Scientific Calendar July 2025

Extracorporeal membrane oxygenation (ECMO) is a technique providing either venoarterial (VA) or venovenous (VV) support for the oxygenation, as well as the carbon dioxide depletion of blood outside the human body. The primary function of ECMO is to provide temporary support, serving as a bridge for clinical decision-making or full recovery. This form of cardiorespiratory support has saved the lives of many severely ill patients suffering from lung and heart disease, with a well-known example being severe COVID-19. Nevertheless, this life-saving technology comes with a price: the risk of heavy bleeding. Due to the shear stress-induced loss of von Willebrand factor (VWF) multimers in the ECMO circuits, the risk for severe bleeding events increases because these VWF multimers are essential for clot formation in arteries. Although only data from small studies are available, the prevalence of acquired VWD appears to range from 70% to 100%. Apart from acquired von Willebrand disease, other mechanisms contributing to ECMO-related bleeding include impaired platelet function and fibrinolysis. [1–3]

Acquired von Willebrand disease is a rare bleeding disorder with clinical symptoms similar to those associated with the inherited form of von Willebrand disease. It appears without previously known bleeding symptoms, has a negative family history, and manifests at an older age; it is caused by heterogeneous mechanisms. Acquired von Willebrand disease typically develops in various conditions such as lymphoproliferative disorders (e.g. multiple myeloma), myeloproliferative disorders (e.g. polycythaemia vera), autoimmune disorders (e.g. lupus erythematosus), malignant neoplasms, and, less commonly, hypothyroidism, certain medications, and other medical conditions. Deficiency or impaired activity of von Willebrand factor can be caused by specific antibodies against it, its adsorption onto the surfaces of neoplastic cells, mechanical injury, or proteolysis. In addition, acquired VWD characterised by a high shear stress-induced loss of VWF multimers has been described in patients receiving transcatheter aortic valve replacement (TAVR) and in ECMO patients. Management of acquired VWD includes desmopressin, von Willebrand factor concentrates, recombinant activated factor VII, intravenous immunoglobulin, and adjunctive antifibrinolytic therapy. [1–4]

A patient with severe right-sided heart failure secondary to idiopathic pulmonary hypertension 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 the 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. Measurement with a PFA-100 showed non-closure results for the Col/EPI (>218 s) and the Col/ADP (207 s) cartridges. While the APTT was just inside the reference interval, the factor VIII level was pathologically low (46%). A decreased VWF:RCo/VWF:Ag ratio (<0.7) and the loss of high-molecular-weight multimers of VWF finally confirmed the diagnosis of acquired von Willebrand disease. [2]

Therefore, specific devices or assays, such as INNOVANCE PFA-200, INNOVANCE VWF Ac or VWF:Ag assays, should be used to detect and monitor VWF levels in patients on ECMO to avoid unnecessary bleeding events. [1]