Blood Transfusions During
Heart Surgery Appear to Increase Death Risk, Study Shows
(July 29, 2004 - PRNewswire)
Patients who received blood
platelet transfusions during coronary bypass surgery were more likely to
have prolonged hospital stays, longer surgeries, more bleeding and higher
risk of infection, stroke and death, according to an international study led
by the Virginia Commonwealth University Medical Center.
The findings, published in the August issue of Transfusion, the official
journal of the American Association of Blood Banks, contribute to
increasingly scientific evidence that blood transfusions do not always
improve outcomes from surgery.
"Although this analysis cannot prove that platelet infusions caused the
increases in adverse events examined, the data are sobering and should be
taken into account when determining the risk-benefit ratio of platelet
transfusion therapy," says Dr. Bruce D. Spiess, professor of anesthesiology
and lead author on the article. "Prophylactic platelet transfusion appears
from this study to increase the risk for serious adverse outcomes in
coronary artery bypass graft patients."
The study examined data collected during six randomized, double-blinded
Phase III clinical trials conducted from January 1990 through May 1995 at 37
medical centers in the United States, Denmark and Israel for licensure by
the Food and Drug Administration of aprotinin, a drug sold by Bayer Corp.
under the trade name Trasylol to control bleeding during surgery and avoid
the need for transfusions. Data from patients in a pilot study also were
included.
Of the 1,720 adult patients analyzed, 284 patients (14.4 percent of the
total) received blood platelet transfusions during coronary artery bypass
graft surgery, which is a common procedure used to improve blood flow and
alleviate chest pains. In coronary artery surgery, doctors remove a clear
vein or artery from a leg, arm or the chest and use it to detour blood flow
around a blocked artery. Because about 20 percent of coronary bypass
patients suffer abnormal bleeding, blood platelets often are given after
surgery to prevent or treat bleeding.
The retrospective analysis showed that death was greater than five times
more likely to occur in patients receiving platelet transfusions, and stroke
was at least three times more likely to occur compared with patients who did
not receive transfusions. In addition:
* The operation was almost one hour longer for patients receiving a platelet
transfusion than for those not receiving one.
* Almost 20 percent of patients who received platelet transfusions returned
to surgery for re-exploration compared with a 2 percent re-operation rate
for those who did not receive platelets.
* The amount of bleeding and length of time in the hospital were greater in
the group who received transfusions.
"Blood transfusions may do more harm than good in virtually every instance
except trauma," says Spiess. "Blood transfusions increase the risk of
pneumonia, infections, heart attacks and strokes. Patients who don't have
transfusions often do better."
Platelets are blood cells that strengthen blood vessel walls, help blood to
clot and help stop bleeding from cuts. Since the early 1980s, concentrates
of platelets increasingly have been used in transfusions, surpassing use of
such other blood products as red blood cells and whole blood.
At the same time, however, questions have been raised about the risks of
transmission of infectious diseases by blood platelet transfusions. Platelet
products also contain a high concentration of donor white blood cells, which
can suppress the immune system and increase the risk of infections. A
European study of 3,500 patients in intensive care units published in 2002
found that the death rate for critically ill patients who received
transfusions was twice as high as those who did not get blood.
As a result of these concerns and the high cost of blood platelets,
scientists have been working to develop alternatives to blood platelet
transfusion, such as drugs to control bleeding and mechanical devices that
can collect a patient's own whole blood during surgery for transfusion, if
necessary. Some patients also store several units of their own blood before
surgery.
Spiess says he is working with his colleagues to reduce the use of
transfusions during surgeries at the VCU Medical Center by 30 percent or
more.
In addition to Spiess, researchers from Harvard Medical School, Emory
University, the University of Oklahoma, Harefield Hospital in London, Munich
Heart Institute in Germany and the University of Western Ontario, as well as
Bayer Corp., participated in the analysis.
EDITOR'S NOTE: A copy of the
platelet transfusion study is available in PDF format via e-mail or by fax.
For information, please call University News Services at (804) 828-1231.