Factor XI deficiency

Autosomal recessive disease, most prevalent in Ashkenazi Jews with a 4.3% gene frequency.

Bleeding involves both males and females with a positive family history.

Spontaneous bleeding, common in hemophilia A and B, is rare in factor XI deficiency.

Typically associated with excessive bleeding related to surgery, trauma, and menses.

Laboratory findings include a normal platelet count, PT, thrombin time and a prolonged thromboplastin time which corrects with mixing studies.

Diagnosis is confirmed by measuring factor XI levels.

Role in thrombosis is unknown, but risk of venous thromboembolism in congenital factor XI deficiency is reduced.

Heterozygotes have about 40-50% of normal factor XI activity and do not manifest clinical bleeding.

Detected in heterozygotes by elevated partial thromboplastin time.

Clinically bleeding cannot be predicted based on the degree of factor XI deficiency and prior history or family history provides the best indication of bleeding potential from surgery or trauma.

Acute bleeding episodes can be treated with fresh frozen plasma at 20 mL/kg body weight.

Fresh frozen plasma most available source of factor XI.

To achieve factor XI levels with 50%, half of a patient’s plasma volume will have to be replaced.

Recovery of factor XI function from plasma is excellent, with a half-life of 40-80 hours.

For dental procedures fresh frozen plasma and antifibrinolytics may be used.

With invasive surgical procedures fresh frozen plasma replacement may be needed for 7-14 days after surgery.

Pregnant women with need for cesarean delivery will require fresh frozen plasma.

Long half-life of factor XI of up to 50 hours.

Factor XI antisense oligonucleotide lowers factor XI and decreases risk of thromboembolism after total knee arthroplasty ( Buller HR et al).

Plasma derived factor XI concentrates associated with hypercoaguable state.

Adjunctive therapy with plasmapheresis, platelet transfusions and epsilon aminocaproic acid may be useful when bleeding is not controlled by fresh frozen plasma alone.

Can occur in conjunction with other inherited coagulopathies and can be acquired in conjunction with the development of autoantibody inhibitors, most common seen with lupus erythematosus.

Alloantibody inhibitors can occur with fresh frozen plasma treatment for severe deficiency disease and may require activated factor VII management for active bleeding.

Factor XI is important for the development of postoperative venous thromboembolism and its inhibition with abelacimab is effective for prevention of venous  thromboembolism after total knee arthroplasty.

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