[1] Newcastle Univ, Sch Populat & Hlth Sci, Northern Vasc Ctr, Freeman Hosp, Newcastle Upon Tyne, Tyne & Wear, England
[2] Newcastle Univ, Sch Populat & Hlth Sci, Dept Vasc Surg, Newcastle Upon Tyne, Tyne & Wear, England
[3] UCL, Div Surg & Intervent Sci, London, England
[4] London Sch Hyg & Trop Med, Dept Med Stat, London, England
[5] Papworth Hosp, Dept Anaesthesia & Intens Care, Papworth Hosp Theatres Crit Care & Anaesthesia Se, Cambridge, England
[6] Univ Hosp Wales Healthcare NHS Trust, Dept Anaesthet, Cardiff, S Glam, Wales
[7] Manchester Univ NHS Fdn Trust, Dept Anaesthesia, Manchester, Lancs, England
[8] St Vincents Hlth Australia, Dept Anaesthesia, Melbourne, Vic, Australia
[9] Univ Western Australia, Dept Vasc Surg, Perth, WA, Australia