The Baseline characteristics of the patients were similar across randomised groups. In particular, about three-quarters of patients had symptomatic cardiac disease, the mean FEV1 was low at 1.7L, 14% had diabetes and the median creatinine concentration was 110µmol/L, all worse than for patients entered into the parallel EVAR 1 trial for fit patients. The extent of aspirin and statin usage was disappointingly low. By December 2004, median follow-up was 2.4 years {IQR 1.6-3.6}.

30-day operative mortality
In the EVAR group, the 30 day operative mortality was 13/150, 9% [95% CI 5-15%], significantly higher than the 1.7% 30 day mortality for EVAR in the EVAR 1 trial (p<0.0001). If only elective cases were included, this operative mortality reduced to 10/147, 7% [95% CI 3-12%]. All grafts used in the EVAR group were commercially available devices (87% bifurcated systems), principally Zenith (Cook, Copenhagen, Denmark) 60%, Talent (Medtronic, Minneapolis, MN, USA) 22% and Excluder (Gore, Flagstaff, AZ, USA) 7%.

All-cause and aneurysm-related mortality
By 31st December 2004 the proportions of patients having the potential to be followed for at least 1, 2, 3 and 4 years were respectively 100%, 62%, 36% and 15%. During this time, a total of 142 deaths occurred, with 42 (30%) of these from aneurysm-related causes [causes of death table]. Kaplan-Meier estimates indicated that overall mortality was 64% by 4 years. However, there was no demonstrable difference in either aneurysm-related mortality or all-cause mortality according to randomised group. The crude hazard ratio for all-cause mortality comparing the EVAR group to the no intervention group was 1.21 [95% CI 0.87-1.69], p=0.25 and this did not change materially with adjustments for baseline characteristics [Kaplan-Meier curves]. The crude hazard ratio for aneurysm-related mortality comparing the EVAR group to the no intervention group was 1.01 [95% CI 0.55-1.84], p=0.98, and this also did not change materially with adjustments [Kaplan-Meier curves]. There were no significant interactions, for either total or aneurysm-related mortality, for the effect of EVAR with age, sex, aneurysm diameter or creatinine (all p>0.1).

In a post hoc analysis, the follow-up was divided into the first 6 months after randomisation and the period after 6 months. The hazard ratios for aneurysm related mortality comparing the EVAR and no intervention groups were 1.67 (95% CI 0.72 to 3.86) and 0.53 (95% CI 0.20 to 1.39) in the two time periods respectively. The corresponding hazard ratios for all-cause mortality were 1.31 (95% CI 0.70 to 2.45) in the first 6 months and 1.18 (95% CI 0.80 to 1.73) after 6 months. These results suggest that an initial disadvantage of EVAR is possibly followed by a longer term benefit.

The deaths from aneurysm rupture in the no intervention group were matched by the rupture and operative deaths in the EVAR group. In total, 32 ruptures were reported across both groups by the end of December 2004, 5/32 underwent attempted repair of whom 2 survived to 30 days. There were 23 ruptures in the no intervention group, crude rupture rate 9.0 [95% CI 6.0 – 13.5] per 100 person years. The aneurysms of 9 patients ruptured before receiving their treatment. Their median time from randomisation to rupture was 98 days with a range of 6 to 767 days. The 3 longest delays of more than a year occurred in patients who were subsequently found to have problematic aortic anatomy that delayed their EVAR procedure and the other 6 patients whose operations were delayed by less than a year were on waiting lists for their procedures or undergoing further fitness tests for co-morbidities. We considered whether the excess of respiratory deaths in the EVAR group was attributable to the use of general anaesthesia. General anaesthesia was used in 83/166 (50%) of patients in the EVAR group versus 27/172 (16%) in the no intervention group. EVAR was used in both groups of the trial in 181 patients of whom 96 (53%) had a general anaesthetic. There were 8 respiratory deaths in the general anaesthetic group and 5 respiratory deaths in the no general anaesthetic group (chi-squared test p=0.45).

Durability and secondary interventions
Analysis by intention to treat showed that by 4 years, 43% of patients in the EVAR group had experienced at least one post operative complication compared to only 18% in the no intervention group, hazard ratio hazard ratio 5.3 [95% CI 2.8-10.0], p<0.0001. [Kaplan-Meier curves]. The overall re-intervention rate was 11.5 per 100 person years in the EVAR group and 1.8 per 100 person years in the no intervention group and by 4 years, 26% of the EVAR group had required at least one re-intervention compared to only 4% in the no intervention group, hazard ratio 5.8 [95% CI 2.4-14.0], p<0.0001 [Kaplan-Meier curves]. The re-intervention rate for the EVAR group of EVAR 2 (11.5 per 100 person years) appeared higher than that observed for patients in the EVAR group of EVAR 1 (6.9 per 100 person years) but this was not a statistically significant difference, hazard ratio 1.4 [95% CI 0.9-2.1], p=0.10.

The types of post operative complication and number of re-interventions that occurred following EVAR in either randomised group are shown. In total, there were 3 conversions to open repair following EVAR deployment, 1 during the primary theatre procedure, 1 more during the primary admission and 1 after initial discharge from hospital. By 31st December 2004, 62 patients had developed a post operative complication (58 following EVAR) and 37 patients had required at least one re-intervention (32 after an EVAR). There were no deaths within 30 days of re-intervention.

HRQL
The baseline EQ5D scores in EVAR trial 2 were substantially lower than for patients randomised in EVAR trial 1. There were no clear and consistent differences in HRQL demonstrated between the two randomised groups whether timed at 0-3, 3-12 or 12-24 months after randomisation or at 1,3 or 12 months after operation. (HRQL over time)

Costs
The mean discounted costs per patient of the primary procedure and hospitalisation were £11016 in the EVAR group versus £3518 for the no intervention group, mean difference of £7498 (SE 776). The mean estimated discounted costs per patient over 4 years were £13632 for the EVAR group and £4983 for the no intervention group, mean difference £8649 (SE 1248). The resource use for surgical procedures in the 47 patients who contravened their no intervention allocation was similar to those receiving EVAR in the EVAR group.