From the Guidelines
The North American Symptomatic Carotid Endarterectomy Trial (NASCET) clearly demonstrated that carotid endarterectomy (CEA) is beneficial for patients with symptomatic high-grade carotid stenosis, reducing the risk of ipsilateral stroke by approximately 65% over two years, with an absolute risk reduction of 17%. The study, reported in 1, compared surgical treatment plus medical therapy versus medical therapy alone in patients with recent carotid territory symptoms and varying degrees of carotid stenosis.
Key Findings
- For patients with severe stenosis (70-99%), CEA reduced the risk of ipsilateral stroke, with a cumulative risk of 9% at 2 years, including perioperative events, compared to 26% for medical therapy alone 1.
- Patients with moderate stenosis (50-69%) showed a more modest but still significant benefit from surgery, with a relative risk reduction of approximately 29% 1.
- The perioperative risk of stroke or death was approximately 6.7% at 30 days for patients with 50% to 69% carotid stenosis 1.
Clinical Implications
- The degree of stenosis is a critical factor in determining who should undergo CEA, with the greatest benefit seen in those with higher-grade stenosis.
- Certain subgroups, including men, patients with recent stroke, and those with hemispheric symptoms, may derive greater benefit from surgery.
- It is essential to perform CEA at centers with low complication rates to maintain the favorable risk-benefit ratio.
Recommendations
- Carotid endarterectomy should be considered for patients with symptomatic high-grade carotid stenosis (70-99%), as it significantly reduces the risk of ipsilateral stroke 1.
- For patients with moderate stenosis (50-69%), CEA may be beneficial, but the decision should be made on a case-by-case basis, considering individual risk factors and perioperative risks 1.
From the Research
Findings of the North American Symptomatic Carotid Endarterectomy Trial (NASCET)
The NASCET has demonstrated conclusive benefit for carotid endarterectomy for patients with symptomatic 70% to 99% internal carotid artery (ICA) stenosis 2. The key findings of the trial include:
- The risk of any ipsilateral stroke at 3 years was 28.3% for medically randomized and 8.9% for surgically randomized patients, with an absolute risk reduction of 19.4% 3.
- The risk of combined disabling or fatal ipsilateral stroke was 14.0% and 3.4%, respectively, with an absolute risk reduction of 10.6% 3.
- Medically treated patients experienced a high risk of occlusion, with 63 (25.5%) of the 247 medically treated patients progressing to occlusion, of whom 31.7% had an ipsilateral stroke before or on the day of occlusion 3.
- The NASCET technique for measuring carotid stenosis can be reliably applied outside the trial, with excellent interobserver and intraobserver agreement 4.
- Medical complications associated with carotid endarterectomy, including myocardial infarctions, other cardiovascular disorders, respiratory complications, and transient confusions, were observed in slightly fewer than 1 of every 10 patients who underwent the procedure 5.
Subgroups that Benefit from Carotid Endarterectomy
The NASCET has identified subgroups that should have expedited investigation and surgery, including:
- Male sex
- Age >75 years
- 90-99% stenosis
- Irregular plaque
- Hemispheric symptoms
- Recurrent events for >6 months
- Contralateral occlusion
- Multiple co-morbidity 6.
Reliability of Carotid Stenosis Measurements
The reliability of carotid stenosis measurements performed by practicing physicians of different specialties and different levels of clinical experience has been validated, with excellent interobserver and intraobserver agreement 4.
Medical Complications
Medical complications associated with carotid endarterectomy, including myocardial infarctions, other cardiovascular disorders, respiratory complications, and transient confusions, were observed in slightly fewer than 1 of every 10 patients who underwent the procedure 5.