CVD - BLOOD CLOTS Flashcards
What is a DVT?
Clot that occurs in a deep vein, usually in calf of one leg
What is a PE?
Detached blood clot which travels to the lungs and blocks the pulmonary artery
What are some risk factors of VTE?
Immobility, Obesity, Malignant disease, History of VT, Thromboembollic disorder, Pts >60, Pregnancy, HRT/COC
What is an example of mechanical prophylaxis?
Compression stockings
What are examples of pharmacological prophylaxis?
Parenteral anticoagulants - LMWH, UFH, Fondaparinux
NOACS - Rivaroxaban, edoxaban, dabigatran
How long would you need to have VTE prophylaxis for if you were undergoing general surgery?
5-7 days or until sufficiently mobile
How long would you need to have VTE prophylaxis for if you were undergoing cancer surgery in the abdomen or pelvis?
28 days
How long would you need to have VTE prophylaxis for if you were undergoing knee or hip surgery?
Extended duration
How long would you treat a patient with LMWH/UFH and what would you monitor?
For at least 5 days and until INR is at 2 or more for at least 24 hours
Monitor APTT if UFH given
Start oral anticoagulant at the same time, usually warfarin
Which heparin would you use in pregnancy and why?
LMWH - do not cross placenta - lower risk of osteoporosis and heparin induced thrombocytopaenia
What are the key differences between LMWH and UFH?
UFH - short duration of action, need to measure APPT, preferred in renal impairment and where there is high bleeding risk
LMWH (tinzaparin, enoxaparin, dalteparin) - longer duration of action, lower side effect profile, used in pregnancy
What are the side effects of heparins?
Haemorrhage - withdraw heparin. antidote = protamine
Hyperkalaemia - higher risk in DM and CKD. Monitor before treatment and if greater than 7 days use
Osteoporosis
Heparin induced thrombocytopaenia - occurs 5-10 days after - 30% platelet reduction, skin allergy, thrombosis
How is enoxaparin dosed?
<49kg = 40mg BD
50-69kg = 60mg BD
70-89kg = 80mg BD
> 90kg = 100mg BD
How long does warfarin take before it starts to work?
48-72 hours
What are the warfarin colours?
0.5 - white
1 - brown
3 - blue
5 - pink
How is warfarin dosed?
5mg initially and monitor INR every 1-2 days
maintenance dose = 3-9mg at the same time each day
How often should you monitor INR once you are stable on warfarin?
Every 3 months once stable
What is the duration of warfarin treatment for an isolated calf DVT?
6 weeks
What is the duration of warfarin treatment for a provoked VTE?
3 months
What is the duration of warfarin treatment for an unprovoked VTE?
3 months - long term
What is the normal INR range for healthy people?
2-3.5
What are warfarin interactions?
Vitamin K antagonists
Daktarin and other inhibitors
What are side effects of warfarin?
Bleeding - if major bleeding stop warfarin and give IV phytomenadione (vitamin e). dried prothrombin complex or fresh frozen plasma - do this if INR is greater than 8 even if bleeding not present
Calciphylaxis
What would you do if the INR was high (5-8) but there was no bleeding?
Withhold 1-2 doses, reduce maintenance dose, measure INR after 2-3 days
How many days before surgery would you stop warfarin?
5 days before
How is edoxaban dosed?
Up to 61kg = 30mg OD
> 61kg = 60mg OD
What is the long term management of a TIA (mini stroke)?
Aspirin 300mg immediately then clopidogrel 75mg OD OR M/R dipyridamole 200mg BD and aspirin 75mg OD
What is the long term management of an ischaemic stroke?
Alteplase within 4.5 hours of onset + aspirin + PPI then clopidogrel 75mg OD or dipyridamole + aspirin
What is the long term management of both a TIA and Ichaemic stroke?
Statin
Treat HTN but not with a BB unless on it already for another indication
How do you take dipyridamole?
30-60 minutes before food
After how many weeks must you discard dipyridamole?
6 weeks
