Thrombosis and Risk Factors For Thrombosis Flashcards
What are the risk factors for arterial thrombosis?
smoking hypertension hypercholesterolaemia diabetes family history obesity physical inactivity age gender - more common in males
What are the pathological causes of venous thrombosis?
Venous stasis
Hypercoagulable states
What is the composition of venous thrombi?
predominantly composed of fibrin
lesser role for platelet accumulation and aggregation
When a deep vein thromobosis forms, it can break off and embolise to where?
Lungs
Pulmonary Embolism
What is the definition of hospital acquired VTE?
any VTE within 90 days of discharge
What is used in hospitals to prevent and treat VTE’s?
Prophylaxis: Consistent risk assessment Appropriate prophylaxis Stockings - stimulates venous circulation Treatment: Prompt diagnosis Guideline led unified care
What are the risk factors for VTE? (NOTE: there are LOADS!!)
Active cancer/cancer treatment over 60 years old Critical care admission dehydration thrombophilias one or more significant comorbidities e.g. cardiac, metabolic, endocrine, respiratory pathologies, acute infectious diseases, inflammatory conditions surgery major trauma history of VTE hormone replacement therapy oestrogen containing contraceptive pill vacicose veins with phlebitis (inflammation of walls of the vein) obesity pregnancy/postnatal peroid immobility first degree relative with VTE
What drugs are not regarded as adequate prophylaxis for VTE’s?
aspirin or other antiplatelet drugs
What pharmacological prophylaxis is normally used?
“Low dose” low molecular weight heparin
Newer anticoagulants:
direct inhibitors of Factor Xa: rivaroxaban
direct thrombin inhibitors:dabigatran
How does unfractioned heparin work on a molecular level?
interacts with anti-thrombin and enhances its effects mostly
some anti 10a effect
How does low molecular weight heparin work on a molecular level?
interacts with molecules bigger than 18 saccharides long
mostly anti 10a effect
How does fondaparinux work on a molecular level?
only anti 10a activity
What exclusion tests are used for DTV’s and PE’s?
Validated numerical clinical probability score: Wells score
D-dimer test - when patients have symptoms of DVT/PE, positive D-dimer indicates the presence of an abnormally high level of cross-linked fibrin degradation products in the body
What radiological scan can be used to detect any thrombus?
Ultrasound - highly sensitive and specific
Look for:
loss of flow signal
intravascular defects
non collapsing vessels in the venous system
What is the dose of low molecular weight heparin for VTE?
Doses are fixed by body weight
Usually once daily by s/c injection
Treat for at least 5 days
Overlap with warfarin until INR > 2.0 for two consecutive days.
