[1] Univ Pittsburgh, Dept Cardiothorac Surg, Pittsburgh, PA USA
[2] Univ Pittsburgh, UPMC Heart & Vasc Inst, Med Ctr, Pittsburgh, PA USA
[3] Univ N Carolina, Dept Surg, Div Cardiothorac Surg, Chapel Hill, NC USA
[4] Katholieke Univ Leuven, Dept Cardiovasc Sci, Leuven, Belgium
[5] Univ Oxford, Oxford Univ Clin Acad Grad Sch, Oxford, England
[6] Hannover Med Sch, Med Hsch Hannover MHH, Dept Cardiothorac Transplantat & Vasc Surg, Hannover, Germany
[7] Univ Pittsburgh, UPMC Heart & Vasc Inst, Med Ctr, 200 Lothrop St, Pittsburgh, PA 15213 USA