Hemostasis II

Question 1

Name 3 important anticoagulants

Answer 1

Antithrombin III
Protein C/ProteinS
Tissue factor pathway inhibitor (TFPI)

Question 2

How does Tissue Factor Pathway Inhibitor (TFPI) work?

Answer 2

It inhibits the function of TF:VIIA complex and FXa

-Prevents TF-induced thrombogenesis (prothrombin–>thrombin)

Question 3

Antithrombin III

Answer 3

STRONGLY inhibits FX and thrombin
Partially inhibits Factors, 9/11/12
-Require cofactor for Heparin

Question 4

What happens when heparin binds to Antithrombin III

Answer 4

Antithrombin’s affinity for coagulation factor increases

Question 5

What factors does activated Protein C inactivate?

Answer 5

Va (5a) and VIIIa (8a)

Question 6

Protein C is activated when?

Answer 6

Thrombin is bound to thrombomodulin on the surface of intact endothelial cells.

Question 7

APTT is part of what pathways?

Answer 7

Intrinsic + Common

Question 8

PT is part of what pathways

Answer 8

Extrinsic + Common

Question 9

Causes for prolonged PT

Answer 9

Deficiencies in extrinsic and common pathway factors

• Vitamin K. antagonists
• Liver Disease

Question 10

Vitamin K. Antagonists

Answer 10

Coumarins

• Coumadin
• Bishydroxycoumarin

Question 11

Blood levels of coumadin peak in ___minutes, and the t1/2 is___?

Answer 11

90minutes, 36-42 hours

Question 12

Vit K. is responsible for making what amino acid?

Answer 12

Gama-carboxyglutamate

Question 13

What is gama-carboxyglutamates purpose?

Answer 13

Allows clotting factors to undergo a calcium dependent conformational change which allows them to bind to phospholipid surfaces leading to generation of membrane bound macromolecule complexes

Question 14

Why is APTT referred to as partial thromboplastin?

Answer 14

because no Tissue Factor was used

Question 15

Causes of prolonged APTT

Answer 15

deficiency in factors specific to the intrinsic pathway
-hemophilia A
-VWD
Heparin
Lupus anticoagulant 
Liver disease
DIC

Question 16

Direct thrombin inhibitors

Answer 16

• Argatroban

- Hirudin (lepirudin)

Question 17

What thrombocytopenic disorder is Argatroban frequently used?

Answer 17

HITT

Question 18

Prolonged PT and normal APTT is indicative of what factor deficiency?

Answer 18

FVII

Question 19

Normal PT and Prolonged APTT is indicative of what factor deficiencies?

Answer 19

Deficiency in any intrinsic pathway factors

Question 20

Prolonged APTT and PT is indicative of what factor deficiencies?

Answer 20

Factors of the common pathway (X, V, II, I)

Question 21

DDAVP is used in the Tx of what blood disorders?

Answer 21

VWD, and Hemophilia A

Question 22

How does DDAVP work?

Answer 22

increases plasma levels of FVIII and VWF due to release from endogenous stores

Question 23

After receiving DDAVP, how long does it take for plasma levels of FVII to increase?

Answer 23

30 minutes, max effect 1-2 hours.

Question 24

What is Novoseven?

Answer 24

Recombinant factor VIIa

-activates FX and FIX which convert prothrombin to thrombin

Question 25

Novoseven is FDA approved to treat what disease?

Answer 25

Hemophilia A