Factor VII deficiency is a rare autosomal
bleeding disorder with a highly variable hemorrhagic predisposition. Severe
bleeding, including
hemarthroses, may be encountered when plasma
factor VII levels are below 1%. Patients have prolonged prothrombin times, and the final diagnosis is established by quantitative
factor VII assays. Some patients have true deficiencies, that is, very low
factor VII activity and low
factor VII antigen (cross-reacting material) levels (CRM-); others have normal
antigen levels but low activity (CRM+). Still others have reduced
antigen levels (CRMR). There is a rather poor correlation between clinical symptoms and
factor VII activity levels in plasma. Treatment of these patients consists of fresh frozen plasma,
prothrombin complex concentrates, or
factor VII concentrates. Recombinant
activated factor VII (
rFVIIa) is a very useful alternative, and several patients have been treated successfully. Because of the short half-life of
factor VIIa, repeated doses have to be administered, and continuous infusion may be even better.
Antibodies to
factor VII have been reported but seem to be rather rare. From the available data it appears that
rFVIIa is a safe and effective treatment modality for patients with congenital
factor VII deficiency.