What is the management approach for a patient who develops seizures and left hemiplegia (weakness on one side of the body) with intact sensation after undergoing mitral valve repair, auriclectomy (removal of the auricle), and maze procedure?

Management of Post-Cardiac Surgery Stroke with Seizures and Left Hemiplegia

This patient has suffered an acute embolic stroke in the right middle cerebral artery territory and requires immediate neuroimaging, neurology consultation, and aggressive stroke management with seizure control—the maze procedure does not eliminate stroke risk, particularly in the early postoperative period when thromboembolism risk is highest.

Immediate Assessment and Diagnosis

Urgent Neuroimaging

• Obtain emergent non-contrast CT head to exclude hemorrhagic stroke, which is critical given recent cardiac surgery and likely anticoagulation exposure 1
• If CT is negative for hemorrhage, proceed immediately with CT angiography or MRI with diffusion-weighted imaging to confirm ischemic stroke location and extent 1
• The clinical presentation of left hemiplegia with intact sensation suggests a cortical stroke affecting the motor cortex, most likely in the right hemisphere 1

Stroke Mechanism Identification

• Embolic stroke is the most likely etiology given the temporal relationship to mitral valve repair, auriclectomy, and maze procedure 1, 2
• Despite the maze procedure, early postoperative thromboembolism remains a significant risk due to:
  • Surgical manipulation of cardiac chambers creating thrombogenic surfaces 2
  • Potential incomplete maze procedure success (only 72-76% achieve sinus rhythm at discharge) 3
  • Left atrial stunning even after successful maze procedure 4
• The auriclectomy (left atrial appendage removal) does NOT eliminate all stroke risk, as thrombus can form elsewhere in the left atrium 5

Acute Stroke Management

Seizure Control (Priority #1)

• Initiate immediate IV antiepileptic therapy with levetiracetam 1000-1500mg IV load, then 500-1000mg IV twice daily (preferred in acute stroke as it has no drug interactions and does not require monitoring) 1
• Alternative: IV fosphenytoin 15-20 mg PE/kg loading dose if levetiracetam unavailable 1
• Continue antiepileptic medication for minimum 7 days, then reassess based on EEG findings and clinical course 1

Anticoagulation Strategy

• If hemorrhagic stroke is excluded on CT, resume therapeutic anticoagulation immediately with IV unfractionated heparin (aPTT 1.5-2.0 times control) given the high-risk cardiac substrate 5
• Transition to warfarin (INR 2.0-3.0) once patient is stable and able to take oral medications 5
• Lifelong anticoagulation is mandatory in this patient regardless of maze procedure success, given the combination of mitral valve surgery and stroke history 1, 5

Blood Pressure Management

• Maintain permissive hypertension (systolic BP 140-180 mmHg) in acute ischemic stroke to preserve cerebral perfusion to penumbra 1
• Avoid aggressive BP lowering unless systolic BP >220 mmHg or diastolic BP >120 mmHg 1

Assessment of Maze Procedure Success

Rhythm Evaluation

• Obtain 12-lead ECG immediately and initiate continuous telemetry monitoring 2
• The maze procedure fails in 25-40% of patients at hospital discharge, with recurrence rates of 28-36% at 5 years 2, 4, 3
• Risk factors for maze failure that increase stroke risk include:
  • Left atrial dimension >70mm 4
  • Preoperative AF duration >10 years 4
  • F-wave voltage in V1 <0.1mV 4

Echocardiographic Assessment

• Perform urgent transesophageal echocardiography (TEE) to:
  • Assess mitral valve repair integrity 5
  • Identify residual left atrial thrombus 5
  • Evaluate left atrial appendage closure completeness (if performed) 5
  • Assess for new valvular dysfunction or endocarditis 5

Long-Term Stroke Prevention

Anticoagulation Regimen

• Continue warfarin indefinitely (INR 2.0-3.0) regardless of whether patient achieves sinus rhythm 1, 5
• The combination of mitral valve surgery history, maze procedure (successful or not), and prior stroke mandates lifelong anticoagulation 1, 5
• Monitor INR every 2-3 days until stable, then weekly for 1 month, then monthly 5

Rhythm Monitoring

• If patient remains in atrial fibrillation despite maze procedure, consider rate control with beta-blockers or calcium channel blockers 1
• Do NOT discontinue anticoagulation even if sinus rhythm is achieved, as AF recurrence risk remains 19-40% at 12 years 4

Rehabilitation and Prognosis

Neurological Recovery

• Initiate early physical and occupational therapy once patient is medically stable (within 24-48 hours) 1
• The presence of intact sensation suggests cortical rather than subcortical stroke, which may have better recovery potential for motor function 1

Cardiac Follow-Up

• Baseline transthoracic echocardiography before discharge to assess mitral valve repair function 5
• Follow-up echocardiography at 3 months to detect recurrent AF and assess valve function 5
• Annual echocardiographic surveillance starting at 5 years post-repair 5

Critical Pitfalls to Avoid

• Do NOT assume the maze procedure eliminates stroke risk—studies show freedom from stroke is only 93.6% at 5 years even with successful rhythm restoration, compared to 80.9% with failed maze 2
• Do NOT discontinue anticoagulation based on sinus rhythm alone after mitral valve surgery and maze procedure 1, 5
• Do NOT delay anticoagulation in confirmed ischemic stroke due to fear of hemorrhagic transformation—the risk of recurrent embolism outweighs hemorrhagic risk in this high-risk cardiac population 5
• Do NOT attribute all neurological deficits to stroke—seizures can cause Todd's paralysis (postictal weakness), but this typically resolves within 24-48 hours 1