1. Funding: Health Foundation, ESVS Surgical Variations GA LA n = 1720 n = 1730 Trainee surgeon: n (%) 242 (14%) 210 (12%) Trainee Anaesthetist: n (%) 246 (16%) 213 (14%) Duration of surgery: (mins) 93 (37%) 93 (36%) Premed used: n (%) 905 (53%) 877 (51%)

2. Funding: Health Foundation, ESVS Type of Surgery Conventional n (%) 1237 (78%) 1145 (72%) Eversion n (%) 317 (20%) 409 (26%) Exploration only n (%) 22 (1%) 14 (1%) Other n (%) 4 (0.2%) 9 (1%)

3. Funding: Health Foundation, ESVS Use of Shunts GA LA Shunt used 738 (43%) 248 (14%) Reason for shunt Neurological deterioration 6* 150 Used routinely 369 35* Reduced TCD velocity 45 3* Unable to use TCD 48 5* Contra-lateral carotid occn./severe stenosis 38 5* Contra-lateral moderate stenosis 4 7* Low stump pressure 108 15* Recent stroke 5 3* Unusual/damaged arteries/veins 2 2* EEG/Evoked potential change 8 1* Hypotension 4 1* Brain oxygen level fall 1 0 Vein bypass 1 0 Unknown 89 21

4. Funding: Health Foundation, ESVS Use of Patches GA LA Patch Used n (%) 861 (50%) 728 (42%) Heparin Used n (%) 1682 (98%) 1678 (97%)