From a recent review:
Nonetheless, given the current state of evidence, CEA is generally superior for symptomatic patients with significant ICA stenosis, including those greater than or equal to 70 years of age. CAS is a reasonable alternative in patients with high operative risk, including those with a hostile neck or significant comorbidities such as uncompensated cardiac or pulmonary disease.
Additionally, the American College of Cardiology/American Heart Association guidelines recommend CAS as an alternative to CEA for symptomatic patients at average or low risk of complications associated with CAS if the anticipated rate of periprocedural stroke or mortality is less than 6%.21 This recommendation is based largely on findings from CREST. However, given a lack of consistent evidence for noninferiority of CAS in other RCTs for symptomatic patients, this recommendation remains debatable, and is not reflected in other guidelines.
In asymptomatic patients, the general recommendation is to consider CEA for significant ICA stenosis in patients who have a life expectancy of at least 3 to 5 years, and low risk of perioperative stroke/death (less than 3%). The role of CAS in asymptomatic patients remains to be established. However, given the results from CREST, some guidelines suggest that CAS may be considered as an alternative to CEA in highly selected asymptomatic patients treated at high-volume centers by experienced operators with low stroke/death rates (less than 3%).