[1] Michael E DeBakey VA Med Ctr, Ctr Innovat Qual Effectiveness & Safety, Houston, TX 77021 USA
[2] Baylor Coll Med, Michael E DeBakey Dept Surg, Houston, TX 77030 USA
[3] VA Boston Hlth Care Syst, Boston, MA USA
[4] Boston Univ, Sch Med, Boston, MA USA
[5] Harvard Med Sch, Boston, MA USA
[6] Baylor Coll Med, Dept Med, Sect Hlth Serv Res, Houston, TX USA