Heart Surgery Patients Transfused With Older Blood Face Greater Risks

A Cleveland Clinic study is reporting that heart surgery patients who receive transfusions with blood that has been stored more than 14 days are likelier to suffer complications and may face reduced short and long-term survival.

"As many as half of all heart surgery patients receive blood transfusions" said the study's Lead Author Colleen Gorman Koch, M.D., M.S., Vice Chair of Research and Education in Cleveland Clinic's Department of Cardiothoracic Anesthesiology. "How frequently transfusions take place and at what point varies among physicians. This study reiterates the need for patients to understand their surgeon's philosophy on giving blood transfusions."

More than 14 million units of blood are transfused in the United State annually and the median duration of blood storage is 15 days. Regulations set forth by the Food and Drug Administration allow for blood to be stored up to 42 days before it must be discarded.

Prior research has shown that the risk of complications, even death, in heart surgery patients increases with blood transfusions.

In their work, Cleveland Clinic researchers examined the data on 6,002 patients who received blood transfusions while undergoing bypass grafting and/or heart-valve surgery between June 30, 1998 and January 30, 2006. Of the patients, 2,872 received 8,802 units of blood that had been stored 14 days or less, whereas 3,130 patients received 10,782 units of blood that had been stored for more than 14 days.

The study's results show that patients who received older blood had higher rates of in-hospital death (2.8% vs. 1.7%, P=0.004), prolonged intubation (9.7% vs. 5.6%, P<0.001), kidney failure (2.7% vs. 1.6%, P=0.003) and sepsis (4.0% vs. 2.8%, P=0.01). Likewise, multiple complications were more common in patients transfused with older blood (25.9% vs. 22.4%, P=0.001). At one-year, death was significantly less in patients given newer blood (7.4% vs. 11%, P<0.001), study results show.

"Our findings suggest a need for more studies to examine blood inventory management practices and the structural and functional changes that take place when blood is stored for increased duration periods," Dr. Koch said.

Researchers at Cleveland Clinic have launched a randomized trial to further examine the relationship between blood storage duration and transfusion. Results should be available within the next two years.