[1] Stanford Univ, Dept Cardiothorac Surg, Stanford, CA 94305 USA
[2] VA Palo Alto Hlth Care Syst, Palo Alto, CA USA
[3] Univ Texas HSC, San Antonio, TX USA
[4] Univ Cincinnati, Cincinnati, OH USA
[5] Indiana Univ, Indianapolis, IN 46204 USA
[6] Boston Univ, Boston, MA 02215 USA
[7] W Virginia Univ, Morgantown, WV 26506 USA
[8] Univ Rochester, Rochester, NY USA
[9] Univ N Carolina, Chapel Hill, NC USA