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Prognosis of abdominal aortic aneurysms. A population-based study
M P Nevitt1, D J Ballard, J W Hallett
1Section of Clinical Epidemiology, Mayo Clinic, Rochester, Minn 55905.
The New England Journal of Medicine
|October 12, 1989
Summary
Abdominal aortic aneurysm expansion is slower than commonly believed. Aneurysms smaller than 5 cm have a low rupture risk, while larger ones pose a substantial threat.
Area of Science:
- Vascular Surgery
- Epidemiology
- Medical Imaging
Background:
- Incomplete data exists on abdominal aortic aneurysm (AAA) expansion rates and rupture risk relative to size.
- Clinical perception suggests rapid AAA growth (0.4-0.5 cm/year), but population-based evidence is limited.
Purpose of the Study:
- To investigate the rate of abdominal aortic aneurysm expansion.
- To determine the risk of AAA rupture in relation to aneurysm diameter.
Main Methods:
- Population-based study of 370 residents in Rochester, Minn., diagnosed with AAAs between 1951-1984.
- Ultrasound examinations used to document aneurysm size and track expansion in 181 patients.
- Analysis of rupture incidence over time for patients with unruptured AAAs.
Main Results:
- Median aneurysm expansion rate was 0.21 cm/year; only 24% expanded ≥0.4 cm/year.
- Cumulative 5-year rupture incidence was 6% for AAAs <5 cm and 25% for AAAs ≥5 cm.
- All 16 reported ruptures occurred in aneurysms ≥5 cm at the time of rupture.
Conclusions:
- Population data challenges the notion of rapid AAA expansion (0.4-0.5 cm/year).
- AAAs <5 cm demonstrate a considerably lower rupture risk than previously reported.
- AAAs ≥5 cm present a substantial rupture risk, necessitating careful monitoring and management.