“Improved Survival in Congenital Heart Disease” by Peter Laussen for OPENPediatrics

“Improved Survival in Congenital Heart Disease” by Peter Laussen for OPENPediatrics


Steve and Collin thank you for the introduction
and for the invitation. It’s great to be home. This is a topic that, for many of you, would
make you glaze over, I’m sure. Congenital heart disease has been the domain of pediatric
critical care. But believe me, these patients are surviving and they’re coming to a ICU
near you. I’m not going to be speaking about a range of congenital heart disease and going
into specific anatomy. I’m going to try and stay a little bit broader than that. And I’m
also going to try and stay a little bit with the critical care theme, because this is an
area where there is just nothing available in literature, other than anecdotal reports. We have not had the opportunity to follow
these patients long enough to really know what their burden is and the impact that we’ll
have in critical care. But there’s no doubt that there are extraordinary successes in
the survival. Right now, any patient that comes into the critical care SickKids, Boston
Royal Children’s, anywhere in major academic centers, the expected survival across that
entire cohort is around 97-98%. Extraordinary. Over three decades there have been great improvements
in surgical technique and diagnostic and therapeutic imaging and in critical care management and
nursing that has contributed to this substantial improvement. I do want to tackle two areas though, one
is the neurodevelopmental outcome of these patients and the longer term quality of life.
And it’s important to remember that many of our patients are corrected, but they’re not
cured. They bring a burden with them that is lifelong. And I will also refer to the
adult with congenital heart disease and the impact that can have on our practices, particularly
in critical care. Now, let’s start with neurodevelopmental outcomes. This was a recent summary that looked at various
aspects related to neurodevelopmental impairment in children with congenital heart disease.
This is not a new phenomenon. This has been something that has been studied for the last
30 years. And, in fact, in my early lab experience in the 1990s was looking exactly at this with
a neonatal piglet model undergoing bypass, placing them in MRI magnet at MIT, and following
them for some days afterwards and looking at their recovery. We have not seen a decrease in the risk for
neurodevelopmental impairment in patients over time. Some of the problem we have is
if there is an era effect. The way patients were managed in the early 90s is really quite
different to the way they are managed now that you would think should have led to an
improvement in this particular problem. On the converse, it’s reported that in patients
that are undergoing the stage I palliation for hypoplastic left heart syndrome, there
is a risk up to 30% of those patients will have significant neurodevelopmental impairment
as they’re growing. Now some of that reflects improved imaging
and improved monitoring that has gone on. But there is no doubt that there is a risk.
And there are a number of factors that contribute to that now. We know that there are underlying
abnormalities, genetic abnormalities, that are in syndromes that consistently lead to
adverse outcomes. There is certainly change in cerebral hemodynamics in the fetus, and
that’s been well characterized by MRI. And there is a large amount of effort now looking
at fetal intervention to try and improve the dynamics of the circulation and improve oxygen
delivery, in particular to the brain, in the fetus. But there are still abnormalities that
are evident in the fetus with heart disease as opposed to the normal patient. And then we have the sequalae of heart disease,
often with chronic severe cyanosis, certainly malnutrition, arrhythmias, cardiac arrest,
these events that are occurring during their immediate recovery. There’s also sequalae
from the interventions, cardiac catheters, surgery, and increasingly concern over the
way in which patients are perhaps managed in the ICU. And the impairment, or the impact
of hemodynamic instability on cerebrovascular hemodynamics, and the vulnerability of the
immature brain. This was a study that was undertaken some
use ago. It came from Boston Children’s Hospital by Jane Newburger, and it came from the Boston
Circulatory Arrest Study. It was a study that enrolled 119 newborns with transposition of
the great arteries. And this was designed to look at the impact of low flow versus deep
hypothermic circulatory arrest bypass strategies. And these patients have been now followed
up for coming up to 20 years. So we’re getting some idea as to what their neurological outcomes
are, longer term. It’s important to remember that these patients were enrolled around 1990,
1991. And as I said, there’s been substantial changes in the way in which these patients
are subsequently managed. But what Jane wanted to demonstrate was that
there was a relationship between the length of stay in the ICU and their longer term neurodevelopmental
outcome, in particular, verbal and full scale IQ scores. And you can see that the longer
the period of time that one spends in the ICU, then the lower the IQ. Well, Jane went
even further to categorize this into looking at associations when adjusting for other predictors,
the impact of the length of stay in the ICU, and other variables that could affect developmental
outcome. And she came up with a conclusion that there
was a reduction in IQ of 1.4 points and 1.6 points in math achievement for every day spent
in the ICU. So we have some patients that are spending upwards of 30, 40 days in the
ICU. I have no doubt that those patients are not leaving us in a vegetative state. But
the implication from this type of information is that the longer you stay in the ICU, the
greater the decrement in your IQ and other achievements scores. Parents read this. It
concerns them. They challenge the management strategies as a result. Now that’s fine. I expect that. I welcome
that. The context of this is still to be determined, however. But that’s the type of information
that is now available and is obviously concerning. And if you look at the neurodevelopmental
outcomes of children some years after undergoing congenital heart surgery, there are some behavioral
signatures here. There are impairments of motor skills, both motor and gross motor,
Visual-spatial skills, working memory, ability to generate hypotheses, vigilance, sustained
attention, higher-order language, specific learning disabilities. That’s quite a large
list of disabilities that these patients can all demonstrate. But I think they fall into two major categories
as they get older. And one is with executive dysfunction, so the ability to integrate and
coordinate skills to achieve higher goals. Their ability to organize, to revise strategies
and plans into structure and monitor their behavior. It’s a bit like ADH. They also have
deficits in social cognition, decreased ability to read other people– I work with colleagues
who are just like that– difficulty identifying and describing their own internal states,
emotional and interpersonal difficulties. Now, this is demonstrated in many of the patients. I do not want you to leave here thinking that
we have generated a population of patients that cannot live in society. That is not the
case at all. The vast majority of patients who undergo congenital heart surgery are doing
very well. They go to school. They go to college. They have successful pregnancies and careers.
Now, they need a lot of support, a lot of intervention to get to that point. But they
are productive citizens in society. Although, this has being looked at in three
different studies now, to look at what is the implication of this lower IQ. And all
this is theoretical. It hasn’t been measured at all. But if you base the impact of congenital
heart disease on average lifetime earnings, it’s been demonstrated, or theorized, that
it’s up to 12 or even 18% reduction in lifetime earnings and then put into, from a government
perspective, and are they going to be good taxpayers in years to come. It looks like
a 16 to $22 billion dollar lifetime earnings lost and loss in productivity. This type of information indicates the importance
of the strategies we undertake in the newborn in the infant period when we’re managing these
patients. The care we provide has an impact on their later outcomes. But as I said, there
is a substantial era effect. And I’m certain that while these figures indicate that there
is a burden, it’s not apparent to the patients that you will see coming into your adult intensive
care units. And in fact, if you look a quality of life,
and we’re starting to look at these in a number of different areas, both physical and psychosocial–
this is patients after going transposition, of Fontan surgery, ECMO– that most of them
match up pretty well to the US general population. They are productive citizens in society. So
when you see them in your adult environments, they are not people that need to be treated
any differently. However, the burden of this disease is not
just in their physical and psychosocial makeup. It’s beyond that. It’s their ability to get
health insurance in the United States. Their ability to be employed in a sustainable way
and get the health insurance that allows them to access care, many patients actually get
lost to followup. They get absorbed back into the community. And then they come to you as
an adult with their disease, often that has undergone– that has not been followed closely
enough, so they come back to you with a residual burden. That’s the aspect of neurodevelopment. In
terms of the adult with congenital heart disease and what you’re likely to see, over this light
blue here are the live births with congenital heart disease. That’s remained relatively
static at around 1 in 1,000 live births. Same with the number of patients with children
and those with 18-year-olds with congenital heart disease. The number that is increasing
consistently are the adults. And in fact, there are more adults with congenital heart
disease in the United States now than there are children being born with congenital heart
disease. It’s a reflection of the extraordinary successes that I mentioned. It’s a very important group of patients that
as of yet have not received the attention that they deserve. The American Heart Association
put together some guidelines in 2008 for the management of adults with congenital heart
disease. Interestingly, they did not address specific pathophysiology or the burdens of
the disease itself but looked at the overall management of these patients. And it’s very
important, because they concentrated, in particular, on the transition of care. Now the transition of care from pediatric
to adult centers varies in the United States. In Boston, we elected to not transition. So
we would have, in our intensive care unit, 10% of our admissions were patients older
than 20 years of age. We would routinely have patients in their 50s undergoing– with congenital
heart disease, born with congenital heart disease, undergoing revision of their surgery.
And it was elected to keep them in our system, because it was where there was a consistent
knowledge base. It wasn’t like trying to re-invent the wheel. Other centers, like in Toronto where there
is a fixed 18-year-old cut off for admission to the Children’s Hospital, it meant they
got transitioned to the adult center. Well, fortunately, the adult center, Toronto General
is just across the road. And what has been maintained is a very close collaboration between
our units. And I think that’s one of the things about congenital heart disease that is going
to bridge pediatric and adult critical care. You can’t go from one to the next and assume
that there is knowledge transfer. And I think this is one area, for me in particular, that
we should concentrate on, breaking down this barrier between– or this dichotomous view
between pediatric and adult. The knowledge base that we have in the pediatric
critical care and the management is patients does translate. One of the things that’s very
important is the patient passport. Every patient with congenital heart disease should have
one of these. And it outlines what their diagnosis is, their history, all the procedures they’ve
been through, and hopefully some information as to their residual burden. It does not actually
tell you what the longer term complications are and doesn’t give you the context or interpret
that data. There are patients who will transition to
the adult setting, and there will be in their passport a whole list of what they’ve been
through, including perhaps some cath data. The interpretation of that cath data, though,
often doesn’t follow. And it’s important that there be this important collaboration between
pediatric and adult centers going forward. Now the problem with that, of course, is how
do you maintain that collaboration and communication? And the American Heart Association has recommended
that there be regionalized centers of excellence for adults with congenital heart disease. As I said, there are different models between
centers; that doesn’t prevent collaboration. But there needs to be an expertise in cardiology,
diagnostic and invention catheterization and in cardiac anesthesia. It’s interesting that
the American Heart Association has not addressed expertise in critical care, in surgery, perfusion,
and in nursing. All of these patients bring a pathophysiology and a strategy for management
that can be really quite different. So I think their recommendations for regionalized
care is fine, but it has to be comprehensive. And as of yet, that’s not the case. So well,
one last point about the recommendations, they did give very broad classifications for
the risk of endocarditis, and rather than being specific or disease-related, it was
basically into three categories, anybody with unrepaired heart disease, anybody repaired
with prosthetic material or devices, and any patient with a residual defect, irrespective
of their underlying anatomy. That makes a lot of sense. I think these broad
categories are important because there are literally hundreds of combinations of congenital
heart disease. And I’m not going to go through these at all other than touch on a couple.
The permutations are significant. And the anatomy to a large extent just doesn’t matter.
It’s understanding what the pathophysiologic burden is, the likelihood of residual lesions,
and what the progress of the disease is likely to be. Focusing on anatomy is the wrong thing. But I think it’s important to provide some
framework. And this is the framework that I’ve used and we use both in Boston, we used
in Toronto in terms of trying to look at adults with heart disease and how you would classify
them, and of those patients who have had an anatomic repair and those patients who have
had a functional repair. By functional repair, I mean that they’re actually fully saturated,
but they may have two ventricles or they may have only one ventricle. So the anatomic repair is a patient whose
morphological left ventricle is the systemic ventricle, right ventricle is the pulmonary
ventricle in the circulations and series. There’s a group of those patients that I would
put into the cured bracket, ASD repairs, VST repairs, patent ductus, those types of patients.
They usually present to you with limited burden over the years. And then there’s the group
that is corrected but certainly not cured. And they’ve undergone some sort of complex
reconstruction. AVF reconstruction such as tetralogy or the
arterial switch procedure is another example. I can tell you with the arterial switch procedure
that there is a 5-10% risk of having outflow obstruction from the right ventricle after
this repair, longer term. That the pulmonary valve that is now in the aortic position,
30% of the patients will have developed neoaortic or pulmonary valve, neoaortic position regurgitation
so the systemic semilunar valve 30% trivial regurgitation. Up to 8% of the patients will
have coronary occlusion following re-implantation. Most patients won’t have symptoms because
they’ve developed collaterals to account for this. Aortic root dilatation, we don’t know
the percentage of patients that have this problem. Arrhythmias, low risk, and most patients
describe themselves as doing extremely well. So this is a procedure where there has been
remarkable recovery, mortality less than 1%, and longer term outcome is terrific. But they
do bring a certain burden. And it seems to be settling around the ability of the pulmonary
valve longer term to support the systemic circulation in this new position and for aortic
root dilation. Now that information is important. To get
that requires going through hundreds and hundreds of retrospective review studies. This is where
the transfer of knowledge between critical care physicians, I think, is really important.
Because this can save and inform and give perspective. Let’s take the patients who have
had some sort of right ventricle outflow reconstruction, so it’s the Tetralogy of Fallot, truncus arteriosis,
a whole lot of patients fall into this category. And they can have basically three different
types of problems. They may have restrictive right ventricular
physiology. And by that, I mean is usually a stiff right ventricle with elevated end
diastolic pressure, usually a hypertrophied ventricle that there is residual pulmonary
stenosis often in these patients downstream. And they need to have cath and/or balloon
dilation and stenting of these lesions. Many of these patients come with a residual ASD.
An ASD is left in many patients in infancy in neonatal period after these repairs as
a pop-off valve at the atrial level to make sure that you have this obligatory right-to-left
shunt to automate cardiac output and a stiff right ventricle. Well, the problem, of course, as they get
older is that ASD doesn’t close, and they are at risk for paradoxical embolism. And
often they need to be closed when they present with acute illness for other reasons. These
patients can develop systolic dysfunction of the right ventricle. And now they have
an elevated end systolic volume and RV dilation, and it’s really related to how much pulmonary
regurgitation they have. Once again, there are some quite defined parameters
through cardiac MRI cath that can help you to find how significant these particular lesions
are. And some patients may require pulmonary valve replacement, particularly in their second
to third decade of life. Finally, arrythmias. There is a risk for sudden death in these
patients that is variably reported up to 5%, up to 8%. Most of them are ventricular arrhythmias,
but they can be supraventricular as well. More commonly in patients with an elevated
end diastolic volume as opposed to a pressure load, but there is no recommendation for prophylaxis. And in fact, arrythmias are one of the most
common problems that, in adult critical care settings, you will need to deal with. There
is no specific guideline. There is no patent here. It’s being prepared and understanding
that a whole range of dysrhythmias can occur in these patients. The way in which you ventilate
these patients is critical as well. This is a patient who– this is their aortic trace
and this is their right ventricular trace. This is a positive pressure breath that is
applied at this point. And you can see with that increase afterload in the right ventricle
in a patient who has residual burden with downstream obstruction of the branch pulmonary
arteries. The RV pressure rises to systemic level very quickly. That may have a significant impact on output.
It may also affect the coronary perfusion of that ventricle as well and lead to early
failure. Once again, it’s a problem that we deal with on a daily basis in pediatric critical
care, less so, perhaps, in an adult critical cares as this translation of knowledge is
very important. The functional repair. These are patients where the circulation is still
in series and they are acyanotic. But you can have two ventricles. In this case,
the right ventricle is now acting as your systemic ventricle. And in the early repair
of the arterial switch– sorry, the early repair of transposition of the great arteries,
there was an atrial level switch. So the tricuspid valve remained the systemic AV valve going
to the right ventricle out to the aorta. Over time, RV failure ensures the tricuspid valve
dilates and sets up a vicious cycle. The more tricuspid regurgitation you have, the greater
the risk for right ventricular failure and for dysrhythmias. And then there’s the population of patients
who have just one ventricle. And they undergo a staged procedure, in particular, the Fontan
operation. These patients have remarkable outcomes in that there’s higher mortality
in the early stage procedures. But after the Fontan procedure, they actually do extremely
well. They function well. They appear to be doing fine until you stress them. And then
their circulation can unravel quite quickly. And that’s because you’ve got one ventricle
and, thus, the flow of blood through the pulmonary circulation is dependent on the preload to
that route. Hey, you’ve redirected systemic venous return
under its own kinetic energy through the pulmonary circulation back into the systemic ventricle.
And they are different pathways and different interventions that you can undertake in terms
of managing these patients. It is a unique circulation. It is one that is well-understood
in pediatric circles and one in which there should be a translation of knowledge. There
is no indication at all, in my mind, for reinventing the wheel here, thinking of different strategies
about the circulation. There certainly can be innovations in the management, but their
impact on disease on the circulation, I think, is pretty well understood. Once again the effective of positive pressure
ventilation is an example here. This is Doppler pulmonary blood flow until you get a positive
pressure breath, and then you start to get some reversal of flow. So pulmonary blood
flow is very much dependent on the intrathoracic pressure and that afterload on the pulmonary
circulation. The group of patients that we would extubate as soon as we can to make sure
that during their expiratory phase and with a subatmospheric inspiratory pressure, they
have augmented pulmonary blood flow. And the Fontan procedures have quite significant
longer-term burden. The risk for arrhythmias may be supraventricular, sick sinus syndrome,
or heart block. And they all develop over various periods of time. The effect of chronic
systemic venous pressure being elevated and the development of cirrhosis is emerging as
a real problem in these patients and may be an indication for early transplantation. They can develop protein-losing enteropathy
that may be independent of the systemic venous pressure. A plastic bronchitis, which is a
terrible disease for some of these patients, where they produce chronic casts within their
lungs that is very debilitating. And then there is much higher risk for thrombosis and
stroke, which is obvious based on simply of Virchow’s Triad and the risk for thrombosis.
So these patients bring longer-term complications and burdens with them as well. I want to finish with just showing an example.
This is a patient, a 24-year-old. She was at Vermont. She was in college studying to
be a social worker. She was about to graduate, and about four months from graduation, I received
a call to say that she had pneumonia, that she was on very high-dose epinephrine, norepinephrine,
high ventilation settings, and that they could hardly keep her saturated, let alone maintain
a blood pressure. And they want to transfer her for ECMO. And this was her anatomy. So the anatomy was
not well-known at the institutional where she was being sent. She hadn’t been able to
communicate that with her, and her family didn’t know. There was no passport. So this
patient had SVC blood flow going just to the right pulmonary artery. This is what’s called
a Glenn Shunt. So all the blood flow to the right lung was through the kinetic energy,
if you like, of the SVC pressure. And then she had a central shunt coming of
the innominate artery supplying the left pulmonary artery. So she had two different sources a
pulmonary blood flow into what was a double-inlet double-outlet right ventricle. It doesn’t
matter those terms, it’s a single ventricle, two sources of pulmonary blood flow, one under
systemic pressure, one under venous pressure. And then this is how she presented to us,
with white out of this left lung. Remember this is supplied by the systemic pressure
through that central shunt and then this lung, which is hyperinflated and black. And this
is her main source of gas exchange, and yet blood flow was clearly impaired, because the
way in which she was being ventilated meant that she had very little blood coming from
her SVC into her right pulmonary artery. She had– it was understandable that she had
impaired perfusion and impaired gas exchange in that– understand why she was on that degree
of support. Her management was to place a double-lumen endotracheal tube to ventilate
lungs differentially, low pressure, higher pressure, and within 24 hours, she was off
inotrope support. Gas exchange had normalized and 48 hours later was back to a much improved
circulation to the point where we could wean her and extubate her. And she went back and
graduated. This type of therapy we’ve used, I guess,
in four or five patients now. But it’s an example, I think, where the underlying burden
of their disease needs to be– you need to be creative, perhaps, in the way in which
they are managed. But it’s important to understand their underlying pathophysiology. And in adult
critical care units that are unfamiliar with this, it’s important that there be this very
clear communication with other centers that can, perhaps, help them in this regard. I do want to make a point of about cardiac
catheterization, in patients in the ICU, adult ICU, who are unwell. Consider it early in
any patient, particularly with those uncertain physiology residual defects or if the patient’s
not recovering as you would expect. It certainly gives you some diagnostic and hemodynamic
assessment. But the interventions in the cath lab for these patients are really critical. They include closing a residual intracardiac
shunt that may have been contributing to their desaturation and the risk for paradoxical
embolism. These patients often develop abnormal aorta pulmonary collaterals, venovenous collaterals
that result in a volume load any impaired systemic perfusion. Calling those and getting
rid of them can make a dramatic improvement. Balloon dilation and stenting of pulmonary
or systemic stenoses, very important. And over the last few years, the percutaneous
placement of the transcatheter valves is very important, not only in the pulmonary valve
position, but we’ve used it in patients who have acute illness from other reasons who
have got severe aortic valve regurgitation or AV valve regurgitation. So being able to deploy these valves to give
you competency during their immediate illness is actually very important. So I think one
of the things that we need to be very aware of in the critical care setting is the value
of catheterization, not just as a hemodynamic evaluation, but as from a therapeutic perspective.
So the considerations in critical care is understanding the pathophysiology, understanding
catheterization value, the sources of pulmonary blood flow, residual lesions, in an estimation
of reserve. All of that is very important, as important is the communication and the
collaboration that must exist between pediatric and critical care environment. So what’s next? Well, early intervention is
the key theme for the potential for neurodevelopmental impairment. And that starts during the first
admission. And a whole field has developed now to make sure these patients are slotted
into longer-term development. Because the recovery and the decrement in their burden
of their neurodevelopment is dramatic if they have early intervention. There must be this very careful and informed
transition of care, perhaps, into regionalized centers with broad expertise. But I really
think we, as critical care clinicians, need to also take the lead with this and make sure
that we also have seamless communication and collaboration with these patients as well.
Thank you for your attention.

Be the first to comment

Leave a Reply

Your email address will not be published.


*