An illustrative case and a review on the dosing of recombinant factor VIIa in congenital factor XI deficiency

Plasma contact factors as therapeutic targets

Direct oral anticoagulants (DOACs) are small molecule inhibitors of the coagulation proteases thrombin and factor Xa that demonstrate comparable efficacy to warfarin for several common indications, while causing less serious bleeding. However, because their targets are required for the normal host-response to bleeding (hemostasis), DOACs are associated with therapy-induced bleeding that limits their use in certain patient populations and clinical situations. The plasma contact factors (factor XII, factor XI, and prekallikrein) initiate blood coagulation in the activated partial thromboplastin time assay. While serving limited roles in hemostasis, pre-clinical and epidemiologic data indicate that these proteins contribute to pathologic coagulation. It is anticipated that drugs targeting the contact factors will reduce risk of thrombosis with minimal impact on hemostasis. Here, we discuss the biochemistry of contact activation, the contributions of contact factors in thrombosis, and novel antithrombotic agents targeting contact factors that are undergoing pre-clinical and early clinical testing.

Rare bleeding disorders - bleeding assessment tools, laboratory aspects and phenotype and therapy of FXI deficiency

Rare bleeding disorders (RBDs) are inherited deficiencies of coagulation factors such as fibrinogen, factor (F) II, FV, FVII, combined FV+FVIII, FX, FXI and FXIII. These disorders usually have a low prevalence in the general population and constitute approximately 3-5% of all coagulation disorders. However, in some countries they may have the same prevalence as haemophilia B due to the practice of consanguineous marriage. The clinical picture of RBDs is highly variable and can vary markedly from mild to severe, making both diagnosis and optimal treatment quite challenging. This review focuses on: (i) the efforts to establish a bleeding assessment tool adequate to RBDs, (ii) the optimal management of patients affected with FXI deficiency and (iii) the correlation between clinical severity and laboratory diagnosis when determining the minimum coagulant activity required to prevent bleeding in each RBD.

First diagnosis of factor XI deficiency in a patient with subarachnoid haemorrhage

Aneurismal subarachnoid haemorrhage (SAH) is a devastating event affecting patients at a fairly young age and accounting for significant morbidity and mortality. Although there is progress concerning diagnostic methods and treatment, this case report might add interesting data to the current understanding of this disease and its clinical management with respect to circumstantial deficiency of the coagulation factor XI (FXI). In this report, we present a unique case of aneurismal SAH in a patient with underlying coagulation FXI deficiency which was incidentally identified after patient's admission, as routine blood tests revealed increased activated partial thromboplastin time. Despite early successful treatment with coiling, the patient had a second episode of SAH a few months after his discharge, due to aneurysm revascularization and rupture. Molecular analysis and identification of new mutations were performed. We describe management of SAH with respect to a coexisting bleeding disorder; also testing of patient's family members for FXI deficiency and decisions about screening for intracranial aneurysm are described. Late complications of SAH are - among others - aneurysm revascularization and rebleeding. Although FXI deficiency could be considered an exacerbating factor, it cannot be definitely implicated.

Factor XI deficiency—resolving the enigma?

The management of factor XI deficiency is not straightforward for three reasons: firstly, the role of this factor in the coagulation pathway is not clearly understood; secondly, the bleeding tendency, although mild, is unpredictable and does not clearly relate to the factor XI level; and thirdly, all treatment products, although available, have some potentially serious side effects. These factors (or enigmas) contribute to the variable management of patients with this coagulation factor deficiency, but recent research is helping to clarify some of these areas.

Review: Factor XI Deficiency: Review and Management in Pregnant Women

Factor XI deficiency is a rare disease found predominantly in Ashkenazi Jews. There is a poor correlation between factor XI level and bleeding in patients with factor XI deficiency. Individuals with severe factor XI deficiency are usually at risk of excessive bleeding after surgery and injury, particularly when trauma involves tissues rich in fibrinolytic activity. Women with partial or severe deficiency are at risk of excessive uterine bleeding during labor. The unpredictable nature of factor XI deficiency complicates management during pregnancy and delivery. This review gives an overview of the management of pregnant women with factor XI deficiency.

[Use of recombinant, activated Factor VII in the treatment and prevention of bleeding complications in two female patients suffering from congenital XI factor deficiency during orthopedic and traumatology intervention. Case reports]

The authors describe the treatment of the bleeding complications in two female patients suffering from a rare, inherited coagulation disorder; Factor XI deficiency after having major orthopaedic and traumatologic operations by activated, recombinant Factor VII (NovoSeven, Novo Nordisk, Bagsvaerd, Denmark). In the first case a total hip arthroplasty was performed because of severe, left-sided osteoarthritis. Despite of the standard protocol prescribed by the National Haemophilia Centre, severe bleeding complication occurred. The authors describe the pattern of the postoperative bleeding, the difficult decision on reoperation and the experience with activated, recombinant Factor VII, as a rescue treatment. In the second case the patient had a right femoral head fracture after falling. In her anamnesis it was known that she had severe bleeding complications despite factor substitution. After discussion with the National Haemophilia Centre operation was made by the use of NovoSeven.

Successful use of recombinant factor VIIa (NovoSeven) during cardiac surgery in a pediatric patient with congenital factor XI deficiency

We report our experience with the use of recombinant activated factor VII (rFVIIa) during cardiac surgery in a 4.5-year-old boy with severe congenital FXI deficiency and a congenital heart disease. After weaning the patient from cardiopulmonary bypass, the first intravenous dose of rFVIIa (90 microg/kg) was administered. This same dosage was repeated eight more times, at 2- to 4-hour intervals postoperatively. There was no bleeding during and after surgery. rFVIIa treatment may be used successfully in children with severe FXI deficiency in major operations such as open heart surgery.

Recombinant Factor VIIa for the Prophylaxis of Perioperative Hemorrhage in a Patient With Congenital Factor XI Deficiency Undergoing Brain Tumor Neurosurgery

The authors report on the first successful use of recombinant activated factor VII for the prophylaxis of bleeding during brain tumor neurosurgery in a patient suffering from inherited factor XI deficiency. Using the agent, surgery was performed without any bleeding complications. In this setting, off-label use of recombinant activated factor VII appears to be a promising alternative for patients suffering from this rare hemostatic defect with hitherto limited therapeutic options.