Thorac Cardiovasc Surg 2012; 60 - P38
DOI: 10.1055/s-0031-1297829

Acquired Von Willebrand Syndrome (AVWS) and bleeding complications in long-term patients with Ventricular Assist Devices (VAD)

C Heilmann 1, B Zieger 2, U Geisen 3, G Trummer 1, C Benk 1, L Nakamura 2, M Berchtold-Herz 1, U Heizmann 1, F Beyersdorf 1
  • 1Universitäres Herzzentrum Freiburg – Bad Krozingen, Herz- und Gefäßchirurgie, Freiburg, Germany
  • 2Universitätsklinikum Freiburg, Zentrum für Kinder- und Jugendmedizin, Hämostaseologie, Freiburg, Germany
  • 3Universitätsklinikum Freiburg, Medizinische Klinik, Zentrallabor, Freiburg, Germany

Objectives: Bleeding events are observed in VAD patients even in the late course after surgery. The acquired Von Willebrand syndrome (AVWS) is suspected to contribute to these bleeding tendencies. It is characterized by impaired function of the Von Willebrand Factor (VWF). Increased shear stress with consecutive loss of high molecular weight (HMW) multimers may lead to reduced binding of platelets to the collagen of injured endothelium. In this study, we analyzed VAD patients in the late course for AVWS and bleeding events.

Methods: HMW multimers were analyzed in 21 patients (4 BVAD, 17 HeartMateII) after 6±1 months (n=21) and 12±2 months (n=9). In addition, ratios of collagen binding capacity (VWF:CB) and of ristocetin cofactor activity (VWF:RCo) to VWF antigen (VWF:Ag) were examined (VWF:CB/VWF:Ag, VWF:RCo/VWF:Ag). VWF:CB/VWF:Ag (normal ≥0.75) describes the binding of VWF to collagen, whereas VWF:RCo/VWF:Ag (normal >0.65) characterizes the binding of VWF to platelets. Missing HMW multimers together with at least one reduced ratio is indicative of AVWS. Further, bleeding complications after 6 months or later were evaluated.

Results: Between 6 and 12 months, 4 of the 21 patients were transplanted or weaned, 2 died, and 6 have not reached 1 year yet.

HMW multimers were missing in all patients after 6 or 12 months. VWF:CB/VWF:Ag was also always diminished (0.40±0.13), VWF:RCo/VWF:Ag was reduced in 6 of 21 patients after 6 months and 3 of 9 after 1 year (overall, 0.61±0.15). International normalized ratio (INR) was 2.2±0.7, activated thromboplastin time (aPTT) was 52±18s, and platelet counts came to 238±66×103/µl. There were no differences between any 6-months and 12-months values.

20 hemoglobin-relevant bleeding events were observed in 13 patients (gastrointestinal, n=6, after interventions, n=6, recurrent epistaxis, n=4, spontaneous, n=2, due to sepsis, n=2). Bleeding patients did not differ with regard to the AVWS, INR, and aPTT from non-bleeding patients, but had lower platelet counts (p=0.04).

Conclusions: The acquired Von Willebrand syndrome may be considered as a persisting disorder in VAD patients. Bleeding events occur frequently in the long-term course after VAD implantation. In analogy to the Heyde sydrome in patients with aortic stenosis, AVWS contributes by all probability to bleeding tendencies in VAD patients.