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Difficulty: HardCardiothoracic and Vascular Surgery

Emergency medical services arrive with a 68-year-old male patient who experienced the sudden onset of severe, sharp chest pain radiating to his back approximately 45 minutes ago. Shortly after the pain began, the patient developed profound shortness of breath. His wife reports his medical history is significant for poorly controlled hypertension and severe chronic obstructive pulmonary disease (COPD), managed with a daily tiotropium inhaler.

Upon arrival in the resuscitation bay, he is in severe respiratory distress and utilizing accessory muscles to breathe. His temperature is 37.0°C (98.6°F), blood pressure is 88/50 mm Hg in the right arm and 112/68 mm Hg in the left arm, pulse is 118/min, and respirations are 28/min. Pulse oximetry shows 87% on room air.

Physical examination reveals markedly elevated jugular venous pressure. Lung auscultation demonstrates diffuse bilateral crackles and prominent expiratory wheezing. Cardiac auscultation reveals a prominent, early decrescendo diastolic murmur heard best at the right second intercostal space. A bedside chest radiograph shows a widened mediastinum and bilateral alveolar infiltrates.

Which of the following is the most appropriate next step in management?

  1. A
    Computed tomography angiography of the chest
  2. B
    Administration of intravenous corticosteroids and nebulized albuterol
  3. C
    Intravenous administration of esmolol
  4. Bedside transesophageal echocardiographyAnswer
  5. E
    Intravenous administration of broad-spectrum antibiotics

Answer

The correct answer is bedside transesophageal echocardiography.
This patient presents with classic signs of an acute Stanford Type A aortic dissection complicated by acute aortic regurgitation and cardiogenic shock. The sudden, tearing chest pain radiating to the back, asymmetric upper extremity blood pressures, and widened mediastinum strongly suggest an aortic dissection. The new early decrescendo diastolic murmur, severe hypotension, and bilateral crackles indicate that the dissection has propagated proximally to involve the aortic root. This separation of the aortic valve commissures causes acute severe aortic regurgitation, sudden left ventricular volume overload, and subsequent acute cardiogenic pulmonary edema. The expiratory wheezing is "cardiac asthma" secondary to peribronchial edema. In a hemodynamically unstable patient with a high clinical suspicion for an aortic dissection, transporting the patient to the CT scanner is strictly contraindicated. Bedside transesophageal echocardiography (TEE) is the diagnostic modality of choice because it is highly sensitive, can be performed rapidly at the bedside or in the operating room, and facilitates immediate transition to emergent surgical repair.

Step-by-Step Solution

1
Identify the primary underlying diagnosis based on the vascular and radiographic findings.
The patient's sudden, tearing chest pain radiating to the back, combined with a significant blood pressure differential between his arms and a widened mediastinum on the chest radiograph, strongly indicates an acute aortic dissection.
These are the classic hallmark signs of an aortic intimal tear that is compromising the brachiocephalic or left subclavian arteries.
2
Determine the cause of the patient's respiratory distress and hemodynamic shock.
The new early decrescendo diastolic murmur, bilateral lung crackles, expiratory wheezing, and hypotension (88/50 mm Hg) indicate that the dissection has propagated proximally to involve the aortic root, causing acute severe aortic regurgitation and cardiogenic shock.
Acute aortic regurgitation leads to sudden left ventricular volume overload, elevated left-sided filling pressures, and acute pulmonary edema (manifesting as bilateral infiltrates and 'cardiac asthma').
3
Select the most appropriate diagnostic or management step for a hemodynamically unstable patient with a highly suspected aortic dissection.
Bedside transesophageal echocardiography (TEE) should be performed immediately.
Transporting a hemodynamically unstable patient to a CT scanner is strictly contraindicated. TEE is highly sensitive and specific, can be performed safely at the bedside or in the operating room, and allows for immediate transition to emergent surgical repair.

Key Concept

Diagnosis and management of acute Stanford Type A aortic dissection complicated by acute aortic regurgitation and cardiogenic shock in a hemodynamically unstable patient.
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Topics

Cardiothoracic and Vascular Surgery

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