1. From the Department of Vascular Surgery (R.G.J.G., R.M.G., A.H.D.), Imperial College School of Medicine, Charing Cross Campus, London, UK; the Department of Public Health Sciences (R.N.), Guy’s, King’s and St Thomas’ School of Medicine, Capital House, Guy’s Hospital, London, UK; and Postgraduate Medical School (R.L.), University of Surrey, Stirling House Campus, Surrey Research Park, Guildford, Surrey, UK.