Management of Right Ventricular Outflow Tract Dysfunction

Additional Info

• Audio File:uab/ua147.mp3
• Doctors:Law, Mark
• Featured Speaker:Mark Law, MD
• CME Series:Clinical Skill
• Post Test URL:https://cmecourses.som.uab.edu/mod/quiz/view.php?id=3968
• Guest Bio:Mark Law, MD is a Pediatric Cardiologist, Associate Professor. 
  
  Learn more about Mark Law, MD 
  
  Release Date: May 22, 2020
  Expiration Date: May 22, 2023
  
  Disclosure Information:
  Dr. Law has the following financial relationships with commercial interests:
  
  Grants/Research Support/Grants Pending - Edwards COMPASSION XT post approval trial, site PI
  Support for Travel to Meetings or Other Purposes - Transportation to Medtronic and Edwards transcatheter pulmonary valve implanters conference
  
  Dr. Law does not intend to discuss the off-label use of a product. No other speakers, planners or content reviewers have any relevant financial relationships to disclose.
  There is no commercial support for this activity.
• Transcription:UAB Med Cast is an ongoing medical education podcast. The UAB division of continuing education designates that each episode of this enduring material is worth a maximum of .25 AMA PRA category 1 credit. To collect credit please visit www.uabmedicine.org/medcast and complete the episode’s posttest.
  
  Melanie Cole (Host):  Welcome to UAB Med Cast. I’m Melanie Cole and today, we’re discussing approaches to pulmonary valve disease. Joining me is Dr. Mark Law. He’s a Congenital Heart Disease Cardiologist and an Associate Professor at UAB Medicine. Dr. Law, it’s a pleasure to have you join us today. Tell us the prevalence of pulmonary valve disease. What are you seeing?
  
  Mark Law, MD (Guest):  So, we see a number of adult patients who were born with congenital heart disease presenting with pulmonary valve dysfunction as adults. Most recently, patients who are born with heart defects are surviving into adulthood and we now have more adult patients who have congenital heart disease than we have pediatric patients. And a lot of the patients with complex congenital heart disease, will have pulmonary valve dysfunction or dysfunction of what we call the right ventricular outflow tract.
  
  And the most common diagnosis we talk about is something called Tetralogy of Fallot. And in patients with Tetralogy of Fallot or other types of congenital heart disease; they will have interventions on their pulmonary valve or surgery on their pulmonary valve that leaves them with both narrowing and insufficiency of their pulmonary valve over time. And we find that in kids, this is very well tolerated for many years. But after a number of years or decades, the higher pressure or the extra volume that’s place on the heart from the dysfunction will cause the heart function to decline or the right ventricle to decline and this sets patients to have abnormal heart rhythms such as ventricular tachycardia and potentially sudden death.
  
  And so we find that a number of adults are presenting with some effects of RV outflow tract dysfunction or pulmonary valve dysfunction that needs to be treated either surgically or with heart cath techniques.
  
  Host:  When do they present typically? Is this something that because they’ve been in surveillance since they were a kid? When is this noticed or found?
  
  Dr. Law:  It happens a number of different ways. In the best scenario, these patients are diagnosed as children and they are followed throughout childhood and then into early adulthood. And they continue to be followed by adult specialists in congenital heart disease or adult congenital heart disease doctors who are cardiologists. And in those cases, we can identify patients who are starting to have problems with pulmonary valve dysfunction and need intervention before they develop too many symptoms of the heart rhythm abnormalities or heart dysfunction.
  
  Unfortunately, as young adult patients transition from pediatric care to adult care, many of them are lost to follow up and in those cases, many times they are absent from care for a number of years until they present with significant symptomatology either back to the outpatient setting or present to the inpatient setting with heart failure or arrythmia.
  
  Host:  Then let’s talk about some treatment options. Tell us about the two main approaches that you would use as recently there’s been the development of percutaneous valve replacement with the benefit of not requiring open heart surgery and overall decreased impact to the patient. It’s not one size fits all, correct?
  
  Dr. Law:  That is correct. So, until about fifteen years ago, the only way to replace the pulmonary valve was through surgery techniques. And that could be done with bioprosthetic valve or a valve conduit or tube from the right ventricle to the pulmonary artery. And many patients who have grown up with congenital heart defects, have pulmonary valve already in place or a conduit but unfortunately, these don’t last forever and they themselves develop dysfunction. About fifteen years ago, we developed transcatheter valves that could be used in a number of patients. Currently, there are two transcatheter valves that are available in the United States. They do require a conduit or a valve to already be in place because they can only be expanded to a certain size.
  
  As time has gone by, we’ve figured out how to make them work in more and more complex situations and those have been very great developments. There are currently trials underway of valve implants and to more complex outflow tracts where there is so much size that the current approved valves don’t fit and we hope that in the upcoming years, we’ll have more and more technology available to treat adult patients and avoid more and more surgery over time.
  
  Host:  As we’re talking about approach considerations Dr. Law, tell us why a multidisciplinary approach is so important and useful. Are you using a hybrid approach? Who is involved in everything we’re discussing?
  
  Dr. Law:  So, I think that’s a great question. So, I think there’s multiple people involved from all sorts of different levels to evaluate and manage these patients and to prepare them for any type of intervention. There’s an adult congenital heart disease specialist who often sees them in consultation in the outpatient clinic or in the hospital and many of these patients require advanced imaging beyond just regular echocardiography such as a CT scan or an MRI. MRI is the most standard imaging that we would perform and that gives us information about how the right ventricle is functioning and it gives us a lot of anatomy of what the pulmonary valve or pulmonary valve outflow tract looks like and that helps us prepare the approach to different types of intervention and whether transcatheter interventions are appropriate.
  
  All of these patients need to be evaluated by a surgical consultant as not all of these procedures can be done transcatheter. And they require a cardiac specialist in intervention and even then, it requires multiple specialists in intervention. As I mentioned, my background is in pediatric cardiology but taking care of adults with congenital heart defects, I find it very useful and necessary to involve adult structural specialists who have understanding of coronary artery disease and complex interventions in adult patients too.
  
  These patients will require special anesthesia needs during the procedure. And so the list of providers that are involved in their care around the time they get interventions is quite long. And because the number of patients is relatively small in the community, they tend to need to be grouped at a tertiary care center where enough patients can be taken care of to build expertise in their management.
  
  Host:  Well as long as we’re talking about that and this multidisciplinary approach, do you have any technical considerations you’d like other providers to know about and while you’re discussing that, tell us about what’s involved in long-term monitoring.
  
  Dr. Law:  So, the technical considerations of pulmonary valve implant are very complex. It’s one of the more complex if not most complex structural interventions that is performed in the cath lab. The important considerations include special equipment. There are many times we will use high pressure balloon to stretch the outflow tract or the conduit and that can place the conduit at risk for rupture. And there are special covered stents that would be necessary to treat that. It’s also some risk in about five to ten percent of the population where trying to perform an intervention, a coronary can become compressed and needs to be recognized. In fact, the procedure should be aborted if that is likely to happen.
  
  So, the procedure itself requires a lot of thought in advance as well as multiple providers to make sure it’s performed safely. And it tends to be a relatively rare performed procedure in the medical field across each state and across the country compared to transaortic valve replacement or transcatheter aortic valve replacement or TAVR. UAB performs multiple hundreds of TAVRs a year and pulmonary valve replacement via transcatheter methods is more in the 20 to 30 range. And it’s the only institution in the state that performs routine pulmonary valve replacement.
  
  But unfortunately, no matter how the pulmonary valve is replaced, whether it’s surgery or transcatheter; the valve will develop dysfunction again over time. And many of these procedures are being performed in 20 and 30 years olds who we expect to have decades worth of longevity in the future. We don’t know yet how long a transcatheter pulmonary valve will maintain competence without any narrowing. We are optimistic that it will last a decade if not two decades but many times, another valve would have to be implanted inside of the current valve or a surgical valve would need to be implanted. So, replacing the pulmonary valve does not get them out of care with the multispecialty group and the adult congenital heart disease specialists. They require at least yearly follow up with EKGs and echocardiograms and Holter monitors and MRIs and occasionally stress tests to monitor how their current pulmonary valve is functioning.
  
  Host:  Well thank you for telling us about the importance of long-term monitoring. Are there some treatments or research that you’re doing that other physicians may not be aware of and while you’re telling us that, tell other physicians what you’d like them to know about this topic and when to refer.
  
  Dr. Law:  We’re involved in research of the current pulmonary valve technology. We are currently doing a post-approval study with one of the pulmonary valves, the Edwards XT valve looking at the outcomes of the valve after it’s implanted into patients and following their outcomes both clinically and via imaging over approximately five years post implant. I have written papers on the cost outcomes of pulmonary valve replacement via surgery and transcatheter as well as a review papers on the short term and medium term outcomes of the pulmonary valve.
  
  I would want physicians in the community to understand that we’re available to help manage patients with pulmonary valve dysfunction and that we would want to help comanage any patient where there’s a question about how the right ventricular outflow tract is functioning as well as any patient who was born with a congenital heart defect that requires long-term chronic follow up.
  
  Host:  Thank you so much Dr. Law. What a fascinating topic. Thank you for joining us. A community physician can refer a patient to UAB Medicine by calling the MIST line at 1-800-UAB-MIST. That concludes this episode of UAB Med Cast. For more information on resources available at UAB Medicine, please visit our website at www.uabmedicine.org/physician. Please also remember to subscribe, rate and review this podcast and all the other UAB Medicine podcasts. I’m Melanie Cole.
• Hosts:Melanie Cole, MS