[1] London Sch Hyg & Trop Med, Dept Hlth Serv Res & Policy, 15-17 Tavistock Pl, London WC1H 9SH, England
[2] Royal Coll Surgeons England, Clin Effectiveness Unit, London, England
[3] Hull York Med Sch, Kingston Upon Hull, N Humberside, England
[4] Univ Hosp North Midlands NHS Trust, Royal Stoke Univ Hosp, Vasc Surg, Stoke On Trent, Staffs, England
[5] Cambridge Univ Hosp NHS Fdn Trust, Cambridge Vasc Unit, Cambridge, England
[6] Univ Cambridge, Dept Surg, Cambridge, England