Device-induced Platelet Dysfunction in Patients after Left Ventricular Assist Device Implantation.

BACKGROUND Non-surgical bleeding (NSB) is a major complication after left ventricular assist device (LVADs) implantation. It has been reported that non-physiological shear stress caused by LVADs could altered platelet receptor expression, which leads to bleeding disorders caused by coagulation dysfunctions. OBJECTIVES Because bleeding diathesis could be multifactorial, we focused on the combined characterization of platelet receptor expression patterns and oxidative stress to compare patients with NSB and patients without coagulation disorder in a monocentric, prospective study. METHODS Blood samples were obtained from LVAD patients with NSB (bleeder group,n=19) and without NSB (non-bleeder group,n=20). The platelet receptors platelet endothelial cell adhesion molecule-1 (PECAM-1), glycoprotein (GP)Ibα, P-selectin, CD63 and GPIIb/IIIa as well as the production of intraplatelet reactive oxygen species (ROS) were quantified by flow cytometry. Aggregation capacity was evaluated by aggregometry. RESULTS The surface expression level of P-selectin and GPIbα on platelets was decreased in bleeders (P-selectin: 465±72U; GPIbα: 435±41U) compared to non-bleeders (P-selectin: 859±115U,p<0.01; GPIbα: 570±49U,p=0.04). Additionally, the mean fluorescence intensity of ADP-stimulated P-selectin and PECAM-1 expressing platelets were reduced in bleeders (P-selectin: 944±84U; PECAM-1: 6,722±419U) compared to non-bleeders (P-selectin: 1,269±130U,p=0.04; PECAM-1: 8,542±665U,p=0.03). Bleeders showed a higher amount of ROS formation in platelets (88.0±2.6%) than non-bleeders (81.5±2.1%,p=0.05). CONCLUSIONS These findings suggested that changes of three platelet receptors (GPIbα, P-selectin, and PECAM-1) and elevated oxidative stress may play a role in patients with bleeding complications following LVAD implantation. These results might help to explain the high incidence of spontaneous hemorrhage during LVAD support through an altered platelet function.