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How I treat low von Willebrand factor levels

Michelle Lavin and James S O'Donnell

Abstract

Partial quantitative deficiency of plasma von Willebrand factor (VWF) is responsible for the majority of cases of von Willebrand disease, the commonest inherited human bleeding disorder. International consensus guidelines recommend that patients with reduced plasma VWF:Ag levels and bleeding phenotypes should be considered in two distinct subsets. First, patients with marked reductions in plasma VWF levels (<30 IU/dL) usually have significant bleeding phenotypes and should be classified with 'Type 1 VWD.' In contrast, patients with intermediate reduced plasma VWF:Ag levels (in the range 30 – 50 IU/dL) should be considered in a separate category labeled 'Low VWF levels.' These patients with Low VWF commonly display variable bleeding phenotypes and often do not have VWF gene sequence variations. Since the pathophysiology underlying Low VWF levels remains largely undefined, diagnosis and management of these patients continues to pose significant difficulties. In this article, we present a number of clinical case studies to highlight these common clinical challenges. In addition, we detail our approach to establishing a diagnosis in Low VWF patients and discuss strategies for the management of these patients in the context of elective surgery and pregnancy.

  • Submitted October 1, 2018.
  • Accepted December 20, 2018.