Thrombosis, Venous, Elevated Factor VIII Level

Synonyms

Increased factor VIII; FVIII

Definition and Characteristics

The gene product is a protein synthesized in the liver. After secretion in plasma it associates with von Willebrandfactor (vWF), which stabilizes its activity as a cofactor in the intrinsic system. FVIII is particularly important for catalyzing the rate of FX activation in the tenase complex. Whereas its absence is associated with a bleeding diathesis (hemophilia A), an increased concentration may increase the rate of thrombin generation and is thrombogenic in an animal model [1].

Prevalence

Not applicable. In the LETS case-control study the odds ratio for deep venous thrombosis for patients with a factor VIII clotting activity level >150% compared to those with a level <100% was 4.8 (95% CI 2.3-10). [2]. A similarly increased risk ratio was found for recurrent venous thrombosis. In a prospective study in patients after a first episode of venous thromboembolism