[1] Washington D C Vet Affairs Med Ctr & Heart Ctr, Div Cardiothorac Surg & Heart Ctr, 50 Irving St. NW,Suite 2A 163, Washington, DE 20422 USA
[2] MedStar Georgetown Univ Hosp, Dept Surg, Washington, DE USA
[3] George Washington Univ, Dept Surg, Washington, DE USA
[4] George Washington Univ, Dept Stat, Washington, DE USA