1. Oxford University Hospitals NHS Foundation Trust; Oxford United Kingdom
2. Royal Brompton & Harefield Hospital NHS Foundation Trust; London United Kingdom
3. Imperial College Healthcare NHS Trust; London United Kingdom
4. Brighton and Sussex University Hospitals NHS Trust; Brighton United Kingdom
5. University College London Hospitals NHS Foundation Trust; London United Kingdom
6. Liverpool Heart and Chest Hospital NHS Foundation Trust; Liverpool United Kingdom
7. University Hospital of South Manchester NHS Foundation Trust; Manchester United Kingdom
8. Leeds Teaching Hospitals NHS Trust; Leeds United Kingdom