Original article
Adult cardiac
Acquired von Willebrand Syndrome in Continuous-Flow Ventricular Assist Device Recipients

Presented at the Forty-sixth Annual Meeting of The Society of Thoracic Surgeons, Fort Lauderdale, FL, Jan 25–27, 2010.
https://doi.org/10.1016/j.athoracsur.2010.04.099Get rights and content

Background

Bleeding is a major cause of morbidity in recipients of continuous-flow left ventricular assist devices (CF-LVAD). A better understanding of the impact of CF-LVAD support on the hemostatic profile is necessary to establish better strategies for anticoagulation therapy and risk assessment for bleeding complications. A prospective multicenter study was conducted to characterize von Willebrand factor (vWF) profiles in patients undergoing CF-LVAD implantation.

Methods

Blood samples were collected before and after CF-LVAD implantation from 37 patients between July 2008 and April 2009 at Duke University and the University of Minnesota. Blood samples were analyzed for vWF, platelet and collagen-binding ability. The presence of high-molecular-weight (HMW) vWF multimers were detected through gel electrophoresis, and deficiency was graded on a scale of 0 (normal) to 3 (severe loss).

Results

All 37 patients exhibited significant loss of HMW vWF multimers within 30 days of CF-LVAD implantation. Ten of the 37 patients experienced bleeding complications after CF-LVAD placement.

Conclusions

All CF-LVAD recipients had acquired von Willebrand syndrome after LVAD placement, demonstrated by reduced or absent HMW vWF multimer levels. However, not all recipients had bleeding complications. These findings suggest that loss of HMW vWF multimers alone cannot predict bleeding risk. Further refinement of laboratory techniques and a larger follow-up is required to identify risk factors for bleeding in CF-LVAD recipients.

Section snippets

Patients

This research protocol was approved by the University of Minnesota and Duke University Institutional Review Boards. Informed consent was obtained from patients included in the study. The enrollment period extended from July 2008 through April of 2009. We report on 37 HeartMate II LVAD recipients enrolled in the study, whose blood samples were obtained at least twice: before LVAD placement and at 7 or 30 days, or both, after CF-LVAD placement. All 37 study participants were followed for bleeding

Results

A total of 37 CF-LVAD recipients were enrolled in the study. The baseline characteristics are outlined in Table 2. The subset of patients who suffered a bleeding event after LVAD placement differed in proportions of blood type from those who did not bleed. Recipients with blood types B, AB, or O had much higher rates of bleeding events than recipients with type A (9 of 21 [43%] versus 1 of 16 [6%]).

Comment

Bleeding complications appear to be more prevalent with CF-LVAD versus earlier generation pulsatile devices [2, 3]. The difference in bleeding rates observed in pulsatile and CF-LVAD recipients makes it logical to assume that pulsatility or device design or both may play a role. The CF-LVAD patients have a narrower pulse pressure analogous to patients with aortic stenosis. Severe aortic stenosis has been associated with a combination of HMW vWF multimer loss and GI bleeding called AVWS, or

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Copyright © 2010 The Society of Thoracic Surgeons. Published by Elsevier Inc. All rights reserved.