"Questions and Answers with William B, Moskowitz, M.D."
Written by:
William B, Moskowitz, M.D.
Director of Pediatric Cardiac Catheterization
Laboratory
Director of Pediatric Heart / Lung Transplantation
Virginia Commonwealth University
Medical College of Virginia
Richmond, VA
Edited by: Mona Barmash
Posted: September 14, 1999
Embolisms
Q. What are some of the reasons air
embolism could cause brain death in a child undergoing
open heart surgery?
A. Air emboli are rare
complications. If they occur, emboli are likely due to
air that has not been completely emptied from the open
heart. Usually the surgeon "vents" the air by
several techniques before the heart starts beating
following the repair, after circulatory arrest and
cardiopulmonary bypass.
Q. How much air would it take to
leave a child brain damaged? Could that amount of air not
have been emptied?
A. A few small bubbles are unlikely
to have any detrimental effects. A small amount (a few
CC's, a tablespoon) in the wrong area could be
devastating. I cannot say exactly how rarely this
happens, but I would expect certainly less than 1%.
Surgeons take painstaking steps to prevent this from
happening.
Cardiac Catheterization
Q. What are some of the risks of
having a cardiac cath done?
A. That depends on the age and size
of the child as well as the size of the catheter and the
intervention being done. The risks go up for
interventional procedures such as balloon dilations, coil
embolization, stents, and so forth because the catheters
and sheaths may be larger than the diagnostic catheters.
In infants, there is a risk for a fever
afterwards, until the dye passes out of the body. For a
routine cath (diagnostic) in a non-infant the risks are
quite small. There is always the low risk of damaging the
vessel, the risk of bleeding (very small) the risk of
infection (very, very small), the risk of perforating the
heart or vessel (extremely low, though higher in
infants). Each interventional procedure has its own list
of possible complications.
Q. Can a cath from the femoral
artery cause a shortening of the leg?
A. The femoral artery and vein are
used most frequently for cath access. When the artery is
used, especially in infants, there is the risk of
damaging the artery. If there is not enough flow to the
leg through the scarred artery, the muscle and bones do
not get adequate nutrition to grow comparable to the
other leg. This is seen less frequently today, because we
routinely use smaller catheters and sheaths, and
routinely use heparin and follow clotting times in the
cath lab in order to minimize the formation of blood
clots.
Heart Transplantation
Q. How are tests going for new
medications for transplants?
A. New drugs are being tested all
of the time. As per usual for the FDA, drugs are tested
in adults then, maybe they are tried in children. New
laws have been passed recently to involve children in
studies sooner so newer drugs become available more
quickly for children in need. While the mainstay of
therapy still remains steroids, Imuran and CYA/ Prograf,
other newer drugs will be coming down the pipe for
children soon.
Q. Is it true that kids who
received heart transplants will eventually need kidney
transplants?
A. Not that I am aware of. It is
true that some of the medications that we use for
immunosuppression can hurt the kidneys. High blood
pressure is a common side effect of the medications. Many
(about 50-60%) of children after transplant will have
high blood pressure and require medications for that. We
always monitor blood levels of drugs and kidney function.
I am unaware that kidney transplant has been required
even in a small minority of patients. I personally have
not seen a case.
Q. Does the location of old
surgical scars eliminate a patient from eligibility for
heart/lung transplant?
A. The difficulty with prior
surgery on heart lung transplants is getting in and
removing the old organs, which can be difficult or
complicated with a lot of bleeding. The midline
sternotomy (splitting the breast bone) is not really a
problem. The thoracotomy (between the ribs on either
side) can be a problem. This is due to adhesions that can
scar down the lungs. This makes it more difficult (with a
greater risk of bleeding problems). This does not mean
that an individual with prior thoracotomies cannot have a
heart/lung transplant (called an absolute
contraindication). It can be done, but at much higher
risk (relative contraindication).
Coarctation of the Aorta
Q. What are the chances of having
more than 1 child born with coarctation of the aorta?
A. Coarctation of the aorta occurs
commonly- about 6%-8% of all CHD. It is a form of left
heart obstruction. It is frequently accompanied (85-90%)
with a bicuspid aortic valve. There may be a hypoplastic
LV and mitral valve problems as well.
The risk of having a second child with
a left heart obstruction is about 2-3 times the general
population (which is 8/1000 or about 1%) or about 3%.
Now, the recurrence could be simply a bicuspid aortic
valve that would cause little or no problem, or it could
be a hypoplastic left heart, which could be
life-threatening. So, we would recommend to the family if
there was a left heart obstructive lesion in the first
child (including coarctation), that fetal echo studies be
performed on any subsequent fetus.
Q. Is it likely that a repaired
coarctation can reoccur in the future?
A. It depends on the age of the
patient at the first procedure. If the coarctation was
repaired in infancy, the risk is higher-somewhere between
15% and 30% of recurrence. If done after the first year,
risk of recurrence is probably 10% or less. The reasons
why we operate sooner rather than later is because we
have to- heart failure, sick child, or severe
hypertension. These days surgery is pretty effective.
After 1 year of age, surgery or balloon dilation offers
options for a given child. Even if recoarctation occurs,
balloon dilation or stenting, not surgery, is the first
choice for the procedure.
Q. How long are kids usually on
blood pressure medication after coarctation repairs?
A. It varies. Most children do not
require BP meds for more than a month following repair.
Now, having said that, it is more likely for a child
older than age 6 years at the time of repair to require
long term BP medications due to changes in the kidneys
and blood vessels.
It is not uncommon for medications to
be needed for a month or two after repair if there was
high BP preoperatively. We will frequently pre-treat
patients with coarctation for 5-7 days before the repair
with a beta-blocker to prevent a lot of hypertension seen
immediately following repair.
Since the child continues to grow, it
should not be surprising that the aorta will grow with
the child, but the suture lines of the coarctation repair
may not. So, all children who have had coarctation
repaired should continue to be followed into adulthood
for changes in BP and heart function.
Cardiomyopathy
Q. How common is it to have HCM
diagnosed in an infant, and how does being diagnosed in
infancy affect the prognosis?
A. There are HCM and then, there
are HCM. You can have HCM due to diabetes in the mother.
This is short-lived or temporary (transient) and
usually resolves within 6 months. The HCM that you are
talking about, familial or genetically determined HCM, is
uncommonly seen in the newborn. It can happen. Usually,
it is more severe and more rapid in its course.
Q. What is "rapid"?
A. The progression of symptoms, the
need for medications or some surgical intervention
depends on the given child. Progression over 6 months to
two years is not uncommon if the child is
symptomatic or the diagnosis is made in the newborn
period or first few months of life.
Q. If a child is born with
Cardiomyopathy and receives a transplant, can the new
heart develop Cardiomyopathy as well?
A. Usually not. It depends on what
was the cause of the cardiomyopathy in the first place.
For genetic syndromes-gene determined hypertrophic
cardiomyopathy- there has not been a recurrence in the
transplanted heart. For idiopathic, I would say the same.
Idiopathic means we don't know the
cause. In the adult it is usually due to coronary artery
disease. This can certainly occur in the transplanted
heart. In the child, idiopathic dilated CM is usually due
to a post infectious (virus) cause and therefore is not
likely to recur. With unknown causes, it is hard to
predict the future of the transplanted heart. But in my
experience, I would think that recurrence would be very
unlikely.
Q. With idiopathic dilated
cardiomyopathy, what is the life expectancy? Does the age
of diagnosis matter?
A. That is hard to say. Again, it
depends on the cause and as you say, the age. Younger
children who present under a few years of age have a
shorter survival than older children and adults. There
are several medications now to treat heart failure, so
that longevity has been prolonged. Typically, infants and
young children presenting with heart failure do not
survive for many years without intervention.
Q. What kind of intervention?
A. First, medications. These
include digoxin, diuretics, afterload reducing agents
(blood pressure medications or vasodilators) and then
beta-blockers. An experimental protocol has shown some
promise with the use of human growth hormone. Then there
are surgical interventions. In older children and young
adults, there are Left Ventricular assist devices. Then
of course there is transplant.
CT Scans
Q. There was an article in the
paper about using CT scans to check for coronary artery
disease. Do you know of anyone who is using this in
conjunction with caths for pediatric heart transplant
patients?
A. At the present time, this is a
research tool in children. The calcium on the CT is
related to CAD (coronary artery disease) risk. If you
have significant atherosclerosis, you may have calcium in
the atherosclerotic lesion in the coronary arteries on
the CT scan and therefore, be at risk for a heart attack.
This is far from being a standard screening tool,
especially in children. More and more studies are coming
out in adults using this technique as a screening tool,
and a tool to predict the likelihood of having a major
event (heart attack) in the future. A good review of this
technique was just published in Clinical Cardiology
(September).
Q. Do you have any thoughts on
using this as another method to check for this disease in
children?
A. There are so many more simple,
less expensive, and useful tests. First, family history
is critical. Next, the lipid profile, blood pressure,
weight/height ratio (obesity), passive smoking or active
smoking. All of these are time tested and proven risk
factors. Since they aggregate in families at risk, it is
pretty easily to identify those who would benefit from
changes in diet, life style (exercise, smoking cessation,
no smoking in the home or around the kids) or need for
medications to control blood pressure or lower elevated
cholesterol levels. In the transplanted heart, while
atherosclerosis and its risk factors are important, other
factors play a more important role. These include
frequent and severe rejection episodes, and some viral
infections such as CMV. Other tests, besides coronary
angiography at the time of cardiac catheterization,
include dobutamine stress testing with echocardiography
and intravascular ultrasound (and echo of the inside of
the coronary artery) done in the cath lab.
Shones Complex
Q. Are HLHS and Shones Complex very
similar?
A. They are similar. They are both
forms of Left Ventricular obstruction. HLHS is usually a
tiny Left Ventricle with aortic stenosis or atresia, and
mitral stenosis or atresia. Shones complex involves
coarctation of the aorta plus, usually subaortic muscular
obstruction and mitral stenosis. The aortic valve may be
stenotic as well.
Q. So then a diagnosis of both
syndromes is possible?
A. I can visualize a patient with
coarctation of the aorta, in whom there is a smallish
Left Ventricle with mitral stenosis and subaortic
stenosis. Yes. The treatment for the severe Shone's is
likely a Norwood operation, just as it would be in HLHS.
ASD Closure Devices
Q. What is the "ideal"
candidate for an ASD closure via a device? At what age
should this be done? What are the advantages over
surgery?
A. First of all, these devices are
still experimental- thank the FDA. Second, the best ASD
for a device is a centrally located defect, with a good
rim of atrial tissue surrounding the defect that can hold
onto the device. A very large defect (I would say greater
than 2 cm) is probably too big for a device.
For more information, please see:
Atrial
Septal Defects: Surgical and Transcatheter Management
Preparing for catheterization
Q. For a teenager, what do you
think are the emotional aspects of a cath? Is it
different for girls and boys? How can parents and doctors
help them cope with them?
A. I guess the most important thing
is communication. The doctor should meet with the family
and the patient and explain, in as much detail as needed
(or wanted), all of the facts about the procedure. I
believe in "truth in advertising" and I tell it
like it is. I do not believe there is a difference by sex
in the preparation for caths.
We always show the kids the lab,
explain and show catheters, balloons, coils, whatever we
will be using to help assure the patient and the parents
that we will do the best for their child and make them as
comfortable as possible. The lab we have has a nice sound
system so we play the music of choice of the patient. The
little ones and babies we have asleep. Not general
anesthesia unless it is going to be a long intervention
or the infant/child is sick. The older ones will sleep
with "oral cocktail", a liquid
combination of morphine and a short acting barbiturate
that is taken by mouth, not an injection. This may be
helped with additional IV meds in the lab once the
catheters are in place. Some of the older children and
adolescents like watching the procedures on the screen.
Endocardial Fibroelastosis
Q. Can you tell me what endocardial
fibroelastosis means in a toddler?
A. EFE for short. It means that
there is scarring of the lining of the cardiac chamber,
usually the Left Ventricle or the Left Atrium. This can
be seen in severe left heart obstructions when the strain
on the heart has caused fibrosis (scarring) in the muscle
because of inadequate oxygen or blood supply.
Q. Can this scarring cause heart
failure?
A. Usually it is a secondary
finding due to the left heart obstruction that was the
cause of the heart failure. True EFE was an entity in the
60's and 70's as a primary disease of newborns that was
almost uniformly fatal. The lining of the Left Ventricle
looked like marble- white, and shiny with very poor heart
function. The EFE we see today is usually seen in
individuals (usually babies) with critical degrees of
aortic stenosis or severe mitral valve disease.
Q. What is the current
treatment?
A. The treatment is the therapy for
the underlying heart defect. Usually surgery, medications
to treat the heart failure- digoxin, diuretics and
afterload reducing agents (ace inhibitors) are helpful
too. There is no surgical therapy for EFE, and surgery is
directed at the underlying heart defects.
Pulmonary Valve
Q. Is a pulmonary valve necessary
for a child to have normal activities or can he go
without it?
A. It is not necessary but it
helps. What I mean is that at rest the heart does pretty
well but with exercise, when a lot more blood needs to go
forward, when there is no valve, the blood will
regurgitate back. I would expect a lower exercise
tolerance than normal. Further, the Right Ventricle may
dilate over time and this may result in tricuspid
regurgitation and the Right Ventricle getting
"sick". At that point or before, the pulmonary
valve should be replaced (usually a pulmonary homograft)
to allow the RV to function normally.
This article was reviewed prior to publication by:
Richard Donner, M.D.
Adult Congenital Heart Program
The Children's Hospital of Philadelphia
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