Risk, causes, and prevention of ischaemic stroke in elderly patients with symptomatic internal-carotid-artery stenosis

Abstract

Background: Carotid endarterectomy benefits patients with symptomatic stenosis of 70-99% in the internal carotid artery, with smaller benefit for 50-69% stenosis. The benefit of carotid endarterectomy in patients of 75 years and older remains unclear.

Methods: Patients aged 75 years or older from the North American Symptomatic Carotid Endarterectomy Trial were compared with those aged 65-74 years and less than 65 years for baseline characteristics and risk of ipsilateral ischaemic stroke at 2 years by degree of stenosis and treatment group.

Findings: Among patients with 70-99% stenosis, the absolute risk reduction of ipsilateral ischaemic stroke with carotid endarterectomy was 28.9% (95% CI 12.9-44.9) for patients aged 75 years or older (n=71), 15.1% (7.2-23.0) for those aged 65-74 years (n=285), and 9.7% (1.5-17.9) for the youngest group (n=303). Among patients with 50-69% stenosis, the absolute risk reduction was significant only in those of 75 years and older (n=145; 17.3% [6.6-28.0]). The perioperative risk of stroke and death at any degree of stenosis was 5.2% for the oldest group, 5.5% for 65-74 years, and 7.9% for less than 65 years. The number of patients aged 75 years or older needed to treat to prevent one ipsilateral stroke within 2 years was three with 70-99% stenosis and six with 50-69% stenosis.

Interpretation: In the prevention of ipsilateral ischaemic stroke, elderly patients with 50-99% symptomatic carotid stenosis benefited more from carotid endarterectomy than younger patients did. To achieve this treatment benefit, surgeons must be skilled and patients with other life-threatening illnesses must be excluded.