[1] Univ Penn, Dept Med, Perelman Sch Med, Philadelphia, PA 19104 USA
[2] Univ Penn, Ctr Clin Epidemiol & Biostat, Perelman Sch Med, Philadelphia, PA 19104 USA
[3] Univ Colorado, Dept Med, Aurora, CO USA
[4] Columbia Univ, Dept Pediat, New York, NY USA
[5] Mayo Clin, Dept Med, Jacksonville, FL 32224 USA
[6] Washington Univ, Dept Med, St Louis, MO 63110 USA
[7] Univ Calif San Francisco, Dept Med, San Francisco, CA 94143 USA
[8] Arizona Pulm Specialists, Phoenix, AZ USA
[9] Vanderbilt Univ, Med Ctr, Dept Med, Nashville, TN USA
[10] Weill Cornell Med, Dept Med, New York, NY USA
[11] Louisiana State Univ, Dept Med, New Orleans, LA USA
[12] Johns Hopkins Univ, Dept Med, Baltimore, MD USA
[13] Kentuckiana Pulm Associates, Louisville, KY USA
[14] Med Coll Wisconsin, Dept Med, Milwaukee, WI 53226 USA
[15] Oregon Clin, Portland, OR USA
[16] Cottage Hlth Pulm Hypertens Ctr, Santa Barbara, CA USA
[17] Inova Fairfax Hosp, Adv Lung Dis & Transplant Program, Falls Church, VA USA
[18] Univ Pittsburgh, Dept Med, Med Ctr, Pittsburgh, PA USA
[19] Univ Minnesota, Dept Med, Box 736 UMHC, Minneapolis, MN 55455 USA
[20] Brown Univ, Dept Med, Alpert Med Sch, Providence, RI 02912 USA