Haemostasis

Question 1

What time is checked to monitor heparin therapy? Which pathway does this assess?

Answer 1

aPTT, Intrinsic Pathway

Question 2

What is checked to monitor Warfarin therapy? What pathway does this assess?

Answer 2

PT (INR), Extrinsic Pathway

Question 3

Which factor starts the Intrinsic pathway in the Coagulation Cascade?

Answer 3

Twelve

Question 4

Which factor starts the Extrinsic Pathway in the Clotting Cascade?

Answer 4

Seven

Question 5

What factor starts the Common Pathway? And what is used to monitor this pathway?

Answer 5

Five, TT (Thrombin time)

Question 6

What 3 components make up Virchows Triad?

Answer 6

Vessel Wall, Blood, Blood Flow

Question 7

What is the therepeutic range for INR?

Answer 7

2-3 (ideally 2.5)

Question 8

What is given for DVT prophylaxis in ‘at risk’ patients?

Answer 8

Daily SC LMWH, TED stockings

Question 9

What antithrombotic molecules are expressed by the vessel wall?

Answer 9

Thrombomodulin, EPCR, Tissue Factor Pathway Inhibitor (TFPI), Heparans

Question 10

How does injury/inflammation make the vessel wall prothrombotic?

Answer 10

Down regulates anticoag mols, upregulates adhesion mols, expresses TF, decrease prostacyclin production

Question 11

What antiplatelet factors are expressed by the vessel wall?

Answer 11

Prostacyclin, NO

Question 12

What 3 factors make up the risk factors of blood in Virchows Triad?

Answer 12

Viscosity (Hct, protein/paraprotein), Plt count, Coagulation system

Question 13

What is the treatment for DVT/PE?

Answer 13

TEDS +LMWH (175u/kg) + warfarin: LMWH stoped when INR in therepeutic range, Warfarin continued for 3-6 months unless recurrent VTE (give lifelong)

Question 14

How long should you give a cancer patient LMWH after a VTE?

Answer 14

3-6 months

Question 15

Which cancer is especially related to VTE’s?

Answer 15

Pancreatic

Question 16

What percentage of idiopathic VTE’s are due to cancer?

Answer 16

10%

Question 17

How does Heparin work?

Answer 17

Potentiates antithrombin III, which inactivates thrombin and factors 9,10, 11

Question 18

How are LMWHs administered and how/when is it monitored?

Answer 18

SC once daily, only requires monitoring in late pregnancy and renal failure via anti-Xa assay

Question 19

How is Unfractionated heparin administered and how is it monitored?

Answer 19

Given IV, loading dose then infusion, monitor APTT

Question 20

What is the Antidote for Heparin?

Answer 20

Protamine Sulphate

Question 21

What are the side effects of Heparins?

Answer 21

Bleeding, HIT (heparin induced thrombocytopenia), osteoporosis with long term use

Question 22

How does Warfarin work?

Answer 22

Inhibits the reductase enzyme responsible for regenerating the active form of Vit K, therefore inhibits the synthesis of factors 2,7,9, 10, and proteins C, S and Z

Question 23

How is Warfarin monitored and how is its effects reveresed?

Answer 23

INR (derived from PT), reversed with IV Vit K/factor concentrates

Question 24

What are the 2 types of Direct Acting Anticoagulants? Give one example of each.

Answer 24

Anti-Xa (Rivoraxaban, Apixaban, Edoxaban), Anti-Iia/Anti-Thrombin (Dabigatran)

Question 25

When is the target INR 2.5?

Answer 25

1st episode DVT/PE, AF, cardiomyopathy, symptomatic inherited thrombophilia, mural thrombus, cardioversion

Question 26

When is the target INR 3.5?

Answer 26

Recurrent DVT/PE, mechanical prosthetic valve (2.5-3.5), coronary artery graft thrombosis, antiphospholipid syndrome

Question 27

Management plan (Warfarin patient): INR 5-8, no bleeding

Answer 27

Withold few doses, reduce maintenance. Restart when INR under 5

Question 28

Management plan (Warfarin patient): INR 5-8, minor bleeding

Answer 28

Stop warfarin. Vit K slow IV. Restart when INR under 5

Question 29

Management plan (Warfarin patient): INR >8, no bleed/minor bleed

Answer 29

Stop warfarin. Vit K (oral/IV, no bleeding/risk factors for bleeding or minor bleeding). Check INR daily

Question 30

Management plan (Warfarin patient): Major bleeding (incl Intracranial haemorrhage)

Answer 30

Stop warfarin. Give prothrombin complex concentrate. If unavailable, give FFP. Give Vit K IV.

Question 31

Why does pregnancy increase the risk of a VTE?

Answer 31

increases VIII + fibrinogen, decreases proteins, compression on blood flow

Question 32

How does malignancy increase the risk of a VTE?

Answer 32

TFs on tumour, inflammation (makes vessel wall prothrombotic), compression on blood flow

Question 33

What is the mortality and recurrence rate of a VTE?

Answer 33

5% mortality, 20% recurrence in 2 years

Question 34

List 5 acquired factors that increase the risk of a VTE.

Answer 34

Age (>60), BMI >30, Hx DVT/PE, Immobilisation, Major surgery, Long distance travel, malignancy, Pregnancy, HRT, Antiphospholipid Syndrome, Polycythaemia, Thrombocythaemia

Question 35

List 5 Inherited factors that increase the risk of a VTE.

Answer 35

Antithrombin deficiency, Protein C def, Protein S def, Factor V Leiden, Prothrombin G20210A, Lupus Anticoag., Coag excess

Question 36

What is the order of factors in the Intrinsic Pathway of the Coagulation Cascade?

Answer 36

TwelvE, EleveN, NinE, EighT, TeN –> Five joins it to Common Pathway

Question 37

What turns Fibrinogen into Fibrin?

Answer 37

Thrombin

Question 38

What turns Plasminogen into Plasmin?

Answer 38

Tissue Plasminogen Activators (TPA)

Question 39

What turns Prothrombin into Thrombin?

Answer 39

Factor V (with Calcium + Platelet Factor)

Question 40

What is increased and decreased in DIC? (INR, APTT, Thrombin Time, Plt Ct, Bleeding Time)

Answer 40

Increased: INR, APTT, TT, Bleeding time; Decreased: PltCt

Question 41

What is increased and decreased in Liver Disease? (INR, APTT, Thrombin Time, Plt Ct, Bleeding Time)

Answer 41

Increased: INR, APTT Decreased: Plt Ct

Question 42

What is increased and decreased in Vit K Def? (INR, APTT, Thrombin Time, Plt Ct, Bleeding Time)

Answer 42

Increased: INR, APTT