When do you anticoagulate atrial fibrillation (AFib)?

From the Guidelines

Anticoagulation is recommended for patients with atrial fibrillation who have a CHA₂DS₂-VASc score of 2 or higher in men, or 3 or higher in women, as stated in the 2016 ESC guidelines 1.

Key Considerations

• The decision to anticoagulate should be based on the patient's risk of stroke, which can be assessed using the CHA₂DS₂-VASc score.
• Patients with a high risk of stroke should receive anticoagulation, with options including direct oral anticoagulants (DOACs) such as apixaban, rivaroxaban, dabigatran, or edoxaban, which are generally preferred over warfarin due to fewer interactions and no need for regular INR monitoring.
• Warfarin remains an option for patients with mechanical heart valves or severe kidney disease.
• Anticoagulation is typically lifelong unless contraindications develop.
• Before starting therapy, assess bleeding risk using tools like the HAS-BLED score and address modifiable bleeding risk factors.

Recommendations

• For patients with AF of greater than 48 hours or unknown duration undergoing elective electrical or pharmacologic cardioversion, therapeutic anticoagulation (with VKA or NOAC) is recommended for at least 3 weeks before and 4 weeks after cardioversion, as stated in the 2018 Chest guideline 1.
• Decisions about anticoagulation beyond 4 weeks should be made in accordance with risk-based recommendations for long-term antithrombotic therapy.

Important Notes

• The 2018 Chest guideline recommends therapeutic anticoagulation for at least 4 weeks after successful cardioversion to sinus rhythm, regardless of the baseline risk of stroke 1.
• Whether a repeat TEE is performed should be individualized, as stated in the 2018 Chest guideline 1.

From the FDA Drug Label

Oral anticoagulation therapy with warfarin is recommended in patients with persistent or paroxysmal AF (PAF) (intermittent AF) at high risk of stroke (i.e., having any of the following features: prior ischemic stroke, transient ischemic attack, or systemic embolism, age >75 years, moderately or severely impaired left ventricular systolic function and/or congestive heart failure, history of hypertension, or diabetes mellitus)

Anticoagulation with warfarin is recommended for patients with atrial fibrillation (AF) who are at high risk of stroke, including those with:

• Prior ischemic stroke, transient ischemic attack, or systemic embolism
• Age >75 years
• Moderately or severely impaired left ventricular systolic function and/or congestive heart failure
• History of hypertension
• Diabetes mellitus For patients with persistent AF or paroxysmal AF (PAF) aged 65 to 75 years, without other risk factors, but at intermediate risk of stroke, antithrombotic therapy with either oral warfarin or aspirin is recommended 2.

From the Research

Anticoagulation in Atrial Fibrillation

• Anticoagulation is recommended for patients with atrial fibrillation (AF) and a CHA2DS2-VASc score of greater than 1, beyond sex 3.
• The CHA2DS2-VASc score is used to predict the need for oral anticoagulation for stroke prophylaxis in patients with AF 4.
• Patients with a CHA2DS2-VASc score of 1 may not require anticoagulation, as the risk of thromboembolic events is lower 5, 6.
• However, the risk of thromboembolic events differs between the risk factors of the CHA2DS2-VASc score, with age 65-74 years associated with the highest risk 5.

Risk Factors for Thromboembolic Events

• Age 65-74 years is a strong risk factor for thromboembolic events in patients with AF 5, 6.
• Vascular disease is also a risk factor, but is associated with a lower risk of thromboembolic events compared to age 65-74 years 5.
• Female sex is a risk factor, but the risk is lower compared to age 65-74 years 5.

Anticoagulation Therapy

• Oral anticoagulation therapy is recommended for all AF patients if the CHA2DS2-VASc score is at least 1 for men and at least 2 for women 7.
• The choice of oral anticoagulant agent should be made by careful consideration of the benefit-to-risk ratio 7.
• Direct oral anticoagulants (DOACs) may be a suitable alternative to anti-vitamin K (AVK) anticoagulants, as they have a lower risk of bleeding and do not require periodic monitoring of International Normalized Ratio (INR) 7.