Blood clots Flashcards
What are the types of venous thromboembolism?
- Deep vein thrombosis - blood clot (thrombus) forms in deep vein in 1 leg + partially/totally blocks blood flow
- Pulmonary embolism - life threatening - blood clot (embolus) travels to lungs + block blood flow
What are the symptoms of deep vein thrombosis?
- Unilateral pain + swelling
- Warm + red skin
- Vein distention
What are the symptoms of pulmonary embolism?
- Dyspnoea
- Chest pain
- Coughing blood
Which Pts require thromboprophylaxis?
- Immobility
- Obesity BMI >30
- 60+
- Pregnancy, postpartum
- Oestrogens: HRT, COC
What are the pharmacological treatment of VTE?
DOAC
Heparin
- Unfractionated in renal impairment
- Alt: fondaparinux
What is the duration of VTE pharmacological prophylaxis?
- General surgery/medical patient: 7 days
- Major cancer surgery in abdomen: 28 days
- Spinal surgery: 30 days
What are the mechanical treatment for VTE?
For excessive bleed risk:
Pneumatic compression
Anti-embolism stockings
- Don’t offer in acute stroke + leg condition (peripheral arterial disease)
What is the duration for VTE mechanical prophylaxis?
- Until sufficiently mobile
- Spinal injury, spinal/cranial surgery: 30 days
- Acute stroke: 30 days
What is used for pharmacological thromboprophylaxis in hip and knee replacement?
FIRST LINE - Rivaroxaban
- Hip: 35 days, Knee: 14 days
LMWH + anti-embolism stockings
- Hip: 28 days, knee: 14 days
Hip: LMWH 10 days + low dose aspirin 28 days
Knee: low dose aspirin 14 days
Alt: apixaban, dabigatran
What is used for mechanical thromboprophylaxis in hip and knee replacement?
- Knee: pneumatic compression
- Hip: anti-embolism stockings
What is the treatment for DVT + PE?
Apixaban OR rivaroxaban
- At least 3m (3-6m if active cancer) (Provoked VTE: surgery, COC, pregnancy, leg cast)
- Unprovoked 3m+ (6m+ if active cancer)
What is the thromboprophylaxis + treatment for VTE used in pregnancy?
- Thromboprophylaxis: LMWH + pneumatic compression (if immobilised)
- VTE: LMWH (unfractionated if INC bleeding)
Which anticoagulants are factor XA inhibitors?
- Apixaban
- Edoxaban
- Rivaroxaban
Which anticoagulant is a thrombin inhibitor?
Dabigatran
What is the mechanism of action of heparins?
Activates antithrombin which inhibits clotting factors Xa + IIa (thrombin)
What are the indications for heparins?
LMWH: tinzaparin, enoxaparin, dalteparin
For pregnancy (RED risk of osteoporosis + heparin induced thrombocytopenia)
Unfractionated heparin - shorter HL
- For high risk of bleeding + renal impairment
What are the side effects of heparin?
Bleeding
- Antidote: protamine (reverse LMWH)
Hyperkalemia (heparins block aldosterone secretion in renin angiotensin system)
- Diabetics + CKD at higher risk
- Monitor: potassium
Heparin-induced thrombocytopenia → DISCONTINUE
- RED 30% platelet, skin allergy, thrombosis
Osteoporosis
What are the interactions of heparins?
- Hyperkalaemia
- Anticoagulants, anti-platelet, NSAIDs, SSRI → INC Bleeding
What is the MOA of warfarin?
Vitamin K antagonist - reduce ability to form blood clots by blocking formation of vitamin K dependent clotting factors (48-72H)
What is the indication of warfarin?
VTE + stroke prevention in AF
What are the rules for a missed warfarin dose?
Missed dose: take ASAP but don’t take more than 1 dose in a day
What are the pill colours for warfarin?
- 0.5mg - white
- 1mg - brown
- 3mg - blue
- 5mg - pink
How long do you take warfarin in provoked VTE + isolated calf DVT?
Isolated calf DVT: 6w
Provoked VTE: 3m
- Surgery, COC, pregnancy, leg cast
Can you take warfarin during pregnancy?
Teratogenic
How often is warfarin monitored?
INR every 12 weeks
- More frequent: intercurrent illness
What are the target INR when taking warfarin?
Must be w/in 0.5 of target
- 2.5: VTE, AF, MI, cardioversion, artifical valves
- 3.5: recurrent VTE if on anticoagulant + INR >2
What are the MHRA warnings for warfarin?
- Reports of calciphylaxis: consider stopping if diagnosed. Risk factor: end stage renal disease. Report painful skin rash
- MHRA: OTC oral miconazole gel CI. Report signs of serious bleeding - if prescribed, monitor INR
What happens if a patient has an INR of 5-8 with no bleed?
w/hold 1-2 doses
What happens if a patient has an INR of 5-8 with minor bleed?
IV phytomenadione + restart when INR <5
What happens if a patient has an INR of >8 with no bleed?
Oral phytomenadione + restart when INR <5
What happens if a patient has an INR of >8 with minor bleed?
IV phytomenadione + restart when INR <5
What happens if a patient is on warfarin with a major bleed?
ADD dried prothrombin complex or fresh frozen plasma + restart when INR <5
What are the food interactions of warfarin?
- Alcohol binge
- Cranberry juice
- Green, leafy veg
What are the OTC interactions of warfarin?
- Miconazole
- NSAID
- Vit E + K supplement
What happens when taking warfarin and undergoing surgery?
- Elective: stop 5 days before
- VTE high risk: bridge w LMWH
- Emergency: IV phytomenadione
What are the interactions of warfarin?
- NSAID, anticoagulant, SSRI → INC bleed
- Enzyme inhibitors → INC anticoagulant effect
- Enzyme inducers → DEC anticoagulant effect
What is the MOA of DOACs?
Directly inhibits clotting factor Xa or IIa (thrombin)
What are examples of DOACs?
- Apixaban
- Dabigatran (special container, protect from moisture: 4m expiry)
- Edoxoban
- Rivaroxaban (MHRA: after food, licensed to be crushed)
What are the indication of DOACs?
VTE, prevent stroke in Non-valvular AF
What are the missed dose rules when taking DOACs?
Missed dose >6h
- Take dose at normal time
- Anticoagulant effect last 12-24h
What are the side effects of DOACs?
Bleeding (Monitor signs of bleeding + anaemia, Renal function test in RI) - MHRA
What are the reversal agents for DOACs?
- Idarucizumab - dabigatran
- Andexanet alfa - apixaban, rivaroxaban
What are the CI of DOACs?
Prosethetic heart valve
- MHRA: rivaroxaban not for thromboprophylaxis
- Inc risk of mortality, thromboembolic + bleeding events
Antiphospholipid syndrome
- MHRA: INC risk of recurrent thrombotic events
MHRA: CI w new oral anticoagulants
What are the interactions of DOACs?
- NSAID, anticoagulant, SSRI → INC bleed
- Enzyme inhibitors → INC anticoagulant effect
- Enzyme inducers→ DEC anticoagulant effect
- Carbamazepine red exposure to apixaban
What are the types of strokes?
Ischaemic (includes TIA - mini strokes that temp interrupt blood supply to brain)
- Atherosclerosis, thromboembolism in AF
Haemorrhagic
- High BP, aneurysm, arteriovenous malformation
What is the treatment for an ischaemic stroke?
Clopidogrel (first line)
- Alt: aspirin
- Co-prescribe PPI, prevent dyspepsia + GI bleed
High intensity statin
Anti-hypertensive if BP is high
- Don’t offer Beta-blocker unless for co-existing condition
Review anticoagulant in patients w AF
What is the treatment for a haemorrhagic stroke?
- Antihypertensive
- AVOID: aspirin, anticoagulant, statin - high risk of bleed
What is used for secondary CVD prevention?
- Low dose Aspirin (75mg OD)
- Clopidogrel
- Dipyridamole
How is dipyridamole taken?
- 30-60min before food
- MR - after food
- MR caps ‘special container’ - discard in 30 days/6 weeks
What are examples of glycoprotein IIB/IIA inhibitor (antiplatelets)?
Prasugrel + ticagrelor
What is used for long term management of a TIA?
MR Dipyridamole and Aspirin
