Poster Session I: Bleeding disorders (congenital and acquired)
Factor XI deficiency is a rare bleeding disorder worldwide. The prevalence of heterozygous and homozygotes among Ashkenazi Jews is 8-9% and 0.22-0.53%, respectively. The severity of bleeding does not always correlate with plasma factor XI levels and many heterozygotes patients, with factor XI levels of 20-70 IU dl−1 are undiagnosed. Data regarding bleeding phenotype is scarce. Likewise, there is no consensus regarding safety of neuro-axial anesthesia (epidural/spinal) in these women. During pregnancy, aPTT is shortened due to physiological changes of pregnancy such as elevation in factor VIII, while the level of factor XI remains stable. Thus, in Ashkenazi Jews there is no indication to test aPTT or factor XI levels before neuro-axial anesthesia. We assume that up to 10% of the Ashkenazi Jewish women who had neuro-axial anesthesia in our center each year undergo neuro axial anesthesia without knowing factor XI deficiency status.
1. Assess the incidence of Jewish Ashkenazi women heterozygotes for factor XI deficiency who underwent neuro-axial anesthesia in our center. 2. Asses the bleeding tendency, aPTT and thrombin generation in Jewish women of Ashkenazi descent with/without factor XI deficiency.
Jewish women from Ashkenazi origin who underwent neuro-axial anesthesia during labor in our center were recruited. After labor and signing an informed consent form, women were asked to complete the SSC ISTH bleeding assessment tool (BAT) and had blood drawn for PT, aPTT, fibrinogen, factor XI and thrombin generation. Thrombin generation was tested on a fully automated coagulation analyzer using low concentration of tissue factor 0.3pM. Reduced factor XI was defined as below 70 IU dl−1. Patients were divided according to factor XI levels; group A <70 IU dl−1 and group B ≥ 70 IU dl−1.
Between August 2017 and October 2018, 248 women were recruited. Of them 81% were of full Ashkenazi ethnicity. Group A included 39 (16%) women with median factor levels of 63 IU dl−1 (range: 32-69.6 IU dl−1) and group B included 209 women with a median of 96 IU dl−1 (range: 70.1-270 IU dl−1). Among group A, 20 women (51%) underwent neuro-axial anesthesia in previous labors and 17 women (44%) underwent amniocentesis in the current pregnancy. No bleeding complications were noted in these procedures as well as in the present neuro-axial anesthesia. Only 1 patient (group B) reported a family history of FXI deficiency. 240 women (97%) completed the BAT. There was no difference in bleeding history as reported in BAT between the 2 groups. 9 women (23%) from group A reported any bleeding complications (2 epistaxis, 1 menorrhagia, 6 postpartum hemorrhages (PPH);1 in the present labor) compared to 48 (23%) women from group B (including 13 women with PPH). Thrombin generation did not differ between the groups (Table 1). Although aPTT was within the normal range in all women, aPTT levels were significantly lower in group A compared to group B.
A significant number of Jewish Ashkenazi women with undiagnosed partial FXI deficiency undergo neuro-axial anesthesia. Bleeding phenotype does not differ between women with or without partial factor XI deficiency. Thrombin generation at delivery does not differ between women with or without factor XI deficiency, suggesting that hypercoagulability of pregnancy may compensate for factor XI deficiency and neuro-axial anesthesia may be safe in these women.