Stored Blood for Transfusion Is Practical After Heart Surgery

Patients often need transfusions of red blood cells to replace the blood they have lost during major surgeries, however, the question of whether stored blood is safe for heart surgery patients has had mixed answers.

Red blood cells (RBCs) or erythrocytes that transport oxygen throughout the body go through several changes while in storage, potentially decreasing their oxygen-carrying ability and until now, it has not been clear as to whether such changes affect patient outcome after receiving transfusions.

Clinical scientists at the Karolinska University Hospital (Stockholm, Sweden) identified all patients who underwent coronary artery bypass graft surgery, heart valve surgery, or both between 1997 and 2012. Transfusion data were obtained from the nationwide register of blood transfusions database. Storage of RBCs was classified with discrete patient groups who had exclusively received blood stored less than 14 days, 14 to 27 days, or 28 to 42 days, and a mixed storage category for patients receiving blood of mixed age. Follow-up was completed on December 31, 2013.

Between 1997 and 2012, 47,071 patients were transfused in connection with cardiac surgery in nine Swedish hospitals. Women constituted 39.2% and the mean ±SD age was 70.0 ±9.7 years. Of these patients, 36.6% exclusively received RBCs stored less than 14 days; 26.8%, RBCs stored 14 to 27 days; 8.9%, RBCs stored 28 to 42 days; and 27.8%, RBCs of mixed age. Most clinical parameters were similar in the groups, although the less common blood groups such as AB and B, were more common with longer storage. Recipients of the freshest blood received more transfusions, 3.1 versus 2. No differences were observed for a range of comorbidities. After investigating patient outcomes, the team found that the use of stored blood units did not influence heart surgery patient outcomes.

Ulrik Sartipy, MD, PhD, the lead author of the study said, “This study is by far the largest investigation focusing on the issue of blood storage in this very sensitive patient group, and we find absolutely no hint of negative health effects associated with stored blood.” The study provides very firm reassurance that the current blood storage practices are safe. The study was published on October 20, 2015, in the Journal of the American Medical Association (JAMA).

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Karolinska University Hospital