Asymptomatic severe carotid stenosis: immediate surgery or watchful waiting? A decision analysis

OBJECTIVE: To analyze, for patients with asymptomatic severe carotid stenosis, the risks and benefits of two strategies: (1) immediate prophylactic carotid endarterectomy (CEA), and (2) medical management followed by CEA only after a transient ischemic attack (TIA) or a minor stroke has occurred. DESIGN: A Markov-based decision analysis model that simulates and counts the possible clinical outcomes (deaths, TIAs, and major strokes) of the two strategies. Data were drawn from the current literature. SUBJECTS: A hypothetical cohort of asymptomatic patients with severe (> 75% diameter reduction) carotid stenosis identified by noninvasive diagnostic tests. MAIN RESULTS: Given the immediate surgery-related risks, patients with a stroke incidence without preceding TIA of 3% per year will benefit from prophylactic CEA only if they survive more than 4 years after the procedure, whereas those with a higher stroke incidence (5% per year) will benefit from prophylactic CEA after just 2 years. However, the gain yielded by prophylactic CEA remains small. As age- or cardiovascular-related mortality increases, the maximum tolerated combined surgical mortality and morbidity rate below which prophylactic CEA yields an improved 5-year stroke- and surgery-related-event-free survival decreases--from 5% for patients aged 55 years to 2% for patients aged 85 years with a stroke incidence of 3% per year, and from 8.5% for patients aged 55 years to 4% for patients aged 85 years with a stroke incidence of 5% per year. On the other hand, for risk-intolerant patients who value the 2-year stroke- and surgery-related-event-free survival more than life in the distant future, the combined surgical morbidity and mortality rate below which prophylactic CEA remains the preferred strategy is below 3% at any age. CONCLUSION: Risk-intolerant patients should not undergo prophylactic CEA. On the other hand, for risk-tolerant patients willing to accept an immediate and dangerous procedure to decrease the future risk of death or chronic disability due to stroke, assessment of both perioperative risk and the risk of premature death from coexistent coronary artery disease should guide individual therapeutic decision-making.