Adults undergoing coronary artery bypass grafting, cardiac valve procedures, or ascending aorta repair, either alone or in combination (n=3835).
Younger red blood cell (RBC) units (median age, 11 days), (n=701).
Older units (median age, 25 days), (n=686).
A total of 5470 RBC units were transfused, including 2783 in the younger RBC storage group and 2687 in the older RBC storage group. The generalized estimating equation (GEE) average relative-effect odds ratio was 0.77 for the composite morbidity and mortality endpoint. In-hospital mortality was lower for the younger RBC storage group (2.1% [n = 15] vs 3.4% [n = 23]), as was occurrence of other adverse events except for atrial fibrillation.