[1] Univ Pittsburgh, Med Ctr, Inst Heart & Vasc, Pittsburgh, PA 15213 USA
[2] Univ Pittsburgh, Sch Med, Dept Cardiothorac Surg, Div Cardiac Surg, 200 Lothrop St,Ste C-700, Pittsburgh, PA 15213 USA
[3] Univ Pittsburgh, Sch Med, Dept Med, Div Cardiol, Pittsburgh, PA 15213 USA