Abstract 18776: Endothelial Function is Not Affected by Fresh or Storage-Aged Autologous Blood Transfusions in Healthy Individuals

Abstract

Background: Red cells play a modulating role in nitric oxide (NO)-mediated signaling and hypoxic vasodilation that may be influenced by blood transfusions, particularly with storage-aged blood (pRBCs). We have shown that brachial artery endothelial function, measured as flow-mediated vasodilation (FMD) is adversely affected in patients receiving aged compared to fresh pRBCs. Here we investigated endothelial NO activity in healthy subjects receiving autologous pRBCs with the hypothesis that aged pRBCs will impair endothelial conductance vessel and microvascular function. Methods: Sixteen healthy participants (aged 31±10 years, 38% female) were transfused 1 unit of fresh (aged 3-7 days) and subsequently with storage-aged (35-42 days) autologous pRBCs. Endothelial function was measured using FMD and reactive hyperemia index (RHI), a measure of microvascular function, was measured using pulsatile arterial tonometry (Itamar Inc., n=7), before, 1 hour, and 24 hours after transfusion. Data were analyzed by repeated measures ANOVA. Results: Hemoglobin was similar before both transfusions (p=0.066) and increased by 1.02±1.0 g/dL (±SD) and 1.2±1.2 g/dL with fresh and storage-aged transfusions, respectively. The FMD before, 1 hr and 24 hr after transfusion of fresh pRBCs (7.8±6.9%, 8.2±4.8% and 6.9±4.3%) or stored pRBCs (7.1±5.5%, 7.4±4.7% and 8.5±4.9%) was similar,( p=0.45). The RHI before, 1 hr and 24 hr after transfusion of fresh pRBCs ( 2.45±0.23, 2.26±0.08 and 2.26±0.21) showed no significant changes, p=0.87 or stored pRBCs ( 2.25±0.67, 2.27±0.53 and 2.22±0.26, p=0.42). Conclusions: Vascular NO activity and microvascular dilatory capacity are not impaired by transfusion of fresh or storage-aged autologous pRBC in healthy individuals, unlike findings with allogeneic transfusions in patients. These differences suggest that the risks of aged blood transfusions are likely to be greater in patients with vascular disease who have underlying endothelial dysfunction.