Jun 11, 2024
Dr. Dunbar Ivy, a pediatric cardiologist at the University of Colorado, discusses the upcoming World Symposium on Pulmonary Hypertension, where experts from around the world will gather to discuss the progress made and future directions. Dr. Ivy highlights the work of the pediatric pulmonary hypertension task force, which aims to develop expert opinions on various topics, including the role of different therapies for patients who have failed all available medical treatments. The task force also focuses on understanding genetic abnormalities and developmental lung disorders, defining pulmonary hypertension in neonates, and addressing the challenges of clinical trials for pediatric patients.The task force plans to publish their findings in 2024 and welcomes feedback from the medical community.
Hi, I’m Dunbar
Ivy. I'm a pediatric cardiologist at the University of Colorado in
Denver, Colorado. I've had an interest in pulmonary hypertension
for very close to 30 years. For me, it's been a very exciting
journey to see things move from really, no therapies, to one
therapy to over 12 therapies. That's really been exciting to be
able to use some of those medicines off label, but I think they
really have helped children and improve survival.
This year will be our next meeting of the World Symposium on Pulmonary
Hypertension. It's a meeting
every five years or so. The goals of the meeting are to get experts
from around the world in all aspects of pulmonary hypertension to
bring together and develop ideas as to where have we come since the
last meeting certainly, and also where should we go? What are the
things that we need to keep working on? It's exciting for us. I
believe this is our third year to have a pediatric pulmonary
hypertension task force. I think it's really wonderful to see how
far pediatrics has come.
There are eight clinicians chosen by the steering committee to meet
and develop our own ideas and to write them down and to develop a
paper so that we can share some knowledge. It's important to note
that they're not guidelines. They're sort of an expert opinion kind
of document. The group is going to focus on several things. One is
in patients who have failed all available medical therapies, what
is the role of the Potts shunt versus an atrial septostomy versus
lung transplant? Which patient would benefit most from which of
those therapies? And is there a preferred order? Some of this I
think really depends on the capabilities of the center, but we'll
try to provide some guidance in terms of which therapy for which
patient.
Other things that we're very interested in is there's been really
an explosion of interest in knowledge in developmental lung
disorders from genetic abnormalities. The TBX4 mutation has raised
a lot of interest in which patients have this, and it's the second
most common gene mutation and is interestingly found even in adults
sort of later on or in newborn babies. So, there's some exciting
pathobiology that we need to learn about, for example, for that
mutation, but also others.
We're going to work on the definition of pulmonary hypertension in
neonates. I think that's well established in adults that they have
a mean pulmonary pressure greater than 20 millimeters of mercury in
an elevated pulmonary vascular resistance. But many of the patients
that we take care of are neonates and we're not able to perform
cardiac catheterization on them. So, we're trying to define some
criteria that would be suggestive of an elevation of pulmonary
artery pressure. Then, the key really is to say why is the pressure
elevated? Is it from a left heart problem? Is it a right heart
problem? Is it from pulmonary veins? Is it from intracardiac shunt,
for example? I think there's a need for that for some definition of
pulmonary hypertension in neonates.
It's
a well-known and well respected conference. These are proceedings,
again, they're not guidelines. But I think they're very well-read
and I think that people take these recommendations seriously. From
being on the committee for the last two sessions, we do get
challenged on our thoughts, which is totally fine. But I think
again, it sort of helps people to focus a little bit and to have a
more clear definition of some things and directions.
One very, very important area is clinical trials for approval of
medications in children with pulmonary hypertension. The approach
is similar but very different between the US and Europe. I think
there's a higher standard showing a drug is effective in the United
States, whereas in Europe, they tend to rely more on the adult
trials for the efficacy. Then, they look at the pharmacokinetics,
how the drug is metabolized and what the drug levels are in safety.
Now, certainly we still do that in children in the States, but we'd
like to have a common pathway for Europe and the US for drug
approval.
One of the things that we will discuss is the challenges of
enrollment. In order to get a drug approved in the United States,
we are going to have to have enrolled trials. Right now, a lot of
the trials are stopped early because they can't enroll. So, there's
been a lot of thought about why that is. The design of the trials
has changed so that I think families were very nervous about repeat
heart catheterizations, for example. So those are not allowed in
the trials anymore. Many of them will have a heart catheterizations
as an entry criteria just to be sure that we know the right
disorder. But then we're looking for non-invasive ways to show that
the drugs are helping the children.
I think the trickle down is that we always learn a lot from our
adult colleagues. They have more evidence-based guidelines than we
do. Ours are more experience-based. So, when I go to that meeting,
I try to attend every session I can to learn from our adult
colleagues. There's 14 other sessions and one pediatric, so we're
in the minority, but it's a very passionate group. I think all of
us like going to the whole meeting and not just to the pediatric
session.
These are the ideas that we have. We will continue to meet at least
monthly to go through these ideas and work them out and see if
we're thinking about things correctly. Then, we're pretty sure the
manuscript will be published this year in 2024. So, we'll be
excited to get our ideas out there and also to get feedback.
My name is Dr. Dunbar Ivy, and I'm aware that my patients are
rare.
Learn more about
pulmonary hypertension trials at www.phaware.global/clinicaltrials.
Follow us on social @phaware Engage for a cure: www.phaware.global/donate
#phaware
Share your story: info@phaware.com #phawareMD
#PPHNet @PPHNet