Haemostasis and Thrombosis

Question 1

What are the components of Virchow’s Triad?

Answer 1

Blood - viscosity
Vessel wall
Blood flow

Question 2

What are the consequences of thromboembolism?

Answer 2

Death
Recurrence
Thrombophlebitic syndrome
Pulmonary hypertension

Question 3

What is thrombophlebitic syndrome?

Answer 3

Recurrent pain, swelling and ulcers

Question 4

What blood properties are relevant in thrombosis?

Answer 4

Viscosity (haematocrit, protein/paraprotein)
Platelet count
Coagulation system

Question 5

What coagulation factors are regulated by TFPI (tissue factor pathway inhibitor)?

Answer 5

TF/FVIIa actions

Question 6

What coagulation factors are regulated by Protein C & S?

Answer 6

FXa and FVIIIa

Question 7

What coagulation factors are regulated by antithrombin?

Answer 7

FXa and Thrombin

Question 8

What is the role of coagulation regulation proteins?

Answer 8

To regulate the system and stop you making blood clots too easily/inappropriately

Question 9

What are the procoagulant factors?

Answer 9

V
VIII
XI
IX
X
II
Fibrinogen
Platelets

Question 10

What are the anticoagulant factors?

Answer 10

TFPI
Protein C
Protein S
Thrombomodulin
EPCR
Antithrombin
Fibrinolysis

Question 11

What is thrombophilia?

Answer 11

A disturbed balance of haemostasis where coagulation occurs more easily

Question 12

What is Factor V Leiden?

Answer 12

Mutated form of factor V that lacks cleavage site for deactivation by proteins C and S (i.e. increases coagulability)

Question 13

What is the normal state of the vessel wall?

Answer 13

Antithrombotic

Question 14

What anticoagulant molecules are expressed by the vessel wall?

Answer 14

Thrombomodulin
Endothelial protein C receptor
Tissue factor pathway inhibitor
Heparans

Question 15

What antiplatelet factors are secreted by the vessel wall?

Answer 15

Prostacyclin

NO

Question 16

What is the role of collagen tissue factor?

Answer 16

Triggers coagulation

Question 17

What stimuli make the vessel wall prothrombotic?

Answer 17

Infection
Malignancy
Vasculitis
Trauma

Question 18

What happens when vessel wall becomes prothrombotic?

Answer 18

Anticoagulant molecules downregulated
TF may be expressed
Prostacyclin production decreased
Adhesion molecules upregulated
Von Willebrand factor release

Question 19

What do neutrophils do under inflammatory stimuli?

Answer 19

NETosis: release contents of their nucleus

Question 20

How does blood stasis promote thrombosis?

Answer 20

Accumulation of activated factors
Promotes platelet adhesion
Promotes leukocyte adhesion and transmigration
Hypoxia produces inflammatory effect on endothelium

Question 21

What are some common causes of stasis?

Answer 21

Immobility
Compression
Viscosity
Congenital

Question 22

What anticoagulant drugs have immediate action?

Answer 22

Heparin

Direct acting anti-Xa and anti-IIa

Question 23

What anticoagulant drugs have delayed action?

Answer 23

Vitamin K antagonists e.g. Warfarin

Question 24

What clotting factors are affected by Warfarin?

Answer 24

II, VII, IX, X

Also protein C and S

Question 25

How is unfractionated heparin administered?

Answer 25

IV infusion, monitored

Question 26

How are low molecular weight heparin and pentasaccharide administered?

Answer 26

Subcutaneously, no monitoring

Question 27

How do heparins work?

Answer 27

Potentiating antithrombin

Question 28

What are the long term disadvantages of heparins?

Answer 28

Injections
Risk of osteoporosis
Variable renal dependence

Question 29

Give some examples of anti-Xa direct acting anticoagulants

Answer 29

Rivaroxaban
Apixaban
Edoxaban

Question 30

Give an example of anti-IIa direct acting anticoagulant

Answer 30

Dabigatran

Question 31

What are some properties of direct acting anticoagulants?

Answer 31

Oral administration
Immediate acting (peak in approx 3-4 hrs)
Also useful in long term
Short-half life
No monitoring

Question 32

How does warfain work?

Answer 32

Indirect effect by preventing recycling of Vit K

Question 33

How is warfarin monitored?

Answer 33

INR (international normalised ratio)

Derived from prothrombin time

Question 34

What interactions occur with warfarin?

Answer 34

Dietary vitamin K
Variable absorption
Interactions with other drugs
Teratogenic

Question 35

Give examples of mechanical thromboprophylaxis

Answer 35

TED stockings

Intermittent pneumatic compression

Question 36

What are the patient risk factors for VTE?

Answer 36

Age >60yrs
Previous VTE
Active cancer
Acute or chronic lung disease
Chronic heart failure
Lower limb paralysis (excluding acute CVA)
Acute infection
BMI >30

Question 37

What are the procedure risk factors for VTE?

Answer 37

Hip or knee replacement
Hip fracture
Other major orthopaedic surgery
Surgery >30 mins
Plaster cast immobilisation of lower limb

Question 38

What are the patient risk factors for bleeding?

Answer 38

Bleeding diathesis
Platelets <100
Acute CVA in previous month
BP >200 systo or 120 dias
Severe liver disease
Severe renal disease
Active bleeding
Anticoag or anti-platelet therapy

Question 39

What are the procedure risk factors for bleeding?

Answer 39

Neuro, spinal or eye surgery
Other with high bleeding risk
Lumbar puncture/spinal/epidural in previous 4 hours

Question 40

What are the symptoms of thrombophlebitic syndrome?

Answer 40

Recurrent pain
Swelling
Ulcers

Question 41

What are the possible consequences of thromboembolism?

Answer 41

Death
Recurrence
Thrombophlebitic syndrome
Pulmonary hypertension

Question 42

What is haemostasis?

Answer 42

Process by which bleeding from an injured vessel is arrested or reduced

Question 43

What regulates TF and FVIIa?

Answer 43

TFPI

Question 44

What regulates FVIIIa and FVa

Answer 44

Protein C&S

Question 45

What regulated FXa and Thrombin?

Answer 45

Antithrombin