Factors Modifying Risk of Bleeding in Patients with Continuous Flow Left Ventricular Assist Devices

Abstract

<h3>Purpose</h3> Bleeding is a common problem in continuous flow left ventricular assist device (CF-LVAD) recipients. CF-LVAD patients can develop von Willebrand factor (vWF) dysfunction, however specific predictors of bleeding have not been elucidated. We hypothesized that vWF function, pump parameters, and platelet dysfunction are important risk factors for bleeding. <h3>Methods and Materials</h3> vWF analysis was performed before, and at multiple time points after device implant in 25 patients enrolled in the Vanderbilt Main Heart Registry who received a HeartMate II CF-LVAD. Platelet function (PFA-100) and VWF multimeric analyses were performed. <h3>Results</h3> All patients (84% male; 28% bleeders) had a reduction in high molecular weight multimers post-implant compared to pre-implant (•) (N - normal pooled plasma). Multimer reduction was similar in bleeders (°) and non-bleeders. [figure 1] Ristocetin cofactor activity was 30% lower than vWF antigen, and PFA-100 ADP closure times were significantly prolonged for all patients post-implant, consistent with the abnormal vWF multimer pattern. Average pump speed was higher in bleeders at all time points. <h3>Conclusions</h3> The development of vWF and platelet dysfunction in conjunction with higher pump speeds may contribute to bleeding events in CF-LVAD recipients. Monitoring these hemostatic parameters may allow us to identify patients prone to bleeding.