Acquired von Willebrand syndrome in paediatric patients during mechanical circulatory support

Bleeding signs can become life-threatening complications in patients on mechanical circulatory support (MCS). Clinical phenotyping and comprehensive analyses of the cause of bleeding are, therefore, essential, especially when risk-stratifying patients during MCS workup. We conducted coagulation analyses and determined von Willebrand factor (VWF) parameters in a paediatric cohort on temporary extracorporeal life support, extracorporeal membrane oxygenation or long-term ventricular assist device support.

We carried out an observational single-centre study including 30 children with MCS (extracorporeal life support, n = 13; extracorporeal membrane oxygenation, n = 5; and ventricular assist device, n = 12). We also assessed the acquired von Willebrand parameters of each study participant: collagen binding capacity (VWF:CB), the ratio of collagen-binding capacity to VWF antigen (VWF:CB/VWF:Ag) and high-molecular-weight VWF multimers. We also documented bleeding events, transfusion requirement, haemolysis parameters and surgical interventions.

All children developed AVWS (acquired von Willebrand syndrome) during MCS, usually during the early postoperative course. They presented no AVWS after device explantation. We detected a loss of high-molecular-weight VWF multimers, decreased VWF:CB/VWF:Ag ratios and reduced VWF:CB levels. Twenty of the 30 patients experienced bleeding complications; approximately 53% of them required surgical revision. There were no deaths due to bleeding during support.

The AVWS prevalence in paediatric patients on MCS is 100% regardless of the types of devices tested in this study. The bleeding propensity of AVWS patients widely varies.