[1] Univ Penn, Perelman Sch Med, Dept Surg, Philadelphia, PA USA
[2] Cooper Univ Hosp, Dept Surg, Camden, NJ USA
[3] Univ Penn, Coll Arts & Sci, Philadelphia, PA USA
[4] Univ Colorado, Sch Med, Dept Surg, Aurora, CO USA
[5] Hosp Univ Penn, Perelman Sch Med, Dept Surg, Div Cardiovasc Surg, Philadelphia, PA 19104 USA