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It may be useful to make a distinction between the above
two categories,even if there is in practice considerable
overlap, especially as techniques advance.
A prosthesis ("fabricated substitute for a diseased
or missing part of the body", according to one dictionary)
we may conveniently use as a term for a substitute part
which is usable in a more or less normal lifestyle.
"Artificial organs" we may regard as a more general
term to include also life-saving devices such as the "iron
lung" and heart-lung machine, which up to now, due
to their unweildy nature, have been used primarily in hospitals
or other static situations.
"Simple" mechanical prostheses (artificial limbs,
teeth) have a long history. Though involving considerably
more practical difficulties, we might also include in this
category more recent developments such as implanted bone-reinforcements
and hip-joint replacements.
Still in the "future-music" category for today's
patient, but definitely practical, are "bionic"
limbs with control and sensory links with the body's nervous
system. Similar, if more ambitious, developments appear
possible with respect to the eye.
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- Periodic announcements to replace
individual patient reports - ABIOMED, Inc. (NASDAQ: ABMD)
today provided an update on the status of patient enrollment
in the AbioCor® Implantable Replacement Heart clinical trial.
As of this date, a total of 10 patients have been enrolled
in the AbioCor initial clinical trial. Three patients are
currently on AbioCor support. These include previously- announced
patients (the eighth and ninth enrollees) implanted on January
7, 2003 and January 22, 2003 respectively at Jewish Hospital
in Louisville, KY, and a tenth enrollee, announced today for
the first time, implanted by Dr. Bud Frazier of the Texas
Heart Institute at St. Luke's Episcopal Hospital in Houston,
TX on February 24, 2003. No further information will be made
available by ABIOMED at this time. The patients and their
families have requested that their confidentiality be maintained,
including names, personal information, and any reports of
their medical condition. "We are very pleased with the rate
of enrollment in the AbioCor clinical trial since the beginning
of the calendar year," said Dr. Robert T. V. Kung, ABIOMED's
Chief Scientific Officer. "We believe we have recaptured the
momentum lost in 2002, and are working diligently to maintain
that momentum. We are excited to be moving forward into the
final third of the 15 implants authorized by the FDA for the
clinical trial of the first generation AbioCor implantable
heart." "Going forward," said Dr. Edward E. Berger, Vice President
for Strategic Planning and Policy, "ABIOMED will be providing
only monthly updates on the status of the clinical trial in
order to keep our investors and the public informed of our
progress. These updates will include any significant events
that have occurred within the month. It is our goal to eliminate
special announcement of individual implants and or patient-specific
events - either positive or negative - as they occur. We believe
that the trial has advanced to a point where monthly updates
should be sufficient to keep all interested parties adequately
informed of material developments. Furthermore, elimination
of the expectation of company announcements on individual
patients will be beneficial to the processes of care within
the trial, the patients and their families, and the overall
management of the trial." ABIOMED will next update the progress
of the AbioCor trial in a presentation at the Banc of America
Securities Healthcare Conference on March 25, 2003 in Las
Vegas, Nevada. Information about how investors will be informed
about the content of this presentation will be made available
prior to the event. Based in Danvers, Massachusetts, ABIOMED,
Inc. (pronounced "AB'-EE-O-MED") is a leading developer, manufacturer
and marketer of medical products designed to assist or replace
the pumping function of the failing heart. The Company's AbioCor
Implantable Replacement Heart is the subject of an initial
clinical trial conducted under an Investigational Device Exemption
from the United States Food and Drug Administration. The AbioCor
has not been approved for commercial distribution, and is
not available for use or sale outside of the initial clinical
trial. ABIOMED currently manufactures and sells the BVS®,
a heart assist device for the temporary support of all patients
with failing but potentially recoverable hearts.
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Department of Surgery, Division
of Thoracic and Cardiovascular Surgery, University of Louisville
School of Medicine, Louisville, Kentucky, USA
The AbioCor implantable replacement
heart (IRH) is the first available totally implantable artificial
heart. We recently initiated a multicenter trial of this
device in patients with severe, irreversible biventricular
failure. Patients who were not candidates for other therapies,
including transplantation, were evaluated. All candidates
were adults with inotrope-dependent biventricular failure,
whose 30-day predicted mortality was higher than 70%. A
three-dimensional computerized fit study predicted fit of
the AbioCor thoracic unit in all recipients. At operation,
the internal battery controller and transcutaneous energy
transfer unit were placed. The AbioCor thoracic unit was
placed in an orthotopic position after incision of the ventricals.
There were 2 intraoperative deaths (due to intraoperative
bleeding or aprotinin reaction). Four late deaths were recorded,
1 from multisystem organ failure and 3 cerebrovascular accidents.
Autopsy revealed thrombus on the atrial struts of the 3
patients with cerebrovascular accident. Blood pumps and
valves were clean on all patients. Significant morbidity
was observed, primarily related to preexisting severity
of illness. However, 3 patients recovered to the point of
being able to take multiple trips outside of the hospital.
Two patients were discharged from the hospital, with 1 patient
being discharged home for more than 7 months. No significant
device malfunctions or multi-system organ failure device-related
infections were noted. The AbioCor IRH may be effective
therapy for patients with end-stage heart failure. Many
milestones have been achieved in the initial trial in humans,
including the successful discharge of a patient to home
and no significant device malfunctions. The occurrence of
stroke is likely related to the presence of thrombus on
the atrial struts and may be decreased as these atrial struts
have been removed for future clinical implants.
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Cardiovascular Surgical Research Laboratories,
Texas Heart Institute at St. Luke's Episcopal Hospital, Houston,
Texas 77030, USA
Feasibility studies are underway
for new axial flow ventricular assist systems and with a
total artificial heart (TAH). The axial flow pumps provide
continuous flow from the left ventricle (LV) to the aorta;
the TAH provides pulsatile flow to the pulmonary and systemic
circulation. Understanding the differences between these
systems is necessary for appropriate patient selection and
management. We compared the Jarvik 2000 axial-flow pump
and the AbioCor TAH. The Jarvik 2000 pump is placed in the
LV with its outflow graft anastomosed to the aorta. This
system is used for bridge-to-transplantation and destination
therapy. The AbioCor TAH provides complete circulatory support.
The AbioCor is used for destination therapy in patients
expected to die in less than 30 days. Worldwide, 45 patients
have received the Jarvik 2000 as a bridge to transplantation
(n = 34) or destination therapy (n = 11) for an average
duration of support of 132.8 days (5 to 853 days). In 30
bridge-to-transplantation cases, 14 patients (47%) have
undergone heart transplantation, 5 (17%) continue to be
supported with the Jarvik 2000 device, and 11 (37%) have
died. Five of 7 patients supported by the AbioCor TAH survived
beyond the perioperative period; 4 were ambulatory, 2 were
discharged from the hospital, and 1 is at home 13 months
after implantation. Anticoagulation therapy and infection
management are necessary for both systems. Therapy with
inotropic agents, vasoactive drugs, a pacemaker, and electrolyte
normalization is necessary for Jarvik patients. AbioCor-supported
patients do not require medications to support heart function.
Vasoactive agents may be useful for controlling blood pressure.
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Hahnemann University Hospital,
Broad & Vine Streets, Philadelphia, PA 19102-1192, USA
The AbioCor is a revolutionary device.
It is the only device of its kind in the clinical world.
The role of the AbioCor is to provide permanent replacement
of the failing heart for patients who are not transplant
candidates. The clinical trial has been successful in the
majority (four of seven) of patients implanted thus far.
Eight more patients are required to complete the initial
feasibility phase of the trial, afterwhich it remains to
be seen if the trial will expand to additional patient populations.
The powerful features of the pump have been demonstrated
in the extremely sick group of candidates that enrolled
in the study. The TET system has worked extremely well.
Lastly, the milestone of discharging a patient to home on
a completely internal artificial heart has been realized.
The profile of CardioWest is very different from AbioCor.
Although both were initially designed as permanent replacement
therapies, the CardioWest has been extremely useful as a
bridging device, and it may have a broader application in
the future. For the CardioWest, the most favorable groups
are patients with cardiomyopathy who decompensate while
awaiting transplantation. On the other hand, the AbioCor
is indicated in nontransplant candidates with biventricular
failure who have a less than 30-day predicted survival.
Proper patient selection is critical to achieving success
with either device.
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