Anticoagulants Flashcards
What are the categories of antithrombotics?
- Anticoagulants
- Fibrinolytics
- Antiplatelets
What do anticoagulants do?
Stop clot formation and extension
What do fibrinolytics do (in general)?
Break up existing clots
What do antiplatelets do?
Decrease platelet activation and aggregation
What are the two types of thrombi and how do they differ?
- White thrombus (platelet rich, forms in arteries, MI)
- Red thrombus (fibrin/RBC rich, forms in veints, DVT/PE)
What does TXA2 do?
Vasoconstriction
What does vWF do?
Binds to exposed collagen fibers at the injured vessel surface
What does fibrinogen do?
- Forms bridges between adjacent platelets
- This results in an aggregate of platelets at the vessel injury site
What does thrombin (factor IIa) do?
Converts fibrinogen to fibrin (which forms the stable clot)
What is the final result of the coagulation cascade?
Fibrin threads create a plug to make a stable clot
What are the overall steps of platelet activation?
- Injury
- Collagen and vWF exposed
- Platelet adherence and activation
- Binding of fibrinogen
- Aggregation and plug formation
What are the mediators of platelet aggregation?
TXA2
ADP
5-HT
What are the pathways of the coagulation cascade and how are they activated?
- Intrinsic (activated by exposed endothelium)
- Extrinsic (activated by tissue damage)
- Common (intrinsic and extrinsic merge together)
What is the first step in the common pathway of coagulation?
Activation of Factor Xa
What is the last step in the intrinsic and extrinsic pathways of coagulation?
Activation of Factor Xa
What factors are necessary to form a clot?
Factor 2 (prothrombin) Factor 10
What does Factor Xa do in the coagulation cascade?
Combines with Factor 2 (prothrombin) to form thrombin
What factors are targeted by Warfarin?
SNOT
Seven, Nine, Ten (0), Two
What does prothrombin time (PT) measure?
Activity of Factors 2, 7, 9, 10
What is INR?
- International Normalized Ratio
- Same as PT but standardized worldwide
What does PTT measure?
Activity of Factors 2, 5, 7, 9, 10, 11, 12
What is activated clotting time (ACT)?
- Same as PTT but used in invasive/operating procedures
- Quicker result turnaround