The most appropriate management is to refer this patient for abdominal aortic aneurysm (AAA) repair. AAA is a common and potentially life-threatening condition, and management of detected aneurysms is based on size or rate of expansion. Elective repair to prevent rupture in asymptomatic patients is optimal management in those meeting criteria for intervention. Once an aneurysm reaches 5.5 cm in men and 5.0 cm in women, repair is generally warranted. Repair may be performed by an open approach or an endovascular approach, if the anatomy of the aneurysm is amenable; the mode of therapy should be decided by the surgeon, the internist, and the patient after a comprehensive discussion of risks and long-term benefits. Randomized trials show that endovascular aneurysm repair (EVAR) is associated with lower perioperative morbidity and mortality compared with open AAA repair, but EVAR does not completely eliminate the future risk of AAA rupture. Open repair is associated with higher perioperative morbidity and mortality than EVAR, but it provides a more definitive repair.

The optimal surveillance schedule for patients once an AAA has been identified has not been clearly defined. Annual surveillance is recommended, but larger aneurysms expand faster than small ones and may require more frequent surveillance. Aneurysm diameter is the most important factor predisposing to rupture, with risk increasing markedly at aneurysm diameters greater than 5.5 cm. For asymptomatic patients, the risk of AAA rupture generally exceeds the risk associated with elective AAA repair when aneurysm diameter exceeds 5.0 cm in a woman and 5.5 cm in a man. This patient's AAA is 5.7 cm in diameter; therefore, she should be referred for repair, rather than continuing surveillance.

Although controlling risk factors for cardiovascular disease is essential in patients with AAA, there is little compelling evidence for treating hypertension in these patients with a specific agent, including β-blockers, to prevent aneurysm expansion. As this patient's blood pressure is well controlled, no change in antihypertensive therapy is indicated.