Factor XI Deficiency
In patients with FXI deficiency, oral antifibrinolytic agents alone may be used for hemostatic management of dental extractions. The bleeding risk depends on the type of surgery. Bleeding complications are much less likely to occur with surgery in areas without fibrinolysis.
A review article of various surgical procedures in people with severe FXI deficiency who did not receive prophylaxis showed that surgical procedures in areas of high fibrinolysis (eg, dental extraction, tonsillectomy, and prostatectomy) were associated with bleeding rates of 49% to 67%. In contrast, orthopaedic procedures were not associated with excessive bleeding.32
Low-dose recombinant activated factor VII (rFVIIa) is effective in preventing bleeding related to surgery in patients with FXI inhibitors.38
Fresh frozen plasma has been the mainstay for replacement therapy, but its use is inconvenient as large volumes may be required. If used, it should preferably be pathogen-inactivated, if available.
Factor XI concentrates are available in some countries: namely, a British product made by Bio-Products Laboratory (BPL), and a French product made by LFB. Both are effective in raising the FXI level and preventing hemorrhage,39 but have an associated risk of thrombotic events, particularly in persons who may have an underlying predisposition to these events, e.g. individuals with pre-existing cardiovascular disease.40 Twelve thrombotic events related to the French concentrate were reported in 2014 and revised guidance on its use was issued.41 Additional in vitro experimental work verified differences between the two concentrates, confirming that a lower dose of the LFB concentrate relative to the BPL concentrate induces normalisation of thrombin generation.15 The thrombotic risk has been reviewed.42 Additional case studies with successful treatment using these concentrates put their use into context.43-45 These products can be used successfully, but with caution must be exercised in those with additional risk factors and with appropriate information and consent. UK guidelines have recently been updated to reflect these cautions.46
Antifibrinolytic agents are very effective and may be used alone for dental extractions, even in cases involving severe FXI deficiency.47 Antifibrinolytics are also very helpful in the management of menorrhagia, together with hormone therapy if needed.33
The development of FXI inhibitors is a significant risk in persons without detectable FXI (e.g. Glu117Stop homozygotes). Up to 30% of these individuals have been found to develop inhibitors.48 Interestingly, inhibitor development is infrequently associated with increased bleeding. Some clinicians recommend avoidance of plasma products to reduce the risk of inhibitor development.Next