discusses the first series of early intervention studies developed in Belfast targeted at key developmental transitions—birth and diagnosis, early childhood, and adolescence
• Includes clinical implications and action points in each section
• Features generalizable potential of interventions across other pediatric populations

Part I

Hearts and Minds

Outline

Chapter 1. Congenital Heart Disease: The Evolution of Diagnosis, Treatments, and Outcomes

Chapter 2. Historical Perspectives in Pediatric Psychology and Congenital Heart Disease

Chapter 1

Congenital Heart Disease

The Evolution of Diagnosis, Treatments, and Outcomes

F. Casey The Royal Belfast Hospital for Sick Children, Belfast, Northern Ireland

Abstract

In this chapter the different forms of congenital heart disease (CHD) and the ways through which the different anatomical abnormalities affect the circulation influencing the symptoms caused by the condition are explained. The modern methods of investigation, diagnosis, and treatment are described. Development of new cardiac surgical treatments and the interventional catheter procedures have transformed the physical outcome for the present generation of children affected by CHD. This is particularly true for children with complex CHD, which has a lifelong impact for them. The increasing number of children surviving with CHD has highlighted to those involved in their care the importance of measuring success in a wider sense so that we ensure that all aspects of the child's well-being are addressed, with neurodevelopmental outcome being a crucial parameter. The key factors at various stages of the patients' journey where neurodevelopmental outcome may be impacted are highlighted.

Keywords

Cardiopulmonary bypass; Congenital heart disease; Cyanosis; Diagnosis; Interventional procedures; Neonatal presentation; Neurodevelopment; Surgery

Outline

Clinical Presentation of Congenital Heart Disease 4

Fetal Diagnosis 4

Neonatal Presentation 4

Cyanotic Conditions 5

Acyanotic Conditions 5

Later Presentation of Congenital Heart Disease 5

The Diagnostic Tools 5

Cardiac Catheterization 6

Surgery for Congenital Heart Disease 6

Cardiopulmonary Bypass 7

Success in the Treatment of Congenital Heart Disease 9

Adult Congenital Heart Disease 10

References 12

Congenital heart disease (CHD) is usually defined as a structural abnormality of the heart or intrathoracic vessels present at birth that is actually or potentially of functional significance.

CHD is the most commonly occurring congenital abnormality and affects about 8 per 1000 live births.¹ There is a wide spectrum of severity ranging from minor defects to very complex abnormalities that have a lifelong impact on the life of the child. Severe CHD is sometimes defined as CHD necessitating surgical intervention or causing death in the first year of life. Even in the modern era where most conditions are surgically treatable CHD still accounts for 5–10% of neonatal deaths.^2,3

Clinical Presentation of Congenital Heart Disease

The clinical presentation of CHD depends on the severity of the defect and its physiological effect.

Fetal Diagnosis

In the current era many of those with major CHD may have the diagnosis made antenatally by fetal echocardiography (a detailed ultrasound examination of the fetal heart). In Great Britain and Ireland during 2013–2014, 46% of children born with CHD requiring surgery in the first year of life had the diagnosis made antenatally.⁴ Diagnosis before birth gives the opportunity to counsel and prepare the family for the birth of the child with CHD and from a medical care viewpoint, allows for a planned delivery of the affected child in a pediatric cardiology center. Thus appropriate treatment can be instituted at the earliest possible point potentially reducing morbidity and mortality.

Neonatal Presentation

If not detected antenatally, those babies with severe CHD will usually present during the neonatal period. The newborn presentation depends on the type of defect and can be with cyanosis or with cardiac failure and shock. In the most severe conditions such as those with only a single ventricle the circulation may be dependent on the patency of the ductus arteriosus. This vessel normally closes within 24–36 h of birth, and this classically is the time interval when such babies present. Others will be diagnosed after detection of a heart murmur on examination. Hoffman and Kaplan⁵ found that 46% of cases of CHD received a diagnosis of CHD by 1 week of age, 88% by 1 year, and 99% by 4 years.

Cyanotic Conditions

Cyanosis is the term used to describe the bluish discoloration of the skin or mucous membranes as a result of inadequate oxygenation of the blood. The conditions that present as cyanotic babies or infants are those where there is right to left shunting of blood in the heart so that flow to the lungs is reduced or abnormal arterial connections and at the severe end of the spectrum hearts where there is only a single ventricular chamber. The cyanotic heart conditions include transposition of the great arteries, pulmonary atresia, truncus arteriosus, total anomalous pulmonary venous drainage, tetralogy of Fallot, and hearts with a single functional ventricle.

Acyanotic Conditions

Acyanotic heart conditions do not cause reduced blood oxygen levels and a number of conditions lead to left to right shunting of blood within the heart due to septal defects resulting in excessive flow to the lungs. Affected children often present with breathlessness, which in turn leads to difficulty feeding and failure to thrive. In cases where there is a large left to right shunt the child will develop congestive cardiac failure. This group of conditions includes ventricular septal defect, atrioventricular septal defect, patent ductus arteriosus, and atrial septal defect. Other important acyanotic conditions are those where there is obstruction to the outflow of either the right or left side of the heart such as pulmonary valve stenosis, aortic valve stenosis, and coarctation of aorta.

Later Presentation of Congenital Heart Disease

Less serious CHD may not cause symptoms in infancy and may be detected incidentally by the finding of a heart murmur on routine examination. Lesions in this category include atrial septal defect, small ventricular septal defect, and mild aortic or pulmonary valve stenosis. Some of these conditions may not require intervention.

The Diagnostic Tools

The gold standard in the diagnosis of CHD in newborns is echocardiography (ultrasound examination of the heart). Echocardiography first came into use during the early 1970s⁶ and with the advent of two-dimensional echocardiography, and the later addition of pulsed wave, continuous wave, and color Doppler, and subsequent improvements in image quality, it is now possible to fully characterize the anatomy of even very complex congenital heart lesions in most patients. The development of echocardiography has led to early and accurate diagnosis in the majority of cases without resort to more invasive techniques such as angiography. In the current era the increasing use of cardiac MRI⁷ and CT has helped to augment the diagnostic information available, and therefore the improving quality of detailed diagnosis in turn has a very significant positive influence in guiding and improving outcomes for surgical procedures.

Cardiac Catheterization

Cardiac catheterization is a procedure where a very fine tube (catheter) is passed from a vein or artery usually at the groin up to the heart. The procedure is performed in a special theater under continuous X-ray guidance called fluoroscopy. In children cardiac catheterization is usually performed under general anesthesia. The purpose of the procedure may be:

1. Diagnostic, to gain more information about the anatomical abnormality of the heart and to measure pressures in the chambers and vessels. A radio-opaque contrast material is injected through the catheter to obtain detailed angiograms outlining the anatomy. In recent years diagnostic cardiac catheterization has been largely superseded by cardiac MRI.

2. Interventional, to treat the heart condition. This technique has been one of the most rapidly evolving areas in pediatric cardiology in the past 30 years.⁸ It has become possible to treat many conditions, previously only treatable by surgery, with this less invasive technique. Using special balloon catheters valvar stenoses of either the pulmonary⁹ or aortic valve...