1. University of Leicester, Leicester, United Kingdom
2. Kettering General Hospital, Kettering, United Kingdom
3. Kings College London, London, United Kingdom
4. University of Liverpool, Liverpool, United Kingdom
5. Kings College Hospital, London, United Kingdom
6. Department of Cardiothoracic Surgery, Liverpool Heart and Chest Hospital, Liverpool, United Kingdom
7. Liverpool Centre for Cardiovascular Science, University of Liverpool and Liverpool Heart and Chest Hospital, Liverpool, United Kingdom.