How do treatment options vary based on the size of an abdominal aortic aneurysm (AAA)?

Updated: Jan 08, 2019
  • Author: Saum A Rahimi, MD, FACS; Chief Editor: Vincent Lopez Rowe, MD  more...
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Answer

Patients with an incidentally discovered AAA that is less than 3 cm in diameter require no further follow-up. If the AAA is 3-4 cm in diameter, annual ultrasound imaging should be used to monitor for further dilatation. AAAs 4-4.5 cm in diameter should be evaluated with ultrasonography every 6 months, and patients with AAAs greater than 4.5 cm in diameter should be referred to a vascular surgeon.

With AAAs 4-5 cm in diameter, elective repair may be of benefit for patients who are young, have a low operative risk, and have a good life expectancy. Additionally, AAAs are known to rupture at smaller diameters in women than in men; therefore, a threshold of 4.5 cm for elective repair has been advocated in women. If there is any evidence of rapid growth (>1 cm in 1 year), the AAA should be repaired

Patients with AAAs 5-6 cm in diameter may benefit from repair, especially if they have other contributing factors for rupture (eg, hypertension, continued smoking, or COPD). A study by Lederle et al found that with AAAs smaller than 5.5 cm, elective repair did not improve survival. [22] Prospective studies suggest that following aneurysms larger than 5.5 cm with serial ultrasonography or computed tomography (CT) is safe; this threshold may be lower for women.


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