How should I manage a 65-year-old man, three months after left atrial appendage excision, surgical Maze ablation, and mitral valve repair, who is on apixaban and has a symptomatic 50% left internal carotid artery stenosis with recurrent amaurosis fugax?

Management of Symptomatic Carotid Stenosis Post-Cardiac Surgery

This patient requires urgent carotid revascularization with endarterectomy or stenting in addition to continuing apixaban, as he has symptomatic 50% carotid stenosis with recurrent amaurosis fugax. 1

Immediate Diagnostic Workup

Brain Imaging

• Obtain urgent brain MRI with diffusion-weighted imaging (DWI) immediately to detect acute ischemic changes that are invisible on CT, as standard CT scans miss 58-100% of embolic events in the first 24 hours post-cardiac surgery 2
• Do not attribute visual symptoms to "post-operative complications" without excluding stroke with MRI, as CT has poor sensitivity for acute ischemic stroke 2

Cardiac Source Evaluation

• Perform transesophageal echocardiography (TEE) to detect left atrial thrombus on surgical lesion lines created by the maze procedure and assess completeness of LAA excision (incomplete closure occurs in 26-57% of cases) 2
• Obtain 30-day continuous cardiac monitoring to detect paroxysmal atrial fibrillation, as 80% of patients with pre-operative AF ≥3 months remain in AF after maze surgery despite the procedure 2, 3

Carotid Imaging Confirmation

• The 50% stenosis at the bulb with recurrent amaurosis fugax indicates symptomatic disease requiring intervention, as amaurosis fugax has a high correlation (0.87) with ulcerated carotid plaque 4

Anticoagulation Management

Current Strategy Assessment

The patient is appropriately on apixaban post-maze procedure, but this must be carefully managed around carotid revascularization. 1

Perioperative Anticoagulation Protocol

• Continue apixaban until 24-48 hours before carotid endarterectomy or stenting 1
• Resume apixaban 24 hours post-endarterectomy once hemostasis is confirmed 1
• Add short-term dual antiplatelet therapy (aspirin + clopidogrel) for 1-3 months post-revascularization only, then discontinue antiplatelet agents and continue apixaban alone 1

Long-Term Anticoagulation

• Continue apixaban indefinitely without long-term antiplatelet therapy after the initial 1-3 month post-revascularization period 1
• The ACC/AHA guidelines mandate therapeutic anticoagulation for at least 3 months after maze procedure and LAA excision regardless of rhythm status (Class 2a recommendation) 1, 2
• Discontinuation of oral anticoagulation has been associated with late stroke, as the LAA is not the exclusive source of all thrombi in AF patients 1

Carotid Revascularization Decision

Indication for Intervention

Symptomatic carotid stenosis >50% with recurrent amaurosis fugax is an absolute indication for revascularization 1

The evidence supporting this includes:

• Three episodes of transient monocular blindness represent high-risk symptomatic disease 4, 5
• Amaurosis fugax correlates strongly (0.87) with ulcerated carotid plaque, which carries high embolic risk 4
• The CHEST guidelines specifically recommend carotid revascularization for AF patients with symptomatic carotid stenosis >50% 1

Choice of Revascularization Method

Carotid endarterectomy is preferred over stenting in this patient for the following reasons:

• Recent cardiac surgery (3 months ago) makes the perioperative risk acceptable for endarterectomy 5
• Endarterectomy has lower perioperative morbidity (3%) in experienced centers 5
• Stenting would require more intensive antiplatelet therapy that conflicts with mandatory anticoagulation needs 1

Critical Thromboembolic Risk Factors in This Patient

Post-Maze Thrombogenic Substrate

• The maze procedure creates endocardial lesions that remain highly thrombogenic for at least 3 months post-operatively, necessitating continued anticoagulation 2, 3
• Blood stasis from loss of atrial contraction post-maze, combined with surgical trauma, creates a prothrombotic state 2
• Persistent AF occurs in 80% of patients who had pre-operative AF ≥3 months, maintaining high thromboembolic risk 2, 3

Incomplete LAA Closure Risk

• Incomplete LAA closure or residual peridevice leak occurs in 26-57% of cases and is associated with increased thromboembolism risk 2, 3
• TEE must confirm complete LAA excision to guide long-term anticoagulation decisions 2

Air Embolization During Valve Repair

• Air embolization during valve repair is a well-documented cause of stroke, particularly if de-airing techniques were inadequate 2

Management Algorithm

Clinical Finding	Action Required
Recurrent amaurosis fugax with 50% carotid stenosis	Urgent carotid endarterectomy [1,4]
Incomplete LAA closure on TEE	Indefinite apixaban continuation [2]
Persistent AF on 30-day monitor	Indefinite apixaban continuation [2]
Complete LAA closure + sinus rhythm at 6 months	Continue apixaban (do NOT discontinue despite successful procedure) [1]
Post-endarterectomy (1-3 months)	Apixaban + aspirin + clopidogrel [1]
Post-endarterectomy (>3 months)	Apixaban alone, discontinue antiplatelet agents [1]

Common Pitfalls to Avoid

• Do not delay carotid revascularization while "optimizing medical management"—three episodes of amaurosis fugax indicate urgent need for intervention 1, 4
• Do not discontinue apixaban based on successful maze procedure or LAA excision, as the maze procedure does not eliminate the need for anticoagulation in the immediate post-operative period 1
• Do not use triple therapy (apixaban + aspirin + clopidogrel) beyond 1-3 months post-revascularization, as this dramatically increases bleeding risk without additional benefit 1
• Do not attribute visual symptoms to "post-operative delirium" without excluding stroke with MRI, as CT misses most acute embolic events 2
• Do not assume LAA excision was complete without TEE confirmation, as incomplete closure occurs in 26-57% of cases 2, 3

Timeline for Intervention

Carotid endarterectomy should be performed within 2 weeks of the most recent amaurosis fugax episode to prevent progression to completed stroke, with apixaban held 24-48 hours pre-operatively and resumed 24 hours post-operatively once hemostasis is confirmed 1, 5.