Congenital FVII deficiency and thrombotic events after replacement therapy

Thrombosis has been occasionally described in congenital FVII deficiency. This report deals with patients with FVII deficiency who presented thrombotic events after substitution therapy. At least 12 patients are reported in the literature. In all but two cases thrombosis occurred after prothrombin complex concentrates or plasma derived FVII concentrates. In two instances pulmonary embolism occurred after the administration of large amounts of whole blood. Concomitant prothrombotic risk factors were present in most of these cases (surgery, immobilization, old age, etc.). Personal files allowed us to add another patient who developed bilateral pulmonary embolism after two vials of an aFVII concentrate. In this case also, concomitant risk factors were present, namely surgery for hysterectomy, immobilization. The pulmonary embolism occurred in spite of the congenital FVII deficiency indicating that no sure antithrombotic protection is assured by this defect. The actual needs of substitution therapy in patients with some variants of FVII deficiency is discussed, together with comments on the therapeutic management of the thrombotic events in these patients.