E. Lock is Chairman of the Department of Cardiology
at Children's Hospital and Professor of Pediatrics
at Harvard Medical School. Lock attended medical
school at Stanford University and pursued his
pediatric residency and cardiology fellowship
at the University of Minnesota. He then trained
in cardiovascular physiology at the University
of Toronto, Hospital for Sick Children. In 1980,
Lock returned to Minnesota, where his research
focused on experimental interventional cardiology.
Most recently, he has pioneered nearly a dozen
new procedures. In September of 1999, a device
invented by Lock became the first septal occlussion
device approved for use inside the human body
in the United States.
his research career, Lock has trained numerous
academic physicians in cardiopulmonary physiology,
and his innovations in experimental cardiology
are internationally recognized. He has been elected
to the Society for Pediatric Research and serves
on the editorial boards of the professional journals
Circulation, the American Journal of Cardiology
links to this scientist's home page and other related
infomation please see our resources
Ankit Vachher asked:
If the fenestration saved Zach's life in the first
place, then why is it necessary that the hole
has to be closed? What could happen to Zach or
Josh if the hole isn't closed?
after open-heart surgery, our open-heart procedure
produces a small but reversible amount of damage
to the lungs and other organs. During the 3 to
10 days following open heart surgery, that damage
makes it much harder for the circulation to get
blood through the lungs and without a fenestration
the patients can die from a low cardiac output
state. However, in Zach's case that situation
would have been made much worse by his viral infection.
Once however, he recovers from the effect of open-heart
surgery and recovers also from his viral infection,
he now has a much better ability to pump all of
the blood through his lungs. By closing the hole
it forces all of the (deoxygenated, used-up) blue
blood through his lungs and allows the rest of
his body to be pink (fully oxygenated). If the
hole isn't closed he remains with mild to moderate
cyanosis for the rest of his life, and over the
course of 10 to 20 years that blueness will produce
damage to organs such as his heart and brain.
Mike Duncan asked:
How long will a stent last? Are they subject to
clogging? Can they be cleared?
stents like this in the pulmonary arteries seem
to last a very long time. We put the first stent
into a pulmonary artery exactly 23 years ago and
that stent is still open without evidence of clogging.
Clogging stents are usually seen in adults with
coronary artery disease but almost never seen
in the pulmonary arteries of children with congenital
heart disease. Thus, we would expect it to last
What is the success rate and the complications
that have shown up to this point? Is it approved
for just planned fenestrations or can it be used
for other holes in the heart? Will there be an
increase in the amount of blood thinners? Is the
plug permanent or will it need to be replaced?
What is the patch made of?
success rate depends on what we use it for. In
closing fenestrations, the success is higher than
99% and there have been essentially no complications.
In closing atrial septal defects, the newest devices
have a success rate of higher than 98%. Occasionally
we will see rare complications such as devices
that were not positioned in the right location
and falling out of the hole or transient periods
of a fast heart rate or clots forming on the device.
None of those complications have been fatal or
produced a serious problem in any of more than
500 patients. For ventricular septal defects,
a much more complicated form of disease, the success
rate is between 90-95%. The complication rate
is much higher but again it is not serious and
it includes thing such as blood loss, arrhythmias
or low blood pressure occurring during the procedure
itself. All three of these complications are obviously
much worse than what one might expect for open-heart
surgery. The patient population with the worst
results are adults who have had heart attacks
and part of their heart muscle has died in between
the two pumping chambers of the heart, producing
an acute hole in the heart. The overall mortality
for this event in adults is somewhere between
30-50% regardless of the form of therapy and we
have really done only about 40 of those patients
with improvements in survival but ongoing difficulties.
Cindy-Jean Dennis asked:
I have read a lot about you and think you do such
amazing work! Dr. Lang is my son's cardiologist
(at Children's Hospital) and Dr. Jonas is his
surgeon. I read about some type of equipment that
Dr. Jonas was working on. It measures the amount
of oxygen to the brain during heart/lung machine
surgeries. Is this approved or being used regularly
yet? If not, is there an expected date?
Jonas's research on oxygen supplied to the brain
continues to work. Some of the devices he used
were approved and are currently being used, and
some of them are not yet approved and when they
become available is a little bit unclear. However,
Dr. Jonas and his colleagues are clearly at the
very front of the field of protecting patients'
brains during open heart surgery and remain committed
to this most important aspect of managing patients.
Do these children require anticoagulant therapy
following this procedure?
do not require formal anti-coagulation following
this procedure. We usually put them on a single
aspirin a day for six months and then stop altogether.
In over 1,000 cases we have not had a significant
clotting complication due to any of the devices
Clarice Parenti asked:
Why can my 5-year-old granddaughter withstand
cold temperatures? While others in the house have
multiple layers of clothing on & still feel cold,
"Shana" has only a pair of pants on, feels cold
to the touch, but will not keep any other clothes
on. She had the Fontan in July 2000, just days
before her 5th birthday; takes Lasix, Aldactone
& aspirin daily; has a lot of energy & her color
is excellent; she sleeps about 6 hours per night
She had her 1st operation at 4 days old, the 2nd
at 4 months. Is this a normal condition after
the Fontan? Thank you for your time.
with the Fontan procedure ordinarily have a reasonably
normal circulation. I must tell you that if your
granddaughter feels that cold temperatures are
of no problem to her following the Fontan procedure,
it is not something due to the Fontan but her
own body metabolism. I am delighted to hear how
well she is doing.
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