clinical aspects of thrombosis Flashcards
thrombosis
inappropriate blood coagulation within a vessel
types of thrombosis
arterial circualrion
venous circualrion
arterial circulation thrombosis
high pressure system
platelet rich e.g. MI, thrombotic stroke
venous system thrombosis
low pressure sysetm
throb are fibrin rich (involve coagulation cascade)
e.g. deep vein thrombosis
pulmonary embolism
treatment summary for each type
Arterial thrombosis
- thrombi are platelet rich therefore required antiplatet drugs
Venous thrombosis
- fibrin rich as a result of activation of the coagulation cascade, require anticoagulant drugs
how does atherosclerotic plaque develop
- initial fatty steak
- plaque enlargement
- turbulence due to protrusion into lumen
- loss of endothelium and collagen exposure
- platelet activation and adherence on top of the rupture
- fibrin meshwork deposition and red cell entrapment
- more turbulence, more platelet and fibrin deposition
- thrombus of layers of platelets, fibrin and red cells
- get thrombus with layers, blocks the blood vessel
- anything distal does not get a blood supply
risk factors for arterial thromosis
Main risk factors - family history - diabetes mellitus - hypertension - hyperlipidaemia - smoking - atrial fibrillation for stroke Other risk factors - male - polycythaemia, gout - collagen vascular disease - lupus anticoagulant high FVIII, high fibrinogen
management of arterial thrombosis
Lifestyle - quit smoking - exercise - diet - weight control Drugs: Antithrombotic - primary prevention in patients with atrial fibrillation
treatment options of arterial thrombosis
aspirin
clopidogrel
asprin
irreversible inhibitor of COX1 inhibiting production of thromboxane
inhibition lasts lifetime of platelet
clopidogrel
irreversible ADP mediated platelet inhibition
indictions for use of thrombolysis
MI
stroke within 3 hours
life threatening pumlmonary embolism
drugs used for thrombolysis
alteplase
streptokinase
invasive treatement of artieral thrombosis
1) percutaneous coronary intervention (caridiac stenting)
- combined with 3-12 months asprin and clopidogrel
2) coronary artery bypass grafting
3) carotid endarterectomy
how does atrial fibrillation cause a stroke
1) Blood pools in atria
2) blood clot forms
3) blood clot breaks off
4) blood clot travels to brain and bocks cerebral artery causing a stroke
venous thrombosis can lead to
pulmonary embolism -
pulmonary hypotension - chronic PE - death
or
deep vein insufficiency
post thrombotic syndrome
leg ulcers
formation of venous thrombosis requres a combination of
hypercoagulability (inherited or aquired)
vascular damage (A)
stasis (A)
acquired causes of venous thrombosis
age previoys VTE malignancy pregnancy chemotherapy hormone replacement therapy
types of heritable thrombophilias and mechanisms
factor V leiden
- protein C resistance
what type of disorder is VTE
multifactorial disrder
- interplay of genetic and environmental risk factors
- reaches threshold
VTE and dental surgey
all its must be risk assessed on admition to hospital and reassessed within 24 hrs
treatment options for acute VTE
1) Anticoagulation
- prevent coagulation cascade
- prevent fibrin formation
2) thrombolysis
- breakdown the clot
3) thrombectomy
4) inferior vena cava filter
- used for those that cannot use anticoagulation
treatment for long term VTE
anticoagulation
stockings
how long should treatment last for VTE
3 months after first event
Provoked events do not need anticoagulation >3 months
Distal DVT do not need anticoagulation > 3 months
Consider long term anticoagulation after 1st unprovoked thrombosis
