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Difficulty: HardCardiovascular System

A 62-year-old man is brought to the emergency department via ambulance due to the sudden onset of severe, excruciating chest pain that radiates to his interscapular region. Shortly after the pain began, he developed severe shortness of breath. His medical history is significant for poorly controlled hypertension, tobacco use, and chronic obstructive pulmonary disease. On arrival, his blood pressure is 185/105 mmHg in the right arm and 178/100 mmHg in the left arm. His pulse is 118/min, and his respiratory rate is 28/min with an oxygen saturation of 88% on room air. Physical examination reveals a diaphoretic man in severe respiratory distress. Lung auscultation demonstrates diffuse bilateral expiratory wheezing with crackles at the lung bases. Cardiovascular examination reveals a new decrescendo diastolic murmur loudest at the right upper sternal border. An electrocardiogram shows sinus tachycardia with left ventricular hypertrophy. Which of the following is the most appropriate initial pharmacological step in the management of this patient?

  1. Intravenous esmololAnswer
  2. B
    Inhaled albuterol and intravenous methylprednisolone
  3. C
    Intravenous sodium nitroprusside
  4. D
    Intravenous ceftriaxone and azithromycin
  5. E
    Intravenous unfractionated heparin

Answer

Intravenous esmolol
Intravenous esmolol is the correct initial step. The patient's presentation is highly suspicious for a Type A aortic dissection complicated by acute aortic regurgitation. The new diastolic murmur at the right upper sternal border and sudden onset of tearing chest pain are classic findings. The acute regurgitation causes left ventricular volume overload and flash pulmonary edema, which can present with cardiogenic wheezing ('cardiac asthma'). In acute aortic dissection, the primary pharmacological goal is to decrease the rate of rise of left ventricular pressure (dP/dtdP/dt) and lower the heart rate to minimize shearing forces on the aortic wall. A short-acting, titratable beta-1 selective blocker like esmolol is the initial drug of choice.

Step-by-Step Solution

1
Analyze the clinical presentation.
The patient has sudden, tearing chest pain radiating to the back with severe hypertension and a new decrescendo diastolic murmur.
These findings are classic for an acute Type A aortic dissection involving the aortic root, causing acute aortic regurgitation.
2
Interpret the pulmonary findings.
Diffuse wheezing and crackles in the setting of acute aortic regurgitation indicate cardiogenic pulmonary edema, often referred to as 'cardiac asthma'.
Acute left ventricular volume overload leads to backward failure, causing peribronchial edema that mimics a COPD exacerbation.
3
Determine the initial management goal for aortic dissection.
The primary goal is to minimize aortic wall shear stress by reducing the heart rate and the rate of ventricular pressure rise (dP/dtdP/dt).
Lowering the dP/dtdP/dt prevents the propagation of the dissection flap.
4
Select the appropriate pharmacotherapy.
Intravenous beta-blockers (e.g., esmolol or labetalol) are the immediate first-line treatment.
Beta-blockers must be given before any vasodilators to prevent reflex tachycardia and increased contractility.

Key Concept

Pharmacological management of acute aortic dissection complicated by acute aortic regurgitation and cardiac asthma.
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Topics

Cardiovascular System

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