[1] Imperial Coll Healthcare NHS Trust, Hammersmith Hosp, Natl Pulm Hypertens Serv, London, England
[2] Royal Sussex Cty Hosp, Brighton, E Sussex, England
[3] Sheffield Teaching Hosp NHS Fdn Trust, Pulm Vasc Dis Unit, Sheffield, S Yorkshire, England
[4] South Tees Hosp NHS Trust, Middlesbrough, Cleveland, England
[5] Royal Berkshire Hosp, Reading, Berks, England
[6] Derby Teaching Hosp NHS Fdn Trust, Derby, England
[7] George Eliot Hosp NHS Trust, Dept Resp Med, Nuneaton, England
[8] Salford Royal NHS Fdn Trust, Emergency Dept, Salford, Lancs, England
[9] Royal Coll Emergency Med, London, England
[10] St Thomas Hosp, London, England
[11] Guys & St Thomas NHS Fdn Trust, Cardiovasc Dept, London, England
[12] Guys & St Thomas NHS Fdn Trust, Womens Hlth Acad Ctr, London, England
[13] City Hosp Nottingham, Dept Resp Med, Nottingham, England
[14] Kings Coll Hosp NHS Fdn Trust, London, England
[15] Royal Papworth Hosp NHS Fdn Trust, Cambridge, England
[16] Glasgow Royal Infirm, Dept Haematol, Glasgow, Lanark, Scotland