Results
One-year survival data were available for 611/613 patients randomized (Figure 1). Of the 613 patients, 536 had proven AAA rupture, and repair was started in 502 (see Figure 1). For the 77 patients without AAA rupture, 22 had acute, symptomatic AAA (with repair in 21), while of the 55 patients with discharge diagnoses unrelated to AAA 45 had co-existing asymptomatic AAA (mean diameter 6.9 cm) and 1 further patient had a thoracoabdominal aneurysm. Baseline characteristics were similar between the randomized groups (see Supplementary material online, Table S4http://eurheartj.oxfordjournals.org/content/suppl/2015/04/07/ehv125.DC1); overall 480 (78%) were men, with mean (SD) age of 76.7 (7.6) years, aneurysm diameter of 8.4 (1.9) cm, and admission systolic blood pressure of 110 (32) mmHg.
(Enlarge Image)
Figure 1.
CONSORT diagram showing flow of patients through the trial. AAA, abdominal aortic aneurysm; rAAA, ruptured abdominal aortic aneurysm; 23% of ruptured abdominal aortic aneurysms were juxtarenal with an aortic neck length <10 mm, 75% infra-renal, and 2% aorto-iliac. One hundred and forty-nine endovascular aneurysm repair and 110 open repair (27 open repairs in patients suitable for endovascular aneurysm repair, breach of protocol mainly for operational reasons, e.g. endovascular suite in use or inadequately staffed), 210 open repairs and 33 endovascular aneurysm repairs in breach of protocol, mainly for avoidance of general anaesthesia. Follow-up pertains to endpoints other than mortality. One patient mortality known to 30 days and one patient mortality known to 3 months. Case record form (CRF) captures re-interventions and re-admissions, and outpatient visits to the trial hospital.
After 1 year, 130 (41.1%) of patients in the endovascular strategy group had died vs. 133 (45.1%) in the open repair group, unadjusted odds ratio 0.85 [95% confidence interval (CI) 0.62, 1.17], P = 0.325. Adjusted results and those restricted to patients with ruptured AAA repair were similar, with odds ratios 0.86 (95% CI 0.62, 1.21) and 0.86 (0.59, 1.24), respectively. Almost half the deaths, in each group, occurred within 24 h and the majority occurred within 30 days (Table 1 and Figure 2A). At 1 year, AAA-related mortality (including all deaths within 30 days) in the endovascular strategy and open repair groups, respectively, was 33.9% and 39.3%, unadjusted odds ratio of 0.79 (95% CI 0.57, 1.10), P = 0.161 (see Supplementary material online, Figure S1http://eurheartj.oxfordjournals.org/content/suppl/2015/04/07/ehv125.DC1). The subgroup analysis of 1-year mortality found weak evidence that the endovascular strategy was more effective in women than in men, ratio of odds ratio 0.41 (95% CI 0.18, 0.93), P = 0.034 (Figure 2B). Among ruptured aneurysm patients with repair started, the 1-year mortality was 98/259 (37.8%) in the endovascular strategy group and 104/241 (43.2%) in the open repair group, adjusted odds ratio 0.86 (95% CI 0.59, 1.24), P = 0.400. The estimated unbiased causal odds ratio for a trial in which everyone adhered to the randomized policy was slightly lower: 0.78 (95% CI 0.49, 1.24).
(Enlarge Image)
Figure 2.
(A) Kaplan-Meier estimates by randomized group, across all patients (log-rank test p = 0.325) and (B) 1-year mortality odds ratios for specified subgroups.
Overall, the time to first AAA-related re-intervention was similar between the randomized groups, P = 0.701 (log-rank test) (see Supplementary material online, Figure S2http://eurheartj.oxfordjournals.org/content/suppl/2015/04/07/ehv125.DC1) and for the 502 ruptured AAA patients who underwent repair P = 0.674 (log-rank test) (Figure 3, Table 1, details with reasons for re-interventions in Supplementary material online, Table S5http://eurheartj.oxfordjournals.org/content/suppl/2015/04/07/ehv125.DC1). Between 31 days and 1 year, there were only 11 patients (4.2%, 12 procedures) with re-interventions in the endovascular group (including 5 endograft related, 1 revision of iliac limb of open repair, 1 limb ischaemia, and 1 colonic ischaemia) and 9 patients (3.7%, 13 procedures) in the open repair group (including 2 for limb ischaemia, 3 colonic ischaemia, 3 for continuing complications of earlier abdominal compartment syndrome, and 1 axillo-bifemoral bypass). Between hospital discharge and 1 year, there was only one AAA-related death, following open repair in the open repair group.
(Enlarge Image)
Figure 3.
Time to first re-intervention for the 502 patients with repair of ruptured aneurysm started. Log-rank test P = 0.674.
In the endovascular strategy group, 10 patients (3%) were transferred to a secondary hospital vs. 36 patients (12%) in the open repair group: at 30 days, 79 patients (13%) remained in hospital (49/79 in the open repair group). The average times to discharge from hospital (primary and secondary hospitals) were 17 (endovascular strategy group) and 26 days (open repair group), P < 0.001; there was an indication of slightly higher cumulative incidence of discharge in the endovascular strategy group, P = 0.114 (Figure 4A). There was strong evidence that a higher proportion of patients from the endovascular strategy group were discharged directly home from the primary hospital, P < 0.001 (Figure 4B).
(Enlarge Image)
Figure 4.
Hospital discharge (A) Overall time to discharge from hospital and (B) time to discharge home from primary hospital.
At 3 months, a higher proportion of patients in the endovascular strategy group reported 'no problems' on the physical health dimensions (mobility, self-care, and pain) of the EQ-5D QoL questionnaire, compared to the open repair group (see Supplementary material online, Table S6http://eurheartj.oxfordjournals.org/content/suppl/2015/04/07/ehv125.DC1). The resultant EQ-5D mean utility scores were higher in the endovascular strategy vs. the open repair group; the mean differences for ruptured aneurysm AAA survivors were 0.087 (95% CI 0.017, 0.158; P = 0.015) and 0.068 (95% CI −0.004, 0.140; P = 0.063) at 3 and 12 months, respectively (Table 2 and Supplementary material online, Table S7http://eurheartj.oxfordjournals.org/content/suppl/2015/04/07/ehv125.DC1). Average total costs (details in Supplementary material online, Table S8http://eurheartj.oxfordjournals.org/content/suppl/2015/04/07/ehv125.DC1), which included the provision of both types of repair at all times, were less in the endovascular strategy (£16 394) vs. the open repair group (£18 723), with a mean incremental cost of –£2329 (95% CI –£5489, £922) (Table 2) or –€2617 (95% CI –€6167, €1036).
The QALY gain at 1 year for the endovascular strategy group was 0.052 (95% CI −0.005, 0.108), with similar results across subgroups (Table 2 and Supplementary material online, Table S9http://eurheartj.oxfordjournals.org/content/suppl/2015/04/07/ehv125.DC1). When the incremental costs and QALYs are represented on the cost-effectiveness plane, most (87%) of the estimates are in the quadrant that designates the endovascular strategy as 'dominant', with lower mean costs and higher mean QALYs (Figure 5). The INB of the endovascular strategy vs. open repair is positive at £3877 (95% CI £253, £7408) or €4788 (95% CI €312, €9149), a finding robust to a range of assumptions (see Supplementary material online, Tables S9 and 10, Figures S3 and S5http://eurheartj.oxfordjournals.org/content/suppl/2015/04/07/ehv125.DC1), including increases in operating theatre staff and varying the costs of the EVAR device from £4000 to £10,000 (vs. £5700 in the base case) or additional interventions, Supplementary material online, Figure S5http://eurheartj.oxfordjournals.org/content/suppl/2015/04/07/ehv125.DC1. The probability that the endovascular strategy was more cost-effective was >0.90 at all realistic thresholds of willingness to pay for a QALY gain (see Supplementary material online, Figure S4http://eurheartj.oxfordjournals.org/content/suppl/2015/04/07/ehv125.DC1).
(Enlarge Image)
Figure 5.
Uncertainty in the mean cost (£GBP) and Quality-Adjusted-Life-Year differences and their joint distribution for endovascular strategy vs. open repair.