Patients excluded from the study
| Reasons | No. of patients | Gender | Age | |
| M (%) | F (%) | |||
| Not eligible | 909 | 499 (55) | 410 (45) | 62 (range 17–98) |
| Declined to participate | 749 | 347 (46) | 402 (54) | 63 (range 17–94) |
| Research team unavailable | 253 | 124 (49) | 129 (51) | 61 (range 22–88) |
| Procedure cancelled | 139 | 78 (56) | 61 (44) | 62 (range 18–88) |
| Did not attend | 100 | 60 (60) | 40 (40) | 56 (range 22–85) |
| Randomisation system maintenance | 6 | 4 (67) | 2 (33) | 67 (range 60–72) |