Study: Older blood poses risk

ATLANTA (AP) — Heart surgery patients were more likely to die or suffer problems if they received transfusions of blood that is more than two weeks old rather than fresher blood, according to a new study that adds to the debate about the shelf life of blood.

Although not the final word, the study underscores concerns that blood deteriorates with age and that rules allowing blood to be stored for six weeks may pose a safety risk, at least for certain patients.

The report was limited to heart surgery patients.

The Food and Drug Administration’s six-week rule allows blood centers to endure shortages in donations and to maintain supplies of rare blood types.

The study’s lead author, Dr. Colleen Gorman Koch of the Cleveland Clinic, said a more rigorous study is already under way that could carry the scientific weight to persuade the FDA to reconsider its policy.

It’s not clear exactly why blood stored for longer periods is riskier. Some researchers say stored blood becomes depleted of oxygen-carrying chemicals. Red blood cells also become more rigid in storage, impeding their flow through the body.

Researchers examined the records of 6,000 patients who were given blood transfusions during heart-bypass or heart-valve surgery. All of the patients were treated at the Cleveland Clinic from June 30, 1998, through Jan. 30, 2006.

A little less than half of the patients received blood that had been stored for 14 days or less, and a little more than half got blood that was older. The study found that the one-year survival rate was 89 percent for those who got older blood, but nearly 93 percent for patients who got fresher blood.

Complication rates were higher in the older blood group,