Should anticoagulation be initiated in a patient with new onset atrial flutter requiring cardioversion on postoperative day 2 after Coronary Artery Bypass Grafting (CABG)?

From the Guidelines

Anticoagulation should be initiated in a patient with new-onset atrial flutter after CABG requiring cardioversion, considering the patient's thromboembolic risk profile and bleeding risk profile, as recommended by the 2019 AHA/ACC/HRS guideline 1. The decision to initiate anticoagulation should be based on the patient's individual risk factors, including the CHADS-VASc score, and the duration of atrial flutter.

• The patient's CHADS-VASc score should be calculated to determine the thromboembolic risk, and anticoagulation should be considered if the score is 2 or greater in men and 3 or greater in women, as recommended by the guideline 1.
• The duration of atrial flutter is also an important factor, and anticoagulation should be considered if the duration is 48 hours or longer, or if the duration is unknown, as recommended by the guideline 1.
• The guideline also recommends that anticoagulation should be achieved before cardioversion and maintained after cardioversion for at least 4 weeks, as stated in recommendation 5 of the guideline 1. Some key points to consider when initiating anticoagulation in this patient include:
• The use of therapeutic-dose heparin (unfractionated heparin infusion or low molecular weight heparin) as a bridge, followed by oral anticoagulation with a direct oral anticoagulant (DOAC) like apixaban 5mg twice daily or warfarin (target INR 2-3) once the patient is stable and taking oral medications.
• The need to balance the benefits of anticoagulation against the patient's bleeding risk, particularly given the recent surgery, as recommended by the guideline 1.
• The importance of consulting with both cardiology and cardiac surgery before initiating anticoagulation, as recommended by the guideline 1.
• The rationale for anticoagulation is that atrial flutter, like atrial fibrillation, increases stroke risk due to blood stasis in the atria leading to thrombus formation, and the early post-CABG period may further increase thrombotic risk due to the inflammatory state following surgery, as stated in the guideline 1. It is also important to note that the 2018 Chest guideline recommends starting anticoagulation at presentation and proceeding to cardioversion rather than delaying cardioversion for 3 weeks of therapeutic anticoagulation or a TEE-guided approach, as stated in the guideline 1. However, the 2019 AHA/ACC/HRS guideline is the most recent and highest quality study, and its recommendations should be prioritized, as stated in the guideline 1.

From the Research

Anticoagulation in New-Onset Atrial Flutter After CABG

The decision to initiate anticoagulation in a patient with new-onset atrial flutter requiring cardioversion on postoperative day 2 after Coronary Artery Bypass Grafting (CABG) depends on various factors, including the patient's risk of thromboembolic complications and the potential benefits and risks of anticoagulation.

• Risk of Thromboembolic Complications: Studies have shown that new-onset postoperative atrial fibrillation (POAF) after cardiac surgery is associated with an increased risk of thromboembolic complications 2, 3. However, the risk of thromboembolism in patients with new-onset POAF after CABG surgery may be lower than that of patients with nonvalvular atrial fibrillation (NVAF) 3.
• Benefits and Risks of Anticoagulation: Anticoagulation has been suggested as a potential therapy to reduce the risk of thromboembolic complications in patients with POAF 2, 4. However, the use of anticoagulation in patients with POAF after CABG surgery has been associated with increased mortality and bleeding complications 5.
• Guidelines and Recommendations: The American College of Chest Physicians Evidence-Based Clinical Practice Guidelines recommend that antithrombotic therapy decisions for patients with atrial flutter follow the same risk-based recommendations as for atrial fibrillation 4. For patients with atrial fibrillation of >48 hours or unknown duration, anticoagulation with an oral vitamin K antagonist is recommended for at least 3 weeks before elective cardioversion and for at least 4 weeks after sinus rhythm has been maintained 4.
• Clinical Considerations: The decision to initiate anticoagulation in a patient with new-onset atrial flutter after CABG should be individualized, taking into account the patient's risk factors for thromboembolic complications, the potential benefits and risks of anticoagulation, and the guidelines and recommendations for antithrombotic therapy in atrial fibrillation and atrial flutter 4, 5.

Key Points to Consider

• The risk of thromboembolism in patients with new-onset POAF after CABG surgery may be lower than that of patients with NVAF 3.
• Anticoagulation has been associated with increased mortality and bleeding complications in patients with POAF after CABG surgery 5.
• Antithrombotic therapy decisions for patients with atrial flutter should follow the same risk-based recommendations as for atrial fibrillation 4.
• The decision to initiate anticoagulation should be individualized, taking into account the patient's risk factors and the potential benefits and risks of anticoagulation 4, 5.