Transposition of the great arteries (TGA) is a severe congenital condition in which the body's largest arteries are incorrectly attached to the chambers of the heart. In this video series, you'll learn how experts from the Fetal Heart Program and Cardiac Center identify TGA during pregnancy, support the baby's delivery, and provide surgery and comprehensive care after birth.
Transposition of the Great Arteries
Donna Lamborne: We had experienced two miscarriages prior to becoming pregnant with Grace. So once we made it through that 12th, 13th week of the pregnancy, we kind of felt like, OK, things are great.
Trai Lamborne: We're beyond that — that hump, that hurdle we hadn't cleared with two miscarriages, and now here it was, like, great, you know.
Donna Lamborne: Things are looking up.
Trai Lamborne: Yeah, clear sailing from here on out.
Donna Lamborne: So then we approached the 20-week anatomy scan and went to the doctor's office. And I could tell that the technician was sticking on the heart for a very long period of time. And she left the room and brought in our maternal/fetal medicine doctor. And she said, you know, "Your baby has a congenital heart defect, and it's referred to as transposition of the great arteries."
Thomas L. Spray, MD: All of heart surgery is 50 years old, and we've come from a situation of being able to treat nothing to being able to at least deal with most, if not the vast majority of, congenital heart defects in a way that allows children to grow into adulthood.
Jack Rychik, MD: We live in an era where there are very few things that we really can't take care of with excellent outcome after birth.
Thomas L. Spray, MD: Only time will tell what the long-term outcome really is.
Jack Rychik, MD: And as we follow them forward in time, there may be new things that we'll learn about them. But the good news is that the vast majority of these patients perform excellently and go on to lead happy, healthy lives.
Peter J. Gruber, MD: Transposition of the great arteries is a complex congenital heart lesion where the two great vessels that come out of the heart, the aorta, which takes blood from the left ventricle to the rest of the body, and the pulmonary artery, which comes off the right ventricle and goes to the lungs, are essentially switched.
Sarah Tabbutt, MD: The blood that comes back from the body goes back out to the body again, and the blood that comes back from the lungs goes to the lungs again. And obviously, that doesn't work.
Thomas L. Spray, MD: Blood is just going in two separate circulations in a circle, and you don't get any oxygenation to the body. So these children can get into trouble very quickly after birth.
Jack Rychik, MD: In order to understand and to comprehend any of the different forms of heart disease that exist, it's very important to make sure we understand what the healthy or the normal heart looks like. The normal heart has two sides, a right side and a left side, and four chambers, the top receiving chambers, or atrium, and the lower chambers, which are thick-walled pumping chambers called ventricles. Red blood cell will come from either the superior vena cava or the inferior vena cava and enter into the right atrium. The blood then flows across the tricuspid valve to the right ventricle. The right ventricle then squeezes and ejects that blood cell into a vessel called the pulmonary artery. The pulmonary artery splits into two vessels, each going to the lungs. As that red blood cell makes its way through the lung, it returns through the pulmonary veins to the left atrium. That blood is now oxygenated. It's picked up oxygen, then goes across the mitral valve into the left ventricle, which does most of the work in terms of delivery of blood flow to the body. That blood cell is now ejected into the aorta to some organ or muscle or skin in the human body. Now, there are some significant differences between the heart in the newborn and the heart in the fetus.
Elizabeth Goldmuntz, MD: The heart actually is — assumes its almost complete anatomy often before a woman would even know she was pregnant.
J. William Gaynor, MD: The heart is actually functioning and pumping blood to the baby throughout most of fetal life.
Jack Rychik, MD: Because the lungs are collapsed in the fetus and it's really the placenta through which much of the oxygenation takes place through the mother, there are various bypass pathways within the fetal heart that direct blood away from the lung. The first is a structure called the foramen ovale. That's communication between the two top chambers of the heart that allows for blood to go from the right atrium to the left atrium. In fact, because there is very little blood that's returning from the lung which would normally go to the left side, the majority of blood that fills the left atrium and left ventricle is coming across the foramen ovale from the right side. Because the lungs are collapsed, there's high pressure, high resistance in the lungs. As blood is ejected out the right ventricle and enters into the main pulmonary artery, very little goes down into the lungs themselves. The majority goes into a structure called the ductus arteriosus, which is the second important communication between the pulmonary artery and the descending aorta. The third structure that's important that connects the umbilical vein to the fetal circulation is a site — a — junction, called the ductus venosus. That acts as somewhat of a resister, if you will, in terms of controlling the return of blood from the placenta to the fetal circulation. Birth is a wonderful process and an amazing process, and there's a dramatic change that takes place in what we call the fetal transition, this transition of the circulation from fetal life to neonatal life. As soon as the cord is clamped, the ductus venosus ceases to carry blood to the heart, and it begins to constrict within the first few hours or days of life. The very first thing that happens when a fetus is born is it takes its first breath, the lungs expand, and so the resistance or pressure in the lungs drop, and that promotes blood flow into the lung itself. The ductus arteriosus begins to constrict and is typically fully closed within 24 to 48 hours of life, and blood is now then fully directed into the lung. As the blood returns to the left side of the heart, after traversing the pulmonary circulation and picking up oxygen, the pressure in the left atrium rises just a bit, and the trap door of the foramen ovale, which was open before birth, now begins to close, usually within the first few days of life.
How Transposition of the Great Arteries Develops
Jack Rychik, MD: In the normal circulation, the two circulations exist in what we call a series, where the blue blood, the deoxygenated blood, drains into the right ventricle, makes its way through the lung, then returns to the left side of the heart as oxygenated pink blood and makes its way to the body.
J. William Gaynor, MD: In transposition, the pulmonary artery and the aorta are switched, or transposed, so they come off the opposite pumping chamber. What that means is that the blue blood comes back to the right atrium to the right ventricle, but now, instead of going to the lungs, it goes back out to the body. So you have blue blood going in a circle, never picks up oxygen.
Peter J. Gruber, MD: Oxygenated blood from the lungs then returns to the left side of the heart, comes from the left side of the heart out to the pulmonary artery, goes to the lungs in a separate circulation.
Jack Rychik, MD: This creates what we call a parallel circulation, where blue blood continues to be ejected back to the body and pink blood begins to get ejected back to the lung, and the two circulations don't meet.
Thomas L. Spray, MD: You cannot survive that situation, of course, unless there's some mixing somewhere in the heart. The mixing can occur at three different places. It can occur at the ductus arteriosus, which is the connection from the arteries to the lungs and the body that's always present at birth but then typically closes because it's programmed to close after birth. Then there can be mixing between the two pumping chambers of the heart if you happen to have a hole there called a ventricular septal defect. But the best mixing occurs at the upper chamber of the heart called the atrial septum, and that can be open or not in these children. So how stable these babies are depends on how much mixing there is at those three levels.
After Delivery: Stabilizing Your Baby
Thomas L. Spray, MD: Most of the time after delivery, a baby with transposition of the great arteries will be extremely blue from inadequate mixing of the circulations.
Sarah Tabbutt, MD: One of the areas where blood can mix is at the ductus, which is a connection between the blood flow to the lungs and the body. You can keep that blood vessel open with a medication called prostaglandins. And so therefore, by giving a baby prostaglandins, you're actually replicating the same physiology that it had in the uterus, when it was very stable, to when it's outside the uterus. But the more important place where the mixing can happen is between the two top chambers of the heart, called the atrium. There's a whole normally there, and blood can mix back and forth there. In some babies with transposition, that hole is not big enough. It's not adequate for there to be enough mixing back and forth, and those babies can actually have fairly low oxygen levels.
Thomas L. Spray, MD: Very commonly, they require a Rashkind procedure, or a balloon to be pulled across the upper chamber of the heart to allow an opening to be created that allows better mixing.
Jonathan J. Rome, MD: You can advance that balloon up through the vein, into the heart under x-ray guidance, which is what catheterization is, and then you position the balloon across one side of this wall between the upper two chambers. You inflate the balloon, and you pull it back very quickly. And you literally rip a hole, and that allows the blue and the red blood to mix, and then the kids get much pinker.
J. William Gaynor, MD: There was this need for which balloon septostomy was developed, and it was developed here at the Children's Hospital by William Rashkind and was the first interventional cath procedure for children, which has led to the whole field of interventional cardiac catheterization today.
Jonathan J. Rome, MD: The children become much pinker. They have oxygen in their blood stream.
Thomas L. Spray, MD: This often stabilizes the baby and allows them to be-- to have better oxygen levels and to be more stable before the actual surgical repair of this heart defect.
Peter J. Gruber, MD: And this is very important because if you're born without a connection between the two sides, oftentimes the child is very sick. And you need time for the child to recover from that initial stress before going forward to surgery in a controlled fashion. And kids do better if they go under surgery in a non-emergent fashion.
J. William Gaynor, MD: In transposition, what you obviously want to do is rearrange the blood flow in some way so that the blue blood goes to the lungs and the red blood goes out to the body to mimic what happens in a normal heart.
Robert E. Shaddy, MD: Many years ago, someone had the courage and the technical skill and insight to say let's just switch the arteries and do an arterial switch operation with the complex part of getting the tiny coronary arteries switched at the same time.
Thomas L. Spray, MD: Remember, the anatomy of transposition, where the arteries to the lungs and the body come off the wrong side of the heart, the arterial switch operation takes those arteries and switches them back where they should have been in the first place. Now, that's pretty straightforward except for the fact that the small arteries that supply blood to the heart itself also have to be moved. Those are called the coronary arteries, and they're very small. Each one is about two millimeters.
Jack Rychik, MD: After the arterial switch operation, the aorta, which was sitting over the right ventricle, now sits over the left ventricle. And we use the term neo-aorta for that — for that vessel because it's now a new aorta. It's in a new position. The pulmonary artery, which was sitting over the left ventricle, now sits over the right ventricle. The vessels themselves are switched, but the base of the vessels which contain the valves that lead to those vessels remain on each of the ventricles. So in fact, when you do an arterial switch operation, you bring the aorta over to the left ventricle, but you're putting that over what has developed and originated as the pulmonary valve. So the old pulmonary valve becomes the neo, or new, aortic valve as it now connects to the aorta. And as we follow these patients forward in time, what we've learned is that sometimes that pulmonary valve, that neo-aortic valve, natural pulmonary valve, can begin to leak a little bit. And so that's something that we need to follow.
Peter J. Gruber, MD: Transposition of the great arteries is one of those lesions in which there are rarely other associated defects.
Jack Rychik, MD: In some, after repair there can be development of narrowing of the pulmonary artery.
Peter J. Gruber, MD: Normally, the pulmonary artery is behind the aorta, but in this situation, we now have to put the pulmonary artery in front of the aorta because it's switched. That ends up draping the two pulmonary arteries that go to the right lung and the left lung on top of the aorta. And this can sometimes result in narrowing of those arteries. So that's one of the things we look at carefully and can be followed with echocardiography.
Jack Rychik, MD: And we've now seen in some of our adolescents that there can be narrowings of the coronary arteries following the switch itself.
Robert E. Shaddy, MD: How this plays out long-term with the coronary artery problems that many people get — if we all live long enough, we'll have coronary artery problems — is yet to be seen.
Jack Rychik, MD: There are no 40- or 50- or 70-year-olds who have had an arterial switch procedure, so we don't know, really what's going to happen to many of these patients when they get much older.
Robert E. Shaddy, MD: But it is something that we'll need to track in these infants. We're optimistic that, actually, they're going to do fine with this and they won't have a significant increase in coronary problems, but that's still unknown.
Jack Rychik, MD: These are patients that need to continue to be monitored and cared for by a pediatric cardiologist and, as they get older now, by our colleagues in the adult congenital heart realm.
J. William Gaynor, MD: But for what's called transposition with intact ventricular septum, or simple transposition, the survival should be excellent. You should have between a 95 and 100 percent chance of surviving the operation, and most kids have good exercise capacity, are going to school and leading relatively normal lives.
Donna Lamborne: Grace is —
Trai Lamborne: You would never know.
Donna Lamborne: No, you would never know in a million years —
Trai Lamborne: That she ever had any type of heart defect or — she's going to be three in May, and she is unbelievable.
Donna Lamborne: Quite a personality.
Trai Lamborne: Oh, yeah, she's a ham.
Donna Lamborne: She is very outgoing. She loves to dance. She loves to sing. She has so many bruises and bumps on her legs from falling and jumping and climbing and crawling and, you know, whatever, any kind of activity. We really — you know, we've been told that she really should have no limitations.
Jack Rychik, MD: One of the other things to look for as an outcome, somewhat of a short-term outcome in patients with transposition, is that in some, after repair there can be development of narrowing of the pulmonary artery. It's a very small percentage, but it is something to look for. And we've now seen in some of our adolescents that there can be narrowings of the coronary arteries following the switch itself. Interestingly, many of those patients are completely asymptomatic at the time, but still no question that this is a group of patients we need to continue to monitor and follow.
Thomas L. Spray, MD: What I tell families is that there are more adults now than there are children living with congenital heart disease which, frankly, is a testimony to the fact we've been pretty successful at dealing with these conditions.
Robert E. Shaddy, MD: Our mission ultimately is to help children with heart disease and to help their families get through this difficult problem, to do whatever we can to make their lives better.
Donna Lamborne: I hope she just stays happy and does whatever she wants.
Trai Lamborne: I hope she can look back at these pictures, look at them again in 20 years and realize what she put us through.
Donna Lamborne: Yeah, exactly, right.
Trai Lamborne: She's just a great kid and like any kid, I mean, who's had a heart defect, who hasn't had a heart defect. You just — you wish the world for them.
Elizabeth Goldmuntz, MD: What moves me is to work with the families and to work with the children and to give them the best possible care that we can provide. That's first and foremost.
Susan C. Nicolson, MD: And to see them grow and to see them integrated into the family and to see them interface with their parents and their siblings just as you would any other routine and normal child.
Thomas L. Spray, MD: To be able to take the heart of a child and fix it so that the physiology is better and the child has a chance at a long life, that's very gratifying.
J. William Gaynor, MD: There's nothing better than seeing the kids come back when they're four or five years old.
Elizabeth Goldmuntz, MD: And really see that they're just like any other kid.
Jack Rychik, MD: Through the Fetal Heart Program, we're now able to offer hope and promise for the future for these children to go on to lead happy and healthy lives, and that's what this is all about.
Jonathan J. Rome, MD: And you can imagine, moving these tiny coronary arteries in a newborn is a technical feat. So they need to know, in some cases, exactly where those blood vessels are.
Thomas L. Spray, MD: They have to be removed and rotated and sewn to the other arteries so that they get blood. Otherwise, the heart will not receive oxygenated blood and can't function. And if those arteries are in any way kinked or twisted or in any way abnormal because they're so small, then no blood goes to the heart, and the heart doesn't work. So the biggest risk of surgery for transposition of the great arteries is related to moving those so-called coronary arteries.
Donna Lamborne: I remember walking down the hallway to where the anesthesiologist picks her up.
Susan C. Nicolson, MD: It's very, very important that the family feels comfortable with you, as an individual, taking their child from them.
Donna Lamborne: That was a really difficult thing, and she just smiled at us, and she said, you know, "Don't worry. We're going to take care of her."
Sarah Tabbutt, MD: For those particular babies with transposition, the surgery is usually done within the first week or so of life.
J. William Gaynor, MD: They'll go to the operating room. The anesthesiologist will put them to sleep. We'll then clean, prepare everything in their chest and abdomen sterilely so that we can do the operation without infection. It's performed through an incision in the front, over the breast bone. And we put them on the heart-lung machine and cool them down to take care of their brain and other organs while we do the repair.
Peter J. Gruber, MD: We're bypassing the heart and the lungs so that the operative field, the area where we're working, is clean and we can see what's going on.
J. William Gaynor, MD: Like other lesions, there's a lot of variation in transposition. There's simple transposition, where the only problem is that the arteries are switched. In more complex forms, there may be a ventricular septal defect or a hole within the heart. There can also be blockage of blood, either going to the lungs or going to the body.
Peter J. Gruber, MD: So the principles of the operation are to switch the vessels and the coronary arteries so they're coming off the right ventricles. And practically, what you do is divide the aorta directly above where the coronary arteries would implant, and you actually cut the coronary arteries out.
Jack Rychik, MD: Cutting out very small buttons of tissue of where the coronary arteries insert into the aorta.
Peter J. Gruber, MD: Once the coronary arteries are cut out and both vessels coming out of the heart are divided, you can switch those two vessels and put them in their proper location. And then you can sew those coronary arteries back into the new aorta in the proper location.
Thomas L. Spray, MD: It's made more complex by the fact that those arteries don't always come from exactly the same spot, nor are there always the same types of arteries. There's a great deal of variability in terms of the anatomy of those arteries. Sometimes there's only one. Sometimes they come off very close together, two of them. Sometimes they run in the wall of the artery to the body before they exit onto the surface of the heart. And each of those variations requires a variation in surgical technique to deal with it. Some of them are much more complex and difficult to move than others, and most of the risk of the repair of transposition of the great arteries is related to moving those little arteries that supply blood to the heart itself.
J. William Gaynor, MD: After surgery we'll make sure that the heart is working OK, that the blood pressure is OK, that the--that there's enough oxygen in the blood, that there's no bleeding. And then usually we leave a couple little tubes inside the heart to let us measure pressures in the heart and give drugs. These come out through the skin. There's also usually two little, blue pacing wires which let us change the heart rhythm. We then leave a drainage tube, and once everything is stable, the baby will come back up to the Intensive Care Unit.
Thomas L. Spray, MD: That operation nowadays takes about three hours to do, from start to finish.
Donna Lamborne: It was quick. For such a big, important thing, it was kind of like, "Are you sure you're done?" They brought her back to the unit, but she was in for that entire week where she was stable prior to having to have the surgery.
Robert E. Shaddy, MD: With the treatment of transposition of the great arteries, most of these children are out of the hospital in a couple of weeks and doing quite well.
Thomas L. Spray, MD: The results with that surgery now are very good. The risk of not surviving that operation, while not zero, is less than 1 percent, so children do extremely well with that particular surgery.
Topics Covered: Transposition of the Great Arteries