Acquired von Willebrand Syndrome in a Patient Undergoing Extracorporeal Membrane Oxygenation: A Case Report.

Acquired von Willebrand syndrome (AvWS) is a rare bleeding disorder caused by dysfunction of the von Willebrand factor (vWF), leading to bleeding manifestations. It usually occurs due to an underlying disorder in patients with no family or personal history of bleeding diathesis. The exact mechanism causing this syndrome is not fully understood, but it involves a complex interplay of factors. Specifically, vWF deficiency or reduced activity can occur due to antibodies, adsorption of vWF onto tumor cells, shear stress, or increased proteolysis. We describe a patient with severe, right-sided heart failure secondary to idiopathic pulmonary hypertension. The patient was admitted to the intensive care unit to be placed on a venoarterial extracorporeal membrane oxygenation (VA ECMO) machine while awaiting bilateral lung transplantation. A few hours after initiation of VA ECMO, the patient experienced epistaxis and continuous bleeding from the cannula tips. The laboratory investigations were based on the measurements of vWF antigen (vWF:Ag), vWF ristocetin cofactor activity (vWF:RCo), and multimer analysis. The obtained results revealed a decreased VWF:RCo/VWF:Ag ratio (<0.7) and the loss of high-molecular-weight multimers of vWF, thus confirming the diagnosis of AvWS. This report reviews how to make the clinical diagnosis of AvWS, including a discussion of necessary laboratory results and their pitfalls, and highlights the importance of having a high index of suspicion of AvWS in the ECMO population so that laboratory values are obtained on time to allow for treatment and successful recovery.