Acquired von Willebrand Syndrome in Pediatric Patients during Mechanical Circulatory Support

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

Methods: We carried out a prospective, observational single-center study including 30 children, median age 5.6 months (range: 3 days–18 years) with MCS (ECLS n = 13, ECMO n = 5, and VAD n = 12). We assessed each study participant’s acquired von Willebrand parameters: collagen-binding capacity (VWF:CB), ratio of collagen-binding capacity to VWF-antigen (VWF:CB/VWF:Ag), and high-molecular-weight (HMW) VWF multimers. Furthermore, we documented bleeding events, transfusion requirement, hemolysis parameters, and surgical interventions.

Results: All children developed acquired von Willebrand syndrome (AVWS) during MCS, usually during the early postoperative course. They presented no AVWS before MCS or after device explantation. We detected a loss of HMW VWF multimers, decreased VWF:CB/VWF:Ag ratios (median 0.26 U/mL during ECLS/ECMO and median 0.44 U/mL during VAD) and reduced VWF:CB levels (median 0.45 U/mL during ECLS/ECMO and median 0.8 U/mL during VAD). Interestingly, children on ECLS/ECMO tended to present lower VWF:CB levels and VWF:CB/VWF:Ag ratios during MCS than the VAD patients. Of the 30 patients, 20 suffered from bleeding complications; about 53% of them required surgical revision. None succumbed to bleeding during support. Discharge home rate was 50% in ECLS/ECMO group and 67% in VAD group.

Conclusion: The AVWS prevalence in pediatric patients on MCS is 100% regardless of device type. The bleeding propensity of AVWS patients varies widely. In those on ECLS and ECMO, the extent of AVWS appears amplified.

No conflict of interest has been declared by the author(s).