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Difficulty: HardDiagnostic Workup and Test Sequencing

A 68-year-old man is brought to the emergency department complaining of a sudden onset of excruciating, tearing pain in his chest that radiates directly to his back. The pain began 45 minutes ago while he was eating dinner. His medical history is significant for long-standing hypertension, type 2 diabetes mellitus, and stage 4 chronic kidney disease with a baseline serum creatinine of 2.6 mg/dL. His current medications include amlodipine, lisinopril, aspirin, and insulin. On physical examination, he appears in severe distress and is diaphoretic. His blood pressure is 185/105 mmHg in the right arm and 140/90 mmHg in the left arm. His heart rate is 105/min. Cardiac auscultation reveals a faint, decrescendo diastolic murmur at the right upper sternal border. The lungs are clear to auscultation bilaterally. Neurologic examination is unremarkable. An electrocardiogram shows sinus tachycardia with voltage criteria for left ventricular hypertrophy, but no acute ST-segment or T-wave abnormalities. A portable chest radiograph demonstrates a widened mediastinum. Laboratory studies reveal a current serum creatinine of 2.9 mg/dL. Which of the following is the most appropriate next step in the diagnostic workup?

  1. A
    Computed tomography angiography of the chest
  2. B
    Invasive aortic angiography
  3. C
    Magnetic resonance angiography of the chest
  4. Transesophageal echocardiographyAnswer
  5. E
    Transthoracic echocardiography

Answer

Transesophageal echocardiography is the most appropriate next step to confirm the diagnosis while avoiding nephrotoxic contrast.
Transesophageal echocardiography is the correct choice because the patient has classic signs of an acute aortic dissection (tearing pain, pulse differentials, widened mediastinum) combined with severe renal impairment (creatinine 2.9 mg/dL). While computed tomography angiography is typically the first-line test, it requires iodinated contrast, which is strictly contraindicated in severe acute-on-chronic kidney disease. Transesophageal echocardiography offers near-equal sensitivity and specificity, requires no nephrotoxic contrast, and can be performed quickly in the emergency department.

Step-by-Step Solution

1
Evaluate the clinical presentation and physical exam findings.
The combination of sudden tearing chest pain, blood pressure asymmetry, widened mediastinum, and a new murmur of aortic regurgitation strongly suggests an acute aortic dissection.
Recognizing this classic presentation is necessary to prioritize immediate diagnostic confirmation and subsequent surgical consultation.
2
Assess patient comorbidities and laboratory results that might restrict diagnostic modalities.
The patient has a serum creatinine of 2.9 mg/dL, indicating severe acute-on-chronic kidney disease.
Diagnostic imaging for vascular pathology typically requires contrast; identifying renal failure is critical to avoid iatrogenic contrast-induced nephropathy.
3
Select the optimal diagnostic imaging test given the patient's constraints.
Transesophageal echocardiography (TEE) is selected over CT angiography.
TEE provides high diagnostic accuracy for aortic dissection without requiring nephrotoxic iodinated contrast, and it can be performed safely and rapidly at the bedside.

Key Concept

In patients with suspected acute aortic dissection who have severe renal impairment or hemodynamic instability, transesophageal echocardiography (TEE) is the preferred diagnostic modality over computed tomography angiography (CTA) to avoid contrast-induced nephropathy and treatment delays.
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Diagnostic Workup and Test Sequencing

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