In a 65‑year‑old man three months after left atrial appendage excision, surgical Maze (atrial fibrillation ablation) and mitral valve repair who is taking apixaban, how should a symptomatic 50 % left internal carotid artery stenosis with recurrent amaurosis fugax be managed?

Management of Symptomatic 50% Carotid Stenosis Post-Cardiac Surgery

This patient requires urgent carotid endarterectomy within 2 weeks of the most recent amaurosis fugax episode, with continuation of apixaban anticoagulation except for a 24–48 hour peri-operative hold. 1

Immediate Diagnostic Workup

Neuroimaging

• Obtain urgent brain MRI with diffusion-weighted imaging (DWI) immediately—not CT scan—because CT misses 58–100% of acute embolic lesions within the first 24 hours after cardiac surgery. 1, 2
• Standard CT has poor sensitivity for small embolic strokes that are the most common post-cardiac surgery neurological complication. 2

Cardiac Evaluation

• Perform transesophageal echocardiography (TEE) to identify left atrial thrombus on maze-procedure lesion lines and verify completeness of left atrial appendage excision, since incomplete LAA closure occurs in 26–57% of cases. 1, 2
• Institute continuous cardiac monitoring for at least 30 days to detect paroxysmal atrial fibrillation, as 80% of patients with pre-operative AF ≥3 months remain in AF after maze surgery. 1, 2

Indication for Carotid Revascularization

Symptomatic carotid stenosis >50% with recurrent amaurosis fugax constitutes an absolute indication for carotid revascularization. 1 This recommendation is specifically reinforced for patients with atrial fibrillation who have symptomatic carotid stenosis >50%. 1

Rationale for Urgent Intervention

• The benefit of carotid endarterectomy (CEA) in preventing stroke is greatly diminished beyond 2 weeks after symptom onset, because the risk of recurrent ischemic events is highest in this early period. 3
• After 4 weeks in women and 12 weeks in men, the benefit of surgery in symptomatic patients is no greater than that observed with surgery for asymptomatic patients. 3
• The 3-year stroke risk with medical treatment alone in patients with transient monocular blindness ranges from 1.8% (0–1 risk factors) to 24.2% (3–4 risk factors). 3

Choice of Revascularization Technique

Carotid endarterectomy is strongly preferred over carotid artery stenting in this clinical setting because stenting would require more intensive dual antiplatelet therapy that conflicts with the mandatory anticoagulation regimen. 1

Peri-operative Anticoagulation Management

Apixaban Management

• Continue apixaban up to 24–48 hours before carotid endarterectomy. 1
• Hold apixaban during this 24–48 hour window and resume 24 hours after the procedure once hemostasis is confirmed. 1

Antiplatelet Therapy

• Add short-term dual antiplatelet therapy (aspirin + clopidogrel) for 1–3 months after carotid revascularization. 1
• After the initial 1–3 month period, discontinue all antiplatelet agents and maintain apixaban alone. 1

Long-Term Anticoagulation Strategy

Indefinite continuation of apixaban is mandatory in this patient, regardless of rhythm status or apparent completeness of LAA excision. 1 This recommendation is based on multiple high-risk factors:

ACC/AHA Guideline Mandates

• Therapeutic anticoagulation is required for at least 3 months after maze procedure and LAA excision, irrespective of rhythm status (Class IIa recommendation). 3, 1
• Discontinuation of oral anticoagulation after maze/LAA surgery is associated with late stroke, indicating that the LAA is not the exclusive source of all thrombi in patients with AF. 3, 1

Specific Thrombogenic Risk Factors in This Patient

Risk Factor	Clinical Impact	Management
Thrombogenic endocardial lesions from maze procedure	Persist ≥3 months, create nidus for thrombus	Continue anticoagulation indefinitely [3,1]
Blood stasis from loss of atrial contraction	Pro-thrombotic state post-maze	Same as above [2]
80% persistence of AF in patients with pre-op AF ≥3 months	Maintains high embolic risk	Same as above [1,2]
Incomplete LAA closure (26–57% of cases)	Increases thromboembolism	Verify with TEE; continue anticoagulation [1,2]
Symptomatic carotid stenosis	Independent stroke risk	Requires revascularization + anticoagulation [1]

Post-Revascularization Antithrombotic Algorithm

First 1–3 Months Post-CEA

• Triple therapy: Apixaban + aspirin + clopidogrel 1
• Monitor closely for bleeding complications given the combination of anticoagulation and dual antiplatelet therapy.

Beyond 3 Months Post-CEA

• Discontinue aspirin and clopidogrel 1
• Continue apixaban alone indefinitely 1

Decision Points for Long-Term Anticoagulation

Do NOT discontinue apixaban even if:

• Sinus rhythm is documented at 6 months 1
• LAA closure appears complete on imaging 1
• Patient has no documented AF recurrence 1

The evidence shows that discontinuation of anticoagulation is associated with late stroke, and the LAA is not the only source of thrombi in this population. 3, 1

Critical Pitfalls to Avoid

• Do not attribute recurrent amaurosis fugax to "post-operative delirium" or benign causes—this represents symptomatic carotid disease requiring urgent intervention. 3, 2
• Do not delay carotid endarterectomy beyond 2 weeks from the most recent symptom, as the benefit diminishes rapidly. 3, 1
• Do not discontinue apixaban based on apparent sinus rhythm or complete LAA closure—multiple thrombogenic mechanisms persist beyond the immediate post-operative period. 3, 1
• Do not use carotid stenting as first-line therapy in this anticoagulated patient—endarterectomy avoids the conflict between mandatory anticoagulation and intensive antiplatelet requirements. 1
• Do not rely on CT imaging to exclude acute stroke—MRI with DWI is mandatory given the high false-negative rate of CT in the first 24 hours. 1, 2

Summary Management Timeline

Timepoint	Action	Citation
Immediate	Brain MRI with DWI, TEE, 30-day cardiac monitor	[1,2]
Within 2 weeks	Carotid endarterectomy	[3,1]
24–48 h pre-op	Hold apixaban	[1]
24 h post-op	Resume apixaban (once hemostasis confirmed)	[1]
Months 1–3 post-CEA	Apixaban + aspirin + clopidogrel	[1]
>3 months post-CEA	Apixaban alone (stop antiplatelet agents)	[1]
Indefinitely	Continue apixaban	[1]