Transfusions of 'Older' Blood Don't Work as Well
Mortality, complication rates higher than with freshly stored units, study finds
WEDNESDAY, March 19, 2008 (HealthDay News) -- Heart-surgery patients who get transfusions of blood that has been stored for more than 14 days do worse than those who get newer blood, a new study shows.
In-hospital death rates, incidence of complications and long-term death rates were higher for those getting older blood, conclude physicians at the Cleveland Clinic.
While other studies have shown the same effect, "we're not necessarily advocating a policy change at this time," said Dr. Colleen Gorman Koch, vice chairman of education and research at the clinic's department of cardiothoracic anesthesia.
But Koch said she and her colleagues are conducting a controlled trial that could lead to a change in the current policy of the U.S. Food and Drug Administration, which says that blood can be stored for as long as 42 days before transfusion.
The trial, which will closely track the condition of heart-surgery patients who get transfusions, will include 2,000 participants, Koch said. Fewer than 100 have been enrolled so far, and results are not expected for at least two years, she said.
The newly reported study, published in the March 20 issue of the New England Journal of Medicine, examined almost 2,900 people who underwent coronary artery bypass procedures or heart valve operations and who got blood that had been stored for 14 days or less. They were compared with more than 3,100 people undergoing those procedures who got blood that had been stored for at least 14 days.
The study found that 2.8 percent of those getting older blood died in the hospital, compared to 1.7 percent of those getting fresher blood. The incidence of infection among the older-blood group was 4.0 percent, compared to 2.8 percent in the fresh-blood group. And in the year following the transfusions, 11.0 percent of those getting older blood died, compared to 7.4 percent of those getting newer blood.
"It's nice to know that other people are coming around to the same conclusion as we did," said Dr. Sunil Rao, assistant professor of medicine at Duke University Medical Center's Division of Cardiology, who worked with Dr. Jonathan Stamler at Duke on a series of studies showing adverse effects of older blood.
"The biggest impact of a paper like this is that it is really a call to arms, coming from a well-established institute with some of the best cardiac surgery in the world," Rao said.
The Duke studies have shown that "blood undergoes changes profoundly, even in the first 24 hours," Rao said. The major effect is loss of nitric oxide, "which is really fundamental to the process of oxygen exchange," he said.
The Duke researchers are trying to get funding for a study in which nitric oxide would be added to transfused blood, to see whether that offers benefits over the long run, he said. "It needs to be tested in studies long enough to improve survival and outcome," Rao said.
While the various studies are considered and conducted, practical steps can be taken to reduce the need for transfusions, Koch said. Patients should be tested before surgery to determine if their hematocrit -- a measure of possible anemia -- is low enough to cause worry. "If there is anemia, you should find the source of it and treat it," she said.
The Cleveland Clinic is also using medication that decreases bleeding, and even gathers red cells that are washed and restored to the patient's body, she said.
To learn more about transfusions and blood donations, visit the U.S. National Library of Medicine.