<qa>  What is the standard-of-care carotid endarterectomy?- Scheduled for a clinically indicated, standard-of-care carotid endarterectomy CEA OR scheduled for a clinically indicated, standard-of- care surgical, laparoscopic or endoscopic intestinal biopsy or excision OR scheduled for a clinically indicated, standard-of-care surgical, laparoscopic or endoscopic liver biopsy or partial resectionexcision 