CHAPTER 2: CVS: Thromboembolism Flashcards
What must the risk of clotting be weighed up against when deciding on thromboprophylaxis?
Bleeding
What are the options for pharmacological prophylaxis in patients undergoing general or orthopeadic surgery?
- LMWH
2. Heparin
Which is the pharmacological thromboprophylaxis of choice in patients with renal impairment?
Heparin
Which is the pharmacological thromboprophylaxis is an option for patients undergoing hip or knee replacements, hip fracture surgery or day surgery?
Fondaparinux
Which NOACs are indicated for thromboprophylaxis following hip or knee surgery? (3)
- Rivaroxaban
- Apixaban
- Dabigatran
How long should pharmacological thromboprophylaxis be continued for following surgery? (2)
- 5-7 days
2. Until patient is mobile
After which surgery should pharmacological thromboprophylaxis be extended to 28 days?
Major cancer surgery in the abdomen or pelvis
What is the choice in pharmacological thromboprophylaxis for general medicine patients?
- LMWH
- Heparin
- Fondaparinux
If pharmacological thromboprophylaxis is contra-indicated, what can be offered?
Mechanical thromboprophylaxis
What is initially used in the treatment of VTE?
LMWH SC injection
What is an alternative to LMWH in the treatment of VTE? (2)
- Heparin infusion
2. Intermittent heparin SC injection
When is the oral anticoagulant started in the treatment of VTE?
At the same time as the LMWH/Heparin
How long can a patient be taking both the LMWH/Heparin and oral anticoagulant in the treatment of VTE?
At least 5 days until INR is >2
What is the treatment of choice for VTE in pregnancy and why?
Heparins - do not cross the placenta
Why are LMWH preferred in VTE pregnancy? (2)
- Lower risk osteoporosis
2. Lower risk thrombocytopenia
What is the antidote for heparin? (only partially works in LMWH)
Protamine sulfate
What is the treatment for TIA?
Aspirin or clopidogrel if intolerant
What is recommended for the treatment of acute ischaemic stroke?
Alteplase
How soon after the onset of symptoms should alteplase be administered?
4.5 hours
How long after thrombolysis with alteplase should aspirin 300mg be administered and for how long?
24 hours
2 weeks
After which type of stroke should anticoagulants be used?
Cardio-embolic
What do you do if a patient already receiving anticoagulation for a heart valve has a stroke?
Stop their anticoagulant for 7 days while giving aspirin
Following the acute treatment of stroke, what is the recommended long term treatment?
Clopidogrel
If clopidogrel is not tolerated or contra-indicated, what is an alternative for long-term treatment after stroke?
Dipyridamole MR + Aspirin
What should patients who had a stroke due to AF be given as long-term treatment?
Anticoagulants
How long after symptom onset of stroke should a statin be started?
48 hours
Following a stroke, what is the blood pressure aim
< 130/80 mmHg
Which drugs should not be used for hypertension after stroke?
Beta blockers unless if being used for a different indication
What is the acute and long-term treatment of cerebral hamorrhage?
NOTHING
In which side of the circulation do anticoagulants exert their effect?
Slower moving, venous side
Which is the vitamin K antagonist used for anticoagulation?
Warfarin
An INR which is in x of the target value is generally accepted
0.5
What is the target INR for: treatment of DVT or PE?
2.5
What is the target INR for: AF?
2.5
What is the target INR for: bioprosthetic heart valves?
2.5
How long must patients with bioprosthetic heart valves be anticoagulated?
3 months
What is the target INR for mechnical valves?
varies according to the make, location and patient factors
What is the target INR for recurrent DVTs?
3.5
How long should isolated deep calf thrombosis be treated with warfarin for?
6 weeks
How long should DVT provoked by surgery or other transinet risk factor be treated with warfarin for?
3 months
How long should unprovoked DVT be treated with warfarin for?
at least 3 months
What is the main adverse effect of all oral anticoagulants?
Bleeding
If a patient experiences major bleeding with an INR >8, what should they be given?
IV Vitamin K
If a patient experiences minor bleeding with an INR >8, what should they be given?
IV Vitamin K
If a patient experiences no bleeding with an INR >8, what should they be given?
Oral vitamin K (injection orally)
If a patient experiences minor bleeding with an INR 5-8, what should they be given?
IV Vitamin K
If a patient experiences no bleeding with an INR 5-8, what should they be given?
Nothing, withhold 1 or 2 doses of their warfarin
How long before elective surgery must warfarin be stopped?
5 days
What must be given by mouth in patients taking warfarin if the day before, INR is >1.5?
Oral vitamin K
When can warfarin be resumed after surgery?
On the evening after
Which patients may require warfarin “bridging” with a LMWH at treatment dose?
High risk of thromboembolism
What would put someone at high risk of thromboembolism? (3)
- History of thromboembolism within the last 3 months
- Mechanical heart valve
- Previous stroke
How long before surgery should a LMWH be stopped?
24 hours
If a patient on warfarin requires emergency surgery that can be delayed for 6-12 hours, what can be administered?
IV Vitamin K
If a patient on warfarin requires emergency surgery that cannot be delayed what can be administered? (2)
- IV Vitamin K
- Dried prothombin complex
- INR checked before surgery
Which has a longer duration of action heparin or LMWH?
LMWH
Why are LMWH preferred in the treatment and prevention of VTE? (2)
- Lower risk of heparin induced thrombocytopenia
2. Once daily administration as longer duration of action
What is the antidote for dabigatran?
Idarucizumab
In which circulation do antiplatelets work?
Arterial
Is there a benefit in using aspirin as primary prophylaxis?
No
If a patient is at high risk of bleeding what can be added with aspirin treatment?
PPI
How long is dual antiplatelet therapy after an MI? (ACSAB)
Clopidogrel and aspirin for 1 year then clopidogrel is discontinued and aspirin is given lifelong
If clopidogrel and aspirin combination cannot be used due to contra-indication to aspirin, what is the option?
Just clopidogrel
Other than clopidogrel, which other drugs can be used in combination with aspirin? (2)
- Prasugrel
2. Ticagrelor
After elective insertion of a bare-metal stent, aspirin is given lifelong. Clopidogrel is also given for how long?
1 month
12 months if due to ACS
12 months if drug eluting
Unless specifically indicated (Kawasaki disease), who should aspirin not be given to?
Children under 16 - risk of Reyes
What is the maximum pack size of aspirin caps/tabs OTC?
32
What is the maximun amount of aspirin caps/tabs that can be sold OTC?
100
How long before elective surgery must clopidogrel be discontinued?
7 days
Apixaban should be avoided in patients with major risk factors for bleeding. Give 2 examples
- Known or suspected oesophageal varices
2. Recent or current gastric ulcers
When should apixaban be dose reduced from 5mg BD to 2.5mg BD? (3)
- eGFR <30
- Weight <60
- Age >80
What is the rivaroxaban dose for VTE treatment?
15mg BD for 3 weeks then 20mg OD thereafter
How long after heparin administration does clinically important thrombocytopeania occur?
5-10 days
What are signs of heparin-induced thrombocytopeania? (3)
- Platelet reduction of 30%
- Thrombosis
- Skin allergy
What should be done if heparin-induced thrombocytopeania occurs?
- Stop the heparin
2. Replace it with danaparoid
Why does heparin cause hypekaleamia?
Inhibition of aldosterone
What must be monitored in patients taking heparin?
- Platelets
2. Potassium
What is the MHRA warning concerning warfarin?
Interaction with hepatitis medicines changing the INR
Why should patient taking warfarin inform their doctor if they develop a rash?
MHRA warning, risk of calciphylaxis with warfarin