Cardiovasular Flashcards
What is the treatment dose for a DVT/PE with rivaroxaban?
15mg BD for 21days then 20mg OD with food
What is the dose of rivaroxaban for prophylaxis of DVT following hip and knee replacement?
Knee: 10mg OD for 2weeks
Hip: 10mg OD for 5 weeks
Both start 6-10 hours after surgery
What is the mechanism of action for rivaroxaban?
Direct inhibitor or factor Xa
When should rivaroxaban NOT be used for thromboprophylaxis?
Patients with prosthetic heart valves including patients who have undergone TAVR (transcatheter aortic valve replacement).
Which DOAC should be taken with food?
Rivaroxaban - due to increased absorption with food (15 and 20mg tabs)
What is the renal cutoff for rivaroxaban?
EGFR: less than 15ml/min/1.73m2
CrCl: 15ml/min
What is the reversal agent for rivaroxaban?
Andexanet Alfa
What is an appropriate alternative for patients who required VTE but have a history of HITT and DOACs/warfarin are contraindicated?
Fondaparinux - does not usually cause HITT but have been some cases reported
What is the renal cutoff and dose adjustments for fondaparinux when used for treatment of ACS or prophylaxis of VTE?
Avoid if CrCl less than 20ml/min
For VTE prophylaxis only: Reduce dose to 1.5mg daily if CrCl 20-50ml/min
What is the renal cut off and dose adjustment for fondaparinux when used for treatment of VTE?
Avoid if CrCl less than 30ml/min
Reduce dose to 1.5mg daily if CrCl 20-50ml/min
What is the mechanism of action for fondaparinux?
Inhibits activated factor X
What is the mechanism of action for dabigatran?
Reversible inhibition of free thrombin, fibrin bound thrombin, and thrombin-induced platelet aggregation.
Which DOAC is not licensed for the prophylaxis of atherothrombotic events?
Edoxaban
Which DOAC has no antidote?
Edoxaban
What is the recommended dose for apixaban for prophylaxis of stroke in AF?
5mg BD
When should the apixaban dose in AF be reduced to 2.5mg?
2 of the following characteristics:
Over 80 years
<60kg
SrCr >133 (or same as 133)
What is the apixaban dose for treatment of VTE?
10mg BD for 7days; 5mg BD
For a minimum of 3 months
What is the apixaban dose for VTE prophylaxis of recurrent DVT/PE? (Following 6 months completion of anticoagulant treatment)
2.5mg BD
What is the recommended dose of dabigatran for treatment of VTE and when would you reduce it? What to?
150mg BD
Reduce to 110mg BD if:
Over 80
Concurrent treatment with verapamil
Reduce to 110-150mg BD if CrCl 30-50ml/min
What is the typical starting dose of warfarin?
10mg OD for 2 days
5mg OD for elderly, frail, low body weight, liver disease, or cardiac failure
What is the usual maintenance dose for warfarin?
3-9mg taken at the same time each day
What is the minimum duration of treatment for distal calf DVT with warfarin?
Six weeks
What measurements should be taken before starting warfarin treatment?
Baseline prothrombin (but initial dose should not be delayed while waiting for the result)
Apart from warfarin, what are the other vitamin k antagonists (2)?
Acenocomarol
Phenidione
What is the duration of treatment for proximal DVT/PE with known temporary risk factors and a low risk of reoccurrence?
3 months
When using warfarin in AF, if the patient undergoes cardioveraion, how long should the target INR be achieved before and after treatment?
3 weeks before and 4 weeks after
When is warfarin contraindicated? (6)
Haemorrhagic stroke
Clinically significant bleeding
Severe hepatic impairment
Within 72 hours of major surgery
Within 48 hours postpartum
Pregnancy - teratogenic
What are the risk factors for bleeding?
History of GI bleeds or peptic ulceration
Recent ischemic stroke
Uncontrolled HTN
Concurrent NSAID use
Recent surgery
Postpartum period (5-7 days after delivery)
Why should warfarin be introduced slowly in thrombophilia?
Risk of skin necrosis
Why is warfarin cautioned in thyroid conditions?
Levels of thyroid hormone can alter rate of warfarin metabolism
What non-pharmacological factors can exaggerate warfarin effect and necessitate a dose reduction?
Weight loss
Acute illness
Smoking cessation
What non-pharmacological factors can reduce the effect of warfarin and necessitate a dose increase?
Weight gain
Diarrhoea
Vomiting
Why is the antidote to warfarin?
Phytomenadione (vitamin k)
What are some of the rare but serious adverse effects of warfarin?
Warfarin-related skin necrosis (more likely with history of HIT or pre-existing protein C or S deficiency)
Calciphylaxis - vascular calcification (occurs more with other risk factors: end-stage renal disease, protein C or S deficiency, hyperphosphataemia, hypercalcaemia, hypoalbuminaeia)
What should you do if a warfarin patient is starting and antibiotic or azole?
Measure INR 4-7 days after the new drug has been started and adjust dose accordingly
What is the likely dose adjustment of a warfarin patient is stated in thyroxine?
Reduce the dose
Why should people on warfarin be told not to change their diet?
Vitamin K containing foods e.g green vegetables can change effectiveness of warfarin
What is the duration of treatment with warfarin for an idiopathic proximal DVT/PE?
Minimum 6 months
What is the recommended dose of Edoxaban for VTE prophylaxis in AF and DVT/PE treatment?
60mg OD
When should the dose of Edoxaban be reduced to 30mg OD?
Weight <60kg
CrCl 15-50ml/min
Receiving concurrent treatment with P-gp inhibitors (ciclosporin, dronedarone, erythromycin, or ketoconazole)
At what INR can you switch a patient from warfarin to Edoxaban immediately?
Less than 2
If between 2 and 2.5, start Edoxaban the next day
How do you switch a person from Edoxaban to warfarin?
If person is on 60mg Edoxaban, prescribe 30mg OD withwarfarin
If person is on 30mg Edoxaban, prescribe 15mg OD with warfarin
Continue concurrent warfarin and Edoxaban until INR reaches target range (2 or more) then stop Edoxaban
How do you switch between DOACs?
Stop current DOAC and start the new one when the next dose is due
How long should a DOAC be held before a minor surgery with a minor bleeding risk?
They should not be held - in general the surgeries are performed 12-24 hours after the last dose was taken
Minor surgery e.gs
Dental
Cataract
Endoscopy without surgery
Smaller dermatological excisions
What monitoring should be carried out before starting DOAC treatment?
Baseline clotting, renal, liver and full blood count
How long should a DOAC be held before a procedure with a low bleeding risk?
At least 24 hours before
If CrCl 15-29ml/min then 36 hours before
Low risk e.gs
Endoscopy with biopsy
Prostate or bladder biopsy
Angiography
Pacemaker implantation
How long should a DOAC be held before a surgery with a high bleeding risk?
48 hours
High risk e.gs
Complex endoscopy e.g polypectomy
Spinal or epidural anaesthesia
Lumbar diagnostic
Thoracic or abdominal surgery
Major orthopaedic surgery
Liver or kidney biopsy
Transurethral prostate resection
Is aspirin licensed for primary prevention of CVD?
No
Why is aspirin contrindicated in under 16 years?
Reye’s syndrome - acute syndrome causing swelling of the brain and liver
Symptoms: repeatedly vomiting, seizures, fatigue, rapid respiratory rate, hallucinations, loss of consciousness
In what condition can aspirin be used in children under 16?
Kawasaki disease - inflammation of blood vessels
What is the 1st line anti-platelet/s for secondarily CVD prevention in ACS?
DAPT - aspirin 75mg plus ticagrelor 90mg BD for 12 months
What is the 1st line anti-platelet for secondary prevention in ACS undergoing a PCI?
Aspirin 75-100mg plus one of the following:
Prasugrel 10mg OD (5mg if <60kg or >75)
Ticargrelor 90mg BD
Clopidogrel 75mg OD (if prasugrel and ticagrelor not suitable)
Treat for 12 months after procedure then continue aspirin alone
What is the 1st line antiplatete for secondary prevention of CVD following a stroke or TIA?
Clopidogrel 75mg OD
What is the 1st line antiplatete for secondary prevention of CVD following a stroke or TIA if clopidogrel is contraindicated ?
Dipyridamole MR 200mg BD combined with low dose aspirin
When is Prasugrel contraindicated?
History of stroke or TIA
Severe hepatic impairment
Active bleeding
Which anti-platelet is preferred in peripheral arterial disease?
Clopidogrel
2nd choice low dose aspirin
Which antiplatelet interacts with omeprazole?
Clopidogrel
Use lansoprazole instead
When should the following antiplatelets be held before surgery: ticargrelor, clopidogrel, prasugrel?
Ticargrelor: 3-7 days before
Clopidogrel: 5-7 days before
Prasugrel: at least 7 days before
What is 1st for secondary prevention of CVD in stable angina?
Aspirin
If contraindicated clopidogrel
Is aspirin contraindicated in pregnancy?
No - but manufacturer advises avoid in 1st and 2nd trimesters and use a max of 100mg/day in third trimester
Can aspirin be used while breastfeeding?
No - low quantities found in breast milk - discontinue breastfeeding if low dose aspirin is used short term
In what condition is dipyridamole contraindicated?
Cardiac conduction difficulties or arrhythmias
When is ticagrelor contraindicated?
Active bleeding
History of intracranial haemorrhage
Severe hepatic impairment
