Anticoagulation or left atrial appendage occlusion: How to choose a stroke prevention strategy for high-risk patients with atrial fibrillation?

‍‍Oral anticoagulant (OAC) effective prevention of stroke is the cornerstone of the management of patients with atrial fibrillation, and the use of OAC can reduce the risk of stroke and death
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How should stroke prevention be done for patients with high-risk atrial fibrillation? In "Warfarin or New Oral Anticoagulants: High-risk Atrial Fibrillation Patients, How to Choose Stroke Prevention Strategies? "In the article, we introduced the anticoagulation strategy for patients with end-stage renal disease, previous intracranial hemorrhage, recent acute gastrointestinal hemorrhage, elderly, frail and multi-drug patients
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This article continues to introduce the selection of stroke prevention strategies for patients with acute ischemic stroke and intracardiac thrombosis and the treatment of left atrial appendage occlusion (LAAO)
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Acute ischemic stroke patients are at high risk of stroke, including patients with atrial fibrillation in the early stage (<1 week) of acute stroke.
The best strategy to prevent stroke is uncertain, especially the best timing of OAC (re)start is uncertain
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The evidence obtained from observational studies is limited, and the guidelines are mainly based on expert consensus
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A cohort study of 1,029 patients with atrial fibrillation and acute stroke (especially extensive ischemic disease) showed that only 74.
4% received OAC treatment after stroke, 22.
5% received antiplatelet therapy, and 3.
1% did not Receive antithrombotic therapy
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Restarting OAC therapy 4-14 days after stroke has a better clinical effect than using heparin bridging or restarting OAC within 4 days/14 days
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Cohort analysis data and meta-analysis results show that the use of NOAC is more effective and safer than VKA
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AHA/ASA stroke and transient ischemic attack patients' stroke prevention statement believes that oral anticoagulation therapy may be beneficial for patients with atrial fibrillation within 14 days after the neurological event.

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The best time to start treatment varies with the severity of the stroke and the associated risk of hemorrhagic transformation
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For patients with transient ischemic attacks or mild strokes, it may be beneficial to restart or even continue oral anticoagulation therapy immediately
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For patients with moderate or severe stroke, before (re)starting anticoagulation therapy, it may be useful to perform brain imaging to further evaluate hemorrhage transformation
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If the risk is significantly greater than the benefit, treatment may need to be postponed (>14 days)
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The use of parenteral anticoagulant bridging is not recommended, but aspirin can be considered before the start of oral anticoagulation therapy
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Long-term use of OAC is beneficial to the secondary prevention of stroke in patients with atrial fibrillation, and the prognosis of NOAC treatment is better than that of VKA
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If a patient has an ischemic neurological event while taking OAC, pay attention to medication compliance and assess whether anticoagulation is adequate before switching to other oral anticoagulants (eg, TTR ≥ 70% in warfarin patients), and Are there other causes of stroke, such as carotid artery stenosis and uncontrolled blood pressure
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For patients with atrial fibrillation who have contraindications to OAC after acute stroke (such as high risk of hemorrhage transformation), LAAO may need to be considered
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In patients with intracardiac thrombosis with atrial fibrillation, about 90% of the thrombus is located in the left atrial appendage
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In different studies, the prevalence of left atrial appendage thrombosis ranged from 3.
5% to 19.
0%, depending on a variety of factors, including treatment (OAC vs.
no anticoagulation), combined antiplatelet therapy, treatment compliance (target INR, TTR≥ 70%), type of atrial fibrillation, left atrial diameter, left atrial appendage shape, left ventricular ejection fraction, left ventricular end-diastolic volume, and comorbidities (hypertension, diabetes, or metabolic syndrome)
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A study showed that despite NOAC treatment, left atrial appendage thrombosis is still related to left atrium enlargement, higher CHA₂DS₂-VASc score (29% risk increase per minute), severe mitral regurgitation, and left ventricular ejection score <50 % Related
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According to 2020 ESC guidelines, effective anticoagulation should be performed for ≥3 weeks after the diagnosis of left atrial appendage thrombosis, and transesophageal echocardiography should be repeated to ensure thrombolysis (especially before cardioversion, LAAO or catheter ablation)
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The 2018 CHEST guidelines point out that for patients with left atrial or left atrial appendage thrombosis, re-imaging is a "reasonable strategy" and emphasizes highly personalized perioperative OAC treatment methods
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A European Heart Rhythm Association (EHRA) survey on the diagnosis and management of left atrial appendage thrombosis in patients with atrial fibrillation treated with cardioversion or LAAO in contemporary clinical practice shows that NOAC is the most commonly used drug
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The general strategy after thrombosis diagnosis is to convert the current OAC to another OAC (such as from VKA to NOAC or NOAC to VKA, INR 2.
5-3.
5) or between two NOACs, 3-4 weeks later Reassess
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If the treatment is not sufficient to dissolve the thrombus, it is recommended to switch to another NOAC or combined with antiplatelet drugs or low molecular weight heparin for multi-channel inhibition
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In fact, apixaban has been shown to resolve left atrial appendage thrombosis that is resistant to both warfarin and dabigatran
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Until more clinical trial data is obtained, NOAC should be used carefully to treat left ventricular thrombosis beyond the instructions
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Left atrial appendage occlusion is usually not possible for patients with atrial fibrillation who have a high risk of bleeding (such as hereditary hemorrhagic telangiectasia).
Percutaneous treatment such as LAAO has become an alternative method of stroke prevention
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However, a head-to-head randomized controlled trial of NOAC and LAAO is still needed
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The 2020 EHRA consensus document states that LAAO can be used for patients with atrial fibrillation who cannot tolerate long-term OAC treatment
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However, LAAO should not be used as an equivalent alternative to OAC.
If feasible, it is best for patients to accept OAC, especially NOAC
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The choice of stroke prevention strategies should be based on the patient's personal situation, including the strict determination of the risk-benefit ratio between OAC treatment and LAAO, and the patient's preference
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Eligible patients include: ①Patients with atrial fibrillation indications for long-term oral anticoagulation therapy but high risk of hemorrhage; ②Patients with atrial fibrillation indications for long-term oral anticoagulation therapy but consenting to LAAO surgery without anticoagulation; ③atrial fibrillation Patients who have indications for long-term oral anticoagulation therapy, but have poor compliance and are difficult to improve; ④Patients who are planning to undergo atrial fibrillation, left atrial ablation, bleeding, and increased risk of stroke, may consider LAAO at the same time during one operation; ⑤To be accepted Patients with atrial fibrillation who have undergone cardiac surgery and have indications for long-term oral anticoagulation therapy may consider removing the left atrial appendage during surgery
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 Conclusion For the high-risk atrial fibrillation cohort, such as patients with very high age, recent gastrointestinal bleeding, acute stroke, or intracardiac thrombosis, the choice of the best stroke prevention strategy remains a challenge
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Before deciding on oral anticoagulation therapy, the net clinical benefit and patient preference should be considered
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Maintaining good anticoagulation and intervention can change the risk factors of bleeding, and to a certain extent can positively affect the prognosis of patients with atrial fibrillation
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Some patients with atrial fibrillation who have absolute contraindications to long-term anticoagulation may consider LAAO
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References: Kotalczyk A, Mazurek M, Kalarus Z, et al.
Stroke prevention strategies in high-risk patients with atrial fibrillation[J].
Nat Rev Cardiol.
2021 Apr; 18(4): 276-290.
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