Clinical aspects of thrombosis Flashcards
What is thrombosis
Blood in BVs should be fluid
Inappropriate blood coagulation within a vessel is called thrombosis
Appropriate blood coagulation occurs when
Blood escapes from a vessel
-failure of this results in bleeding
Types of thrombosis and properties
In the arterial circulation -high pressure system -platelet rich In the venous circulation -low pressure system -fibrin rich
Arterial thrombosis can cause
MI
Thrombotic stroke
Venous thrombosis can cause
Leg deep vein thrombosis (MI) Pulmonary embolism (PE)
Treatment for arterial thrombosis
Antiplatelet drugs
Treatment for venous thrombosis
Anticoagulant drugs
Formation of arterial thrombosis
Atherosclerotic plaque
- initial fatty streak
- plaque enlargement
- turbulence due to protrusion into lumen
- loss of endothelium and collagen exposure
- platelet activation and adherence
- fibrin meshwork deposition and red cell entrapment
- more turbulence, more platelet and fibrin deposition
- thrombus of layers of platelets, fibrin and red cells
Main risk factors for arterial thrombosis
Family history Diabetes mellitus Hypertension Hyperlipidaemia Smoking Atrial fibrillation for stroke
Other risk factors for arterial thrombosis
Male sex
Polycythaemia, gout
Collagen vascular disease
Lupus anticoagulant, high FVIII, high fibrinogen
Management of arterial thrombosis
Stroke and MI are in the top 5 of causes of death.
Lifestyle
-quit smoking
-exercise
-diet
-weight control
Antithrombotics: primary prevention in pts with atrial fibrillation.
Treatment options for arterial thrombosis
Antiplatelet agents: start acutely, continue long term Thombolysis Invasive Rehabilitation in all cases Secondary prevention
Antiplatelet agents for arterial thrombosis
Aspirin
Copidogrel
Aspirin
Irreversible inhibitor of cyclooxygenase (COX1), inhibiting the production of thromboxane.
Inhibition lasts for the lifespan of platelet: ≈ 1 week.
Risk reduction of non fatal vascular event by 30%.
Risk reduction of fatal vascular event by 15%.
Clopidogrel
Irreversible ADP mediated platelet inhibition.
Inhibition lasts for the lifespan of platelet: ≈ 1 week.
Decreases the risk of MI 18%,
Risk of coronary stent thrombosis/recurrent stroke by 30%
Thrombolysis indications
MI
stroke within 3 hours,
Life-threatening PE
Thombolysis drugs
ALTEPLASE (rt-PA, tissue-type plasminogen activator)
STREPTOKINASE
Others
Main side effect: bleeding
Invasive arterial thrombosis treatment
Percutaneous coronary intervention (cardiac stenting)
Combined with 3 – 12 months aspirin + clopidogrel
Coronary artery bypass grafting
Carotid endarterectomy