(Circulation. 2000;102:2672-c.)
© 2000 American Heart Association, Inc.
CLINICAL ABSTRACTS |
The Department of Veterans Affairs Aneurysm Detection and Management (ADAM) Study.
for the ADAM VA Cooperative Study Group, VA Medical Centers, Minneapolis MN, West Haven CT, Long Beach CA.
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.
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