[1] Univ Perugia, Dept Internal & Cardiovasc Med, I-06100 Perugia, Italy
[2] Guys & St Thomas NHS Fdn Trust, Dept Haematol Med, London, England
[3] Imperial Coll Healthcare NHS Trust, Hammersmith Hosp, Natl Pulm Hypertens Serv, London, England
[4] IRYCIS, Hosp Ramon y Cajal, Vasc Dept, Madrid, Spain
[5] Santa Lucia Hosp, Dept Med, Murcia, Spain
[6] Hosp Badalona Germans Trias & Pujol, Dept Med, Badalona, Spain
[7] Geneva Univ Hosp & Fac Med, Dept Internal Med Rehabil & Geriatr, Div Gen Internal Med, Geneva, Switzerland
[8] Washington Univ, Sch Med, Div Pulm & Crit Care Med, St Louis, MO USA
[9] Washington Univ, Sch Med, Div Gen Med Sci, St Louis, MO USA
[10] Hosp Ramon & Cajal, Resp Dept, E-28034 Madrid, Spain
[11] Univ Alcala de Henares, IRYCIS, Madrid, Spain