Growth rates of small abdominal aortic aneurysms.

A policy of utilizing B-mode ultrasound scan measurements of abdominal aortic aneurysms to help determine operability in poor-risk patients with small asymptomatic aneurysms has been pursued for the past 6 years. Indications for surgery in such patients have included enlargement to 6 cm. in any transverse diameter, the development of symptoms, or evidence of leak or rupture. In addition, patients treated nonoperatively have been followed by serial B-mode echo scans, permitting the accumulation of aneurysm growth rate data. Such data indicate that small aneurysms grow an average of 0.4 cm. per year, but that dramatic increases in aneurysm size may occur unexpectedly in asymptomatic patients. These data appear to have value in both individual decision making and as a baseline for weighting the various risk factors in the poor-risk patient with a small asymptomatic abdominal aortic aneurysm.