Keyhani S, Cheng EM, Hoggatt KJ, Austin PC, Madden E, Hebert PL, Halm EA, Naseri A, Johanning JM, Mowery D, Chapman WW, Bravata DM. Comparative Effectiveness of Carotid Endarterectomy vs Initial Medical Therapy in Patients With Asymptomatic Carotid Stenos