[1] Allegheny Gen Hosp, Gerald McGinnis Cardiovasc Inst, Pittsburgh, PA 15212 USA
[2] ICON Clin Res, San Francisco, CA USA
[3] Univ Chicago, Med Ctr, Chicago, IL 60637 USA
[4] Mayo Clin, Rochester, MN USA
[5] Univ Alabama Birmingham, Birmingham, AL USA
[6] Baylor Coll Med, Houston, TX 77030 USA
[7] Columbia Univ Coll Phys & Surg, New York, NY 10032 USA
[8] Univ Colorado, Denver, CO 80202 USA
[9] Intermt Med Ctr, Salt Lake City, UT USA
[10] Univ Utah, Salt Lake City, UT USA