By Emile Bacha, MD
Emile Bacha, MD, is a senior associate in the Department of Cardiac Surgery at Children's Hospital Boston. He specializes in minimally invasive pediatric cardiac surgery; hybrid cardiac procedures, which use interventional techniques during surgery; and cardiac surgery in low birth weight infants. He's also interested in human factors and safety in pediatric cardiac surgery.
How often is cardiac surgery required in children?
There are approximately 30,000 children born each year in the U.S. with congenital heart defects. That's about 1 percent of all live births. Not all of them require surgery. It can be something very simple that will go away without intervention, or it can be something very severe and life-threatening that requires surgical intervention. As a result, about .2 to .3 percent of all live births require surgery.
What are the most common conditions that require surgery?
The most common malformation we see is VSD, or ventricular septum defect. In cases of VSD, there's a hole between the heart's two major pumping chambers. That hole can sometimes close by itself, but if it doesn't, surgery is required. The second most common defect is atrial septum defect, or ASD, a hole between the upper chambers of the heart.
Fortunately, both VSD and ASD are on the simple end of the treatment scale, and surgeries to repair them are very gratifying because you can perform them with extremely low risk and expect a complete recovery more than 99 percent of the time. You can basically promise the parents that it's a cure; their child can go on living whatever life they choose, even ones involving sports. After a successful surgery, I tell parents to pretend that it never happened.
What are some of the more complex conditions requiring surgery?
The patients we're concerned with here are called "single ventricle patients," and that includes those with hypoplastic left heart syndrome (HLHS). Normally, you're born with two circulations: the right heart supplies the pulmonary circulation and the left heart supplies the systemic, or bodily, circulation. Some kids are born, unfortunately, with a deficient ventricle. In HLHS, it's that all-important left one. It can be so small that it's not even visible, and there's no evidence that it's there. Those are children who, 20 years ago, would have uniformly died.
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Now, they often live because we perform palliative surgery on them. That may sound like a misnomer, but we call it palliation because it's not a cure. These babies live with their cardiac defect for the rest of their lives, in one way or another. Even under the best circumstances, they will need three surgeries very early on: one at birth (the Norwood), one at 6 months (the bi-directional Glenn Shunt) and one at 2 years of age (the Fontan). On the positive end of this spectrum, a patient can undergo these palliative surgeries and be asymptomatic. On the other end, there are those children who struggle with the one ventricle and who will need a heart transplant or, unfortunately, don't make it through the palliation.
Are there alternatives to the three-stage surgical approach for HLHS?
Yes, there's a hybrid procedure. The traditional way to treat HLHS begins with a Stage I Norwood Procedure, which is major reconstructive surgery laying out the connections in such a way that the right ventricle outflow of blood is directed into the body and pulmonary inflow is enabled passively. That's a lot of surgery and has to be done in the first two weeks of life.
By using the hybrid procedure, you basically establish a stable outflow by implanting a stent in the ductus arteriosus, which connects the pulmonary artery to the aorta. You then band the branch pulmonary artery to restrict some of the pulmonary blood flow. That can all be done without cardiopulmonary bypass. It typically takes between an hour and 90 minutes, as opposed to a six-hour, much more invasive Norwood. Most importantly, you're delaying the major reconstruction until the second stage. The reasoning behind this is that, at that point, the baby is older and stronger and has built up some immune defenses. A further advantage is reducing the number of "pump runs," those stretches of operating time involving the bypass machine, from three to two. Saving that pump run could result in a better outcome.
Why is it called a hybrid procedure?
It's called a hybrid because we're combining techniques that the interventional cardiologist typically uses in the cath lab, such as stenting, with surgical techniques. There are two operators—the interventional cardiologist and the cardiovascular surgeon—working together. This teamwork really distinguishes Children's.
What research projects are you
working on?
I have two interests that join each other. Basically, the overall theme is making heart surgery less invasive and safer for children. I work at it from two sides. One is trying to develop less invasive methods, such as the hybrid techniques, where we minimize time on the heart-lung machine. The other aspect of the research is focused on patient safety. I have a grant from the American Heart Association to study the systems in the OR and see whether we can find problems that lead to less than ideal outcomes. Then we can try to eliminate them.
