I have a pulsatile sensation in the epigastric area; could this be an abdominal aortic aneurysm and how should it be evaluated?

Evaluation of Pulsatile Epigastric Sensation

Order an abdominal aortic ultrasound immediately to distinguish between normal aortic pulsation and an abdominal aortic aneurysm (AAA), as this is the definitive first-line test with near 100% sensitivity and specificity. 1

Understanding the Clinical Context

A pulsatile sensation in the epigastric area can represent either normal aortic pulsation or pathologic aortic enlargement. The key distinction is critical because:

• In thin individuals, a palpable abdominal aorta is often a normal finding and does not imply pathology. 2
• However, approximately 30% of asymptomatic AAAs are discovered as a pulsatile abdominal mass on routine physical examination. 3
• An AAA is defined as aortic diameter ≥3.0 cm, representing at least 50% enlargement from the normal infrarenal aortic diameter (up to 2.0 cm). 1, 4

The natural history of AAA involves progressive expansion with potential rupture—a medical emergency carrying 65-85% mortality. 5 This makes accurate diagnosis essential for morbidity and mortality reduction.

First-Line Diagnostic Approach

Ultrasound is the definitive initial imaging modality for the following reasons:

• Diagnostic accuracy approaches 100% for detecting AAA, with only 1-2% of studies technically inadequate due to body habitus or bowel gas. 1, 2
• Ultrasound is radiation-free, widely available, low-cost, and can be performed at bedside in emergency settings. 2
• The test reliably detects AAA presence in 98-99% of cases. 2

Technical Requirements for Optimal Ultrasound

• Patients should fast overnight before the study to minimize bowel gas and improve aortic visualization. 2
• Scanning must include longitudinal and transverse images from the diaphragm to the aortic bifurcation. 2
• The greatest outer-to-outer (OTO) aortic diameter should be measured perpendicular to the centerline of the aorta. 1, 2
• Measurements should be obtained in the proximal, mid, and distal infrarenal aorta and common iliac arteries. 1

Interpreting Results and Next Steps

If Aortic Diameter is <3.0 cm (Normal)

• Reassure the patient that the palpable pulsation is a normal anatomic finding, particularly in thin individuals. 2
• Investigate alternative causes for any associated symptoms, as AAA rarely presents with nonspecific gastrointestinal or neurologic symptoms. 2

If AAA is Confirmed (≥3.0 cm)

Implement size-based surveillance and management:

• 3.0-3.4 cm: Repeat ultrasound every 3 years 4
• 3.5-4.4 cm: Annual ultrasound surveillance 4
• 4.5-5.4 cm: Ultrasound every 6 months 4
• ≥5.5 cm (men) or ≥5.0 cm (women): Obtain CTA for surgical planning and refer to vascular surgery immediately 1, 4

The lower threshold for women reflects their four-fold higher rupture risk at equivalent AAA sizes compared to men. 4

If Ultrasound is Technically Inadequate

• Obtain a non-contrast CT of the abdomen, which offers diagnostic equivalence to ultrasound for AAA detection while avoiding iodinated contrast. 1, 2

When to Use CT Angiography (CTA)

Do NOT proceed directly to CTA for initial evaluation in asymptomatic patients. This exposes patients to unnecessary radiation and contrast when ultrasound provides equivalent diagnostic accuracy. 2

CTA is specifically indicated for:

• AAA ≥5.5 cm in men or ≥5.0 cm in women requiring surgical or endovascular planning 1
• Clinical suspicion of contained rupture (acute severe pain, hemodynamic instability) 1, 2
• Pre-intervention planning for endovascular or open repair 1, 2
• Better characterization of aneurysm morphology when saccular features are suspected, as these increase rupture risk even below the 5.5 cm threshold 4

CTA provides thin-section acquisition timed with peak arterial enhancement, interpreted using multiplanar reformations and 3-D renderings—essential for surgical planning. 1

Critical Risk Factors to Assess

Major risk factors for AAA include:

• Advanced age (>65 years), male sex, smoking history, and family history of AAA 1, 6
• Hypertension, coronary artery disease, and peripheral artery disease 6, 3

If AAA is confirmed, aggressive risk factor modification is mandatory:

• Smoking cessation is the single most important intervention, as smoking is the strongest modifiable risk factor for AAA expansion and rupture. 4
• Optimal blood pressure control is essential, as hypertension accelerates aneurysm growth rates. 4
• Initiate statin therapy for cardiovascular risk reduction in all patients with AAA. 4

Common Pitfalls to Avoid

• Do not interpret a palpable aortic pulsation as pathological in thin individuals without imaging confirmation. 2
• Do not proceed directly to CTA in asymptomatic patients; this exposes them to unnecessary radiation when ultrasound provides equivalent accuracy. 2
• Do not attribute nonspecific symptoms to AAA without imaging confirmation, as most AAAs are asymptomatic until rupture. 2, 5
• Remember that other pathologies can mimic AAA, including a congested liver from right heart failure with tricuspid regurgitation. 7

Screening Considerations

If the patient meets screening criteria:

• Men aged 65-75 years who have ever smoked should undergo one-time screening with ultrasonography. 8
• Men in this age group without smoking history may benefit from screening if they have other risk factors (family history of AAA, coronary artery disease). 6, 8
• Women without smoking history should not undergo routine screening, as harms likely outweigh benefits. 8