The Department of Veterans Affairs Aneurysm Detection and Management (ADAM) Study.
Aortic aneurysm is the 13th leading cause of death in the US, and most of these deaths are due to rupture or elective repair of abdominal aortic aneurysm (AAA). Because AAA diameter is the strongest known predictor of AAA rupture, a principal question in AAA management is the appropriate AAA diameter at which to offer elective repair to both prevent rupture and minimize deaths from elective surgery. The Society for Vascular Surgery has recommended elective surgery for AAA ≥ 4.0 cm. More than three fourths of AAA ≥ 4.0 cm are also < 5.5 cm. In the US, 33000 elective AAA repairs are performed annually with an operative mortality of 8.4%. The Veterans Affairs Aneurysm Detection and Management (ADAM) Study (VA Cooperative Study #379) was a multicenter randomized clinical trial designed to compare long-term survival from two strategies for managing small AAA, immediate open surgical AAA repair vs. imaging surveillance with elective repair of AAA ≥ 5.5 cm. Sixteen VA medical centers enrolled 1136 veterans aged 50–79 years with AAA 4.0–5.4 cm. Of these, 99% were male, 94% were white, and 42% had coronary artery disease. Mean follow-up was 4.8 years. AAA repair was performed in 92% of the Surgery group and 61% of the Surveillance group (8.8% against protocol) by the end of the 8-year study. Operative mortality at 30 days was 1.8% overall (Surgery 2.1%, Surveillance 1.5%). There was no significant difference between the two groups in the primary outcome of long-term mortality. Death occurred in 141 of 569 Surgery patients and in 121 of 567 Surveillance patients (RR 1.20, 95% CI: 0.94, 1.53, p = 0.14). This non-significant trend toward increased mortality in the Surgery group was strongest in patients with the smallest AAA at entry (4.0–4.4 cm, RR 1.43, 95% CI: 0.89, 2.30, p = 0.14), although the operative mortality in this Surgery subgroup was only 0.7%. This observation is consistent with a previous VA Cooperative Study finding that late survival may be reduced after major peripheral vascular surgery. Nine Surveillance patients (0.5% per year at risk) had AAA rupture, of which two were incidental findings at elective repair and five resulted in death. In the Surgery group, one patient who delayed elective repair had non-fatal AAA rupture, and another died of thoracic aortic aneurysm rupture after AAA repair. In addition to 30-day post-operative deaths and known rupture deaths, there were 25 sudden deaths in the Surveillance group and 23 in the Surgery group. We conclude that long-term survival is not improved by repair of AAA smaller than 5.5 cm even when operative mortality is very low, that deferring repair until the AAA has enlarged to 5.5 cm does not increase operative mortality, and that rupture is rare in this population.
- Copyright © 2000 by American Heart Association