Atherosclerotic Peripheral Vascular Disease Symposium II

Abdominal aortic aneurysms (AAAs) are the result of a progressive degenerative process characterized by elastin depletion and inflammatory changes of the aortic wall. The process leads to gradual enlargement and a localized weakening of the aorta, with eventual rupture. Risk factors include age, sex, family history, and smoking.1 The normal aortic diameter varies with age, sex, and body size. An infrarenal abdominal aorta with a diameter >3 cm is considered aneurysmal. The risk of rupture increases directly with aneurysm size, and the death rate associated with rupture is very high (90%). Surgical repair has been the standard therapy for patients with AAAs but is associated with a risk of death and a high rate of complication. Thus, in considering open repair, the risk of the procedure is weighed against the risk of rupture.2 Patients with AAA, especially those with larger aneurysms at high risk of rupture, are usually elderly, and most have multiple comorbidities that increase the risk of surgical treatment. The treating physician, therefore, must balance the natural history of AAA, the operative risk of treatment, and the life expectancy of the patient.Two prospective, randomized trials of good-risk patients with small AAAs (4.0 to 5.5 cm) found no difference in all-cause death rate between patients who were monitored with ultrasound surveillance and those who underwent early surgical repair3,4; however, despite close surveillance with ultrasound, ruptures occurred in 1% of the monitored aneurysm patients each year. Risk of rupture is higher in women, patients who smoke, and those with a family history of aortic aneurysm. Furthermore, most patients with small AAAs undergoing surveillance in these studies ultimately required surgical repair because of AAA enlargement, development of symptoms, or rupture. Therefore, intervention for AAAs <5.5 cm in diameter may be justified in selected patients, and the …