Review Question - QID 221301

This patient with a history of hypertension, smoking, and a pulsatile abdominal mass most likely has an abdominal aortic aneurysm (AAA). An asymptomatic aneurysm of size < 5.5 cm with expansion < 0.5 cm per year does not require surgical intervention.

Abdominal aortic aneurysms (AAA) occur when all 3 layers of the aortic wall weaken to the point of dilatation of greater than 50%. They are most commonly associated with atherosclerosis. One-time screening with abdominal ultrasound is recommended in 65- to 75-year-old men with a history of smoking. Risk factors include hypertension, high cholesterol, other vascular diseases, smoking, male gender, and older age. The condition is usually asymptomatic and found incidentally on physical exam or imaging. Typical physical exam findings include a pulsatile abdominal mass or abdominal bruits. Characteristics that would prompt surgical treatment of AAA include size greater than 5.5 cm, rapid expansion of the aneurysm at > 0.5 cm per 6 months or 1 cm per year, or symptoms such as pain or limb ischemia. Otherwise, close monitoring with serial abdominal ultrasounds is appropriate.

Ulug et al. review the role of surgery for small asymptomatic AAAs. They discuss that there is no evidence to support early repair for small AAAs regardless of whether open repair or endovascular repair is performed. They recommend further research into the surgical management of AAAs among patient populations poorly represented in current trials.

Figure/Illustration A is a contrast-enhanced CT scan showing contrast in the aorta with notable dilation (red circle). This finding is consistent with a diagnosis of abdominal aortic aneurysm.

Incorrect Answers:
Answer 1: Size is 2 cm and the patient is symptomatic describes an AAA that warrants surgical intervention. Any symptomatic AAA requires surgical management regardless of size.

Answer 2: Size is 3 cm and expanding 1 cm over 1 year meets the criteria for a rapidly expanding AAA. A rapidly expanding AAA greatly increases the risk of rupture. Rapidly expanding lesions are generally managed with surgical intervention rather than close monitoring.

Answer 4: Size is 5.5 cm with an expansion of 1 cm over 6 months describes an AAA that warrants surgical intervention as the next step in management. Both the size of the aneurysm and rapid expansion both greatly increase the risk for rupture.

Answer 5: Size is 6 cm and the patient is asymptomatic describes an AAA that would warrant surgical treatment due to the large size of the aneurysm. For aneurysms > 5.5 cm in size, most studies have found the morbidity from surgical intervention is outweighed by the risk of rupture and death from monitoring alone. This finding is independent of whether the patient is symptomatic from the AAA.

Bullet Summary:
Surgical treatment for abdominal aortic aneurysm is warranted if the aneurysm is > 5.5 cm, rapidly expanding, or causing symptoms.