Carotid endarterectomy provides the greatest absolute benefit in which scenario?

• A. Asymptomatic high-grade stenosis
• B. Symptomatic high-grade stenosis (≥70%)
• C. Symptomatic low-grade stenosis
• D. Asymptomatic low-grade stenosis

Answer: (D)

The main idea is that the biggest absolute benefit from carotid endarterectomy comes from situations where a patient has the highest baseline risk of stroke without intervention. If someone has symptoms from carotid disease and the stenosis is high-grade, their chance of having a future stroke without treatment is relatively high. In that setting, removing the plaque and by-passing the diseased segment markedly lowers the overall risk of stroke, producing the largest absolute decrease over time.

In asymptomatic disease, the baseline stroke risk is lower, so even with treatment the absolute number of strokes prevented is smaller. Among asymptomatic patients, those with low-grade stenosis have the lowest baseline risk, so the absolute benefit from surgery is minimal. Even if asymptomatic high-grade stenosis can benefit, the absolute reduction tends to be less than in symptomatic high-grade cases.

So the greatest absolute benefit occurs with symptomatic high-grade stenosis, while asymptomatic low-grade stenosis provides the smallest absolute benefit.