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Difficulty: HardCardiovascular System

A 58-year-old man is evaluated in the emergency department for sudden-onset, severe, "tearing" chest pain that radiates to his back. The pain began one hour ago while he was lifting heavy boxes. He has a history of poorly controlled hypertension. His temperature is 37.2°C (99.0°F), pulse is 112/min, and respirations are 22/min. Blood pressure is 215/115 mm Hg in the right arm and 175/95 mm Hg in the left arm. Physical examination reveals a new early diastolic decrescendo murmur heard best at the right upper sternal border. An electrocardiogram shows sinus tachycardia and left ventricular hypertrophy without acute ischemic changes. Chest radiography reveals a widened mediastinum.

Arrange the following patient management steps in the most appropriate chronological order.

  1. 1Administer an intravenous beta-adrenergic antagonist (e.g., esmolol)
  2. 2Administer an intravenous vasodilator (e.g., sodium nitroprusside)
  3. 3Obtain a computed tomography angiogram of the chest and abdomen
  4. 4Proceed with emergent operative repair of the ascending aorta

Answer

The correct sequence is to initiate anti-impulse therapy with an intravenous beta-blocker, followed by an intravenous vasodilator, then confirm the diagnosis with a computed tomography angiogram, and finally proceed to emergent surgical repair.
The correct chronological management of acute aortic dissection prioritizes immediate reduction of aortic wall shear stress (anti-impulse therapy). This begins with an intravenous beta-blocker (e.g., esmolol) to reduce heart rate and left ventricular contractility (dP/dt). Once the heart rate is controlled, an intravenous vasodilator (e.g., sodium nitroprusside) is added to achieve a target systolic blood pressure of 100-120 mm Hg. After medical stabilization is initiated, the patient should undergo a computed tomography angiogram to confirm the diagnosis and define the anatomy. Because this patient has signs of ascending aortic involvement (right arm hypertension, aortic regurgitation murmur), it is a Stanford Type A dissection, which ultimately requires emergent surgical repair.

Step-by-Step Solution

1
Administer an intravenous beta-adrenergic antagonist (e.g., esmolol).
Heart rate and left ventricular contractility are decreased.
Reduces aortic wall shear stress (dP/dt). This must be done first to prevent dissection propagation.
2
Administer an intravenous vasodilator (e.g., sodium nitroprusside).
Systolic blood pressure is rapidly lowered to a target of 100-120 mm Hg.
Further decreases wall stress. It is given second because administering it without prior beta-blockade causes reflex tachycardia and increased contractility, which can worsen the dissection.
3
Obtain a computed tomography angiogram of the chest and abdomen.
Confirmation of the dissection flap and anatomic classification (Stanford Type A).
Definitive imaging is necessary to plan the surgical approach, but only after initial hemodynamic control has been established to prevent imminent rupture.
4
Proceed with emergent operative repair of the ascending aorta.
Surgical replacement of the ascending aorta and potential aortic valve repair.
Stanford Type A dissections carry a significantly high mortality rate if treated medically alone. Emergent surgery is the definitive treatment.

Key Concept

In the management of acute aortic dissection, initial stabilization requires strict anti-impulse therapy starting with a beta-blocker, followed by a vasodilator, before obtaining definitive imaging and proceeding to surgical repair.
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Topics

Cardiovascular System

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