Graham Hemostasis 2012 / Exam 2 / 3rd deck / Platelet Inhibition Flashcards Preview

CVPR 330 Blood > Graham Hemostasis 2012 / Exam 2 / 3rd deck / Platelet Inhibition > Flashcards

Flashcards in Graham Hemostasis 2012 / Exam 2 / 3rd deck / Platelet Inhibition Deck (37):
1

3 Choices to Inhibit Thrombin ?

- Unfractionated Heparin
- Low Molecular Weight
Heparins
- Direct Antithrombins

2

Unfractionated-Heparin inhibits what factors?

Factor IIa
Factor Xa

3

Test of choice to monitor Heparin ?

PTT

4

Low molecular weight heparin (LMW)-inhibits what factor?

Xa

5

How many units are required to Inhibit factor IIa ?

13 + Units

6

How many units are required to Inhibit factor Xa ?

5 units

7

Heterogeneous mixture of many different size molecules that acts by enhancing the effect of antithrombin and has an Immediate action when it enters the bloodstream

Unfractionated Heparin

8

Heparin Risks

- Hemorrhage
- Heparin-induced
thrombocytopenia
- Osteoporosis associated with long term therapy

9

Anticoagulation and clearance are influenced by ?

Chain Length

10

Activated Clotting Time normal range ?
Threshold determined for optimal heparinization ?

100 - 150 sec


>400 sec

11

Celite times are artificially prolonged by

Aprotinin

12

Low Molecular Weight Heparins have a longer biologic half-life. Name 6 LMW heparins?

Nadroparin calcium - Fraxiparin
Enoxaparin sodium - Lovenox
Dalteparin - Fragmin
Ardeparin - Normiflo
Tinzaparin - Innohep
Revipatin - Clivarine

13

Direct Antithrombins

Inhibit thrombin without requiring antithrombin

14

Approved medications for anticoagulation in patients with HIT ?

Hirudin and argatroban

15

While heparin can catalyze multiple reactions, ______ irreversibly binds to thrombin and may potentially be used up. It does however have a greater ability to inhibit thrombin activity.

hirudin

16

snake venom which causes the calcium-independent activation of prothrombin by cleaving the 323Arg-324Ile bond, producing meizothrombin. This active form of thrombin is inhibited by hirudin (and r-hirudin), but not the heparin-AT complex.

Ecarin

17

Argatroban (ACOVA)

- A direct thrombin inhibitor that reversibly binds to the thrombin active site
- Metabolized by the liver
- Monitored by ACT or APTT

18

Used to prevent clotting in patients with atrial fibrillation without heart valve disease
Oral thrombin inhibitor

Pradaxa

19

How long does it take for patients to become HIT antibody negative ?

Approximately 3 months

20

Treatment Options for HIT in CPB

- Ideally, delay elective surgery until patients are antibody negative.
- Use heparin with protamine reversal during surgery
- Use alternative anticoagulants in pre and post op period

21

alternative anticoagulants throughout CPB for patients with HIT ?

Bivalirudin

22

- Oral direct Xa inhibitor, use expanded to include treatment or DVT and PE.
- No antidote available.
- Not dialyzable do to its high plasma protein binding.

Xarelto (rivaroxaban)

23

Direct Xa inhibitor Cleared for prevention of stroke in non-valvular atrial fibrillation

Eliquis (apixaban)

24

Polybrene

added to counteract heparin (up to 1 U/mL) in our reagents does NOT NEUTRALIZE hirudin, r-hirudin, or argatroban

25

Vitamin K dependent factors ?

II
VII
IX
X
Protein C & S

26

Coumadin

- Inhibits vitamin K dependent factors.
- Monitor with PT test.

27

Warfarin or Coumadin mechanism of action ?

Antagonizes Vitamin K which in turn synthesizes Non-Functional coagulation factors II, VII, IX, X,

28

International Normalized Ratio (INR)

International effort to standardize reporting of prothrombin times.

INR = Patients PTT^ISI/Normal PTT

29

Recommended Therapeutic INR Range for Pulmonary Embolus, DVT, A-Fib, and Prophylaxis ?

2.0 - 3.0

30

Recommended Therapeutic INR Range for prosthetic heart valves and recurrent systemic embolisms?

3.0 - 4.5

31

3 medications for Anti-platelet Therapy ?

Aspirin
Plavix
Effient

32

Plavix (clopidogrel)

- Inhibits ADP receptor on platelets (P2Y12)
- Some monitor with “aspirin tolerance testing” aka mini-aggregation studies

33

Effient (prasugrel)

- Inhibits ADP receptor on platelets (P2Y12)
- Claims to have more rapid inhibition of platelet activity than Plavix.
- Often used in conjunction with aspirin

34

Thrombolytic Therapy

Drugs or enzymes that act on pre-existing thrombi.
- Streptokinase
- Pro-urokinase
- Tissue plasminogen
activator (tPA)
greater specificity for fibrin

35

Anti-Fibrinolytic Therapy

Inhibit fibrinolysis by blocking the binding sites of plasminogen to prevent formation of plasmin.

- Epsilon amino caproic acid
(EACA)
- Tranexemic acid

36

Epsilon Amino Caproic Acid (EACA, Amicar)

Synthetic anti-fibrinolytic forms an irreversible complex with plasminogen or plasmin

37

Tranexemic Acid

Synthetic anti-fibrinolytic forms an irreversible complex with plasminogen or plasmin

10X as potent