Theme 7 Haematology: Thrombosis Flashcards
What is Virchow’s triad?
- stasis
- vessel wall injury
- hypercoagubility
What is thrombosis and why does it arise?
-abnormal clotting inside a blood vessel
occurs either because:
- vascular endothelium damage (because blood is too sticky)
- or because blood flow has been altered
- this produces stasis which results in hypercoagulability
What is the usual primary abnormality that leads to arterial thrombosis?
atherosclerosis
What are the risk factors for arterial thrombosis?
smoking hypertension hypercholesterolaemia diabetes family history obesity physical inactivity age male sex
What are thrombi predominantely composed of?
fibrin
What is the most common clinical manifestation of venous thrombosis?
DVT
what is VTE and what are the long term complications of VTE?
- Venous thromboembolism
- can develop chronic VTE
- can develop post thrombotic syndrome (damage to the vein leads to reduction in flow, chronic swelling, chronic pain and leg ulceration
Why is hospital admission a risk factor for VTE?
- because of the underlying condition
- because of the fact they are immobile when they are in the hospital bed
- definition includes any VTE within 90 days of discharge
What is NICE guidelines ‘care pathway’ for VTE?
- consistent risk assessment
- assess VTE risk and assess bleeding risk and balance
- offer VTE prophylaxis if appropriate but not if there is risk of bleeding
What are the risk factors for VTE?
- active cancer or cancer treatment
- age > 60
- critical care admission
- dehydration
- personal history of VTE
- use of hormone replacement therapy
- use of oestrogen containing contraceptive therapy
- varicose veins with phlebitis
- known thrombophilias
- obesity
- immobility
- surgery
- co morbidities
- major trauma
- pregnancy
Why does a heritable thrombophillia leave you at increased risk of VTE?
-deficiencies in factors in blood that protect us from having thrombus
Why do we use white stockings to prevent VTE?
They exert graduated pressure on the veins up the leg to keep the blood flowing in the right direction when they are immobile
What are the the options for prophylaxis against VTE?
- low dose low molecular weight heparin
- fondaparinux (an alternative to heparin as it comes from pigs lungs or patients could be allergic)
What is rivaroxaban?
- new anticoagulant
- direct inhibitor of FXa
How do heparins work?
- by binding to the natural anti coagulant called antithrombin
- antithrombin is an inhibitor of thrombin and FIIa and FXa
- so this prevents blood clots