From the Guidelines
After carotid stent implantation, surveillance with ultrasound is recommended within the first month. This initial scan is crucial for establishing a baseline and confirming proper stent placement and patency 1. The European Heart Journal's 2024 guidelines for the management of peripheral arterial and aortic diseases recommend this early follow-up to assess for potential complications such as in-stent restenosis or stent migration 1.
Key points to consider in the follow-up of patients with carotid stents include:
- Assessing neurological symptoms and cardiovascular risk factors (CVRFs) at least yearly 1
- Long-term use of aspirin or clopidogrel after ICA revascularization to prevent further complications 1
- Monitoring treatment adherence and adjusting the surveillance schedule as needed based on individual patient factors 1
The initial ultrasound within the first month sets the stage for subsequent monitoring, which may include ultrasounds at 6 months, 12 months, and then annually thereafter, depending on the patient's condition and findings on previous ultrasounds. However, the most recent and highest quality study, the 2024 ESC guidelines, specifically recommends surveillance with DUS within the first month without detailing the exact frequency of subsequent ultrasounds 1.
In clinical practice, the decision on the frequency of subsequent ultrasounds would be tailored to the individual patient, considering factors such as the presence of symptoms, comorbidities, and the results of previous ultrasounds. Patients with abnormal findings may require more frequent monitoring, while those with consistently normal results might eventually extend to less frequent surveillance. This approach is in line with the guidelines' emphasis on individualized care and the importance of monitoring for potential complications without symptoms 1.
From the Research
Ultrasound Surveillance after Carotid Stent
- The rationale for clinical and Duplex ultrasound (DUS) surveillance after carotid artery stenting (CAS) is to detect recurrent stenoses and prevent future carotid-related cerebral ischemic events 2.
- Multicenter randomized controlled trials published between 1990 and 2013 were reviewed, and the follow-up intervals were similar, with DUS surveillance recommended at 1 month, 3 or 4 months, 6 months, and 12 months after CAS, and then at least once a year 2.
- The incidence of recurrent carotid stenosis (≥50%) or occlusion ranged around 6% four years after CAS, and the annual incidence of any ipsilateral cerebral ischemic event was about 1% and 0.5% after CAS for symptomatic or asymptomatic stenosis, respectively 2.
- Certain subgroups of patients, such as women, diabetics, patients with dyslipidemia, and smokers, might have increased rates of restenosis after CAS 2, 3.
Predictors of Carotid Stent Restenosis
- Predictors of carotid stent restenosis have not been firmly established, but previous carotid endarterectomy (CEA) or neck radiation (XRT) are associated with an increased risk of restenosis 3.
- Restenosis after carotid stenting is uncommon, but patients with previous CEA or XRT are at increased risk, and restenotic lesions may be safely treated with further percutaneous interventions 3.
Follow-up of Stented Carotid Arteries by Doppler Ultrasound
- Doppler ultrasound is a sensitive follow-up method after placement of a carotid artery stent for detecting significant stenosis, occlusion, and other complications at early and intermediate follow-up 4, 5.
- The significance of alterations in blood flow velocity (BFV) in the carotid artery after stent placement is unknown, and strict BFV criteria for restenosis after carotid artery stenting are less reliable than change in BFV over time 5.
- An immediate post-stenting Doppler study must be obtained to serve as a reference value for future follow-up evaluation 5.
Management of Carotid Restenosis
- Carotid artery restenosis remains an unsolved problem, and the current treatment recommendations are not as clear as those for primary stenosis 6.
- The incidence rates of stroke and complications in patients with carotid stenosis are derived from studies that did not use contemporary techniques and materials, and rapidly changing guidelines, updated techniques, and materials, and modern medical treatments make actual incidence rates barely comparable to previous ones 6.
- Randomized controlled trials are critical for determining whether patients with restenosis after CEA or CAS should be treated with more aggressive treatments additional to best medical therapy and identifying those patients indicated for surgical or endovascular treatments 6.