What is the frequency of surveillance for carotid (carotid artery) stenosis?

From the Guidelines

Carotid stenosis surveillance should be performed annually for asymptomatic patients with 50-69% stenosis and every 6 months for those with 70-99% stenosis, as recommended by the 2011 ASA/ACCF/AHA/AANN/AANS/ACR/ASNR/CNS/SAIP/SCAI/SIR/SNIS/SVM/SVS guideline 1.

Key Points

• The frequency of carotid stenosis surveillance depends on the degree of stenosis and the presence of symptoms.
• Asymptomatic patients with 50-69% stenosis should undergo annual surveillance, while those with 70-99% stenosis should be monitored every 6 months.
• Patients who have undergone carotid revascularization (endarterectomy or stenting) should have follow-up ultrasound at 1 month post-procedure, then at 6 months, 12 months, and annually thereafter 1.
• More frequent monitoring may be necessary for patients with progressive stenosis (increase of >20% between examinations) or those with multiple cardiovascular risk factors.

Surveillance Methods

• Carotid duplex ultrasonography is the recommended method for surveillance, as it is non-invasive and provides information on both the degree of stenosis and plaque characteristics.
• The technical panel rated annual studies as appropriate for moderate ICA lesions, and an ultrasound study at 6 months and then every 6 or 12 months as appropriate for severe ICA lesions 1.

Importance of Surveillance

• Carotid stenosis can progress over time, and early detection of significant progression allows for timely intervention before stroke occurs.
• The rate of progression varies widely among individuals, with approximately 4-8% of patients with moderate stenosis progressing to severe stenosis annually.
• Risk factors for more rapid progression include smoking, diabetes, hypertension, hyperlipidemia, and advanced age, so patients with these conditions may benefit from more vigilant surveillance.

From the Research

Frequency of Carotid Stenosis Surveillance

• The frequency of carotid stenosis surveillance is crucial for patients who have undergone carotid endarterectomy or stenting, as it helps to identify potential restenosis or progression of the disease 2.
• According to the Society for Vascular Surgery, duplex ultrasound testing is recommended within 30 days of the procedure, then every 6 months for 2 years, and annually thereafter 2.
• The optimal management of patients with asymptomatic carotid stenosis (ACS) is still debated, and individualized management strategies are recommended, taking into account clinical, imaging, and patient-related factors 3.

Diagnostic Methods for Carotid Stenosis

• Duplex ultrasound (DUS) is a commonly used diagnostic method for carotid stenosis, and its accuracy has been evaluated in several studies 4.
• The diagnostic accuracy of DUS is high, especially at discriminating between the presence or absence of significant carotid artery stenosis (< 50% or 50% to 99%) 4.
• However, the accuracy of DUS may vary depending on the reference standard used, and clinicians should exercise caution when using DUS as the single preoperative diagnostic method 4.

Surveillance After Carotid Revascularization

• Surveillance after carotid revascularization is essential to identify potential complications, such as restenosis or occlusion 5, 2.
• A duplex ultrasound surveillance algorithm can be used to detect high-grade stent stenosis or occlusion, and prompt reintervention can be performed if necessary 5.
• The benefit of surveillance outweighs its risk, as duplex testing is free of complications and accurate in the detection of internal carotid artery (ICA) stenosis or occlusion 2.