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Current status of the prospective, randomized trials of symptomatic carotid bifurcation disease
1Department of Clinical Neurological Science, University of Western Ontario, London, Canada.
Insights
Carotid endarterectomy (CE) significantly reduces stroke risk by 80% in patients with severe carotid stenosis. This surgical benefit, proven in trials like NASCET, underscores the importance of prospective studies for evaluating interventions.
Area of Science:
- Neurology
- Vascular Surgery
- Clinical Trials
Background:
- Symptomatic carotid disease poses a significant stroke risk.
- Previous epidemiological studies underestimated stroke risk from severe carotid stenosis.
- Anecdotal evidence was insufficient to establish treatment efficacy.
Purpose of the Study:
- To evaluate the efficacy of carotid endarterectomy (CE) in reducing future stroke risk.
- To highlight the power of prospective clinical trials in assessing surgical procedures.
- To establish guidelines for managing symptomatic carotid disease.
Main Methods:
- Analysis of data from three contemporary clinical trials.
- Inclusion of patients with high-grade carotid stenosis (>70%) and symptomatic disease.
- Strict adherence to criteria including low perioperative risk, precise stenosis measurement, and clear symptoms.
Main Results:
- Carotid endarterectomy (CE) reduced the relative risk of major stroke by at least 80% at 2 years.
- Prospective trials, like NASCET with 659 patients, effectively demonstrated CE's benefit.
- The natural history of TIAs and minor strokes in severe disease was more malignant than previously thought.
Conclusions:
- Carotid endarterectomy is highly beneficial for patients with symptomatic high-grade carotid stenosis.
- Prospective clinical trials are crucial for definitive evaluation of surgical interventions.
- Further studies on moderate stenosis will refine management guidelines for all symptomatic carotid disease patients.
Abstract:
Three contemporary trials that are studying patients who have symptomatic carotid disease have proven beyond doubt that CE is extremely beneficial in reducing the risk of future stroke in patients with high-grade stenosis (greater than 70%). The relative risk of major stroke is reduced by at least 80% at 2 years of follow-up. That such a remarkably positive result for surgery was not predicted is a consequence of the unanticipated malignant natural history of TIAs and minor stroke in severe carotid disease. Previous epidemiological studies had underestimated the risk of future stroke by almost threefold. The current studies also highlight the remarkable power of prospective clinical trials to evaluate the effectiveness of a surgical procedure. In the case of NASCET, only 659 patients were required to prove the benefit of CE, whereas, innumerable previous anecdotal cases had failed to provide a convincing answer. However it must be remembered that the benefit from CE is dependent on a low rate of perioperative morbidity and mortality, a strict measure of the degree of stenosis on angiography, recency of ischemic events, and unequivocal carotid symptoms. The ongoing study of patients with moderate degrees of carotid stenosis holds the promise that in the very near future precise guidelines, which have been properly evaluated by careful scientific scrutiny,, will be available to guide surgeons in the proper management of all patients who present with symptomatic carotid disease.