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A 68-year-old woman is evaluated in the emergency department for the sudden onset of severe pain, which began 3 hours ago. The pain is in the middle of her chest and radiates to her back. Medical history includes hypertension treated with hydrochlorothiazide and lisinopril.

On physical examination, the patient is afebrile. Her blood pressure is 190/110 mm Hg, pulse is 108/min and regular, and respiration rate is 18/min. An S₄ gallop is auscultated. No pericardial rub or murmur is present. Distal pulses are equal, full, and symmetric. Neurologic examination is normal. Laboratory results include normal serum cardiac troponin and serum creatinine levels. Oxygen saturation is 99% while breathing ambient air.

Electrocardiogram shows tachycardia but is otherwise normal. CT scan of the chest with intravenous contrast demonstrates a crescent-shaped density within the media of the aorta, arising just distal to the origin of the left subclavian artery and extending to just above the celiac axis. Contrast dye is not present within this crescent.

In addition to analgesia and intravenous β-blockade, which of the following is the most appropriate treatment?

A) Endovascular repair
B) Intravenous sodium nitroprusside
C) Intravenous unfractionated heparin
D) Urgent surgical repair

MKSAP Answer and Critique

The correct answer is B) Intravenous sodium nitroprusside. This item is available to MKSAP 15 subscribers as item 30 in the Cardiology section. MKSAP 16 will release Part A on July 31. More information is available online.

The abrupt onset of severe chest pain is consistent with acute aortic disease. The CT scan findings for this patient are characteristic of an acute distal (type B) intramural hematoma. Analgesia is imperative in the treatment of acute aortic syndromes, as pain control is integral in management of blood pressure and heart rate. Medical management, consisting of control of heart rate with intravenous β-blockade, followed by intravenous administration of a rapidly titratable parenteral arterial vasodilator (such as sodium nitroprusside, fenoldopam, or enalaprilat), is the preferred therapy. Heart rate should be reduced to 60 to 80/min with the use of a parenteral β-blocking agent, such as esmolol, labetalol, or metoprolol. Blood pressure should be lowered to a systolic pressure of 100 to 120 mm Hg, mean arterial pressure of 60 to 75 mm Hg, or the lowest blood pressure commensurate with vital end-organ perfusion.

Certain findings on physical examination, including unequal upper-extremity blood pressures and a pulse deficit, increase the likelihood of acute aortic disease (including dissection and intramural hematoma); however, the absence of these findings, as in this patient, should not influence the decision to pursue further diagnostic testing.

Surgical therapy together with medical hemodynamic control would be appropriate for an ascending aortic (type A) hematoma. Whereas endovascular repair has been used for treatment of aortic dissection, there is no current role for endovascular treatment of isolated acute intramural hematoma. Surgical therapy of type B aortic syndromes is associated with significant morbidity and mortality. Endovascular repair or surgical intervention should be considered when distal intramural hematoma arises in association with a deep (≥10 mm) and wide (≥20 mm) penetrating atherosclerotic ulcer.

Aortic hematoma is caused by acute bleeding, possibly from rupture of the vasa vasorum, contained within the media of the aorta. There is no role for anticoagulation as part of management.

With treatment, patients with type B acute intramural hematomas fare as well as, or better than, patients with type B aortic dissection. Over time, intramural hematomas may follow one of three courses: resorption and normalization, aneurysmal dilation, or conversion to typical dissection. Because of this, follow-up surveillance by CT is reasonable.

Key Point

• Medical management of pain, heart rate, and blood pressure is the preferred treatment for type B (distal) acute intramural hematoma.

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