1. Scottish Pulmonary Vascular Unit, Golden Jubilee National Hospital, Glasgow, United Kingdom
2. Pulmonary Hypertension Service, Hammersmith Hospital, London, United Kingdom
3. Pulmonary Vascular Disease Unit, Royal Papworth Hospital NHS Trust, Cambridge, United Kingdom
4. Sheffield Pulmonary Vascular Disease Unit, Royal Hallamshire Hospital, Sheffield, United Kingdom
5. Pulmonary Vascular Unit, Freeman Hospital, Newcastle-upon-Tyne, United Kingdom
6. Pulmonary Hypertension Service, Royal Brompton Hospital, London, United Kingdom