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Difficulty: Very hardInterpreting Imaging Results

A 64-year-old man with a history of poorly controlled hypertension presents to the emergency department with sudden-onset, severe, tearing pain between his shoulder blades that began 2 hours ago. He appears in severe distress. Blood pressure is 195/110 mmHg and heart rate is 108/min. The pulses are equal in all four extremities. An electrocardiogram is unremarkable. A non-contrast computed tomography (CT) scan of the chest reveals a crescent-shaped, high-attenuation area within the wall of the descending thoracic aorta, extending from just distal to the left subclavian artery down to the diaphragmatic hiatus. Subsequent CT angiography shows no intimal flap, no double lumen, and no contrast extravasation into the aortic wall. Based on the interpretation of these imaging findings, which of the following is the most appropriate next step in management?

  1. Intravenous esmolol infusionAnswer
  2. B
    Urgent open surgical repair of the descending aorta
  3. C
    Thoracic endovascular aortic repair (TEVAR)
  4. D
    Intravenous heparin infusion
  5. E
    Admission to a general medical floor for oral antihypertensive titration

Answer

Intravenous esmolol infusion
The correct answer is the administration of an intravenous beta-blocker. The patient's imaging demonstrates a crescent-shaped, high-attenuation area in the aortic wall on non-contrast CT, with no intimal flap or double lumen on CTA. These findings are the classic imaging hallmarks of an aortic intramural hematoma (IMH), a variant of acute aortic syndrome caused by rupture of the vasa vasorum. Because the IMH is located distal to the left subclavian artery, it is classified as a Stanford Type B IMH. For uncomplicated Type B IMH, the standard of care is immediate medical management with anti-impulse therapy. Intravenous beta-blockers (such as esmolol or labetalol) are the first-line agents to reduce both heart rate (target <60/min) and aortic wall shear stress (dP/dt), followed by vasodilators if blood pressure remains elevated.

Step-by-Step Solution

1
Interpret the non-contrast CT and CT angiography findings.
Diagnosed as an aortic intramural hematoma (IMH).
The hyperdense crescent on non-contrast imaging without an intimal flap or double lumen on CTA distinguishes IMH from a classic aortic dissection or penetrating atherosclerotic ulcer.
2
Determine the anatomical classification based on the imaging description.
Classified as Stanford Type B IMH.
The lesion is located exclusively in the descending thoracic aorta, distal to the origin of the left subclavian artery.
3
Select the appropriate evidence-based management for this specific classification.
Select intravenous beta-blockade.
Uncomplicated Type B acute aortic syndromes require aggressive anti-impulse medical therapy (reducing heart rate and blood pressure) to prevent propagation, rather than immediate surgical or endovascular intervention.

Key Concept

Interpretation of aortic intramural hematoma (IMH) on CT imaging and the indication for immediate medical anti-impulse therapy in uncomplicated Stanford Type B cases.
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Topics

Interpreting Imaging Results

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