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Old Blood and Cardiac Surgery Risk

A study of transfusions during cardiac surgery raises troubling questions.

Evidence is emerging that blood that has been stored for longer periods may confer a higher risk for complications after transfusion than blood that has been obtained more recently. The mechanisms of such complications are not clear but may relate to cell damage, accumulation of proinflammatory substances, and nitric oxide depletion, among other possibilities. In a large observational study, investigators at the Cleveland Clinic compared 2872 cardiac-surgery patients who received blood within 2 weeks of donation with 3130 cardiac-surgery patients who received blood more than 2 weeks after donation.

Patients given older blood had a higher risk for in-hospital death than did those given newer blood (2.8% vs. 1.7%, P=0.004). They were also significantly more likely to need prolonged ventilatory support and to have renal failure, sepsis, or multisystem organ failure. A dose response was found between days of storage and probability of a composite outcome of serious adverse events. In an adjusted analysis, recipients of older blood had a significantly higher risk for the composite outcome than did newer-blood recipients (adjusted odds ratio, 1.16). Survival to 1 year was more common in newer-blood recipients than in older-blood recipients (92.6% vs. 89.0%, P<0.001).

Comment: This report raises important concerns about the use of blood that has been stored longer than 2 weeks for transfusion during cardiac surgery. A high proportion of patients at the Cleveland Clinic who received blood older than 2 weeks were at elevated risk for adverse outcomes, a finding which is likely to be true throughout the U.S. With a blood supply in constant demand, finding a solution to this problem will not be easy. For now, it seems reasonable to try to ensure that patients needing transfusions who are at the highest risk for adverse events receive blood that is as fresh as possible.

— Harlan M. Krumholz, MD, SM

Published in Journal Watch Cardiology March 19, 2008

Citation(s):

Koch CG et al. Duration of red-cell storage and complications after cardiac surgery. N Engl J Med 2008 Mar 20; 358:1229.

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