[1] VA North Texas Hlth Care Syst, Dallas, TX USA
[2] Minneapolis Heart Inst, Minneapolis, MN 55407 USA
[3] Univ Texas Dallas, Southwestern Med Sch, Dallas, TX USA
[4] VA Cooperat Studies Program Coordinating Ctr, Mountain View, CA USA
[5] VA Boston Healthcare Syst, Boston, MA USA
[6] Brigham & Womens Hosp, Heart & Vasc Ctr, 75 Francis St, Boston, MA 02115 USA
[7] Harvard Med Sch, Boston, MA USA
[8] Univ Arizona, Sarver Heart Ctr, Tucson, AZ USA
[9] Mayo Clin, Sch Grad Med Educ, Rochester, MN USA
[10] Durham VA Med Ctr, Durham, NC USA
[11] Duke Univ, Durham, NC USA
[12] San Francisco VA Med Ctr, San Francisco, CA USA
[13] Univ Calif San Francisco, San Francisco, CA 94143 USA
[14] Atlanta VA Med Ctr, Atlanta, GA USA
[15] Emory Univ, Atlanta, GA 30322 USA
[16] Memphis VA Med Ctr, Memphis, TN USA
[17] Univ Tennessee, Memphis, TN USA
[18] North Florida South Georgia Vet Hlth Syst, Gainesville, FL USA
[19] Univ Florida, Gainesville, FL USA
[20] Minneapolis VA Med Ctr, Minneapolis, MN USA
[21] Univ Minnesota, Minneapolis, MN USA
[22] Oklahoma VA Med Ctr, Oklahoma City, OK USA
[23] Univ Oklahoma, Oklahoma City, OK USA
[24] Denver VA Med Ctr, Denver, CO USA
[25] Univ Colorado, Denver, CO 80202 USA
[26] Michael E DeBakey VA Med Ctr, Houston, TX USA
[27] Baylor Coll Med, Houston, TX 77030 USA
[28] Clin Res Pharm Coordinating Ctr, VA Cooperat Studies Program, Albuquerque, NM USA
[29] VA Hlth Econ Resource Ctr, Menlo Pk, CA USA
[30] Stanford Univ, Dept Surg, Stanford, CA 94305 USA
[31] Stanford Univ, Dept Hlth Res & Policy, Stanford, CA 94305 USA