[1] Newcastle Univ, Freeman Hosp, No Vasc Ctr, Newcastle Upon Tyne NE7 7DN, Tyne & Wear, England
[2] Newcastle Univ, Sch Surg & Reprod Sci, Newcastle Upon Tyne NE1 7RU, Tyne & Wear, England
[3] Univ Birmingham, Dept Vasc Surg, Birmingham, W Midlands, England
[4] Birmingham Heartlands & Solihull NHS Trsut Teachi, Birmingham, W Midlands, England
[5] Univ Aberdeen, Dept Vasc Surg, Aberdeen AB9 1FX, Scotland
[6] Univ Nottingham, Sch Med & Surg Sci, Nottingham NG7 2RD, England
[7] Leeds Gen Infirmary, Vasc Surg Unit, Leeds, W Yorkshire, England
[8] UCL Royal Free Hosp, Dept Clin Biochem, Vasc Dis Prevent Clin, London NW3 2QG, England
[9] UCL Royal Free & Univ Coll Med Sch, London, England