Table 2.

Summary and comparison of the European Society of Cardiology (ESC) and American College of Cardiology/American Heart Association (ACC/AHA) recommendations for antithrombotic therapy in patients with atrial fibrillation (AF).

ESC guidelines [1]	ACC/AHA guidelines [2]
Prevention of thromboembolism—general
	Antithrombotic therapy based on shared decision making, discussion of risks of stroke and bleeding, and patient’s preferences (Level 1C)
The CHA2DS2-VASc score is recommended for stroke risk prediction in patients with AF (Level IA)	CHA2DS2-VASc score recommended to assess stroke risk (Level IB)
In general, patients without clinical stroke risk factors (CHA2DS2-VASc = 0) do not need antithrombotic therapy (Level IIIB)	With NVAF and CHA2DS2-VASc score of 0, it is reasonable to omit antithrombotic therapy (Level IIa B)
OAC therapy is recommended in all patients with a CHA2DS2-VASc score ≥2 (men) or ≥3 (women) (Level IA)	With prior stroke, TIA, or CHA2DS2-VASc score ≥2, OACs recommended. Options include: •Warfarin (Level IA) •Dabigatran, rivaroxaban or apixaban (Level IB)
In patients with a CHA2DS2-VASc score of 1 (men) or 2 (women), OAC should be considered to prevent thromboembolism, considering individual characteristics and patient preferences (Level IIa B)	With NVAF and a CHA2DS2-VASc score of 1, no antithrombotic therapy or treatment with OACs or aspirin may be considered (Level IIb C)
When OAC is initiated in a patient with AF who is eligible for a NOAC (apixaban, dabigatran, edoxaban, or rivaroxaban), a NOAC is recommended in preference to a VKA (Level IA)	Selection of antithrombotic therapy based on risk of thromboembolism (Level 1B)
When patients are treated with a VKA, time in therapeutic range (TTR) should be kept as high as possible and closely monitored (Level IA)	With warfarin, determine INR at least weekly during initiation and monthly when stable (Level IA)
Antiplatelet monotherapy is not recommended for stroke prevention in AF patients, regardless of stroke risk [Level IIIA (harm)]
Combinations of OACs and platelet inhibitors increase bleeding risk and should be avoided in AF patients without another indication for platelet inhibition [Level IIIB (harm)]
Renal function
The assessment of kidney function by serum creatinine or creatinine clearance is recommended in all AF patients to detect kidney disease and to support correct dosing of AF therapy (Level IA) All AF patients treated with OAC should be considered for at least yearly renal function evaluation to detect chronic kidney disease (Level IIa B)	Evaluate renal function prior to initiation of direct thrombin or factor Xa inhibitors, and reevaluate when clinically indicated and at least annually (Level 1B)
	Direct thrombin dabigatran and factor Xa inhibitor rivaroxaban are not recommended in patients with AF and end-stage chronic kidney disease (CKD) or on dialysis because of a lack of evidence from clinical trials regarding the balance of risks and benefits (Level IIIC)
	With moderate-to-severe CKD and CHA2DS2-VASc scores ≥ 2, reduced doses of direct thrombin or factor Xa inhibitors may be considered (Level IIb C)
	With CHA2DS2-VASc score ≥ 2 and end-stage CKD (CrCl < 15 mL/min) or on hemodialysis, it is reasonable to prescribe warfarin for OAC (Level IIa B)
If VKA is not an option
AF patients already on treatment with a VKA may be considered for NOAC treatment if TTR is not well controlled despite good adherence, or if patient preference without contraindications to NOAC (e.g., prosthetic valve) (Level IIb A)	Direct thrombin or factor Xa inhibitor recommended if unable to maintain therapeutic INR (Level 1C)
Mechanical heart valves and mitral stenosis
VKA therapy (INR 2.0–3.0 or higher) is recommended for stroke prevention in AF patients with moderate-to-severe mitral stenosis or mechanical heart valves (Level 1B)	Warfarin recommended for mechanical heart valves and target INR intensity based on type and location of prosthesis (Level IB)
	Direct thrombin inhibitor dabigatran should not be used with a mechanical heart valve [Level IIIB (harm)]

Classes of recommendation: I, evidence and/or general agreement that a given treatment or procedure is beneficial, useful, effective; II, conflicting evidence and/or a divergence of opinion about the usefulness/efficacy of the given treatment or procedure; IIa, weight of evidence/opinion is in favor of usefulness/efficacy; IIb, usefulness/efficacy is less well established by evidence/opinion; III, evidence or general agreement that the given treatment or procedure is not useful/effective, and in some cases may be harmful.

Levels of evidence: A, data derived from multiple randomized clinical trials or meta-analyses; B, data derived from a single randomized clinical trial or large nonrandomized studies; C, consensus of opinion of the experts and/or small studies, retrospective studies, registries.

INR = international normalized ratio; NOACs = non-vitamin K antagonist oral anticoagulants; NVAF = nonvalvular atrial fibrillation; OAC = oral anticoagulation; TIA = transient ischemic attack; TTR = time in therapeutic range; VKA = vitamin K antagonist.