From the Guidelines
Anticoagulation is recommended for patients with atrial fibrillation (AF) and large vessel occlusion (LVO) post-thrombectomy, despite the risk of hemorrhagic transformation (HT), as the benefits of reducing recurrent stroke risk outweigh the bleeding risks. The decision to anticoagulate should be individualized based on shared decision-making, considering the absolute risks and relative risks of stroke and bleeding, as well as the patient's values and preferences 1. The CHA2DS2-VASc score is recommended for assessing stroke risk in patients with nonvalvular AF, and oral anticoagulants are recommended for patients with a score of 2 or greater 1.
When considering anticoagulation post-thrombectomy, the timing is critical, and anticoagulation should typically be delayed for 7-14 days, with the exact timing based on infarct size, presence of hemorrhagic transformation on follow-up imaging, and individual bleeding risk factors. Direct oral anticoagulants (DOACs) like apixaban or rivaroxaban are preferred over warfarin due to their lower intracranial bleeding risk 1.
Key considerations for anticoagulation in this context include:
- Infarct size and presence of hemorrhagic transformation on follow-up imaging
- Individual bleeding risk factors
- Risk of recurrent stroke, which is approximately 5-12% annually in AF patients
- Close neuroimaging follow-up with CT or MRI before initiating anticoagulation to exclude developing hemorrhagic transformation
- Alternative approaches like left atrial appendage closure could be considered in patients with very large infarcts or evidence of hemorrhagic transformation.
The benefits of anticoagulation in reducing recurrent stroke risk must be carefully balanced against the potential risks of bleeding, particularly in the acute post-stroke period when reperfusion injury and blood-brain barrier disruption are most pronounced 1.
From the Research
Anticoagulation in Patients with Atrial Fibrillation and Large Vessel Occlusion Post-Thrombectomy
- The decision to anticoagulate patients with atrial fibrillation (AF) and large vessel occlusion (LVO) post-thrombectomy is complex and depends on various factors, including the risk of hemorrhage (HT) 2, 3.
- Studies have shown that AF is associated with a higher incidence of LVO strokes, and the presence of AF can affect the outcome of mechanical thrombectomy 4, 5, 6.
- The optimum time to initiate anticoagulation after endovascular thrombectomy for AF-related LVO stroke is still debated, but research suggests that a longer time to anticoagulation may be associated with an unfavorable outcome, while an earlier initiation may increase the risk of hemorrhage events 3.
- A study found that the cumulative incidence of major bleeding was higher in patients with prior antiplatelet therapy for LVO in patients with non-valvular AF newly initiated on apixaban, particularly in those without intravenous thrombolysis (IVT) or endovascular treatment (EVT) 2.
- Another study showed that AF patients achieved a higher proportion of first pass effect (FPE) compared to non-AF patients, highlighting the need for preparedness for multiple passes and potential adjuvant/rescue therapy in non-AF-related strokes 4.
- The incidence of AF in LVO strokes is significant, with nearly half of the patients found to have AF, and extended cardiac monitoring can frequently discover AF in patients with large embolic stroke of undetermined source (LESUS) 5.
- AF has been associated with poor long-term outcome after mechanical thrombectomy for anterior LVO stroke, with patients with AF having a lower percentage of good functional outcome and a higher mortality rate 6.
- The optimal initiation time of anticoagulant after EVT is around 4.5 days, and there is no significant difference in recurrent AIS/TIA or mortality among patients who started anticoagulation at ≤ 4 days, ≥ 15 days, or 4 to 15 days 3.