CVS thrombosis Flashcards
What is thrombosis?
Solid mass of blood formed within the
cardiovascular system involving the interaction
of endothelial cells, platelets and the
coagulation cascade that impedes blood flow
What are the four key components that makes a blood clot?
- Endothelium
- Platelets
- Coagulation
- Fibrinolysis
What are the steps involved in normal haemostasis?
- Response to injury, vessel constriction
- Formation of unstable platelet plugs
-Primary haemostasis
–Platelet adhesion
–Platelet aggregation - Stabilisation of the plug with fibrin
-Secondary haemostasis
–Blood coagulation - Dissolution of clot and vessel repair
-Fibrinolysis
VIEW SLIDES FOR CLOTTING FACTORS
VIEW SLIDES FOR CLOTTING FACTORS
What are the symptoms of DVT?
- Pain & tenderness of
veins - Limb swelling
- Superficial venous
distension - Increased skin
temperature - Skin discoloration
What does development of a venous thrombus depend on?
- Changes in normal blood flow
- Alterations in the constituents of the
blood - Damage to the endothelial layer
What is Virchow’s triad and what does it involve?
Implicates three contributing factors in the formation of thrombosis:
1. venous stasis,
2. vascular injury
3. hypercoagulability
What can cause endothelial damage?
- Endothelial dysfunction
-Smoking hypertension
-Hypertension - Endothelial damage
-Surgery
-Catheter
-Trauma
What can cause hypercoagulability?
- Hereditary
-Factor V Leiden
-Prothrombin G20210A
-Protein C and S deficiency - Acquired
-Cancer
-Chemotherapy
-OCR/HRT
-Pregnancy
-Obesity
-HIT
What can cause stasis?
- Immobility
- Polycythemia
What alterations can cause hypercoagulability?
-Decrease in fibrinolytic factors, anticoagulant proteins/activity
-Increase in coagulation factors, platelets
What veins can proximal DVT occur in?
- External iliac
- Common femoral
- Deep femoral
- Saphenous
- Femoral
- Popliteal
What is a higher risk of proximal DT?
Higher risk of pulmonary embolism
and post-thrombotic syndrome
(pain, swelling, maybe even ulcers)
What veins can distal DVT occur in?
- Tibial
- Small saphenous
What do distal DVT rarely cause?
Rarely cause pulmonary embolism
Rarely cause post-thrombotic syndrome
What does post thrombotic syndrome result from?
Results from venous
hypertension
What does post thrombotic syndrome reduce?
Reduces calf muscle
perfusion
What does post thrombotic syndrome increase?
Increases tissue permeability
What do anticoagulants do?
Anti-coagulants prevent blood clots
What do thrombolytics/fibrinolytics reverse?
Thrombolytics/fibrinolytics reverse blood clots
What is the treatment for patient that is cardiovascularly stable with acute VTE?
- Anticoagulate
-Immediate anticoagulant effect
-Heparin then warfarin/DOAC or immediate DOAC - Rivaroxaban or apixaban
What is the treatment for patient with circulatory collapse due to PE?
- Thrombolysis
-Alteplase (tissue plasminogen activator)
-Streptokinase
-Followed by heparin and warfarin or other - prevent recurrence
What are the investigations pre-treatment for VTE?
- Clotting screen
– Prothrombin time (INR)
– Partial thromboplastin time
– Thrombin time - Full blood count
- Urea and electrolytes
– usually part of routine screen – to know creatinine
clearance - Liver function tests
– If clinical suspicion of liver disease
What are examples of indirect Xa inhbitors and what do they do?
-Enhance antithrombin
–Fondaparinux
–Idraparinux
What are examples of Direct Xa inhibitors and method of intake?
Oral
-Rivaroxaban
-Apixaban
