How is atherosclerosis of the aorta diagnosed in middle‑aged or older adults with cardiovascular risk factors such as hypertension, hyperlipidemia, diabetes, smoking history, or family history of cardiovascular disease?

Diagnosis of Aortic Atherosclerosis

Contrast-enhanced computed tomography (CT) is the primary diagnostic modality for detecting and characterizing aortic atherosclerosis, offering comprehensive visualization of plaque burden, calcification, ulceration, and associated complications throughout the entire aorta. 1, 2

Initial Diagnostic Approach

Clinical Assessment

• Evaluate for symptoms that may indicate advanced disease: chest or back pain (suggesting penetrating ulcer or dissection), stroke or transient ischemic attack (embolic complications), claudication (concurrent peripheral disease), or hoarseness (laryngeal nerve compression from expanding lesions) 1
• Measure blood pressure in both arms to detect differential readings that suggest aortic involvement, and assess all peripheral pulses for diminished flow 1
• Document cardiovascular risk factors including smoking history (pack-years), duration of hypertension and diabetes, lipid levels, and family history of aortic disease or sudden death 1

Laboratory Testing

• Obtain baseline lipid panel (LDL-C, HDL-C, triglycerides), fasting glucose or HbA1c, and renal function (creatinine, eGFR) to assess atherosclerotic risk factors 1
• Consider inflammatory markers (C-reactive protein, fibrinogen) as they correlate with total aortic plaque burden and may reflect disease activity 3

Primary Imaging Modalities

Computed Tomography (First-Line)

• Perform contrast-enhanced CT of the chest and abdomen to visualize the entire aorta from root to bifurcation, identifying plaque location, extent, calcification pattern, wall thickness, and luminal diameter 1, 2
• CT is the technique of choice for detecting penetrating atherosclerotic ulcers (sensitivity 96%), showing characteristic out-pouching through calcified plaques, and for identifying associated intramural hematoma or periaortic hemorrhage 1, 2
• Use multiplanar reformations to measure aortic diameter perpendicular to the axis of blood flow, avoiding overestimation from oblique measurements 1
• Include the aortic wall in diameter measurements when assessing for aneurysmal dilation, as recent prognostic data are based on this methodology 1

Magnetic Resonance Imaging (Alternative)

• Consider cardiac MRI when repeated surveillance is needed to avoid cumulative radiation exposure, particularly in younger patients or those with stable moderate-sized disease 1
• MRI provides excellent soft tissue characterization of plaque composition, intramural hematoma, and aortic wall inflammation, though it cannot visualize calcification as well as CT 1
• Use the same imaging modality and institution for serial studies to enable accurate side-by-side comparison of matching anatomic segments 1

Echocardiography (Targeted Assessment)

• Perform transthoracic echocardiography (TTE) to evaluate the aortic root, proximal ascending aorta (up to ~40mm diameter), aortic valve calcification, and left ventricular function 1
• Transesophageal echocardiography (TOE) visualizes the ascending aorta, arch, and proximal descending thoracic aorta with high resolution, detecting plaques ≥3mm thickness and mobile components 1, 4, 5
• TOE has 75.9% sensitivity and 67.7% specificity for detecting significant coronary artery disease when thoracic aortic atherosclerosis is present, making it a useful marker for systemic atherosclerotic burden 5

Chest X-Ray (Screening Only)

• Chest radiography may incidentally detect abnormal aortic contour, widening, or calcification prompting further evaluation, but normal findings do not exclude disease 1
• Aortic arch calcification visible on plain chest X-ray (graded 0-3 by extent) independently predicts cardiovascular events beyond traditional risk factors (hazard ratio 2.49-2.56), providing valuable prognostic information 6

Anatomic Considerations

Regional Susceptibility Patterns

• Thoracic aortic plaques correlate primarily with LDL cholesterol and age, while abdominal aortic plaques associate more strongly with smoking and systolic blood pressure 3, 7
• The mid-to-distal descending thoracic aorta is the most common site for penetrating atherosclerotic ulcers, typically occurring in heavily calcified segments 1
• Complex plaques in the abdominal aorta (ulcerated, mobile thrombi) associate with myocardial infarction and unstable coronary lesions, suggesting shared plaque instability mechanisms 7

Screening for Associated Vascular Disease

Concurrent Arterial Involvement

• Perform duplex ultrasound screening for femoro-popliteal aneurysms in all patients with documented aortic atherosclerosis 8, 2
• Screen for carotid stenosis with duplex ultrasound when two or more cardiovascular risk factors are present 8
• Consider abdominal aortic aneurysm screening with ultrasound, particularly in men ≥65 years who have ever smoked or have first-degree relatives with AAA 1, 8
• Assess for coronary artery disease given the strong association between aortic and coronary atherosclerosis—75.9% of patients with significant CAD have thoracic aortic atherosclerosis 5

Diagnostic Pitfalls to Avoid

• Do not rely on chest X-ray alone to exclude aortic disease, as sensitivity is poor especially for ascending aortic pathology 1
• Avoid single imaging studies for critical decisions—require repeated high-quality measurements using the same technique to confirm progression before intervention 2
• Do not assume isolated aortic atherosclerosis—systematically evaluate other vascular beds (carotid, coronary, peripheral) as atherosclerosis is a systemic process 1, 8, 3
• Recognize that normal aortic diameter does not exclude significant atherosclerosis—plaque burden and ulceration matter independently of size 1

Surveillance Imaging Strategy

Frequency Based on Findings

• For mild-to-moderate atherosclerosis without complications: Annual echocardiography plus CT or MRI for comprehensive assessment 2
• For high-risk features (ulcerated plaques >13-20mm width, >10mm depth, mobile thrombi, or saccular components): More intensive surveillance at shorter intervals (1 month, 3 months, 6 months, then yearly) 1, 8
• Tailor surveillance frequency to the severity, anatomical location, and presence of complications such as penetrating ulcers or intramural hematoma 8, 2