High Plasma Levels of Factor VIII and the Risk of Recurrent Venous Thromboembolism

Elevated plasma levels of factor VIII are associated with an increased risk of venous thrombosis. 1 – 3 In the Leiden Thrombophilia Study, plasma levels of factor VIII above 150 IU per deciliter were associated with a quintupled risk of venous thrombosis, 1 an observation that was confirmed by another study from the Netherlands. 3 Among patients with venous thrombosis, the prevalence of an elevated plasma level of factor VIII is approximately 20 percent. 2 , 3 High factor VIII levels persist over time, 3 , 4 are not attributable to an acute-phase reaction, 2 – 5 and may involve a genetic predisposition. 3 The mechanism by which a high factor . . .