1. Department of Medicine, Chelsea and Westminster Hospital, London SW10 9NH, UK
2. Faculty of Medicine, Imperial College London, South Kensington Campus, London SW7 2AZ, UK
3. Department of Medicine, St James University Hospital, Leeds LS9 7TF, UK
4. North West Thames Academic Foundation School, Imperial College London, London SW7 2AZ, UK
5. The Norfolk and Norwich University Hospital, Norwich NR4 7UY, UK
6. Section of Vascular Surgery, Department of Surgery & Cancer, Imperial College London, London SW7 2AZ, UK