CHD May Research Update

In mid-March, Dr. Alexander Egbe, along with Dr. William Miranda and Dr. Carole Warnes, went to and presented at the American College of Cardiology Conference. After the conference, Dr. Egbe took some time to discuss what was presented at the conference, the importance of the conference, as well as an overall update of congenital heart disease research since discussing the importance of research about CHD at the end of January.

When we last spoke, we discussed the importance of research for congenital heart disease. Since then you’ve attended one of the three major heart medical conferences. What was the name of this conference? Where and when did it take place?

The conference is the American College of Cardiology Conference, ACC, and it is the largest conference held in the United States.  The last one was in New Orleans and was held from March 15- 17. We had about 12,000 physicians and scientists in attendance.

What is the goal of conferences like ACC? Is it simply to get everyone together and share research across institutions?

 Yeah, so the importance of that conference is that the high-impact research that’s been done in the last 12 months is shared, and then people come to review and discuss it. That becomes a great environment to cross-pollinate ideas, about what to be done the next year.

The other thing is, it takes a while for research to make it into the mainstream where people actually know about it and use it. This conference has become a way to allow problems to be compared to something that is new. That will decrease the literacy period between the time the study’s done to the time it takes to be used in real life.

These conferences then are a way that the Congenital Heart Disease department can reach that goal of changing the way congenital heart disease is treated not only nationally but globally as well?

Correct. So congenital heart disease is a very small segment of this conference. This all of cardiology so you can’t attend everything. When I’m there, I kind of restrict myself to the congenital heart disease programs which generally run from morning till evening those three days.

You presented multiple research papers at this conference correct?

Correct we actually participated very actively this year just like every other year as we presented seven different studies.

The first study was about the management of atrial arrhythmias in patients with tetralogy of Fallot. Actually, all seven studies are about tetralogy of Fallot. Just to give you an overview, tetralogy of Fallot is the most common cyanotic heart disease in children. These children grew and became adults so it became the most common cyanotic heart disease in adults and is the most common cause of sudden death and heart failure. So trying to understand how to manage it and prolong the life of the patients is important. So what we’ve done in the last year is focus all our research attention in a 12-month period on this single diagnosis.

One of the things we worked on is arrhythmias which is atrial fibrillation and atrial flora, because these two arrhythmias are part of the reason why the survival of this population is low. The median survival is about 55 years, compared 75-80 years in the general population. What we found out in our study is contrary to popular belief that atrial fibrillation is not very common in this population, the study at Mayo showed that atrial fibrillation is the most common atrial arrhythmia in people with tetralogy of Fallot, and is the major driver for heart failure and for death. We found that if you send patients for rhythm control through ablation, the survival is better.

The second study that we did, was trying to come up with risk model, that would help us predict the patients who are at risk for death. It’s almost like having a crystal ball to try and predict the future, instead of waiting for it to happen. Looking forward with this mathematical formula can help us know who’s at risk. The goal then would be to do something about it, hopefully, to modify their risk. We came out with a comprehensive risk model, and this risk model has everything in it. The patient’s age, demographics, their heart function on echocardiogram, MRI, cardiac catheterization, all the information. So we came up with a risk core that allows you to type in a patient’s information and it will spit out their risk of death in ten years, and it will give you the things that are driving the risk. So then you’ll see somebody has valve obstruction or has very poor function of one of the pumps, the right ventricle for example, so that will allow you to say this is the problem that will likely make the patient die within the next ten years. You can do something about valve obstruction by replacing it. You can do something about the ventricular function by trying to treat everything that you know can affect ventricular function.

The third study that we did, was that we looked at coronary artery disease, in patients with tetralogy of Fallot. Because we traditionally think about congenital heart disease of children and young people, we tend not to worry about their acquired heart disease. Coronary artery disease is the most common reason people have heart failure in the elderly, we found out that in the patients we see here at Mayo, who are at risk of heart failure in their early 50s, a number of them had coronary artery disease. The big finding here was, the type of coronary artery disease that somebody else would survive and be okay, with these patients, they would have heart failure and death with that same coronary artery disease. We don’t know why, but what we think is happening is that these group have a lot of people who have had surgeries. So their pump function, that is their ventricular function on the left side and right side is weak, that any of them superimposed in salt will make it irregular and lead to a bad outcome. Based on the result of the study what we are now doing, is creating an aggressive plan for coronary artery disease, and counseling the patients on what they can do like, weight control, exercise, don’t smoke, give cholesterol medications when indicated. Then the second thing we can do is prevent them from having coronary artery disease, because once they have it, the outcome is not very good.

The next study, the fourth, is about endocarditis. Endocarditis is an infection, inside the heart. Generally patients with tetralogy of Fallot have the surgery in childhood, and by the time they get to adulthood one of their valves, one of the pulmonary valves, tend to leak a whole lot, and the treatment is to replace the valve. Once you replace that valve, and put an artificial valve into the heart, that increases the chance of infection more than ten-folds. What we found out from our series is that having the artificial valve will put you at risk, which is already known, but what is new from this study is that, even with the modern-day medicine and care at Mayo Clinic, about one in three of the patients that have the infection, when they go for surgery they will die. It’s a very scary thing.  On the side of the patient, what this research means for them is being more meticulous with dental hygiene, regularly visit the dentist and they should get antibiotics before they have any dental procedure done. What it means to us as clinicians, based on this very sovereign result, is that we now have very high index of suspicion, in case a patient is complaining of having a high fever or doesn’t feel well, you assume it’s endocarditis until you can prove otherwise. Because if you overlook it, there is a one in three chance that the patient will die.

The fifth study, is about management of heart failure in patients with tetralogy of Fallot. That study ties in with the first study about atrial arrhythmias. What we did is we looked over a 28- year period, and we looked at everyone with tetralogy of Fallot that was admitted for heart failure to Saint Marys hospital. We found that about 15 percent of the patients, were admitted for atleast one episode because of heart failure. Interestingly, the main reason why they came in was atrial fibrillation. That brings us back to being aggressive managing atrial fibrillation by recommending an ablation that will control atrial fibrillation that will prevent heart failure and death.

The sixth study that we looked at was about outcomes of pregnancy in patients with this diagnosis. Normally during pregnancy, the blood volume in the patient increases by about 50 percent. This is well tolerated in someone without heart disease, but in someone with heart disease it can be a problem. What we try to do, is when we see the patient before they get pregnant is try to predict, is how their heart is going to react to this volume stress during pregnancy. What happens is that even a valve disease of ventricular dysfunction, that is not severe when you are not pregnant, may become severe when you are, and at that time it becomes late because they are already pregnant, and your solution of surgery is not their because you’d probably lose the baby. We’ve all seen bad things happen, so with some foresight, being careful and trying to fix whatever is needed in the heart before allowing the patient to get pregnant. What we found out is that, for pulmonary regurgitation, which is leakage of the right sided valve, even if you don’t do any procedure, they tend to do well. So this is different than what we know from disease where the problem is on the right side, where they tend to get into heart failure they tend to have bad outcomes in pregnancy. If you have someone with tetralogy of Fallot that wants to get pregnant, and all they have is pulmonary valve regurgitation, no matter how sever it is, they tend to do well without any problems. That will save you from having to do an elective procedure, that they don’t need at that time, allow them to get pregnant and wait until they meet the guideline to do something.

The last study we looked at was using ECG, which a cheap test that is used routinely during clinic visits, using it to predict the future of the patient. So again, it’s trying to see what’s the risk of having a cardiac arrest or the risk of having heart related death or transplant. Normally, we look at ECG and it gives us the rate and whether they have an arrhythmia, but we came up with something called QRS fragmentation, based on the ECG, it takes less than a minute to do. That can actually give you very useful information to decide what to do for the patient. So why did this study get a lot of traction at the conference is because ECG is the cheapest that we do during our visits, it can be done even in a remote place, you don’t need any special equipment just look at the paper, calculate the fragmentation and that’s all you need.

In a nutshell that’s the major studies that we did in the last few months that we showcased at the ACC.

Outside of the ACC conference we just discussed, are there other developments between now and when we last spoke that you would like to discuss?

 Yeah, so in addition to the things that we’re doing, that we’re publishing, we’re running a number of prospective studies, those are the studies that we’re doing in real-time, as they are happening. We have a number of studies in the echo lab, where we are using exercise stress to identify subclinical diseases. With people that have normal studies at rest, we are trying to apply exercise stress to see if it will unmask any of their problems. We also have a pilot study taking place in the cardiac catheterization laboratory where we are trying to use exercise as well. The rationale for this is that when the patients come to us, they tell us that they are short of breath when they exercise, or I get chest pain when I do something, So we try to replicate their symptoms at home and hopefully help us to determine what to do with the patient. What is coming in the future is that we’ll be doing a clinical trial using a new drug called entresto, that is used for heart failure and we are gonna try it for the first time in congenital heart disease patients. That trial is going to end at some time near the end of the year.

Thank you for educating us on the latest research on congenital heart disease. When and where will the next conference be?

Of the major cardiac conferences, the next major cardiac conference will be the ESC, the European Society of Cardiology Conference, which is going to be in Paris August, and again we’ll be presenting a number of studies there. And the AHA, the American Heart Association conference is going to be in November.

For more information on these studies, you can find them on the US National Library of Medicine National Institute of Health’s PubMed website.

HELPFUL LINKS

• Learn more about the Center for Congenital Heart Disease
• Connect with others talking about heart conditions on Mayo Clinic Connect.
• Explore Mayo Clinic's Rochester campus.
• Request an appointment.