What are the implications of 40% stenosis of the proximal left Internal Carotid Artery (ICA)?

From the Guidelines

A 40% stenosis of the proximal left internal carotid artery (ICA) is considered mild to moderate and typically does not require surgical intervention. The recommended management includes antiplatelet therapy with aspirin 81-325 mg daily or clopidogrel 75 mg daily if aspirin intolerant, as supported by guidelines from the European Heart Journal 1, 2. Aggressive risk factor modification is essential, including statin therapy (such as atorvastatin 40-80 mg daily) to achieve LDL levels below 70 mg/dL, blood pressure control targeting less than 140/90 mmHg, smoking cessation, diabetes management, and lifestyle modifications including regular exercise and a heart-healthy diet.

Key aspects of management include:

• Antiplatelet therapy to reduce the risk of stroke
• Aggressive risk factor modification to slow the progression of atherosclerosis
• Regular follow-up with carotid ultrasound every 6-12 months to monitor for progression of stenosis, as recommended by guidelines 1, 2
• Immediate medical evaluation if the patient develops neurological symptoms such as transient ischemic attacks or stroke, as this may change management recommendations

This approach is based on evidence that medical therapy is effective for mild to moderate carotid stenosis, as the risk of stroke with stenosis less than 50% is relatively low, as indicated by the 2024 ESC guidelines for the management of peripheral arterial and aortic diseases 1, 2. Surgical interventions like carotid endarterectomy or stenting are generally reserved for patients with stenosis greater than 70% or those with moderate stenosis (50-69%) who have experienced symptoms, as stated in the guidelines 1, 2. The most recent and highest quality study, the 2024 ESC guidelines, supports this approach, emphasizing the importance of optimal medical treatment for all symptomatic patients with carotid stenosis 1, 2.

From the Research

Implications of 40% Stenosis of the Proximal Left Internal Carotid Artery (ICA)

• The implications of 40% stenosis of the proximal left Internal Carotid Artery (ICA) can be understood through various studies that discuss the management and diagnosis of carotid artery stenosis 3, 4, 5, 6, 7.
• A study published in the Acta neurologica Scandinavica journal found that statin therapy can delay the progression and even reverse the degree of stenosis in patients with ICA stenosis ≥40% 5.
• Another study published in the Frontiers in neurology journal found that large plaques might increase the risk of ischemic stroke or TIA among patients with low-grade ICA-stenosis of 20-40% 6.
• The management of carotid artery stenosis involves aggressive medical management, with intensive risk factor control and antithrombotic therapy, as well as lifestyle modifications such as diet and physical activity 3, 4.
• Carotid endarterectomy and carotid stenting are primarily advocated procedures for symptomatic severe stenosis, with similar long-term outcomes 4, 7.
• The treatment target for patients with atherosclerotic stroke, including those with carotid artery stenosis, is low-density lipoprotein <70 mg/dL, and blood pressure should be treated to goal <140/90 mm Hg 3.

Risk Factors and Management

• Comorbid hypertension, diabetes, and chronic kidney disease (CKD), and lifestyle aspects, including smoking and diet, play a significant role in plaque development 4.
• High-intensity statins are recommended for patients with atherosclerotic stroke, including those with carotid artery stenosis, and ezetimibe and PCSK9 inhibitors are beneficial for those who fail to reach low-density lipoprotein targets or those with statin intolerance 3.
• A minimum of 10 minutes of moderate-intensity aerobic activity 4 times a week is recommended for patients who are capable of exercise 3.
• Duplex ultrasound (DUS) imaging is the widely preferred method in clinical practice for diagnosing carotid artery stenosis 4.