Replacement therapy for congenital Factor X deficiency.

We studied a young woman with severe (less than 1%) congenital factor X deficiency during a 2-year period in order to document the levels of factor X required to provide hemostasis for vaginal bleeding, epistaxis, and hemarthroses, as well as during surgery. Factor X levels of 9 to 17 percent, achieved with fresh-frozen plasma (FFP) were satisfactory for minor bleeding. Hemostasis was achieved during emergency surgery for hemoperitoneum by increasing the factor X level to 35 percent with a Factor IX concentrate, followed with infusions of FFP to maintain levels between 10 and 20 percent for 6 days postoperatively. These data suggest that factor X levels of 10 to 20 percent are sufficient for hemostasis in factor X-deficient patients even in the immediate postoperative period.