Aortic Aneurysm Ultrasound

An aortic aneurysm is a loss of vascular wall strength in the aorta which results in separation of the layers that lead to swelling and possibly rupture. High pressure, large arteries cause the greatest risk for sudden exsanguination and death. Of these, the aorta is the largest.

Risk factors for Aortic Aneurysm

An aneurysm diagnosis is established when the full-thickness dilation of a blood vessel is greater than 50% larger than its normal diameter (2-3 cm). For clinical purposes, aortic aneurysm is recognized to have a diameter greater than 3 cm. Its risk factors are:

  • Age.

  • Male gender.

  • Smoking.

  • Family history.

  • Presence of aneurysms elsewhere.

Use of Ultrasound in Aortic Aneurysm

Screening via ultrasound to measure aortic diameter is used in men aged 65-75 who had ever smoked, or (regardless of smoking history) who who have/had a close relative who had required surgical aortic aneurysm repair or who had died from rupture.

Once diagnosed, the stability or progress of an aortic aneurysm can be followed by ultrasound over time, and if there is progression, can indicate the time that surgical intervention is prudent to avert a catastrophic rupture.

Symptoms of Aortic Aneurysm

In the abdomen, aortic aneurysm does not usually cause symptoms unless it is actively expanding, compresses surrounding structures, is inflamed, or ruptures. When present, symptoms include abdominal, back, or flank pain, distention, and hemodynamic changes.

In the thoracic cavity, aortic aneurysm, following the same symptom-causing provocations as with abdominal aneurysms, can result in sudden chest, back, or abdominal pain. Dyspnea can occur if there is compression of the pulmonary trachea or bronchi.

Repair of either abdominal or thoracic aortic aneurysms is indicated with symptomatology or if a critical diameter is breached which raises the risk of rupture to unacceptable levels.

Diagnosis of Aortic Aneurysm

Most patients are not aware of an aneurysm at diagnosis. The diagnosis is gleaned from an incidental ultrasound for unrelated reasons or a pulsating mass is noted on an otherwise routine physical exam.

Aortic aneurysm can progress to rupture without warning or predictive symptoms. For this reason, screening is important for groups at risk:

  • Asymptomatic patients with risk factors for aneurysm: Smoking, male gender, advanced age, Caucasian, atherosclerosis, family history of aneurysm, or connective tissue disorder (marfan, ehlers-danlos, loey-dietz syndromes) in the patient or family. 

  • Physical exam that demonstrates a pulsating abdominal mass or aneurysms in places other than the aorta.

  • Signs and symptoms: Abdominal, chest, or back pain, limb ischemia, different blood pressures in opposite limbs, etc. 

Emergency versus Non-Emergency Diagnosis

Whether ultrasound of the aorta or more involved testing such as a computed tomography (CT) scan is used depends on the presentation.

Ultrasound

In emergencies, bedside ultrasound offers the fastest assessment in hemodynamically unstable patients that can prompt the decision for sending them to the operating room. Ultrasound is also useful in screening and in following patients with an established diagnosis.

CT Scan

Alternately, symptomatic aneurysm patients who are stable are usually evaluated with the addition of CT scans.