Von Willebrand factor (VWF) is a blood glycoprotein involved in hemostasis. It is synthesized in endothelium and megakaryocytes, where it forms large multimers and anchors platelets to sub-endothelium. VWF levels vary by blood group, and are decreased in conditions like Von Willebrand disease and increased in cardiovascular disease. Von Willebrand disease is the most common inherited bleeding disorder, classified into types 1, 2, and 3 based on quantitative or qualitative VWF deficiencies. Treatment involves cryoprecipitate, DDAVP, or factor VIII concentrate.

1. VON WILLEBRAND FACTOR
SURAMYA BABU

2.  VON WILLIBRAND FACTOR (VWF) is a blood glycoprotein involved in hemostasis
 Synthesis in endothelium and megakaryocytes
 Forms large multimer
 Anchors platelet to sub-endothelium

3. Reference range
 VWF Ag: 61.3-158 %
 VWF activity: 49-170 %

4. Relationship between blood group and
VWF level
Blood groups VWF LEVEL %
O 74.8
A 105.9
B 116.9
AB 123.9

5. VWF DECREASED CONDITION VWF INCREASED CONDITION
Von Willibrand disease Cardiovascular disease
Thrombotic thrombocytopenic
purpura
Neoplastic disease
Heydes syndrome Connective tissue disease
Hemolytic uremic syndrome

6. Von willibrand disease
 Most common inherited( autosomal dominant) bleeding disorder
 Incidence: 1:100 – 1: 1000
 Presents most commonly as platelet –type bleed
 Spontaneous bleeding, mucocutaneous bleed
 Prolonged bleeding time , normal platelet count

7. Classification of VWD
TYPE 1 VWD TYPE 2 VWD TYPE 3 VWD
Most common 75-80 % Less common 15-20 % Rare (1;500,000)
Autosomal dominant Autosomal dominant Autosomal recessive
Quantitative deficiency
(reduced VWF)
Qualitative deficient
(dysfunctional VWF)
Absent VWF
Mild Mild to moderate Severe, present in early
childhood

8. Lab evaluation of VWD
ASSAY TYPE 1 VWD TYPE 2 VWD TYPE 3 VWD
VWF antigen normal
VWF activity
Multimer analysis Normal Normal Absent

9. Treatment of VWD
 CRYOPRECIPITATE
• Source of fibrinogen , factor VIII AND VWF
• Only plasma fraction that consistently contains VWF multimers
 DDAVP (DEAMINO -8 – ARGININE VASOPRESSIN)
• It increase plasma VWF levels by stimulating secretion from endothelium
• Not generally used in type 2 disease
• Dosage 0.3 ug/kg q 12 hour intravenously
 Factor VIII concentrate
• virally inactivate product