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Difficulty: HardCardiovascular System

A 58-year-old man is brought to the emergency department for sudden, excruciating chest pain radiating to his interscapular region. He appears diaphoretic and in severe distress. Blood pressure is 210/110 mm Hg in the right arm and 170/95 mm Hg in the left arm. Heart rate is 118/min. A new early diastolic decrescendo murmur is heard at the right upper sternal border. Neurologic examination reveals no focal deficits. Electrocardiogram shows sinus tachycardia and left ventricular hypertrophy without acute ischemic changes. Chest radiograph demonstrates a widened mediastinum. Arrange the following next steps in the management of this patient in the most appropriate chronological order.

  1. 1Administer an intravenous beta-blocker
  2. 2Administer an intravenous vasodilator
  3. 3Obtain computed tomography angiography of the chest
  4. 4Consult cardiothoracic surgery for operative repair

Answer

The correct sequence is to first control heart rate and contractility with a beta-blocker, followed by blood pressure reduction with a vasodilator, then perform definitive imaging, and finally obtain a surgical consultation for operative repair.
In acute aortic dissection, the immediate goal is to halt the propagation of the false lumen. This is achieved by first reducing the sheer stress (dP/dt) on the aortic wall with an intravenous beta-blocker (e.g., esmolol). Only after the heart rate is controlled (usually < 60/min) should an intravenous vasodilator (e.g., nitroprusside) be added to reach a target systolic blood pressure of 100-120 mm Hg; using a vasodilator first can cause reflex tachycardia, worsening the sheer stress. Once hemodynamically stabilized, the patient should undergo CT angiography to definitively diagnose the condition and evaluate its extent. Finally, given the clinical signs of a Stanford Type A dissection (ascending aorta involvement causing a new aortic regurgitation murmur and blood pressure differential), an urgent cardiothoracic surgery consultation is required for definitive repair.

Step-by-Step Solution

1
Administer an intravenous beta-blocker (e.g., esmolol, labetalol).
Heart rate and left ventricular contractility decrease.
Decreasing the rate of rise of the left ventricular pressure (dP/dt) reduces the shear stress on the aortic wall, halting the propagation of the dissection.
2
Administer an intravenous vasodilator (e.g., sodium nitroprusside).
Systolic blood pressure rapidly decreases to a target of 100-120 mm Hg.
Lowering the blood pressure further reduces aortic wall stress. This must only be done after beta-blockade to prevent reflex tachycardia.
3
Obtain computed tomography (CT) angiography of the chest and abdomen.
The diagnosis is confirmed and classified as Stanford Type A or Type B.
Definitive imaging is necessary for surgical planning, but the patient must be hemodynamically stabilized first to prevent rupture during transport or imaging.
4
Consult cardiothoracic surgery for operative repair.
Patient is taken to the operating room.
Type A aortic dissections (involving the ascending aorta) have a high mortality rate and require emergent surgical intervention.

Key Concept

The sequential pharmacological and diagnostic management of acute aortic dissection.
Estimated Time:1m 30s
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Topics

Cardiovascular System

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