What is the purpose of a carotid (carotid artery) ultrasound after carotid artery stenting?

From the Guidelines

Carotid ultrasound surveillance after carotid stenting should be performed at 1 month, 6 months, 12 months, and then annually thereafter. The purpose of this surveillance is to detect early complications like restenosis or stent deformation, and to monitor for in-stent restenosis, which occurs in approximately 5-10% of patients within the first year 1. During these ultrasounds, the sonographer should assess peak systolic velocities, end-diastolic velocities, and velocity ratios across the stent. Velocities exceeding 300 cm/s or a doubling from baseline may indicate significant restenosis requiring further evaluation. Color and power Doppler imaging should be used to assess for uniform flow through the stent and to identify any areas of turbulence. If significant restenosis (>70%) is detected or if the patient develops new neurological symptoms, additional imaging with CT angiography or conventional angiography may be warranted to determine if reintervention is necessary 1. Patients should remain on dual antiplatelet therapy (typically aspirin 81mg daily indefinitely plus clopidogrel 75mg daily for at least 1-3 months) during this surveillance period to prevent stent thrombosis. Regular ultrasound monitoring is essential as early detection of restenosis allows for timely intervention to prevent stroke.

Some key points to consider:

• The severity of stenosis is defined according to angiographic criteria, but generally corresponds to assessment by sonography and other accepted methods of measurement 1.
• Restenosis after carotid stenting is generally benign and does not require revascularization except when it leads to recurrent ischemic symptoms or progresses to preocclusive severity 1.
• The role of stent-generated artifacts in ultrasound velocity measurements has yet to be resolved with angiographic comparisons 1.
• Duplex ultrasonography is recommended to detect carotid stenosis in patients who develop focal neurological symptoms corresponding to the territory supplied by the left or right internal carotid artery 1.

Overall, regular carotid ultrasound surveillance after carotid stenting is crucial for detecting restenosis and preventing stroke, and should be performed in accordance with established guidelines and recommendations 1.

From the Research

Purpose of Carotid Ultrasound after Carotid Artery Stenting

The purpose of a carotid ultrasound after carotid artery stenting (CAS) is to:

• Detect recurrent stenoses and prevent future carotid-related cerebral ischemic events 2
• Identify patients developing in-stent restenosis (ISR) after CAS 3
• Evaluate the incidence of carotid recurrent stenosis and postprocedural strokes 2
• Determine the usefulness of duplex ultrasound examination for patient follow-up and determination of ISR 4

Key Findings

• The incidence of recurrent carotid stenosis (≥50%) or occlusion ranged around 6% four years after CAS 2
• The annual incidence of any ipsilateral cerebral ischemic event was about 1% and 0.5% after CAS for symptomatic or asymptomatic stenosis, respectively 2
• Neovascularization observed on superb micro-vascular imaging (SMI) was significantly associated with the development of ISR 3
• Duplex ultrasound examination after CAS is a useful tool for patient follow-up and determination of ISR 4

Surveillance Intervals

• The evidence for routine duplex ultrasound (DUS) surveillance after CAS is limited, and the level of evidence for any recommendation on DUS surveillance is consistently low 2
• A practice with one periprocedural DUS and one DUS after 12 months after CAS seems to be reasonable 2
• Imaging at 6 months and then annually may be reasonable for patients after CAS 2
• Customized velocity criteria for grading carotid ISR can guarantee a correct follow-up after CAS if validated by skilled operators using a specific protocol of follow-up in a certified laboratory 5