Acquired von Willebrand syndrome in patients with a centrifugal or axial continuous flow left ventricular assist device.
OBJECTIVE
The aim of this study was to determine whether differences in continuous flow left ventricular assist devices (LVADs) may lead to differences in the von Willebrand profile and the occurrence of bleeding and thromboembolic events.


BACKGROUND
The HeartMate II (Thoratec Corp., Pleasanton, California) and HeartWare Ventricular Assist Device (HVAD) (HeartWare, Inc., Framingham, Massachusetts) systems are the most frequently implanted LVADs worldwide. In all patients with an axial-flow HeartMate II, acquired von Willebrand syndrome (AvWS) due to the loss of large molecular weight multimers was found. The large molecular weight multimers of the von Willebrand factor (vWF) play a key role in primary hemostasis through interactions with platelets.


METHODS
This was a retrospective study of the vWF profile and incidence of bleeding and thromboembolic events in 102 patients receiving the HeartMate II (n = 51) and HVAD (n = 51). Between January 2003 and December 2010, vWF testing was performed in 102 of 175 consecutive patients after LVAD implantation.


RESULTS
AvWS was found in all patients, demonstrated by a decrease in the high molecular weight multimers of vWF to 30 ± 14% in HeartMate II patients and 34 ± 13% in patients with an HVAD. Significant predictors of vWF antigen included age (p = 0.011), number of days on the device (p = 0.035), C-reactive protein (p < 0.001), and blood group (p = 0.007). Bleeding and thromboembolic event rates were similar. However, lower fractions of vWF antigen and high molecular weight multimers did not correlate with the rate of bleeding complications or thromboembolic events.


CONCLUSIONS
AvWS developed in all patients after centrifugal or axial flow pump implantation. Different patterns of AvWS were seen between the devices as well as individually. However, the complication rates after implantation were similar.
Heart Center Leipzig University, Clinic for Heart Surgery, Leipzig, Germany.
Anna L
AL
Meyer
Department of Cardiothoracic, Transplantation and Vascular Surgery, Hannover Medical School, Hannover, Germany.
Doris
D
Malehsa
AescuLabor Hamburg, Hamburg, Germany.
Ulrich
U
Budde
Department of Cardiothoracic, Transplantation and Vascular Surgery, Hannover Medical School, Hannover, Germany.
Christoph
C
Bara
Department of Cardiothoracic, Transplantation and Vascular Surgery, Hannover Medical School, Hannover, Germany.
Axel
A
Haverich
Heart Center Leipzig University, Clinic for Heart Surgery, Leipzig, Germany. Electronic address: martin.strueber@med.uni-leipzig.de.
Martin
M
Strueber
D000925:Anticoagulants / Q000009:adverse effects; D002097:C-Reactive Protein / Q000378:metabolism; D005260:Female; D006333:Heart Failure / Q000150:complications / Q000628:therapy; D006353:Heart-Assist Devices / Q000009:adverse effects*; D006470:Hemorrhage / Q000209:etiology*; D006487:Hemostasis; D006801:Humans; D008297:Male; D008875:Middle Aged; D011474:Prosthesis Design; D012086:Reoperation; D012189:Retrospective Studies; D013923:Thromboembolism / Q000209:etiology*; D014842:von Willebrand Diseases / Q000150:complications*; D014841:von Willebrand Factor / Q000378:metabolism
D000925:Anticoagulants; D014841:von Willebrand Factor; D002097:C-Reactive Protein
HeartMate II; HeartWare; LVAD; bleeding; von Willebrand syndrome