Inherited Thrombophilia Flashcards
Factor V Leiden heterozygote
List: prevalence VTE risk without prior VTE VTE risk with prior VTE percentage of all VTE
prevalence 1-15%
VTE risk without prior VTE 0.5-3.1%
VTE risk with prior VTE 10%
percentage of all VTE 40%
Factor V Leiden homozygote
List: prevalence VTE risk without prior VTE VTE risk with prior VTE percentage of all VTE
prevalence <1%
VTE risk without prior VTE 2.2-14%
VTE risk with prior VTE 17%
percentage of all VTE 2%
Antithrombin deficiency
List: prevalence VTE risk without prior VTE VTE risk with prior VTE percentage of all VTE
prevalence 0.02%
VTE risk without prior VTE 0.2-11.6%
VTE risk with prior VTE 40%
percentage of all VTE 1%
Protein C deficiency
List: prevalence VTE risk without prior VTE VTE risk with prior VTE percentage of all VTE
prevalence 0.2-0.4%
VTE risk without prior VTE 0.1-1.7%
VTE risk with prior VTE 4-17%
percentage of all VTE 14%
Protein S deficiency
List: prevalence VTE risk without prior VTE VTE risk with prior VTE percentage of all VT
prevalence 0.03-0.13%
VTE risk without prior VTE 0.3-6.6%
VTE risk with prior VTE 0-22%
percentage of all VTE 3%
What is the MOA for FVL deficiency?
Mutation renders FVL refractory to proteolysis by activated protein C
What is the MOA for Prothrombin G20210A?
The prothrombin G20210A mutation is a point mutation that results in elevated circulating prothrombin levels
Prothrombin gene heterozygote
List: prevalence VTE risk without prior VTE VTE risk with prior VTE percentage of all VT
prevalence 2-5%
VTE risk without prior VTE 0.4-2.6%
VTE risk with prior VTE >10%
percentage of all VTE 17%
Prothrombin gene homozygote
List: prevalence VTE risk without prior VTE VTE risk with prior VTE percentage of all VT
prevalence <1%
VTE risk without prior VTE 2-4%
VTE risk with prior VTE >17%
percentage of all VTE 0.5%
Factor V Leiden/Prothrombin double heterozygote
List: prevalence VTE risk without prior VTE VTE risk with prior VTE percentage of all VT
prevalence 0.01%
VTE risk without prior VTE 4-8.2%
VTE risk with prior VTE >20%
percentage of all VTE 1-3%
What is the MOA for Protein S Deficiency?
2 causes:
a silenced gene or a mutation that results in reduced free protein S antigen levels and activity
Thrombophilias(2) associated with neonatal purpura fulminans
Protein C Deficiency and homozygous protein S deficiency
Do Methylenetetrahydrofolate Reductase Mutations increase your risk for VTE?
What does this condition cause?
No
Hyperhomocysteinemia
Which of the following are associated with inherited thrombophilias?
Stillbirths
Preeclampsia
Fetal Growth Restriction
Placental Abruption
None
Who are the candidates for thrombophilia evaluation?
- Personal history of VTE, with or without a recurrent risk factor, and no prior testing.
- First-degree relative (parent or sibling) with history of high-risk inherited thrombophilia
What are the laboratory tests for thrombophlia evaluation?
factor V Leiden mutation prothrombin G20210A mutation antithrombin protein S deficiency protein C deficiency
Ideally, 6 weeks after a thrombotic event, not pregnant or taking anticoagulation/hormonal therapy
In the nonpregnant state, what is the value of free protein S consistent with protein S deficiency?
< 55%
Prophylaxis is recommended when the risk of VTE exceeds ____%
3
What are the thrombophilias associated with a high risk of VTE?
FVL homozygotes
Prothrombin gene homozygotes
FVL/PT double heterozygotes
Risk with no prior VTE 4-5 % –> anticoagulate
prior VTE 15-20% –> anticoagulate
When do you discontinue prophylactic anticoagulation in the postpartum period?
What is the exception?
After 6 weeks
Life-long anticoagulation for women with recurrent VTEs
What are the tests that are reliable during pregnancy to test for Inherited Thrombophilias?
FVL mutation [activated protein C resistance assay]
[if abnml, DNA analysis]
Prothrombin G20210A mutation [DNA analysis]
Protein C deficiency [activity <65%]
Antithrombin Deficiency [activity <55%]
*not Protein S deficiency [functional assay <55%]
In the second trimester, below what value of free protein S is consistent with protein S deficiency?
< 30%
In the third trimester, below what value of free protein S is consistent with protein S deficiency?
< 25%
Which of the following conditions may be evaluated during pregnancy?
Factor V Leiden mutation Prothrombin G20210A mutation Antithrombin deficiency protein S deficiency protein C deficiency
All but Protein S deficiency
Factor V Leiden mutation Prothrombin G20210A mutation Antithrombin deficiency protein S deficiency protein C deficiency
Which of the following conditions may be evaluated during an acute thrombosis?
Factor V Leiden mutation Prothrombin G20210A mutation Antithrombin deficiency protein S deficiency protein C deficiency
Factor V Leiden mutation
Prothrombin G20210A mutation
Which of the following conditions may be evaluated while on anticoagulation?
Factor V Leiden mutation Prothrombin G20210A mutation Antithrombin deficiency protein S deficiency protein C deficiency
Factor V Leiden mutation
Prothrombin G20210A mutation
What are the high risk thrombophilias?
Factor V Leiden homozygous mutation
Prothrombin G20210A homozygous mutation
Antithrombin deficiency
Double heterozygotes: FVL/PT
Adjusted dose LMWH should be held ___ hours before anticipation of neuraxial anesthesia
24
Prophylactic dose LMWH should be held ___ hours before anticipation of neuraxial anesthesia
12
UFH and LMWH should be restarted ____ hours following vaginal delivery and ____ hours following a cesarean delivery.
4-6 ; 6-12
What thrombophilia is due to a mutation renders that renders FVL refractory to proteolysis by activated Protein C
Factor V Leiden deficiency
