Coagulation-Freeman Flashcards
(blank) pathway is the main system that causes clotting
Extrinsic pathway
Why do you get hypercoag because of factor V Leiden?
In this disorder, the Leiden variant (form) of factor V cannot be inactivated (switched off) by activated protein C, and so clotting is encouraged
What does normal factor 5 do?
APC binds to factor V and cleaves it into 2 inactive fragments
(blank) thrombophilia is a genetically inherited disorder of blood clotting. It is a variant (mutated form) of human factor V that causes an increase in blood clotting (hypercoagulability)
Factor V Leiden
In the normal person, factor V functions as a cofactor to allow factor (blank) to activate an enzyme called thrombin. Thrombin in turn cleaves fibrinogen to form fibrin, which polymerizes to form the dense meshwork that makes up the majority of a clot. Activated protein C (aPC) is a natural anticoagulant that acts to limit the extent of clotting by cleaving and degrading factor V.
Xa
What is the incidence of factor V leiden?
3-8%
What is the risk of hypercoagulable in heterozyg of factor V leiden?
8X
What is the risk of hypercoagulable of homozy factor V leiden?
20X
What do heparins do?
bind to Anti thrombin III to block Xa
What is the key to degrading clots or preventing them?
inhibiting fibrin formation
(blank) and (blank) can cause vasoconstriction
epi and nicotine
What are the two components in flow dynamics?
mechanical and chemical
What are the components for flow dynamics?
prior sites of thrombus
compression (obesity)
chemical (nictone, vasoconstricting agents)
What are the modifiable factors for coagulation?
- Obesity
- Sedentary life-style
- Travel
- BCPs
- Pregnancy
- Surgery (elective)
- Smoking
- Prior DVT
What are the unmodifiable factors for coagulation?
- factor V leiden
- prothrombin gene mutation
- malignancy
- surgery (emergent)
- chronic illness
- lupus anticoagulant
The body need how many risk factors to clot?
4 (the body has a near perfect system to prevent clotting)
In acute thrombogenesis, what should you give patients?
7-10 days of full heparinization (LMWH) (regardless of coumadin levels)
What are the vit-K dependent factors?
2,7,9,10
Protein C/S
What is the 1/2 life of factor X?
What is the 1/2 life of protein C?
48H
6H
***notice that protein C has shorter half life so you might get a hypercoag state)
When can you initiate coumadin?
at time of heparin-> course of coumadin is based on etiology of thrombogenic event
(blank) anticoagulants may be seen at time of acute thrombotic events (acute phase reactants).
Lupus anticoagulants (LA)
Repeat serology is recommeneded (blank) months after acute events prior to making long-term therapeutic coumadin decisions.
3
Lupus anticoagulant is actually a (Blank)
pro-coagulant (misnomer)
If you have LA in vitro, what will you see?
prolonged PTT
If you have LA in vivo, what will you see?
procoagulant
If your patient has HIT what should you give them?
agatroban
What are the 2 types of HIT?
Type I and Type II
What is this:
modest, transient decrease in platelets 2/2 heparin-induced platelet agglutination. Self-limited; plt counts can return to normal while heparin is continued.
Type I HIT
What is this:
a drug-induced, immune-mediated response 2/2 abs directed against heparin-plt factor 4 complex that results in 50% or greater drop in platelet counts. Severe thrombocytopenia w/ bleeding is rare!
HIT (type II)
Severe hit involves heparain and what clotting factor?
factor 4
What is the major problem with HIT?
the creation of a prothrombic state which can occur even after heparin has been discontinued
When do you typically see HIT?
in major surgery where large volumes of heparin are required (CABG) -> less commonly seen in medical patients
When should you be thinking about HIT?
in all recently hospitalized patients returning w/ acute thrombosis w/ in 1-2 weeks of their hospital stay
If you see thrombocytopenia AND thrombosis what should you be thinking?
HIT
How do you test for HIT?
radiolabeled platelet-serotonin release assay
How do you treat HIT?
direct thrombin inhibitors to treat the thrombosis