The AbioCor Artificial Heart - keeping expectations in check
by DrRich
Dateline: 04/23/01
Sometime between now and June 30, a patient dying of heart
failure somewhere in the U.S. will receive the first self-contained, implantable
artificial heart. The new
artificial heart, the AbioCor, is manufactured by Abiomed, Inc., based in
Danvers, MA. The company has now
received permission from the U.S. Food and Drug Administration to proceed with
human investigation of the AbioCor. (The first use of the AbioCor will not
be preannounced, nor will it be revealed that the device has been implanted
until at least 30 days has passed after the event.)
While artificial hearts have been implanted in humans
before, previous artificial hearts were primitive compared to the AbioCor.
The older mechanical hearts required the patient to be attached to a
large console (via tubes and electrical power lines extending through the
patient's skin,) and essentially required that the patient be bedridden.
The “best case” for using these previous artificial hearts was as a
means of keeping patients alive until a heart transplant was available.
With the AbioCor, on the other hand, the ultimate goal is
to develop a more-or-less permanent replacement for the heart.
The device is completely self-contained within the body, and there are no
tubes or lines protruding through the skin.
Patients will not be tied to a console, and should be able to carry out
routine ambulatory functions. Power
is supplied to AbioCor by an external battery pack worn on the belt.
A coil attached to the battery pack sends power through the skin to an
implanted coil, which then transmits the energy to the AbioCor. (The AbioCor also contains an internal, continually charging
short-term battery, that can keep the device pumping for up to 30 minutes
without the external battery pack.) Similar
to a pacemaker, the AbioCor contains an activity sensor that can tell when the
patient is active, and can automatically increase the rate of pumping during
exertion.
The AbioCor weighs about 3 pounds, and the external battery
pack weighs 4 pounds.
Abiomed and the FDA have modest goals for the first human
implantations of the AbioCor. The
FDA has given permission for only 5 implantations.
The first recipients will be carefully chosen. They must be older than 18, and must have such severe heart
failure that, despite maximum medial treatment, they are expected to die within
30 days. They must be ineligible
for heart transplantation, and except for the heart, all other vital organs must
be functioning appropriately. They can have no significant infections or
neurological disorders.
An assessment of each patient receiving the AbioCor will be submitted to the FDA 60 days after implantation (approximately twice the expected survival without the device). If the preliminary results for the first 5 patients appear favorable, Abiomed will be able to expand the trial to 15 patients.
Five medical centers have been approved for use of the
AbioCor under this clinical trial: Brigham & Women's and Massachusetts
General in Boston, Hahnemann University Hospital in Philadelphia, the Jewish
Hospital in Louisville, KY, the Texas Heart Institute in Houston, and the UCLA
Medical Center in Los Angeles.
Why expectations should be kept in
check
The results of this first clinical trial with the AbioCor
are not destined to be earth-shattering. Patients
receiving this device will be extremely sick, and it is likely that one or more
will not even survive the implantation surgery.
“Success” in this trial will be defined as survival for 60 days with
a reasonable quality of life – hardly a goal to write home about.
And it is almost a sure thing – as the CEO of Abiomed pointed out in a
recent press conference – that every patient enrolled in this trial will die
with the AbioCor.
Why, despite this, the AbioCor is a landmark
The AbioCor is a marvel of technology and design compared
to older artificial hearts, and the promise it represents is astounding.
While many problems (both foreseen and unforeseen) will need to be worked
out, for the first time the holy grail for heart disease appears feasible.
For the first time a self-contained, implantable, artificial heart will
be keeping a person alive and functional – a person who would otherwise be
dead.
What do you think? Enter the Heart Disease Forum:
