Loss of von Willebrand factor large multimers in patients undergoing hemodialysis: A single-center, retrospective study.

INTRODUCTION

Von Willebrand factor (VWF) is produced by vascular endothelial cells as large multimers and is cleaved by ADAMTS13 into an appropriate size in a shear stress-dependent manner. Excessive shear stress enhances VWF cleavage, leading to a hemorrhagic disease known as acquired von Willebrand syndrome. No clear reports on the prevalence of the loss of VWF large multimers in patients receiving hemodialysis are currently available. Therefore, this study investigated the prevalence of the loss of VWF large multimers in patients undergoing hemodialysis.

METHODS

This single-center, retrospective study involved 90 patients undergoing hemodialysis and 32 healthy participants as controls. VWF antigen levels (VWF:Ag), VWF activity (VWF:RCo), and ADAMTS13 activity were measured. VWF multimer analysis was performed by modified western blotting with an agarose gel electrophoresis, followed by densitometric evaluation of band intensities to calculate the VWF large multimer index (VWF-LMI). A VWF-LMI <80 % was defined as the loss of VWF large multimers, and the prevalence of the loss of VWF large multimers was calculated.

RESULTS

VWF:Ag and VWF:RCo levels in patients undergoing hemodialysis were significantly higher than those in healthy individuals (p < 0.01 both) and were negatively correlated with ADAMTS13 activity (p < 0.01, R = -0.353 and p < 0.01, R = -0.392, respectively). A VWF-LMI <80 % was present in 24 of 90 patients.

CONCLUSIONS

The loss of VWF large multimers was identified in 26.7 % of patients receiving hemodialysis. However, the prevalence of the loss of VWF multimers in these patients may be underestimated, as their relatively high VWF activity makes significant bleeding manifestations less likely.