From the Guidelines
For left atrial thrombus, the primary recommendation is to use a direct oral anticoagulant (DOAC) such as rivaroxaban 20mg daily or apixaban, as they have shown comparable thrombus resolution rates to heparin/warfarin therapy. The 2018 European Heart Rhythm Association practical guide suggests that using NOACs for left atrial thrombus resolution may be an option, particularly in patients where a vitamin K antagonist (VKA) is not well tolerated or adequate INR control cannot be obtained 1.
Key Considerations
- The prospective X-TRA study indicated a thrombus resolution rate of 41.5% with standard dose rivaroxaban, comparable to the retrospective CLOT-AF registry with heparin/warfarin treated patients 1.
- The EMANATE trial showed a similar thrombus resolution rate in patients treated with apixaban as with conventional therapy 1.
- In the absence of data, adherence to current institutional practice with heparin/LMWH with or without transesophageal echocardiography (TOE) may be prudent in such patients 1.
Anticoagulation Therapy
- Rivaroxaban 20mg daily or apixaban can be used as the primary anticoagulation therapy for at least 4-6 weeks.
- In cases requiring more rapid anticoagulation, initial treatment with intravenous unfractionated heparin or subcutaneous low molecular weight heparin should be started while transitioning to oral therapy.
- Follow-up transesophageal echocardiography (TEE) is recommended after 4-6 weeks to confirm thrombus resolution before any planned cardioversion or ablation procedures.
Long-term Anticoagulation
- For patients with atrial fibrillation, long-term anticoagulation is typically required beyond thrombus resolution to prevent recurrence, with the specific regimen determined by stroke risk factors using scoring systems like CHA₂DS₂-VASc.
- The use of a single dose of NOAC 2-4 hours before cardioversion to replace LMWH may be justified in patients with AF <48 hours, without a TOE, but this approach should be used with caution, particularly in high-risk patients 1.
From the Research
Recommendations for Left Atrial Thrombus
- The presence of left atrial thrombus (LAT) is a significant risk factor for thromboembolic events in patients with atrial fibrillation (AF) 2.
- Anticoagulation therapy is the primary treatment for LAT, with both warfarin and non-vitamin K antagonist oral anticoagulants (NOACs) being effective in resolving LAT 3, 4.
- The choice of anticoagulant depends on various factors, including the patient's CHA2DS2-VASc score, with a lower score being associated with a higher likelihood of LAT resolution 3, 5.
- Switching to a different NOAC or transitioning to a vitamin K antagonist (VKA) may be considered if LAT persists despite optimal NOAC therapy 5.
- The duration of anticoagulation therapy is crucial, with a minimum of 3 weeks recommended before reassessing for LAT resolution 6.
- Repeat transesophageal echocardiography (TEE) is necessary to confirm LAT resolution, with some patients requiring extended anticoagulation or changes in anticoagulant therapy 3, 4.
Anticoagulation Strategies
- Warfarin, dabigatran, and rivaroxaban have been shown to be effective in resolving LAT, with no significant differences between them 3.
- NOACs offer a promising alternative to VKAs, with recent prospective research demonstrating their efficacy in treating LAT 6.
- The supplementation of antiplatelet therapy may be considered in some cases, although its effectiveness is still being studied 5.
Diagnostic Imaging
- Transesophageal echocardiography (TEE) is the gold standard for diagnosing LAT, although other imaging modalities such as cardiac multidetector computed tomography and cardiac magnetic resonance imaging may be used as alternatives 6.
- Repeat TEE is necessary to confirm LAT resolution and guide changes in anticoagulant therapy 3, 4.