Is Carotid Endarterectomy Advisable For Blockage In Carotid Artery?

for carotid endarterectomy referral....wondering how necessary. 70% block on right,,,100% (I know, leave it alone) on the left. borderline serious at 70%...on right....do we treat tight more aggressively because of the left 100% block. or one side should not indicate treatment of other side.