cardiovascular- anticoagulation Flashcards
What is tranexamic acid used for and how does it work?
Prevents bleeding by inhibiting fibrinolysis
Why should patients on oral contraception use tranexamic acid in caution?
Risk of thrombosis
What is prothrombin complex used for and who is it contraindicated in?
Haemorrhage. patients with history of heparin induced thromboctopenia
What do you use to prevent ischaemic neurological defects following a subarachnoid haemorrhage?
nimodipine
What are the risks for VTE?
reduced mobility, obesity, malignant disease, history of VTE, thrombophilic disorders, over 60 years
What are the risks for bleeding?
acute stroke, thrombocytopenia, inherited bleeding disorders
What VTE prophylaxis is preferred in renal failure?
unfractionated heparin
What surgical patients can have fondaparinux?
hip/knee replacement, GI bariatric, day surgery
What surgery types can have DOACs after?
hip or knee replacement
How long should pharmacological prophylaxis continue post surgery?
5-7 days or until mobile
What surgery should have pharmacological prophylaxis extended to 28 days?
major cancer surgery in the abdomen or pelvis
How do you treat VTE?
Initially a LMWH/unfractionated heparin at the same time an oral anticoagulant. Continue heparin for at least 5 days and until the INR is >=2 for at least 24 hours.
How do you monitor heparin?
APTT
How do you manage VTE in pregnancy?
Heparins do not cross the placenta. LMWH are eliminated more rapidly in pregancy (BD dosing)
What reverses heparin?
Protamine
How do you initially manage a TIA?
immediately receive aspirin (if not tolerated give clopidogrel)
When should alteplase be administered?
within 4.5 hours of symptom onset of acute ischaemic stroke
When should aspirin be given in stroke management?
24 hours post thrombolysis. Within 48 hours of symptom onset in patients not receiving thrombolysis
Why shouldn’t you treat hypertension in the acute phase of ischaemic stroke?
Can reduce cerebral perfusion
What is the long term management following a TIA?
MR dipyridamole with aspirin. Intolerant to aspirin then just MR dipyridamole or aspirin if vice versa. Last option is clopidogrel
What is the long term management following an ischaemic stroke?
clopidogrel long term.
If contraindicated give MR dipyridamole in combo with aspirin.
If have AF then anticoagulate
Start statin 48 hours after stroke
Blood pressure following acute phase target <130/80- don’t start on beta blocker
Name 3 vitamin K antagonists?
warfarin, acenocoumarol, phenindione
How long does warfarin take to work?
48 to 72 hours
What is the target INR for treatment of DVT/PE and AF?
2.5
What is the target INR for the recurrent DVT/PE and also mechanical heart valve?
3.5
How long should you anticoagulate someone with an isolated calf DVT?
6 weeks
How long should you anticogulate someone with a VTE provoked by transient risk factors?
at least 3 months
How do you control major bleeding?
stop warfarin, IV phytomenadione (vitamin K), dried prothrombin complex
How do you control minor bleeding with INR>8?
stop warfarin, IV phytomenadione (vitamin K), can repeat vit K if INR still high after 24 hours. Restart warfarin when INR<5
What do you do if INR>8 and no bleeding?
stop warfarin, give vitamin K orally using the IV preparation, can repeat vitamin K if INR still high after 24 hours
How do you control minor bleeding with INR 5-8?
stop warfarin, give vitamin K IV
What do you do if INR 5-8 with no bleeding?
hold 1 or 2 warfarin doses and reduce subsequent maintenance doses
How do you control warfarin before surgery?
stop 5 days before before elective surgery. Give Vit K the day before if INR >=1.5.
If at high risk (VTE in last 3 months, AF with previous stroke/TIA, or mechanical heart valve) bridge with LMWH treatment dose.
How do antiplatelet drugs work?
Decrease platelet aggregation and inhibit thrombus formulation in arterial circulation (mainly platelets)
What do you need to control before you give aspirin?
Unduly high BP
Heparin
initiates anticoagulation rapidly. Has a short duration of action
Why are LMWH preferred?
Lower risk of heparin induced thrombocytopenia, does not require monitoring, duration of action longer
Name a Heparinoid and what it is used for?
Danaporoid. Used for prophylaxis of DVT in patients undergoing surgery. Role in HIT
What are the different doses of aspirin?
Secondary prevention: 75mg OD
NSTEMI: initially 300mg then 75mg for 12 months
STEMI: initially 300mg then 75mg for at least 4 weeks
acute ischaemic stroke: 300mg for 14 days
What are the side effects of aspirin?
blood disorders, GI haemorrhage, increased bleeding time
Who is aspirin contraindicated in?
peptic ulcers, under 16, haemophilia
What are the different doses of clopidogrel?
Prevention in PCI: loading dose 300mg
NSTEMI with aspirin: 300mg then 75mg for up to 12 months
STEMI: 300mg then 75mg for at least 4 weeks
Name some factor 10a inhibitors?
Apixiban, fondiparinux, rivaroxaban
What are the different doses of apixiban?
VTE prophylaxis following TKR: 2.5mg BD for 10-14 days, starting 12-24 hours post surgery
VTE prophylaxis following THR: 2.5mg BD for 32-38 days, starting 12-24 hours post surgery
DVT/PE treatment: 10mg BD for 7 days, then 5mg BD
Prophylaxis of recurrent DVTs: 2.5mg BD following completion of 6 months
Prophylaxis in AF with 1 risk factor; under 80: 5mg BD, over 80: 2.5mg BD
What are the risk factors to allow use of DOAC?
Previous stroke or TIA, HF, age over 75, diabetes, HTM
What renal function should you avoid apixiban?
less than 15
What is fondiparinux used for?
VTE prophylaxis, treatment of unstable angina/NSTEMI/STEMI, VTE treatment
CI in renal function less than 30
What are the different doses of rivaroxaban?
VTE prophylaxis following TKR: 10mg OD for 2 weeks, starting 6-10 hours post surgery.
VTE prophylaxis following THR: 10mg OD for 5 weeks, starting 6-10 hours post surgery
DVT treatment: 15mg BD 3 weeks, then 20mg OD
Prophlyaxis in AF with 1 risk factor: 20mg OD
Prophylaxis in ACS: 2.5mg BD for 12 months
When are heparins contraindicated?
acute bacterial endocarditis
What is a side effect of heparins?
osteoprosis
What is heparin induced thrombocytopenia, when does it develop and what are the signs of it?
immune mediated, develops after 5-10 days,
30% reduction in platelet count, thrombosis or skin allergy.
Why do heparins cause hyperkalaemia?
inhibit aldosterone secretions
What monitoring is required for heparins?
Platelets before and after 4 days
Potassium before and regularly after
When should you be cautious with enoxaparin?
low body weight. Reduce dose if CrCl<30
Name 3 direct thrombin (2a) inhibitors
Agatroban, Bivalirudin, Dabigatran
What is the use of Agatroban?
anticoagulation in patients with type 2 HIT who require parenteral anticoagulation
How do you monitor Agatroban?
APTT 2 hours after start of treatment, then 2-4 hours after infusion rate altered, then OD
What renal function should you avoid rivaroxaban?
CrCl less than 15
What are the different doses of dabigatran?
- VTE prophylaxis TKR: <75yrs 110mg 1-4 hours post surgery, then 220mg OD for 9 days (12-24 hours after inital dose) >75yrs have 75mg and 150mg
- VTE prophylaxis THR: 27-34 days
- DVT treatment: <75 150mg BD following 5 days of parenteral treatment. 75-79 110-150mg BD, >80 110mg BD
- AF: 110-150mg BD
What happens to the dose of dabigatran if patient is on verapamil or amiodarone?
second dose is 150mg. take dose at the same time as verpamil or amiodarone
What renal function should you avoid dabigatran?
less than 30
How often do you have to monitor renal function with dabigatran?
before starting and annually
Name a Tissue Plasminogen Acitvator
Urokinase (IV infusion)
What food interactions are there with warfarin?
major changes in diet and alcohol can affect control
avoid cranberry juic
can pregnant women have warfarin?
no- teratogen
what are side effects of warfarin?
hepatic dysfunction, jaundice, pancreatitis
What do you need monitor with warfarin?
baseline prothrombin time, INR daily/alternate days during early treatment, then longer intervals up to 12 weeks. Change in condition then increase monitoring
When should you avoid warfarin?
severe hepatic impairment.
Caution mild to moderation renal impairment. Monitor INR