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New Treatments for Congenital Heart Disease in the Newborn

We are going to talk about congenital heart disease. Congenital heart disease represents about 1% of all live-born children; 8:1,000 of live-born children will have some form of congenital heart disease of varying severity. Some cases are very very mild and cause no problems throughout the life-span. Others are very severe and cause some compromise at birth. We are actually aware of some children with congenital heart disease by fetal ultrasound.

In terms of etiologies, just doing some overview; as far as etiology of congenital heart disease, we think of primary genetic factors and of course this category is growing - and we are excited about that as the molecular biologists and geneticists are identifying more and more genetic factors with regards to etiology of congenital heart disease.

Here are some associations with autosomal dominant syndromes and the type of congenital heart disease that we see in association. For example, we’ll talk about tetralogy of Fallot and tetralogy of Fallot is related to - or may be related to - Apert’s syndrome. As we look down this list we will see that … we will talk about coarctation for example and its association here.

In this one we talk about some of the selective chromosomal aberrations and some that are familiar to you. Cri du chat for example, with the most common lesion being a ventricular septal defect, patent ductus being second, and ASD. These congenital heart diseases occur in about 25% of the patients with cri du chat. Trisomy 18 for example, the majority of these patients - 99% of them - will have some form of congenital heart disease and most commonly a ventricular septal defect. Trisomy 21, for example - you are very familiar with - about 50% of those patients will have congenital heart disease in the form of ventricular septal defect as the most common, atrial ventricular septal defect or AV canal or endocardial cushion defect and ASD, just to name some of the associations we see with these selected chromosomal aberrations. Do you recognize this child? This syndrome that he represents? DiGeorge syndrome. DiGeorge syndrome is one of a group of chromosomal or genetic defects that we can make some specific associations of congenital heart disease. For the most part DiGeorge is associated with cono-truncal abnormalities; tetralogy of Fallot, truncus arteriosus, etc.

With regards to chromosome 21 there is an association "Catch-22". And the CATCH is an acronym for the defects that we commonly see here. This includes the cardiac anomalies, the facial abnormalities, the thymic hypoplasia, the cleft palate and the hypocalcemia as the components that we frequently associate with aberrations on chromosome 21. The cardiac anomalies are for the most part, the cono-truncal abnormalities. So patients with tetralogy of Fallot, truncus arteriosus. Tetralogy of Fallot again being associated independent of either of these syndromes with chromosome 22 aberrations as well. We list a couple of other associations here with specific chromosomes.

Here again, as we talk about the other group of factors as etiology of congenital heart disease and think about environmental factors - teratogens, if you will - there are some specific associations of congenital heart disease with certain teratogens; fetal alcohol syndrome for example. Twenty-five to thirty percent of those babies will have ventricular septal defects, PDA’s or ASD’s. We’ll talk about, for example, transposition of great arteries, and there is an association of transposition, tetralogy of Fallot, hypoplastic left heart syndrome with anticonvulsants of the trimethadione group. Tricuspid atresia, for example, is one of the cyanotic congenital heart diseases.

As we think about the differential between peripheral cyanosis and central cyanosis, again a distinguishing feature with regards to the mucous membranes is that in peripheral cyanosis the mucous membranes are pink. In contrast to cyanotic mucous membranes in central cyanosis as with congenital heart disease or pulmonary disease. The pulse oximetry can be helpful in terms of peripheral cyanosis. The pulse oximetry can be very normal, whereas in central cyanosis the saturation is abnormal. But I must warn you - because this happened to me in my clinic just last week - the examination rooms were particularly cold that day and I had two children, both of whom had had Fontan’s, and Fontan’s often have some peripheral vasomotor instability.

If we focus on cyanotic congenital heart diseases and try to resolve the case presentation, if we think of the five T’s then we have included the majority of cyanotic congenital heart diseases that may be represented here in this patient.

If our baby has tetralogy of Fallot, let’s think about what that means in terms of the pathology involved. The embryologic aberration is probably a single phenomenon and that’s of mal-distribution of the division of the conus so that the conal septum is deviated anteriorally, crowding out the pulmonary outflow tract, if you will, leaving a defect in the ventricle septum and also a disproportionately large overriding aorta. So as complicated as tetralogy may seem, it’s probably a single embryologic problem. The presentation of tetralogy of Fallot can be quite variable, often depending upon the age.

The treatment for the transposition, and especially what can be done from the point of view of the primary care physician, would be to implement the prostaglandin. What the prostaglandin does here in this setting is to increase the ductal flow so that you have increased pulmonary flow via the ductus, bringing increased volumes of flow back to the left atrium, sort of stretching open this foramen ovale or ASD so that you end up with more saturated blood shunted to the right atrium, which then carries the blood out to the aorta. So in this fashion you can increase the oxygen saturation in a baby with a transposition. It’s not a typical ductal-dependent lesion as, for example, tetralogy of Fallot. The atrial mixing becomes quite key as well. Another part of the management, usually once it gets into my hands or my colleague’s hands, is to assess the atrial communication and if it is compromised at all, then to use the catheterization to effect a balloon atrial septostomy.

Then the surgery of choice these days is the arterial switch operation which allows transection of the great arteries and re-anastomosis so that they come off the appropriate ventricle. Along with this it is important for us as a cardiologist to alert the surgeons of the coronary artery anatomy so that they will be able to re-implant these coronary arteries with a near aorta without compromise to coronary flow.

I put this up to remind you that before our surgeons were so skilled at arterial switch operations, we did venous switch and the names that are associated with the venous switch approach, i.e. redirecting the systemic venous flow to the pulmonary artery via the left ventricle, and redirecting the pulmonary venous flow to the right ventricle to the aorta; either by a stenting operation or a Mustard operation, and we still occasionally have reason to use one of these two approaches rather than arterial switch. If our baby has tricuspid atresia he might remind us that we are dealing with an atretic bicuspid valve here, no orifice, no communication from the right atrium to the right ventricle. And usually as a result, a very hypoplastic underdeveloped right ventricle, which is

What can you do about these babies as a primary care physician? Again, to effect pulmonary flow or to enhance it with the use of prostaglandin. When you refer that baby to the pediatric cardiologist then again we will assess the atrial septum to be sure that the defect is adequate. That’s the only way we decompress the right atrium in this setting. Then if not, then we do the balloon atrial septostomy. Then these babies require surgical intervention in the newborn period. Usually in the form of a

If our patient turns out to have total anomalous pulmonary venous return, let’s remember what that means. First of all, there are four different types of total anomalous pulmonary venous return. The majority of which are super-cardiac type. The intracardiac type accounts for the second category and the infradiaphragmatic - which is usually the most problematic - accounts for 10-20%. And then there is a form in

On the other hand, the baby who presents a few weeks out with mild cyanosis and a low congestive heart failure may have an x-ray that looks like this. And this is a "snowman" that we talk about in blue babies, associated with total anomalous

The management, the early management, is recognizing the congestive heart failure and treating it. Usually these babies go on to surgery once we make the diagnosis, at whatever age, of total anomalous pulmonary venous return.

The fifth of these cyanotic congenital heart diseases would be truncus arteriosus. Again, to remind us that we are dealing with a single trunk arising from the base of the heart which then subsequently divides into an aorta and into a pulmonary artery. There are actually four different types of truncus arteriosus depending on whether that pulmonary artery comes off the single trunk or as separate vessels.

The presentation, like that of the total anomalous super-cardiac, is usually not in the immediate newborn period so our case presentation would not likely be either of these last two diagnoses. But these babies often get out for a week or two and then begin to look a little cyanotic and to have some signs of congestive heart failure. Some of the

The treatment initially is that of managing the congestive heart failure, but early surgical intervention and early surgical correction is appropriate as well. In fact we worry about waiting too late in these babies because of the high flow, high pressure

We turn our attention to a little different kind of setting, of the newborn who presents in shock. A typical case presentation may be this; the baby who gets out of the newborn nursery and goes home and appears to be doing well for the first few days of life, but at about a week of age is noted to be fussy, not eating very well, diaphoretic and to have signs of respiratory distress. These babies will often present in the ER in shock, appearing quite pale and clammy and lethargic. The differential that comes to mind with a young infant presenting in shock should include sepsis, perhaps some metabolic disorder, but of the cardiac lesions we should consider, we should think of hypoplastic left heart and coarctation of the aorta. Coarctation of the aorta … here’s a picture, another drawing of the aorta and the coarctation being an obstruction usually at the

Switching gears again to talk about an older patient with cyanotic congenital heart disease and what might be a typical presentation is a toddler who is playing vigorously on a hot day in the Valley, who becomes progressively cyanotic and may even collapse on the playground. Usually gets rushed off to the ER via the paramedics and if you have the opportunity to get some history there may be history that the child has appeared to be mildly cyanotic for some time now and has episodes in which he appeared to have increased cyanosis. Often associated with hyperpnea. On examination, the child is severely cyanotic. The precordium is active but there is a very short, short murmur. And in the 2 ½-year-old you may see that there is mild clubbing. So here’s a child with a typical presentation of tetralogy spell. And what usually happens with a child playing is it decreases his systemic resistance so that there is a tendency for more blood from the right ventricle out the aorta and at the same time can increase the obstruction dynamically of the right ventricle outflow tract, increase sympathetic tone with play activity etc. to obstruct even further the pulmonary flow.

The pathology we talked about, increased outflow obstruction, decreased peripheral resistance, this may be triggered by acidemia or anemia. Spells often occur in the early morning. It’s thought to be associated with a sort of relative acidemia. And certainly has the tendency to occur in children who are anemic with tetralogy of Fallot.

The management; we teach the parents, once we make this diagnosis, knee-chest position to effect an increase in the systemic vascular resistance acutely. Under medical management, they will often receive oxygen, morphine, propanolol and