Acquired von Willebrand syndrome after exchange of the HeartMate XVE to the HeartMate II ventricular assist device

Instead of pulsatile ventricular assist devices an increasing number of nonpulsatile ventricular assist devices are introduced to clinical practice. The different flow characteristics of this new technique lead to alteration in shear stress on blood components, which may affect the coagulation system. Repeated von Willebrand factor analyses were performed in a patient who first was implanted with a pulsatile ventricular assist device (Thoratec HeartMate XVE), which had to be replaced after 405 days with an axial flow device (HeartMate II). During support with the pulsatile ventricular assist device there was no sign of any coagulation disorder. However, on the axial flow device acquired von Willebrand syndrome Type 2 developed. Inhibition of platelet function was also observed, which may be in part due to the von Willebrand syndrome. The HeartMate II axial flow device may induce von Willebrand syndrome, which was not observed in HeartMate XVE pulsatile ventricular assist device. Patients put on continuous flow devices should be screened for acquired von Willebrand syndrome. (C) 2009 European Association for Cardio-Thoracic Surgery. Published by Elsevier B.V. All rights reserved.