[1] Univ Alabama Birmingham, Univ Alabama Birmingham Lung Hlth Ctr, Birmingham VA Med Ctr, Birmingham, AL USA
[2] Univ Hosp, Wales Heart Res Inst, Dept Cardiol, Cardiff CF14 4XN, S Glam, Wales
[3] Univ Penn, Sch Med, Dept Med, Hypertens Program, Philadelphia, PA 19104 USA
[4] Univ British Columbia, Vancouver Gen Hosp, Dept Radiol, Vancouver, BC V5Z 1M9, Canada
[5] Univ British Columbia, Vancouver Gen Hosp, UBC James Hogg Res Ctr, Vancouver, BC V5Z 1M9, Canada
[6] GlaxoSmithKline, Resp & Immunoinflammat Med Dev Ctr, Res Triangle Pk, NC USA
[7] Univ Michigan Hlth Syst, Div Pulm & Crit Care Med, Ann Arbor, MI USA