Thrombosis and Anticoagulation

Question 1

what is thrombosis?

Answer 1

blood coagulation inside a vessel

Question 2

describe appropriate coagulation

Answer 2

when blood escapes a vessel, failure of coagulation in this situation leads to bleeding

Question 3

when can thrombosis occur?

Answer 3

arterial circulation: high pressure: platelet rich

venous circulation: low pressure fibrin rich

Question 4

symptoms of arterial thrombosis in coronary circulation

Answer 4

pain in left arm
angina

Question 5

symptoms of arterial thrombosis in cerebral circulation

Answer 5

slurred speech, headaches

Question 6

symptoms of arterial thrombosis in peripheral circulation

Answer 6

pain in leg

Question 7

symptoms of arterial thrombosis in Superior mesenteric artery

Answer 7

belly ache

Question 8

what are the underlying causes of arterial thrombosis in most cases?

Answer 8

–Atherosclerosis
-Inflammatory
-Infective
-Trauma
-Tumours
-Unknown
-Platelet driven

Question 9

what are the presentations of arterial thrombosis?

Answer 9

-Myocardial infarction
-CVA
-Peripheral vascular disease
-Others

Question 10

what are the treatments for arterial thrombosis in the coronary circulation ?

Answer 10

Coronary:
-Aspirin other antiplatelets
-LMWH or Fondaparinux or UFH
-Thrombolytic therapy: streptokinase tissue plasminogen activator
-Reperfusion – Catheter directed treatments and stents
-Aspirin inhibits platelet function
TPA generates plasmin, degrades fibrin

Question 11

Why is Fondaparinux used instead of heparin?

Answer 11

Fondaparinux- used to prevent clotting
much higher risk of bleeding with heparin than fondaparinux- also has a much higher half life than heparin

Question 12

what is the treatment of arterial thrombosis in the cerebral circulation?

Answer 12

-Aspirin,
-other anti-platelets
Thrombolysis
-Catheter directed treatments
Reperfusion

Question 13

Why is heparin not used in cerebral circulation?

Answer 13

too much bleeding

Question 14

what is the treatment of arterial thrombosis in other sites?

Answer 14

Antiplatelets, statins
Role of anticoagulants evolving
Endovascular vs Surgical

Question 15

where does deep vein thrombosis occur peripherally?

Answer 15

Peripheral –Ileofemoral, femoro-popliteal
between ivc and popliteal vein

Question 16

what are the non specific symptoms for venous thrombosis?

Answer 16

calf pain
chest pain
breathlessness
pulled muscle
groin strain

Question 17

what are things that can change blood flow in virchows triad?

Answer 17

Immobilisation
-Surgery
-Long haul flights
-Trauma

Question 18

what are things that can change endothelium in virchows triad?

Answer 18

Injury – physical, chemical

Question 19

what are things that can change blood constituents genetically in virchows triad?

Answer 19

Factor V Leiden (5%)
PT20210A (3%)
Antithrombin deficiency
Protein C deficiency
Protein S deficiency

Question 20

what are the components of virchows triad?

Answer 20

blood constituents
blood flow
endothelium

Question 21

what are things that can change blood constituents acquired in virchows triad?

Answer 21

-Anti-phospholipid syndrome
-Lupus anticoagulant
–Hyperhomocysteinaemia

Question 22

what is the main treatment for venous thrombosis?

Answer 22

• heparin or LMWH
  -Warfarin
• DOAC- direct oral anti coagulation- only once daily- don’t have to monitor
  -endovascular- catheter inserted into vein
  -surgical - very rare

Question 23

how is venous thrombosis prevented?

Answer 23

-Mechanical or chemical thromboprophylaxsis
-Also early mobilisation and good hydration

Question 24

describe heparin

Answer 24

heparin is given IV via a canula on a continuous infusion- measured with various ratios/ APTT depending on why given medication
- short half life

Question 25

what does heparin do?

Answer 25

-Binds to antithrombin and increases its activity -Indirect thrombin inhibitor

Question 26

what is the difference with low molecular weight heparin?

Answer 26

-smaller molecule, less variation in dose and renally excreted -Once daily, weight-adjusted dose given subcutaneously -Used for treatment and prophylaxsis

Question 27

describe warfarin

Answer 27

- orally active -Antagonist of vitamin K Long half life (36 hours)

Question 28

what does warfarin do?

Answer 28

-Prevents synthesis of active factors II, VII, IX and X -Prolongs the prothrombin time

Question 29

drawbacks of warfarin

Answer 29

-Difficult to use, -Individual variation in dose -Need to monitor -Measure INR (international normalised ratio, derived from prothrombin time)

Question 30

describe DOAC

Answer 30

Orally active Directly acting on factor II or X No blood tests or monitoring Shorter half lives so bd or od Not used in pregnancy

Question 31

when is DOAC used?

Answer 31

Used for extended thromboprophylasis and treatment of AF and DVT/PE

Question 32

describe fondaparineux

Answer 32

Pentasaccharide Indirect Xa inhibitor

Question 33

what does aspirin do?

Answer 33

-Inhibits cyclo-oxygenase irreversibly -Act for lifetime of platelet, 7-10 days -Inhibits thromboxane formation and hence platelet aggregation -Used in arterial thrombosis, 75-300 mg od

Question 34

symptoms of DVT

Answer 34

leg pain, swelling

Question 35

signs of DVT

Answer 35

tenderness, swelling, warmth, discolouration

Question 36

complications of DVT

Answer 36

Phlegmasia Alba Dolens and Phlegmasia Cerulae Dolens, PE

Question 37

What are the investigations done for DVT?

Answer 37

-D-dimer: normal excludes diagnosis positive does not confirm diagnosis Ultrasound compression CT or MR venogram catheter venogram?

Question 38

DVT treatments

Answer 38

-LMW Heparin (for min 5 days) -Oral warfarin (INR 2-3) for 3-6 months -Or DOAC/NOAC -Compression stockings – symptoms vs PTS -Treat/ seek underlying cause

Question 39

describe re- canalisation - endovenous

Answer 39

Chemical Mechanical Mechanico-chemical Stents

Question 40

how are dvt prevented?

Answer 40

Mechanical- hydration and early mobilisation, Compression stockings, Foot pumps Chemical- LMW Heparin

Question 41

symptoms of pulmonary embolism

Answer 41

breathlessness, pleuritic chest pain symptoms of DVT risk factors for DVT

Question 42

signs of pulmonary embolism

Answer 42

tachycardia, tachypnoea, pleural rub, Signs of DVT

Question 43

how are pulmonary embolisms treated?

Answer 43

Supportive treatment LMW Heparin Oral warfarin (INR 2-3)for 6 months DOAC/NOAC Treat underlying cause

Question 44

how is PE prevention/

Answer 44

Anticoagulation IVC filters