1. From the Durham Department of Veterans Affairs Medical Center, the Center for Health Policy Research and Education, and the Division of Neurology, Duke University, Durham, NC (L.B.G.); the Section of Vascular Surgery, University of California at Los Angeles School of Medicine (W.S.M.); the Department of Neurosurgery, University of Tennessee Medical Center (Memphis) (J.T.R.); and the Department of Neurology, Wayne State University, Detroit, Mich (S.C.).