Postop Complications, Mortality Climb With Longer Storage of Blood for Transfusion

Steve Stiles

March 20, 2008

March 20, 2008 (Cleveland, OH) - Patients transfused with red cells that have been stored longer than 14 days are likely to have worse outcomes than those who receive fresher red cells, at least when the transfusions are given in the setting of cardiac surgery, suggests a large single-center experience described in the March 20, 2008 issue of the New England Journal of Medicine [1].

The study, in which the risks of major postoperative complications and short- and long-term mortality in about 6000 patients were significantly increased when the older blood was given, adds to a mixed body of evidence regarding storage-time-related risks of transfused blood, observe the authors, led by Dr Colleen Gorman Koch (Cleveland Clinic, OH).

As Koch observed for heartwire , the commonly used "first in, first out" strategy for inventory management at blood banks is intended to cut down on the amount of blood wasted; regulations allow red cells to be stored for up to 42 days, after which they must be discarded. A downside, she said, is that it also promotes the use of older units and therefore might increase postoperative morbidity.

The current findings, according to Koch, suggest a need to reevaluate blood-inventory management strategies, perhaps adopting ones that accept a certain degree of waste but promote the use of fresher blood. The cost of wasted blood should be compared with the cost, both financial and in terms of patient suffering, of reliance on older blood for transfusions, she said, "but no one's really done a cost/benefit analysis."

In an accompanying editorial [2], Dr John W Adamson (University of California, San Diego) observes that the 42-day storage time "gives blood centers the flexibility to manage the blood supply through seasonal swings and sudden demands . . . and to collect and ship blood products from one part of the country to another." Although the current study suggests that older red-cell units should be avoided, he notes, it doesn't address some major blood-inventory management issues, such as the coordination of supply and demand for different blood types and the limits of donor recruitment. "It is just not feasible to shorten storage time significantly without restricting the blood supply."

The analysis included patients undergoing CABG, valvular surgery, or both in the same session over seven and a half years at a major center who were transfused with units of red cells that had been stored for either <14 days or >14 days. Importantly for the strength of the analysis, according to the group, patients who received both older and newer red-cell units were excluded.

Postoperative Outcomes by Duration of Red-Cell Storage
End Point Storage <14 d, n=2872 (%) Storage >14 d, n=3130 (%) p
Inhospital
Composite* 22.4 25.9 0.001
Mortality 1.7 2.8 0.004
Ventilatory support >72 h 5.6 9.7 <0.001
Renal failure 1.6 2.7 0.003
Septicemia or sepsis 2.8 4.0 0.01
1 y
Mortality 7.4 11.0 <0.001
*Serious adverse events such as death, MI, stroke, and sepsis as described in the article.

Those who received blood stored >14 days showed a significantly increased rate in the primary end point, a prospectively defined composite of serious complications including inhospital death, MI, cardiac arrest, stroke, pulmonary embolism, renal failure, respiratory failure, sepsis, other infections, and prolonged postoperative ventilation. Rates for some of the individual events and for the secondary end point of one-year mortality were significantly increased as well.

Noting that the literature is conflicted about the nature and degree of any risks associated with blood-storage time, Dr John R Hess (University of Maryland Medical Center, Baltimore), who is assistant director of his center's blood bank and a pathologist with a background in epidemiology but not associated with the current study, told heartwire that it is, at least, one of many indications that blood transfusions "should not be given cavalierly."

However, he expressed doubts that the analysis shows what the group claims it shows. It appears to be "deeply confounded" by a retrospective design, Hess said, as well as suggestions that risks rose with blood-storage time because the recipients of older blood were at higher risk to begin with. Those patients, he said, appear to have received more units of blood, and it is known that the number of units patients receive is a function of how sick they are. The analysis, he said, after examining the report from Koch et al, doesn't appear to control for those issues.

Koch et al write, however, that the homogeneity of their population and their use of propensity scoring in a multivariate analysis, one that accounted for the number of red-cell units received per patient, "strengthened the finding of an association between increased duration of storage and adverse outcomes."

  1. Koch CG, Li L, Sessler DI, et al. Duration of red-cell storage and complications after cardiac surgery. N Engl J Med 2008; 358:1229-1239.

  2. Adamson JW. New blood, old blood, or no blood? N Engl J Med 2008; 358:1295-1296.

The complete contents of Heartwire
, a professional news service of WebMD, can be found at www.theheart.org
, a Web site for cardiovascular healthcare professionals.

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