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Melanie Cole (Host): Today's topic is hope and support for patients after the Fontan procedure, and the Fontan Clinic at St. Louis Children's Hospital. My guest is Dr. Kathleen Simpson. She's a Washington University Pediatric Cardiologist at St. Louis Children's Hospital. Dr. Simpson, tell us a little bit about single ventricle heart defects. What are they?

Dr. Kathleen Simpson, MD (Guest): Sure, thank you for having me. Well single ventricle heart defects are essentially a very basic term for any patient who has anatomy where only one good pumping chamber exists. And this can be a variety of different complex cardiac anatomy, but ultimately these patients have only one ventricle and possibly other complicating anatomy as well.

Melanie: What's the clinical presentation and how and when are these defects detected?

Dr. Simpson: Well, it used to be that we only detected these patients right after birth when they either were desaturated, or they struggled. Sometimes patients presented early on with just sudden death and cardiac arrest, however with the increase in screening in fetal life, we are now getting more referrals prior to birth to our fetal care center where we make a diagnosis. There are still some patients that are diagnosed after birth, and some patients are actually now being screened with universal post proximity newborn screening, which has been initiated in Missouri as well as many other states that are now catching patients before they're discharged home, but still some patients are found after discharge, usually in the newborn period. They typically have issues with low oxygen saturation, they may have failure to thrive, they may have difficulty breathing or poor profusion.

Melanie: Then if you detect this, how are they treated?

Dr. Simpson: So it can be a real emergency, depending on the anatomy of the patient, where they need very quick surgical intervention or medical intervention, versus some patients which may do okay for a little bit, but typically what they most likely need is surgery in the newborn period.

Melanie: Tell us a little bit about the Fontan procedure.

Dr. Simpson: So the Fontan procedure is one of the safest that we have for patients with single ventricle anatomy. Typically patients, as I mentioned, require some sort of intervention in the newborn period, but that's ultimately not their final procedure. This usually only palliates them until they can get a little bit bigger and their pulmonary vascular resistance goes down with time.

The Fontan procedure is typically the second or third surgical palliative procedure in single ventricle patients, and although there's many forms of the Fontan procedure, ultimately what it results in is that blood flow to the lungs is separate from blood flow to the rest of the body as the inferior and superior vena cava will flow directly into the branch of pulmonary arteries and bypass the flow. The single ventricle pump, as these patients only have one good ventricle, it's used to pump blood flow to the systemic circulation. Some patients also have what we call fenestration at the time of Fontan, which is a small hole that connects the Fontan circulation to the atrium of the heart and allows for a pop-off pressure from the Fontan.

Melanie: Wow. So what are some of the long-term effects for single ventricle heart patients? And what is the prognosis like after the procedure?

Dr. Simpson: Well, there are very interesting questions, but the Fontan procedure has not been around for very long. We now have our first set of Fontan patients reaching their thirties and forties, so some of the long-term data is really only become available in the past several years through large registries and single center reports. We have known for some time that Fontan patients are at risk for certain cardiac issues such as arrhythmias or even slower heart rates and pump failures over time. We also recognize that they're more at risk for clotting as well as development of some very specific Fontan diseases such as protein neuropathy where you lose large proteins through your gut and you get associated diarrhea, gluten retention, and malnutrition. As well as something called plastic bronchitis where you get this abnormal protein material that collects in the airways.

That's been known for a while, but more recently in the past several years, we're starting to describe some of the other organ issues long-term, and this includes difficulty with obtaining predicted normal height, poor growth, low bone density, delayed puberty, immunodeficiency as well as progressive dysfunction of the kidney, liver, and lungs.

Melanie: What are you looking for post-surgery?

Dr. Simpson: So early post-surgery, some patients will do quite well, some patients will struggle, and we think that those patients that struggle probably have a rougher time post-Fontan compared to other patients. But we're really watching to see how these patients grow, and whether or not they're thriving after Fontan.

Melanie: Then tell us when and why the Fontan Clinic at St. Louis Children's Hospital was established. How did it come about?

Dr. Simpson: So as a pediatric cardiologist, one of my particular interests is the Fontan patients, especially because I am one of the cardiac transplant patient cardiologists at Children's Hospital, and I over the years have been taking care of many Fontan patients who eventually have failing physiology and are referred for heart transplantation. And one of the things that we recognize in the transplant community is that many of these Fontan patients by the time they are referred for transplant often have multi-organ disease, which can make their care quite challenging, and even in some instances make transplantation not an option. Or even in some patients require a multi-organ transplantation such as heart/kidney or heart/liver.

And so like many large referral institutions, we felt that we needed to proactively start screening and treating these patients for multi-organ disease now that we recognize all Fontan patients are at risk for these issues long-term. So we've recently started the clinic in January of 2018 to address these issues in an organized multi-specialty fashion.

Melanie: So as I understand it, the Fontan Clinic is more about the evaluation of non-cardiac issues that a child may experience.

Dr. Simpson: Right. Our purpose in the Fontan Clinic is not to replace a patient's cardiologist or their cardiac care. Really we focus actually more on the non-cardiac organ issues that can be seen in the Fontan patients long-term. Although each patient will see myself or one of the other heart failure specialists, really what's more important I think in the Fontan Clinic is focusing on these other issues which may not be addressed until they have pretty advanced disease.

Melanie: Dr. Simpson, for other providers, and do you feel that it's important for children to maintain a medical home to go through their well visits and their chronic care issues? Are there some warning signs or specific red flags that should be identified as far as other organs?

Dr. Simpson: So that's challenging because we're increasingly finding that many of the labs and even the imaging of certain organs can be very abnormal before these patients will show outward signs of disease, which is part of the reason to initiate screening early on before people actually start to show evidence of disease, because by then it's pretty late.

However, we do know that patients who struggle often have issues with weight gain, growth, they may have chronic diarrhea or breathing problems, and they may have some swelling in their belly or legs.

Melanie: Speak about the multi-disciplinary aspect of the clinic, and what these disciplines address. What kind of providers are involved?

Dr. Simpson: So we have a whole panel of sub-specialists who are available, and each patient has a tailored visit based on their highest risk assessment for certain disease processes considering how far they are from Fontan, and what evaluation they've had in the past. So what we do is when we receive a referral, we review their chart and all available records to see which providers would be best for each patient. Most patients will end up seeing a heart failure cardiologist, the pulmonologist, the hepatologist who specializes in liver disease, as well as the kidney doctors.

We also have additional specialists in hematology, immunology, and endocrinology for patients who have specific concerns based on their history. We also have a dietician who specializes in cardiac heart failure and transplantation who will also be seeing these patients with specific dietary deficiencies that are more common in Fontan patients, such as vitamin D deficiency.

Melanie: What can a referring provider expect from the Fontan Clinic team after referral, and what else would you like them to know about single ventricle heart defects and hope and support for patients after Fontan?

Dr. Simpson: Well, as I mentioned, we are not here to replace the care that is provided by their normal cardiologist and primary care provider. We hope to complement their care by doing a more intensive intermittent evaluation. We start seeing patients about ten years after they've had their Fontan procedure, and in cases where they're doing well and we don't find any issues with their screening, lab, or evaluation, they would only be seen every three years in the Fontan Clinic unless there were concerns in between.

Each referral physician will be receiving a detailed evaluation note going through every sub-specialty and the recommendations. In addition, if there's any major concerns or need for major intervention or further testing, we would discuss with the referring provider. But really I think we're hoping to empower patients by talking to them about the long-term effects of the Fontan circulation and giving them real up-to-date information based on our latest knowledge so that they can anticipate the challenges that they may have over time. We hope that by evaluating and identifying issues early on, that we hopefully can prevent or at least understand better the multi-organ disease in these patients.

Melanie: And that segues into our final question very well, Dr. Simpson. What are some promising therapies? What are you looking at in the next ten years in terms of these types of heart defects?

Dr. Simpson: Well I think that's really challenging because right now really what the community is doing is trying to define better what the actual end organ effects are and how those end organ diseases such as the liver and the kidney affect patients long-term. There's a lot of debate in the transplant community as to how much end organ disease is a contraindication or how much end organ disease should be an additional push to think about heart transplantation in these patients. Doing anything we can to optimize the physiology of these patients will hopefully ameliorate some of the effects that we see, especially on the liver, but really we're still just learning so much about the severity and extent of these other organ involvement in these patients that we don't have a good handle on how they're going to affect patients long-term.

Melanie: Thank you so much for being on with us today, and explaining so very clearly why a patient should be referred to the Fontan Clinic. Thank you again for joining us. A physician can refer a patient by calling Children's Direct Physician Access Line at 1(800) 678-HELP. That's 1(800) 678-4357. You're listening to Radio Rounds with St. Louis Children's Hospital. For more information on resources available at St. Louis Children's Hospital, you can go to www.StLouisChildrens.org. That's www.StLouisChildrens.org. This is Melanie Cole, thanks so much for listening.