[1] Univ Virginia, Dept Surg, Div Thorac & Cardiovasc Surg, Charlottesville, VA 22908 USA
[2] Innova Heart & Vasc Inst, Cardiovasc & Thorac Associates, Falls Church, VA USA
[3] Virginia Cardiac Surg Qual Initiat, Richmond, VA USA
[4] Virginia Commonwealth Univ, Dept Surg, Div Cardiothorac Surg, Richmond, VA USA