[1] Brigham & Womans Hosp, Pulm Crit Care Med, Boston, MA USA
[2] Univ Colorado, Med, Aurora, CO USA
[3] Imperial Coll London, Natl Heart & Lung Inst, London, England
[4] Univ Hosp Giessen, Internal Med, Giessen, Germany
[5] Marburg GmbH, Giessen, Germany
[6] GWMFA Heart & Vasc Inst, Cardiol, Washington, DC USA
[7] Hop Bicetre, Pneumol, Le Kremlin Bicetre, France
[8] Univ Michigan Hosp, Ann Arbor, MI USA
[9] Tufts Med Ctr, Pulm Crit Care & Sleep Div, Boston, MA USA
[10] Univ Sao Paulo, Heart Inst, Med Sch, Sao Paulo, Brazil
[11] Thoraxklin Heidelberg, Heidelberg, Germany
[12] German Ctr Lung Res, Heidelberg, Germany
[13] Jagiellonian Univ, Med Coll, John Paul II Hosp, Krakow, Poland
[14] Ctr Hipertensao Pulmonar, Porto Alegre, Brazil
[15] Hannover Med Sch, Hannover, Germany
[16] Univ Hosp Cologne, Cologne, Germany
[17] Merck & Co Inc, Rahway, NJ USA