Clinical anticoagulants Flashcards Preview

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Flashcards in Clinical anticoagulants Deck (47):
1

Why are platelets important for clotting?

They provide the phospholipid surface
Contain clotting factors
binds collagen, vWF and fibrinogen

2

What is the structure of serine proteases?

They have a GIa domain which is hydrophobic to bind to the phospholipid surface

3

what are some serine proteases?

Clotting factors II,VII,FIX,X

4

in brief how is the fibrin strand produced?

Prothrombin is converted to thrombin by FX.
thrombin can then convert fibrinogen to fibrin.

5

what are some indications for anticoagulation?

- AF
- Valvular heart disease
- cardiomyopathy
- VTE
-MI

6

what factors does the CHAD 2 score take into account?

CHF
hypertension
Stroke/TIA
Age>75
Diabetes
valvular disease
female

7

what factors does HASBLED take into account?

- hypertension
- abdominal, renal or liver dysfunction
- Stroke
- Bleeding
- INR
- eldery
- drugs/ alcohol

8

using the CHAD system who gets anticoagulants?

all men with a score of 1
anyone with a score of 2

9

why can factor 8 increase after surgery?

its an acute phase reactant

10

what are absolute contraindications of anticoagulants?

Acute bleedings

11

what are relative contraindications of anticoagulation?

Active peptic ulceration
alcohol or drug use
poor compliance
severe liver disease
renal impairment
uncontrolled hypertension
dementia
pregnancy

12

what is unfractionated heparin?

a linear sulphated polysaccharide consisting of negatively charged glycosaminoglycans with a 1;1 raio of anti X and anti II

13

what is low molecular weight heparin?

Has differing Anti X and anti II ratio's
produced by depolymerisation of unfractionated heparin

14

how is heparin produced?f

from bovine lung/ porcine intestine

15

what is the MOA of heparin?

it binds to anti thrombin causing a conformational change, this increases the inhibiton of FX and thrombin

16

how is unfractionated heparin cleared?

reticuloendothelial

17

what is the half life of unfractionated heparin?

1.5 hours

18

how is unfractionated heparin given?

IV or sc

19

what is the reversal for unfractionated heparin?

protamine

20

how is LMWH cleared?

renal

21

what is the half life of LMWH?

12 hours

22

what is the amount of time before LMWH is peak?

3-4hours

23

how is LMWH administered?

Sc

24

what is the reversal for LMWH?

minimal reversal can be achieved with protamin

25

what people need anti Xa monitoring?

Pregnant people
renal impairment
Obesity

26

what tests will unfractionated heparin effect?

APTT

27

What tests will LMWH effect?

Anti Xa

28

what tests will vitamin K antagonists affect?

PT/INR

29

what tests will dabigatren affect?

TT

30

what are the side effects of heparin?

- bleeding
- thrombocytopenia
- osteoporosis

31

what do you do for heparin induced thrombocytopenia with thrombosis?

stop heparin and given danaparoid or hirudin

32

how does warfarin work?

Its a vitamin K antagonist

33

What process does vitamin K interfer with?

gamma carboxylation of GIa domain

34

what does gamma carboxylation of the GIa domain normally allow?

interaction with the phospholipid of platelet membranes which localises coagulation

35

how is warfarin initiated in patients with thrombosis?

with heparin

36

what is warfarin dose sensitive to?

diet
drugs
ethnicity
age

37

what test is warfarin monitored with?

INR/PT

38

For warfarin VTE prophylaxis what INR is ideal?

2-2.5

39

For people on warfarin due to mechanical heart valves what INR value is ideal?

3-4

40

for people on warfarin due to antiphospholipid syndrome what INR is a good range?

2.5-3.5

41

what are the side effects of warfarin?

Bleeding, skin necrosis, birth skeletal abnormalities, increased foetal loss

42

what does warfarin cause skin necrosis?

Due to a protein C deficiency

43

what does warfarin cause birth skeletal abnormalities

Lack of gamma carboxylation of bone protein takens place

44

how do DOAC's work?

targeted inhibition of Xa or thrombin

45

what tests can be done to monitor dabigatran?

aPTTR

46

what does a normal TT mean in dabigatran?

It excludes the possibility that there is any circulation

47

what is the reversal agent for dabigatran?

idarucizumab