[1] Univ Pittsburgh, Dept Cardiothorac Surg, Pittsburgh, PA USA
[2] Univ Pittsburgh, UPMC Heart & Vasc Inst, Med Ctr, Pittsburgh, PA USA
[3] Katholieke Univ Leuven, Dept Cardiovasc Sci, Leuven, Belgium
[4] Baylor Coll Med, Michael E DeBakey Dept Surg, Div Cardiothorac Surg, Houston, TX USA
[5] Texas Heart Inst, Houston, TX USA
[6] CHI St Lukes Baylor St Lukes Med Ctr, Houston, TX USA
[7] Univ Pittsburgh, UPMC Heart & Vasc Inst, Med Ctr, 200 Lothrop St, Pittsburgh, PA 15213 USA