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Von Willebrand Disease (VWD)
Part 1: NHLBI Diagnosis Guidelines

Introduction & Clinical Assessment Recommendations



Disorders Pathophysiologically Associated with Acquired von Willebrand Syndrome (AVWS)3

Slide 8

May 2011

Acquired von Willebrand syndrome (AVWS) refers to defects in VWF quantity, structure, or function that are not inherited directly, but are consequences of other medical disorders. Bleeding symptoms in AVWS are similar to those in VWD, and are mainly muco-cutaneous or surgical. However, in contrast to VWD, there is no antecedent personal or family history of VWD. Acquired VWF abnormalities, but without recognized clinical bleeding, may be referred to as "AVWA;" however this abbreviation is not standardized, and the risks of future bleeding associated with AVWA are currently not well understood.

This Table summarizes etiologic (pathophysiologic) categories and disease associations for AVWS and AVWA. Antibodies to VWF can rarely occur in autoimmune disorders such as lupus (SLE); however, monoclonal IgG or IgM antibodies such as in MGUS (monoclonal gammopathy of undetermined significance) or other dysproteinemias (eg, myeloma, macroglobulinemia, amyloidosis, etc) are relatively common causes of AVWS. Shear-induced VWF proteolysis (believed to be mediated by ADAMTS13) is an increasingly recognized cause of AVWS and AVWA, and can occur in association with severe aortic valvular stenosis (AS), ventricular septal defect (VSD), hypertrophic obstructive cardiomyopathy (HOCM), certain left ventricular assist devices (LVADs), or primary pulmonary hypertension (PPH). Marked thrombocytosis (blood platelets of 1 million or more per microliter) can cause AVWS or AVWA, and mainly occurs in association with essential thrombocythemia (ET) and other myeloproliferative disorders such as polycythemia vera (PV) or AMM (agnogenic myeloid metaplasia with myelofibrosis). Other listed conditions and pathophysiologies of AVWS are relatively rare, but should be considered in the etiologic differential diagnosis of AVWS. Laboratory findings in AVWS and AVWA are similar to those in VWD subtypes, especially Types 1, 2A, or 3. However, laboratory testing results currently cannot readily distinguish between VWD and AVWS (or AVWA); therefore, clinical assessment is essential for this important distinction.

AVWS, and disorders causing it, should be considered in persons found to have abnormal VWD test results and clinical bleeding, but without an antecedent personal or family history consistent with VWD. Conversely, when bleeding occurs in association with one of the causative medical conditions, AVWS should be considered and initial VWD testing performed if indicated.

Disorders Associated with AVWS3

 


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