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Difficulty: MediumDiagnostic Workup and Test Sequencing

Following an emergency medical transport, a 6868-year-old male is urgently evaluated in the resuscitation bay for sudden-onset, excruciating retrosternal pain that radiates directly to his thoracic spine. The episode began one hour prior while he was resting. His medical history is notable for medication-noncompliant hypertension and tobacco use disorder. On initial assessment, the patient is overtly pale, diaphoretic, and lethargic. Vital signs reveal a blood pressure of 82/5082/50 mm Hg in the right arm and 60/4060/40 mm Hg in the left arm, a pulse of 118118/min, and a respiratory rate of 2222/min. Auscultation of the precordium demonstrates a new early diastolic decrescendo murmur at the right upper sternal border. An electrocardiogram reveals sinus tachycardia with no ST-segment or T-wave abnormalities. A portable anteroposterior chest radiograph shows widening of the mediastinal silhouette. Which of the following is the most appropriate next step in the diagnostic workup of this patient?

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

Answer

Transesophageal echocardiography
Transesophageal echocardiography (TEE) is the diagnostic test of choice for suspected aortic dissection in hemodynamically unstable patients. This patient's tearing back pain, asymmetric blood pressures, new aortic regurgitation murmur, and widened mediastinum strongly suggest an aortic dissection (Stanford type A). His hypotension and lethargy indicate shock (likely due to tamponade, severe aortic regurgitation, or rupture). TEE can be performed rapidly at the bedside without interrupting continuous monitoring and resuscitation, making it vastly superior in this specific context compared to CT angiography, which requires transporting an unstable patient.

Step-by-Step Solution

1
Analyze the clinical presentation and physical findings.
The patient exhibits classic signs of an acute ascending aortic dissection, including tearing retrosternal pain radiating to the back, an upper extremity pulse/blood pressure differential, a new diastolic murmur of aortic regurgitation, and a widened mediastinum on chest radiograph.
Establishing a high pretest probability for aortic dissection is necessary to guide the diagnostic algorithm.
2
Assess the patient's current hemodynamic status.
The patient has severe hypotension (82/5082/50 mm Hg), tachycardia (118118/min), and lethargy, indicating cardiogenic or obstructive shock (potentially secondary to cardiac tamponade or acute aortic valve incompetence).
Hemodynamic stability is the primary branch point in the algorithm for evaluating suspected aortic dissection.
3
Select the most appropriate, safest diagnostic imaging modality.
Transesophageal echocardiography is selected over computed tomography angiography because it can be rapidly performed at the bedside in the resuscitation bay.
Transporting a hemodynamically unstable patient to the CT scanner is unsafe. Bedside imaging allows for continuous resuscitation and monitoring while still providing high diagnostic sensitivity and specificity.

Key Concept

In patients with a high clinical suspicion for acute aortic dissection who present with hemodynamic instability, bedside transesophageal echocardiography is the most appropriate next diagnostic step to confirm the diagnosis without risking clinical deterioration during transport.
Estimated Time:1m 0s
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Topics

Diagnostic Workup and Test Sequencing

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