University of Southern Denmark The effects of sampling from a peripheral venous catheter compared to repeated venepunctures on markers of coagulation, inflammation, and endothelial function

Peripheral venous (PV) catheters are often used for serial blood sampling, but studies suggest that PV catheters increase markers of coagulation activation and inflammation. Whether the increase is caused by irritation of the vessel wall or diurnal variation is unknown. We therefore compared the effects of a PV catheter and repeated venepunctures on markers of coagulation, inflammation, and endothelial function. A PV catheter was inserted at 07:45 in a hand vein in 10 healthy subjects, and blood samples were collected at 8:00, 10:00, 12:00, and 14:00. In the contralateral arm, blood was simultaneously obtained by venepunctures. Measures of coagulation, i.e. activated partial thromboplastin time (APTT), prothrombin time (PT), fibrinogen, prothrombin fragment 1+2 (F1+2) and thrombinantithrombin (TAT), inflammation, i.e. interleukin 6 (IL-6) and C-reactive protein (CRP), and endothelial function, i.e. plasminogen activator inhibitor 1 (PAI-1), tissue plasminogen activator (tPA), von Willebrand factor (vWF), and tissue factor (TF) were measured in plasma. The concentrations of TAT and F1+2 were significantly increased (10:00; p<0.01, 12:00; p<0.05, and 14:00; p<0.01) in PV catheter samples compared with venepuncture samples. There was a minor increase in PT and INR and no increase in APTT, fibrinogen, CRP, PAI-1, tPA, vWF, and TF, with no differences between sampling methods. IL-6 concentrations increased in many PV catheter samples and venepuncture samples, but the response varied between the subjects. Blood collection through a PV catheter induces coagulation activation, whereas endothelial function is not affected. More studies are needed to disclose the effect of blood sampling on IL-6.