Acquired von Willebrand Syndrome during Mechanical Circulatory Support and Extracorporeal Membrane Oxygenation: Rapid Onset and the Demand for Point of Care Testing

Introduction: Unexplained bleeding episodes are frequently observed in patients being treated with mechanical circulatory support (MCS) and extracorporeal membrane oxygenation (ECMO), and this is often associated with acquired von Willebrand syndrome (AVWS). AVWS is characterized by loss of high molecular weight (HMW) multimers of von Willebrand factor (VWF) and decreased ratios of collagen binding capacity to VWF as a result of high shear stress, which results in diminished binding to collagen and to the platelets. The aim of this observational study is to analyze the AVWS coagulopathie in intensive care patients supported by different MCS systems.

Methods: We analyzed patients treated with veno-venous ECMO (n = 8), veno-arterial ECMO (n = 2) and impella (n = 1) for laboratory parameters of VWD (VWF:Ag, VWF:CBA and VWF multimer analysis). Parameters were obtained before MCS and during therapy (1h, 24 hour and 48 hour after device implantation).

Results: All patients of the different MCS systems developed AVWS within 48 hour hours after implantation. The AVWD detection rate oft the VWF:CBA assay was higher than the VWF multimer analysis. These results indicate that a single assessment oft the VWF:CBA: VWF: Ag ratio is not sufficient for determining AVWD in patients with MCS.

Conclusion: Due to vWD heterogeneity and assay limitations, no single laboratory procedure is sufficient to detect vWD quickly and effective. The standard methods are complex and time-consuming and, therefore, a Point of Care Test of AVWD can markedly improve early diagnosis and specific treatment of AvWD.

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