Carotid endarterectomy in asymptomatic carotid stenosis patients

The role of carotid endarterectomy in patients with asymptomatic carotid artery stenosis is controversial because:

• the risk of stroke is lower than in patients with symptomatic stenoses
• the importance of operative complications becomes correspondingly more significant

A meta-analysis showed that carotid endarterectomy (1):

• in an analysis of trials involving 2440 patients with stenosis >=50%
  • approximately 30% reduction in the combined end-point of ipsilateral stroke plus perioperative death and stroke
  • an absolute risk reduction for this end-point of only 2% over 3.1 years
  • this data would suggest that patients with an asymptomatic carotid artery stenosis should not routinely undergo endarterectomy unless other factors suggest a high risk for stroke

However a more recent trial investigated the use of immediate carotid endarterectomy in patients with unilateral or bilateral carotid artery stenosis (>= 60%) but no stroke or ischaemia in the previous 6 months, for whom both physician and patient were substantially uncertain whether to choose immediate carotid endarterectomy or deferral of any carotid endarterectomy until a more definite need for it was thought to have arisen (2):

• 3120 patients - mean age 68 years, 66% men
• this trial revealed that asymptomatic patients younger than 75 years of age with carotid diameter reduction about 70% or more on ultrasound (many of whom were on aspirin, antihypertensive, and, in recent years, statin therapy), immediate carotid endarterectomy halved the net 5-year stroke risk from about 12% to about 6% (including the 3% perioperative hazard). Half this 5-year benefit involved disabling or fatal strokes. Note also that the authors stated that outside trials, inappropriate selection of patients or poor surgery could obviate such benefits

Reference:

1. Benavente, O, Moher, D, Pham, B. (1998) Carotid endarterectomy for asymptomatic carotid stenosis: a meta-analysis. BMJ; 317: 1477-80.
2. Halliday A et al. Prevention of disabling and fatal strokes by successful carotid endarterectomy in patients without recent neurological symptoms: randomised trial. Lancet 2004; 363:1491-502