Medical Care
Although a plasma-derived factor V concentrate is undergoing preliminary testing, [25] no concentrates of factor V are commercially available. Instead, fresh plasma or fresh frozen plasma (FFP, Octaplas) infusions are used to correct the deficiency temporarily and should be given daily during a bleeding episode. The loading dose of FFP is 15-20 mL/kg and then 3-6 mL/kg daily. Subsequent dosages depend on monitoring the factor V level by obtaining peak and trough factor V level assays. The half-life ranges from 24-36 hours, with the aim being a factor V level of 25%. Fluid overload and viral transmission may be a complication of plasma therapy.
Alternatively, platelet transfusions are emerging as an alternative to FFP. Factor V stored within platelet alpha granules has greater procoagulant potential and is released locally at sites of vascular injury. [26]
Preoperative and postoperative care when patients with factor V deficiency require surgery include the following:
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In pregnant women, considerable bleeding can occur at the time of delivery; however, the administration of FFP can properly control bleeding, with excellent fetal outcome.
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The safe level of factor V for adequate surgical hemostasis is 25% of the activity of factor V in normal control plasma. [27]
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Postoperatively, FFP should be administered for 3-10 days, with careful observation of wound bleeding.
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Tooth extraction in a patient with factor V hereditary deficiency is safely performed with both supplementation of FFP and application of local hemostasis. [28]
Female patients with factor V deficiency can be given oral contraceptives to decrease menometrorrhagia, thereby improving anemia and decreasing transfusion needs. [20] Patients who may require plasma-derived coagulation factor concentrates should receive hepatitis B vaccine.
The optimal treatment of patients with factor V inhibitors is uncertain. Plasma exchange combined with immunosuppression has proved effective. [29] Fu et al were successful in using a combination of factor replacement, chemotherapy, and plasmapheresis in a patient with spontaneous, life-threatening intracranial bleeding caused by a factor V inhibitor. The patient's condition deteriorated after initial treatment with FFP and platelet transfusions. He was subsequently treated with a combination of plasma exchange and chemotherapy, and he completely recovered. [30] The experience of Fu et al shows that combinations of therapies may be needed in patients with serious hemorrhage caused by acquired factor V deficiency.
Corticosteroids have been used successfully in acquired factor V deficiency. A case report by Wang et al describes successful elimination of a low-level factor V inhibitor and control of bleeding with corticosteroid therapy, in a patient with reduced factor V activity and a factor V inhibitor level of 1.9 BU, probably secondary to a urinary tract infection. [16] Gavva et al report two cases successfully treated with corticosteroids, one likely secondary to antibiotics and the other, to either hepatitis C virus or antibiotic exposure. [26] Wu et al report successful treatment with immunosuppressive therapy including steroids and cyclophosphamide in a patient with acquired factor V deficiency and life-threatening pelvic hemorrhage. [31]
Gene therapy is a promising future approach to treatment of factor V deficiency. Nakamura et al report successful correction of F5 mutation in induced pluripotent stem cells from a factor V–deficient patient through the use of a clustered regularly interspaced short palindromic repeats (CRISPR)/CRISPR-associated 9 (Cas9). [32]
Consultations
Consultations may include hematologists, blood bank specialists, pathologists, and others as indicated based on hemorrhagic complications.
Long-Term Monitoring
Ideally, a hematologist who has experience in the diagnosis and management of inherited bleeding disorders should monitor individuals with severe factor V deficiency.
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Antithrombin sites of action.
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Cell surface-directed hemostasis. Initially, a small amount of thrombin is generated on the surface of the tissue factor (TF)–bearing cell. Following amplification, the second burst generates a larger amount of thrombin, leading to fibrin (clot) formation. Adapted from Hoffman and Monroe, Thromb Haemost 2001, 85(6): 958-65.
