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Study Affirms Heart Pump As Permanent Implant
ARLINGTON, Va., May 17, 2002 – A new study shows that an implantable
heart pump could provide permanent assistance to heart failure patients while
substantially improving their quality of life.
The study, appearing in the journal
Circulation,
is one
of the longest follow-up studies on an implantable left ventricle assist
device (LVAD), and it adds to the growing body of evidence supporting LVADs
as permanent implants.
Although LVADs have been in development for decades, they have
been targeted primarily as a bridge to a heart transplant and not meant as
a permanent therapy for congestive heart failure.
In the study, a team of British and American researchers followed
four British patients for up to 20 months after they received an LVAD called
the Jarvik 2000.
The Jarvik 2000 consists of a continuous rotary pump about the
size of a “C” battery implanted inside the heart’s left
ventricle, the heart’s
main pumping chamber. A synthetic tube allows the pump to deliver oxygen-rich
blood via the aorta throughout the body. Power comes from rechargeable
batteries,
worn at the waist or carried in a small shoulder bag, and connects to an
implanted cable through a small port just behind the ear.
All the patients were considered ineligible for heart transplants
due to their age and poor kidney function, and all were in class IV heart
failure, in which the heart
can’t pump enough blood to meet the body’s needs. Such patients
experience
severe shortness of breath and frequent chest pain. They quickly tire and
have great difficulty performing simple activities.
Three of the patients went home three to eight weeks after receiving
the pump and returned to normal activities. There were no infections or blood
clots reported in or near the device. One of the four British patients who
was too sick to walk across the surgeon’s office before getting the
heart-assist
device nearly two years ago now routinely walks 5 miles a day and has completed
a long-distance charity walk.
After receiving the pump, three patients could perform moderate
to heavy exertion before experiencing chest pain or breathlessness. One
patient developed a brain hemorrhage under the electrical port, which is
mounted in the skull. Although the hemorrhage was successfully treated, he
suffered right heart failure and died about three months later. Surgeons
subsequently modified their technique to prevent such complications.
The fluid retention caused by a failing heart disappeared in all
three patients, the researchers wrote. In fact, after three months, patients
were able to stop taking diuretics, the drugs commonly given to heart-failure
patients to help rid the body of excess fluid. Also during the first three
months, echocardiography showed improvement in the patients' left and right
ventricle function.
"This small, simple, safe pump can be implanted with little or
no time on a heart-lung machine. It poses very little risk and can boost
the patient's native heart function," says author O.H. "Bud" Frazier, M.D.,
chief of cardiopulmonary transplantation and director of surgical research
at the Texas Heart Institute in Houston.
The current study indicates that a patient's own heart function
improves after time on the pump. "In most of these patients, all their hearts
need is a boost," Frazier says. "That's what the pump does. With the Jarvik
2000 taking over part of the work, the heart thinks it's normal again. There
has to be a synergy. It is not designed to totally take over or replace left
ventricular function."
The American Heart Association estimates that between 60,000 to
70,000 of the nation’s 4.8 million congestive heart failure patients are
class IV, but only about 2,000 hearts are available for transplant each year.
The researchers estimate that half of all class IV patients, or some 30,000
patients, could benefit from the Jarvik 2000 and other left ventricular assist
devices, such as the
Arrow LionHeart™
and the
HeartMateŽ
. The U.S. Food and Drug Administration has approved all three devices only as
a bridge to transplant.
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