Improved values regarding acquired von Willebrand syndrome in patients with HeartMate III compared to HeartMate II

U. Geisen1, K. Brehm1, G. Trummer1, F. Beyersdorf1, M. Berchtold-Herz1, C. Heilmann1, J. Schelling1, A. Schlagenhauf2, B. Zieger1 (1Freiburg, Germany, 2Graz, Austria)

Acquired problems and alterations of coagulation
Date: 17.02.2017,
Time: 17:15 - 18:15

Objective: Impaired binding of Von Willebrand factor (VWF) to platelets and to collagen due to an acquired Von Willebrand syndrome (AVWS) has been observed in patients with left ventricular assist device (LVAD) support. In addition, platelet count and function are also affected in patients with LVAD. Due to AVWS, decreased platelet count and impaired platelet function, the bleeding symptoms seem to be enhanced in LVAD patients. The new HeartMate III (HM III) is a left ventricular assist device featuring several design improvements that show promise to ameliorate the severity of AVWS in comparison to its predecessor, the Heartmate II (HM II). In this study, our aim was to analyze AVWS parameters and platelet function in patients with HM III compared to patients with HM II support.

Methods: Data sets of 14 patients under HM III support and 23 patients under HM II support were analyzed pre-surgery as well as 1, 3, 7, and 30 days post-surgery. Collagen binding capacity (VWF:CB), VWF antigen (VWF:Ag) as well as VWF:CB/VWF:Ag-ratios were determined. Presence of high molecular weight multimers of VWF was investigated. Platelet counts were monitored and platelet function was tested using light transmission aggregometry. The number of bleeding events and amount of fresh frozen plasma transfusions after implantation was recorded.

Results: The VWF:CB/VWF:Ag ratios were significantly higher in patients with HM III than in patients with HM II at day 1, 3, and 7 after implantation (p < 0.001, p < 0.05 and p < 0.05). More HM III patients had intact VWF high molecular weight multimers compared to HM II patients at day 1 and 3 after LVAD implantation (p < 0.05). Platelet counts and functions were comparable in both study groups. The HM III cohort exhibited a tendency towards less bleeding events compared to the HM II group (2/14 versus 8/23). In addition, the need for fresh frozen plasma transfusions was significantly lower in HM III patients compared to HM II patients (p < 0.05).

Conclusion: Severity of AVWS was milder in HM III patients compared to HM II patients, especially during the days after surgery when usually most hemorrhagic events occur. The lower severity of AVWS coincided with a trend towards less bleeding symptoms,