coagulation and anticoagulants

Question 1

characteristics of arterial coagulation?

Answer 1

occurs under high flow usually due to endothelial injury
pale - fibrin and platelets
adhere to vessel wall

Question 2

characteristics of venous coagulation?

Answer 2

occurs in non-injured veins due to stasis or hypercoagulability
red - RBC and fibrin
loosely attached to vessel wall

Question 3

examples of arterial vs venous thrombus?

Answer 3

arterial - MI, stroke
venous - DVT, portal vein thrombosis

Question 4

3 drug classes that reverse thrombus formation?

Answer 4

anticoagulants
antiplatelet agents
fibrinolytic agents

Question 5

what signs of DVT might be seen in patients?

Answer 5

asymmetrical legs - size and circumference
hot and hard skin

Question 6

risks caused by thrombus in leg?

Answer 6

damage vessels so circulation may not return to normal
can cause pulmonary embolism

Question 7

veins associated with DVT?

Answer 7

popliteal vein - knee crease
common femoral vein - groin crease

Question 8

3 steps of blood clotting?

Answer 8

vasoconstriction
platelet plug formation
coagulation

Question 9

what happens in vasoconstriction?

Answer 9

cells around injured area send signal
nerve reflexes myogenic spasm

Question 10

what happens in platelet plug formation?

Answer 10

Vw factors assist platelets to attach to exposed collagen
platelets release chemicals to attract more
fibrin mesh sticks platelets together to form clot

Question 11

what does conversion, of prothrombin A2 to thromboxane A2 do?

Answer 11

vasoconstriction
stimulates activation of new platelets as well as increases platelet aggregation

Question 12

which part of coagulation cascade is triggered by negative charge?

Answer 12

12 to 12a

Question 13

order of intrinsic coagulation cascade?

Answer 13

12a, 11a, 9a, 8a, 10a, 5a, 2a(thrombin), 13(fibrin)

Question 14

order of extrinsic coagulation cascade?

Answer 14

tissue factor(3), 7a, 10a

Question 15

what reaction does INR measure?

Answer 15

rate of 7 to 7a reaction

Question 16

what activates factor 13 (fibrinogen)?

Answer 16

thrombin

Question 17

what other role does thrombin have?

Answer 17

amplification reaction/negative feedback
inhibits 5,8,11 reactions for control

Question 18

what reactions does protein C+S inhibit?

Answer 18

8 to 8a
5 to 5a

Question 19

what does antithrombin 3 inhibit?

Answer 19

factor 10a (Xa)

Question 20

what are protein C+S?

Answer 20

natural anticoagulant that is vitamin k dependent

Question 21

how do heparins and lmwh work?

Answer 21

activators of prothrombin 3 that inhibit thrombin and factor Xa to stop cascade

Question 22

how does warfarin work?

Answer 22

vit k reductase inhibitor
no gamma-carboxyglutamic acid
inhibits factor 2,7,9,10

Question 23

what drugs are used if a thrombus is already formed?

Answer 23

tPA- tissue plasminogen activator
streptokinase

Question 24

what do tPA and streptokinase do?

Answer 24

activate conversion of plasminogen to plasmin and promotes degradation of fibrin

Question 25

what is TTR monitoring for warfarin?

Answer 25

total time in range taken each visit exclude results for first 6 weeks use

Question 26

what results of INR and TTR require reassessing for suitability?

Answer 26

2 INR reading > 5 or 1>8 2 INR reading <1.5 TTR<65%

Question 27

what monitoring is in place for DOACs?

Answer 27

no INR pre treatment - baseline clotting - U+Es - LFTs - FBC

Question 28

what is used to assess risk of clotting?

Answer 28

CHA2DS2-VASc

Question 29

what is used to assess risk of bleeding?

Answer 29

ORBIT score

Question 30

what CHADS-VASc score needs anticoagulation?

Answer 30

male - more than or equal to 1 female - more than or equal to 2

Question 31

what do ORBIT scores mean?

Answer 31

0-2 low risk 3 medium risk 4-7 high risk