| CAS candidates | CEA candidates |
Anatomical factors | Lesion above C2 | lipid-rich soft plaque |
Below collarbone injury | further injury to 15 mm |
Reoperation after previous CEA | preocclusive injury |
Cervical stoma | severe circumferential Calcification |
Previous cervical radiotherapy | aorto-iliac tortuosity |
Previous ablative cervical surgery | Great angulation of the aortic arch and carotid artery |
| heavily calcified aortic arch or with severe atherosclerosis |
Pathophysiological factors | Heart disease | Patient over 80 years |
Contralateral vocal cord paralysis | |