[1] Univ Wisconsin, Sch Med, Dept Med, Div Cardiovasc Med, Madison, WI 53792 USA
[2] Duke Univ, Med Ctr, Div Cardiovasc Med, Durham, NC 27706 USA
[3] Tulane Univ, Hlth Sci Ctr, Ctr Cardiovasc Hlth, New Orleans, LA 70118 USA
[4] Tulane Univ, Hlth Sci Ctr, Dept Epidemiol, New Orleans, LA 70118 USA
[5] Wake Forest Univ, Sch Med, Div Vasc Ultrasound Res, Winston Salem, NC 27109 USA