A Cochrane review [Abstract] 1 included 4 studies with a total of 3 314 subjects with small (diameter 4.0 to 5.5 cm) asymptomatic aneurysms in the abdominal aorta (AAA). Two studies compared surveillance (regular, routine ultrasounds to check for aneurysm growth at minimum once every 6 months) with immediate open repair and 2 studies compared surveillance with immediate endovascular repair (EVAR). Among the patients randomised to surveillance, the aneurysm was repaired if it was enlarging, reached 5.5 cm in diameter, or became symptomatic.
The four trials showed an early survival benefit in the surveillance group because of the number of deaths within 30 days of surgery (operative mortality) but no significant differences in long-term survival (table T1). Some 31% to 75% of the participants randomised to surveillance eventually had the aneurysm repaired.
A pooled analysis of participant-level data from 2 studies (with a maximum follow-up of 7 to 8 years) showed no statistically significant difference in survival between immediate open repair and surveillance (propensity score-adjusted HR 0.99, 95% CI 0.83 to 1.18; 2 studies, n=2 226), and that this lack of treatment effect did not vary to 3 years by AAA diameter (P = 0.39), participant age (P = 0.61), or for women (HR 0.84, 95% CI 0.62 to 1.11). There was no evidence of a survival benefit for early EVAR at 12 months compared to surveillance (RR 1.92, 95% CI 0.73 to 5.06; 2 studies, n=846). Quality-of-life results among trials were conflicting.
Two studies reported costs. The mean UK health service costs per participant over the first 18 months were higher in the open repair surgery than the surveillance group (mean difference (MD) GBP 1064, 95% CI 796 to 1332), and there was a similar difference after 12 years. The mean USA hospital costs for participants at 6 months were higher in the EVAR group than in the surveillance group (MD USD 27 951, 95% CI 25 156 to 30 746). After 4 years, there was no evidence of a difference in total medical costs between groups.
| Study (intervention) | Mean follow-up | HR (95% CI) | Mortality (immediate repair) | Mortality (surveillance) | |
|---|---|---|---|---|---|
| * HR for mortality between surveillance versus immediate repair | |||||
| UKSAT (surgery) | 10 years | 0.88 (0.75 to 1.02) | 63.9% | 67.3% | |
| ADAM (surgery) | 4.9 years | 1.21 (0.95 to 1.54) | 25.1% | 21.5% | |
| CAESAR (endovascular repair) | 32.4 months | 0.76 (0.30 to 1.93)* | 14.5% | 10.1% | |
| PIVOTAL (endovascular repair) | 20 months | 1.01 (0.49 to 2.07) | 4.1% | 4.1% | |
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