Anticoagulation in
Atrial Fibrillation
Jesse Tran
R2
Class I recommendations
•
In patients with nonvalvular AF, calculate
CHA2DS2-VASc
•
CHA2DS2-VASc of 2 or greater, oral anticoagulation
recommended.
•
Wafarin with INR 2-3, dabigatran, rivaroxaban, or
apixaban.
•
In patients with A flutter, anticoagulation is
recommended as above.
Class IIa, IIb
•
In patient with nonvalvular AF and CHA2DS2-VASc of 0,
no need for anticoagulation.
•
CHA2DS2-VASc of 1, can consider anticoagulation or
ASA.
•
Patients undergoing PCI, BMS considered to minimize
duration of dual anti platelet therapy.
•
Following coronary revascularization in pts with A fib and
a CHA2DS2-VASc of 2 or greater, can use plavix with
oral anticoagulants, but without ASA.
Class III
•
Direct thrombin inh and factor Xa inh are not
recommended in patents with AF and end-stage
CKD or HD. Lack of evidence
•
Direct thrombin inh, dabigatran, should not be used
in pts with AF and mechanical heart valve.
Bleeding Risk
•
HAS-BLED: HTN - sbp >160, Abnormal renal/liver
function, Stroke, Bleeding hx or predisposition,
Labile INR, Elderly - >65, Drugs/alcohol.
•
Score of greater than or equal to 3 indicates patients
at higher risk of bleeding.
Antiplatelet Therapy
•
ASA has been shown to be beneficial in both
primary and secondary prevention of stroke, though
inferior to other methods of anticoagulation.
•
Plavix + ASA vs Warfarin was compared in the
ACTIVE-W trial. Ended early due to inferiority
between these two groups in pts with CHADS2 = 2.
•
Plavix + ASA proved to be superior to ASA alone in
ACTIVE-A trial.
Warfarin
•
Vitamin K antagonist
•
ARR 2.7% per year, NNT 37 in one year to prevent 1 stroke,
NNT of 12 in pts with prior stroke.
•
Risk of stroke in pts with warfarin 1.66% annually
•
Risk of intracranial hemorrhage was significantly increased in
those with oral anticoagulants.
•
Numerous drug interactions, affects on diet, need for frequent
monitoring.
Direct Thrombin Inhibitor
•
Renally excreted, lower dose approved in pts with CrCl 15-30
mL/min.
•
Compared with warfarin in RE-LY trial
•
Dabigatran at 150mg BID superior to warfarin in this study, 110mg
BID non inferior for primary outcomes of stroke and systemic
embolism.
•
Lower rates of intracranial bleeding, but higher rates of GI bleeding
in the 150mg BID group.
Factor Xa Inhibitor
•
Single daily dose for reduction of stroke and
systemic embolism in patients with nonvalvular AF.
•
Renal excretion
•
ROCKET AF trial which showed non inferiority.
•
Major bleeding was similar between warfarin and
rivaroxaban, but had less fatal bleeding and less
ICH.
Factor Xa Inhibitors
•
Hepatic elimination
•
ARISTOTLE trial - showed significant reduction in
overall stroke, emboli, and major bleeding events.
•
Fewer ICH with similar GI bleeding complications.
Benefits of new
anticoagulation agents
•
Fewer drug-drug interactions
•
No dietary effects
•
Less risk of ICH
•
No need for frequent monitoring
•
No reversal agents, though short half life
Dose Adjustments