SPAF Flashcards
Can you give antiplatelet for SPAF?
NO
Criterias in mCHA2DS2VASc
CHF: 1
HTN: 1
DM: 1
Prior stroke or TIA: 2
Vascular disease (prior MI, PAD or aortic plaque): 1
Age 65-74: 1
Age >=75: 2
What does mCHA2DS2VASc estimate?
Stroke risk
What should you do if mCHA2DS2VASc score = 0?
No need anticoagulant or antiplatelet agents
What should you do if mCHA2DS2VASc score = 1?
Consider anticoagulation
No antiplatelet agents
What should you do if mCHA2DS2VASc score >= 2?
Recommend warfarin or a NOAC if not CI
What does HASBLED estimate?
Bleeding risk
Criterias in HASBLED
HTN (SBP>160): 1
Abnormal renal function: 1
Abnormal liver function: 1
Stroke (Hx): 1
Bleeding (Hx or predisposition) : 1
Labile INRs: 1
Elderly (>65y/o): 1
Drugs (eg. antiplatelet, NSAID): 1
Alcohol: 1
What is the goals of therapy for AF?
ABC pathway:
A- avoid stroke
B- better symptom control
C- CV and other comorbs or RFs
What is LAA occlusion?
Reserved for very high bleeding risk. Watchman device- “Umbrella” to catch broken off clots .
What is the dose of dabigatran
150mg BD
110mg BD if >=80y/o, using PGP inhibitors or high risk of bleeding
What is the dose of rivaroxaban?
20mg QD
What is the dose of apixaban?
5mg BD
2.5mg BD for any 2:
- >=80y/o
- <=60kg
- SCr >= 1.5mg/dl or 13.6mmol/L
What is the dose of edoxaban?
60mg QD
30mg QD if any 1:
- CrCL 30-50ml/min
- <=60kg
- concom verapamil, quinidine, dronedarone
How to renally dose adjust dabigatran?
CrCl 30-50ml/min: no dose adj unless have DDI
CrCl < 30ml/min: CI
How to renally dose adjust rivaroxaban?
CrCl 30-50ml/min: 15mg QD
CrCl 15-30ml/min: use with caution
CrCl <15ml/min: CI
How to renally dose adjust apixaban?
CrCl 15-29 ml/min: 2.5mg BD
How to renally dose adjust edoxaban?
CrCl <15ml/min: not recommended
Which DOAC is recommended in elderly?
Apixaban based on RCTs
Which DOACs require dose adj for lower BW <60kg?
Apixaban and edoxaban
Why are DOACs preferred over warfarin?
1) Ease of dosing: easier to dose, no need for titration
2) Monitoring: warfarin has a narrow TI and requires tight monitoring. DOACs wide TW.
3) Safer: less major bleeding while non-inferior to warfarin
4) Drug Interaction: significantly less DDI
What PGx impacts warfarin?
VKOR, 2C9 polymorphisms
How does bacteria affect warfarin dose?
Disruption of gut bacteria due to AB killing the bacteria= less menadione (type of Vit.K from gut) ->
Less clotting factors -> Increases INR -> increase bleeding so might need to adjust dose.
Which ABs will affect warfarin dose and what is the dose adjustment?
Bactrim (sulfamethoxazole/trimethoprim): 25-50% reduction
Ciprofloxacin: 20-30% reduction
How is INR affected by alcohol binging, chronic alcoholism, sudden incr in physical activity and smoking?
Alcohol binge: increase INR
Chronic alcoholism, sudden incr in physical activity and smoking: increase warfarin metabolism –> decrease INR
How does liver disease, fever, thyroid disease and fluid retention affect INR?
Liver disease, fever, fluid retention in liver, hyperthyroidism: increase INR
Fluid retention in gut, hypothyroidism: decrease INR
What conditions would warfarin be used instead of DOACs?
Left ventricular thrombus
Prosthetic heart valve/mitral stenosis
Antiphospholipid syndrome related VTEs
Which clotting factor that warfarin inhibits has the shortest t1/2?
Factor VII
If CrCl < 60ml/min, how to determine when will be the next blood test?
CrCl/10
What should be reviewed at every follow up session?
Adherence, TE S&S, bleeding, SE, Co-meds, blood tests PRN, screen and mitigate for RFs for bleeding, assess optimal DOAC choice/dosing
Which TB AB has DDI with DOACs and warfarin?
Rifampicin
How to switch warfarin to NOAC?
INR <=2: start NOAC immediately
INR 2-2.5: start NOAC immediately or next day
INR 2.5-3: recheck INR in 1-3days
INR >=3: postpone NOAC
How to switch NOAC to warfarin?
Continue NOAC while starting on warfarin and check INR after 3-5days
If INR is still <2, continue NOAC
If INR is >=2, stop NOAC
Which anti-seizure meds have DDI/CI with DOACs?
Dabi + riva: Carbamazepine, phenytoin
Riva: Phenobarbital
Valproic acid: all DOACs
Which herbal meds is CI with all DOACs?
St. John’s wort inducers PGP and CYP3A4
What type of drugs should be avoided with rivaroxaban and apixaban?
Potent dual inhibitors/inducers
Examples of potent dual inhibitors of CYP3A4 and PGP are azoles, ritonavir, clarithromycin
How should the warfarin dose be adjusted if taken with metronidazole?
20-30% reduction
How should warfarin dose be adjusted if taken with amiodarone?
Pre-emp reduce warfarin dose by 30-50%
How to manage bleeding while using a NOAC?
Mild bleeding: wait first
Non-life threatening major bleeding: supportive meausres or consider hemodialysis / idarucizumab (for dabigatran) but it is v. ex
Life threatening or bleeding into critical site: idarucizumab (for dabigatran) or PCC
How to manage DOACs during unplanned invasive procedures?
High bleeding risk during procedure: hold off DOAC
Low bleeding risk: can just give DOAC
What is the target INR for mechanical heart valve?
2.5-3.5
At what INR do we have to reverse warfarn and what can we give?
INR > 10: give PO Vit. K 2-5mg
If major bleeding and INR > 1.5, give IV Vit.K 5-10mg
Note: fresh frozen plasma and PCC can also be used to reverse warfarin. PCC is more effective if urgent reversal is needed
Why should we avoiding giving high levels of Vit. K?
Confer resistance when you try to redose warfarin
Are azole antifungals CI with DOAC?
Yes.
Only keto/intraconazole for dabi
Which DOAC is CI in ESRD?
Dabi, riva
Are warfarin and DOACs CI in severe hepatic dysfunction, esp with coagulopathy?
Yes
