What is the best diagnostic test for a 60-year-old male smoker with sudden onset of chest pain radiating to the back and absent left radial and femoral pulses?

Computed Tomography Angiography is the Best Diagnostic Test for Suspected Aortic Dissection

For a 60-year-old male smoker with sudden onset chest pain radiating to the back and absent left radial and femoral pulses, CTA of the chest, abdomen, and pelvis is the recommended diagnostic test of choice.

Clinical Presentation Analysis

The patient's presentation strongly suggests acute aortic dissection:

• Sudden onset chest pain radiating to the back (classic for aortic dissection)
• Absent left radial and femoral pulses (indicates vascular compromise)
• 60-year-old male smoker (risk factors for aortic disease)

This constellation of symptoms represents a vascular emergency requiring immediate diagnosis.

Diagnostic Test Selection

CTA (Option C)

• First-line recommendation: The 2021 AHA/ACC guidelines explicitly state that "In patients with acute chest pain where there is clinical concern for aortic dissection, computed tomography angiography (CTA) of the chest, abdomen, and pelvis is recommended for diagnosis and treatment planning" (Class 1, Level C-EO) 1
• CTA provides:
  • Excellent visualization of the aortic lumen and wall
  • Identification of the intimal flap
  • Assessment of branch vessel involvement
  • Evaluation of end-organ perfusion
  • Information for surgical planning

ECG (Option B)

• Limited utility in diagnosing aortic dissection
• May show non-specific changes or be normal
• Cannot visualize the aorta or detect vascular compromise
• May be useful to rule out myocardial infarction but is insufficient for suspected aortic dissection

Echocardiography (Option A)

• Limited role as initial test for suspected aortic dissection
• According to guidelines, transthoracic echocardiography (TTE) should only be performed "to make the diagnosis if CT is contraindicated or unavailable" (Class 2, Level C-EO) 1
• TTE has limited sensitivity for detecting aortic dissection, especially in the descending aorta
• Cannot adequately visualize the entire aorta

Clinical Reasoning

The patient's presentation with:

1. Sudden onset chest pain radiating to the back (classic for aortic dissection)
2. Pulse deficits (absent left radial and femoral pulses)
3. Risk factors (male, age 60, smoking history)

Creates a high clinical suspicion for aortic dissection, which is a time-sensitive diagnosis requiring immediate and accurate imaging.

Diagnostic Algorithm for Suspected Aortic Dissection

1. Recognize high-risk features:

   • Sudden severe chest/back pain
   • Pulse deficits or blood pressure differentials
   • Neurological deficits
   • Risk factors (hypertension, smoking, connective tissue disorders)

2. Obtain immediate CTA of chest, abdomen, and pelvis

   • Provides comprehensive assessment of entire aorta
   • Highly sensitive (nearly 100%) and specific for aortic dissection 2
   • Allows classification of dissection type (Stanford A or B)
   • Identifies complications (branch vessel involvement, rupture)

3. If CTA unavailable or contraindicated:

   • Transesophageal echocardiography (TEE) or cardiac MRI 1

Pitfalls to Avoid

• Delayed diagnosis: Aortic dissection has high mortality (1-2% per hour in the first 24-48 hours if untreated)
• Incomplete imaging: Failure to image the entire aorta may miss extent of dissection
• Misdiagnosis as ACS: Treating suspected aortic dissection with anticoagulation (as for ACS) can worsen outcomes
• Relying on ECG alone: ECG cannot rule out aortic dissection and may be normal or show non-specific changes

CTA represents the optimal balance of speed, accuracy, and comprehensive assessment for this potentially life-threatening condition, making it clearly superior to ECG or echocardiography in this clinical scenario.