Endarterectomy is basically opening the artery and scraping out all the plaque, making it clean. The artery is clamped first. It reduces the risk of stroke by around 70%. It is more effective than stenting, but stenting is the only option when patients have particular risk factors or are unable to go through surgery.
I think a tortuosity of an internal carotid artery (ICA) is basically a 'kink' in the vessel.