What medication should a 68-year-old woman with a history of smoking, diabetes, and hypertension, who presented with transient monocular vision loss and 30-40% left internal carotid artery (ICA) stenosis, be started on for secondary prevention of ischemic events?

Management of Transient Monocular Vision Loss with Carotid Stenosis

Take aspirin plus clopidogrel for 3 weeks and continue aspirin daily (Option A) is the most appropriate recommendation for this patient with transient monocular vision loss and mild carotid stenosis.

Rationale for Dual Antiplatelet Therapy

This 68-year-old woman has experienced a transient monocular vision loss (TMVL) episode lasting 10 minutes, which represents a transient ischemic attack (TIA) affecting the retinal circulation. Her case is complicated by multiple vascular risk factors (smoking, diabetes, hypertension, obesity) and 30-40% stenosis of the left internal carotid artery.

According to the American Heart Association guidelines, for patients with minor stroke or TIA with a National Institutes of Health Stroke Scale score ≤3, an initial course of 21 days of dual antiplatelet therapy followed by long-term treatment with a single antiplatelet agent is recommended 1. This approach is supported by evidence showing reduced risk of recurrent ischemic events.

Treatment Algorithm:

1. Initial therapy (first 21 days):

   • Aspirin (75-100 mg daily) plus clopidogrel (75 mg daily)

2. Long-term therapy (after 21 days):

   • Continue aspirin 81 mg daily monotherapy

Why Not Other Options?

• Option B (Start clopidogrel alone): While clopidogrel monotherapy is effective for secondary prevention, it's not the optimal initial treatment for recent TIA. The combination of aspirin plus clopidogrel has been shown to be more effective in the early period after TIA 1.

• Option C (Start warfarin): Antiplatelet agents are recommended rather than oral anticoagulation for patients with atherosclerosis of the extracranial carotid arteries 1. Warfarin would be indicated if the patient had atrial fibrillation or another cardioembolic source, which was not identified in this case.

• Option D (Endarterectomy): Surgical revascularization is typically reserved for patients with high-grade stenosis (>70%). This patient's 30-40% stenosis does not meet the threshold for surgical intervention 1.

Additional Management Considerations

Beyond antiplatelet therapy, comprehensive management should include:

1. Blood pressure control: Target <130/80 mmHg 2

2. Lipid management: High-intensity statin therapy is recommended for all patients with atherosclerotic carotid disease to reduce LDL cholesterol below 100 mg/dL, with a goal near or below 70 mg/dL for those with ischemic events 1, 2

3. Diabetes management: Optimize glycemic control through diet, exercise, and appropriate medications 1

4. Smoking cessation: Provide counseling and pharmacological support 1

5. Weight management: Implement strategies to achieve BMI <25 kg/m² 1

Important Clinical Considerations

• Transient monocular vision loss should be treated as a TIA and requires urgent evaluation and treatment to prevent progression to stroke
• The risk of stroke is highest within the first few days after a TIA, making early intervention crucial
• Regular follow-up is essential to monitor for recurrent symptoms and ensure adequate risk factor control
• Patient education about recognizing and promptly reporting recurrent symptoms is vital

By implementing dual antiplatelet therapy for 3 weeks followed by aspirin monotherapy, along with aggressive risk factor modification, this patient's risk of subsequent stroke and cardiovascular events can be significantly reduced.