April 2024
Factor XI deficiency
- Rare prevelance is 1/1 million Caucasian/ Ashkenzi Jews
- However among rare bleeding disorders, it tops the list
- Deficiency - two types- quantitative and qualitative
- Severe disease if homozygous or compound heterozygous
- Severe def if factor XI levels < 15 to 20 IU/dl
- Clinical manifestations- due to injury, increased bleeding with circumcision, tonsillectomy, increased menstrual and post partum bleeding
- If no personal hx of bleeding, that was the best predictor of low risk. Also if levels > 40 IU
- Older pt- factor XI remains the same. Can use anticoagulation for Afib if no bleeding hx or def is not severe. Using factor XI / VII a to counteract bleeding after surgery can lead to thrombosis in rare cases.
- May develop inhibitors to Factor XI but don't get spontaneous bleeding
- No standard prophylaxis even if levels < 1%
- High risk surgery e.g neurosurgery- tranexamic acid, FFP, FXI concentrate, off label factor 7a
- Gross hematuria in GU surgery contraindication to antifibrinolytic such as tranexamic acid
- Minor surgery : 3-5 days TXA or EACA
- Major surgery: 7-10 days of TXA or EACA, FFP, Factor XI and off label factor 7a recombinant( mostly for those with factor XI inhibitors from prior FFP)
- Dose of FFP 20 ml /kg q 24
- Dose of Factor XI 10-20 IU/kg repeat q 48 hr
- Dose of Novo Seven- single dose 10-15 microgram /kg
Factor XI inhibitors for VTE prevention
- Three categories- Monoclonal Ab, small molecule oral agents, DNA antisense oligonucleotide
- While Factor XI inhibitors reduced risk of VTE esp post op, these drugs were not effective in secondary stroke reduction
- Inferior efficacy compared to DOAC in Afib and stroke reduction
- These drugs caused less bleeding than DOAC
Interesting MCQ question for ASH: Name the gene variation associated with gestational thrombocytopenia?
Ans: PEAR1 ( plt endothelial aggregation receptor)
No comments:
Post a Comment