May 4, 2018
Dr. Ronald Mark Grady, MD is a pediatric cardiologist at the Washington University School of Medicine in St Louis. He has over 29 years of diverse experience, especially in Cardiovascular Disease. He is affiliated with many hospitals including St Louis Children’s Hospital. In this episode, Dr. Grady discusses the surgical procedure called a Potts shunt as a treatment option for children who suffer from pulmonary hypertension.
I'm Mark Grady. I have been a pediatric cardiologist at Washington University in St. Louis and St. Louis Children's Hospital for close to 30 years.
A bit over 10 years ago or so I became interested in pulmonary hypertension. We had a small program at that time but it has grown significantly over the years. We specialize in some of the surgical treatments for pulmonary hypertension which includes lung transplantation. In fact, our center is one of the busiest pediatric lung transplant centers in the world. More recently, however, we have also become interested in treating kids with severe pulmonary hypertension with a surgical procedure called a Potts shunt. We think that it holds a lot of promise in certain kids, providing them an improved quality of life whereas before transplantation might have been their only other option.
Traditionally, if you are diagnosed with pulmonary hypertension, there are a number of medications that one tries to slow down, or if you're lucky, even reverse the disease process. Unfortunately, as most people know, a cure is not really likely and progression, despite medical therapy, is often the case. If the disease worsens to the point of frank right heart failure, up until recently, there has not been many options aside from transplantation, which is a huge leap for a lot of kids and their families.
This is where the Potts shunt comes in. It's named after a cardiothoracic surgeon, Willis Potts, who practiced in Chicago during the 1940s and 50s. He developed a surgical procedure that was designed to help "blue" babies who didn't have enough blood going to their lungs. The shunt basically involves connecting the pulmonary artery, which is the main artery coming out of the right side of the heart, to the aorta, which is the main vessel coming out of the left side of the heart. Because you make this connection, it allows blood to go from one side of the heart to the other fairly easily. When it was first developed it was, again, meant to help blood get into the lungs. Over time, the Potts shunt fell out of favor for more definitive types of surgery.
It really wasn't until the early 2000s when a French group based in Paris had the innovative idea of using this shunt not to provide blood flow into the lungs but to actually allow blood to escape the lungs. Their thought was that in severe pulmonary hypertension, the lung disease gets so bad that pressures in the right heart, which has to pump blood through the lungs to the left side, have skyrocketed. These high pressures eventually cause the right heart to fail. With a Potts shunt, however, some of the blood going to the lungs can now cross directly over to the aorta where the left heart pumps. This "pop off" helps lower lung pressures, reducing strain on the right heart and hopefully making the child feel better.
The French have placing Potts shunts for pulmonary hypertension for close to 15 years now. We have been doing them for about 5 years. Our combined experience has shown that in the right child, a Potts shunt can make a dramatic impact upon a child's quality of life. Weve seen it turn a child who's very symptomatic from their disease on really aggressive medications, into one that’s running around looking like a little kid again.
But when do you use it? That's the interesting question. I think for the shunt to be most effective, it needs to be utilized in somebody who's heart is still functioning well, in other words the right heart still needs to have some oomph to it. If you wait too long, and the right heart has started to fail, then the shunt's not going to help. So in our opinion any child with severely elevated lung pressures should have a Potts shunt considered as part of their therapy, especially if they are not responding to medications.
Potts have not been utilized to any extent in the adult world. I think that in part this is due to the fact that most providers of adult pulmonary hypertension care are pulmonologists rather than cardiologists. I think that pulmonologists are less likely to think about plumbing the way a cardiologist like myself might think about it. I also think that, in the adult world, having really high pressures in the right side that makes the shunt successful is less common than it is in children.
The procedure is not one that involves opening up the heart or using a heart lung machine. It often can be done while the heart's still beating. Traditionally, the Potts shunt is placed through an incision along the side of the chest, although we have done it a few times from the front of the chest as well. Children have also had shunts successfully placed in the cardiac catheterization lab, which avoids the whole chest incision process. We have done several of those, but it's a unique child that has that opportunity to have a shunt placed in that manner. Some of the European groups have been more aggressive about utilizing a catheter-based approach to placing a Potts shunt.
We're one of the leading pediatric lung transplant centers in the world and so I'm involved with a lot of children that are referred to us for possible transplant. And as well as I think that we do it, it has some serious limitations, especially if you compare lung transplantation to other solid organs in kids like heart or kidney. Lung transplants just don't do as well. Consequently, I still feel anything you can do to avoid a transplant is to your child's benefit and I think that a Potts shunt has that potential. We still consider a child who has had a Potts shunt a future lung transplant candidate should that consideration arise.
There's still some hesitation and/or skepticism in the pediatric pulmonary hypertension world about the utility of a Potts shunt. I think that’s unfortunate, because I do think that there's been enough data from kids now more than 10 years out from this procedure that clearly have done well. I'm not saying it's a cure all. But I do think that it should take its place alongside all the other ways that we have to treat children with pulmonary hypertension. It's nice that there's a forum such as this that allows a little bit more awareness of it, which I think is the most important thing, just to think about it.
I am Dr. Mark Grady, and I am aware that I am rare.
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