INTRODUCTION: The high shear rates induced by left ventricular assist devices cause @entity2880 ( @entity2880 ). We hypothesised that an ex vivo model could be established to study whether mechanical shear stress alone causes @entity2880 or whether this process depends also on the @entity2881 cleavage protein @entity2105 and on platelets. MATERIALS AND METHODS: Healthy volunteers and two @entity1 with congenital @entity2105 deficiency donated blood. In vitro closed extracorporeal circuits were established using medically approved left ventricular assist devices (LVAD). @entity2881 multimers were quantified by gel electrophoresis; @entity2881 antigen, @entity8325 cofactor activity ( @entity2881 :RCo), @entity2105 levels and platelet function were assessed. RESULTS: The high shear stress in the extracorporeal circulation rapidly decreased @entity2881 :RCo and thereby the @entity2881 :RCo/ @entity2881 :Ag ratio by 47% (p<0.01) to pathologically low values. Concomitantly, high molecular weight multimers (HMWM) decreased: up to 14-15 mers were visible on the gels at baseline, which were reduced by a maximum of 6-7 mers, corresponding to an average 68% lower densitometry signal of HMWM (p<0.001). This was accompanied by marked reduction of aggregation by various agonists (p<0.005). In contrast, the two @entity1 with @entity882 with @entity24901 of @entity2105 activity had only a minimal or no decrease in multimers (p<0.005 vs. healthy controls). Similarly, no or minimal depletion of large multimers occurred, when normal plasma circulated without platelets. CONCLUSION: An in vitro model for LVAD associated @entity2880 demonstrated that @entity2105 and platelets contribute to the depletion of HMWM of @entity2881 .

Acquired von Willebrand factor deficiency caused by LVAD is XXXX and platelet dependent.

@entity1 :: ('9606', 'Species') :: ['patients'] @entity882 :: ('MESH:D013921', 'Disease') :: ['congenital thrombocytopenic purpura'] @entity2105 :: ('11093', 'Gene') :: ['ADAMTS-13'] @entity8325 :: ('MESH:D012310', 'Chemical') :: ['ristocetin'] @entity2881 :: ('7450', 'Gene') :: ['VWF'] @entity24901 :: ('MESH:D007926', 'Disease') :: ['virtually complete deficiency'] @entity2880 :: ('MESH:D014842', 'Disease') :: ['acquired von Willebrand disease', 'aVWD']
@entity2105 :: (11093,Gene) :: ['ADAMTS-13']
