Background: In different centers for cardiothoracic surgery throughout the world, different policies are followed concerning the maximum storage time of to-be-transfused red blood cells (RBCs). The aim in this study was to investigate the possible role of the storage time of RBC transfusions on the outcome of coronary artery bypass graft (CABG) surgery patients.
Study design and methods: In a single-center study, all patients who had undergone CABG surgery in the period 1993 until 1999 were identified. Only those patients who had received standard, allogeneic, buffy coat-depleted, unfiltered RBCs in saline-adenine-glucose-mannitol were entered in the analyses (n = 2732). Endpoints were 30-day survival, hospital stay, and intensive care unit (ICU) stay. Storage time of the perioperative RBC transfusions was analyzed in the following four ways: 1) mean storage time of all perioperative RBC transfusions; 2) storage time of the youngest RBC transfusion; 3) storage time of the oldest RBC transfusion; and 4) comparing outcome in patients receiving only RBCs with a storage time below the median storage of 18 days with patients receiving only RBCs with a storage time above the median.
Results: The univariate analyses showed a strong correlation between storage time and the endpoints survival and ICU stay, but also a correlation with an established risk factor such as the number of transfusions. The multivariate analyses showed no independent effect of storage time on survival or ICU stay.
Conclusion: In these analyses, pertaining to 2732 CABG patients, no justification could be found for use of a particular maximum storage time for RBC transfusions in patients undergoing CABG surgery.