Background The duration of red blood cell (RBC) storage may have a negative impact on endothelial nitric oxide bioavailability. We tested the hypothesis that transfused fresh blood will have a more favorable effect on microvascular endothelial function as compared to older standard issue blood.
Methods Participants requiring chronic RBCtransfusions were enrolled in a crossover design study to receive fresh (b7days of storage) or standard (up to 42 days of storage) blood on 2 separate visits. Endothelial function was assessed by reactive hyperemia peripheral arterial tonometry that was measured before and after transfusions. For each participant, the difference between endothelial function pretransfusion and posttransfusion was assessed in relation to blood storage time.