RESUMO
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 RBC transfusions were enrolled in a crossover design study to receive fresh (<7 days 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. RESULTS: Twenty-one patients (71 ± 16 years, 52% females) were enrolled. Mean age of fresh blood was 5.5 days (±1.0), and that of standard blood was 24.5 days (±7.9 days). The pretransfusion hemoglobin was 83.1 ± 2.5 g/L; and posttransfusion, 98.9 ± 2.6 g/L. An average of 2 U of packed RBCs was transfused. Microvascular endothelial function decreased more frequently after transfusion of standard blood compared to fresh blood. Standard issue blood transfusion was associated with decrease in reactive hyperemia peripheral arterial tonometry index (-0.25 ± 0.63) compared to fresh blood (+0.03 ± 0.49); P = .026. CONCLUSION: Transfusions of standard issue blood are associated with less favorable effect on microvascular endothelial function as compared to fresh blood.