[1] Univ Iowa Hosp & Clin, Dept Cardiothorac Surg, Iowa City, IA 52242 USA
[2] Missouri Baptist Med Ctr, Div Cardiothorac Surg, St Louis, MO USA
[3] Carolinas Med Ctr, Dept Thorac & Cardiovasc Surg, Sanger Heart & Vasc Inst, Charlotte, NC 28203 USA
[4] Harvard Univ, Beth Israel Deaconess Med Ctr, Div Cardiac Surg, Dept Surg,Med Sch, Boston, MA 02215 USA
[5] Fred & Lena Meijer Heart & Vasc Inst, Spectrum Hlth, Grand Rapids, MI USA
[6] Hartford Hosp, Dept Cardiac Surg, Hartford, CT 06115 USA