Thoracic aortic aneurysms (TAA)

Introduction:

Abnormal dilatation/bulging in a blood vessel due to the intrinsic weakness of the vessel wall.

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Aetiology

Risk factors:

• Male gender
• Increased age
• Hypertension
• Chronic obstructive pulmonary disease (COPD)
• Coronary artery disease (CAD)
• Smoking
• Previous aortic dissection
• Family history of TAA (strong risk factor, 20%)

Syndromic association (5% cases):

• Marfan syndrome
• Loeys-Deitz syndrome
• Ehlers-Danlos syndrome

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Clinical features

Rarely manifest with symptoms, and about 95% of the patients are asymptomatic. If they become large enough, they may occasionally cause symptoms.

• Chest pain (because of compression of adjacent structures)
• Difficulty breathing (d/t airway compression)
• Hoarseness of voice (d/t compression of recurrent laryngeal nerve)

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Complications

22% of individuals die before reaching the hospital during an aneurysm complication

• Aortic dissection/rupture: . Chest pain radiating to the back with severe hypotension
• Superior vena cava (SVC) syndrome

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Diagnosis

• Contrast-enhanced CT (CECT) scan (M/C)
• MRI
• Transesophageal echocardiography (TEE)
• Ascending aortography
• PET scans
• Chest x-ray
• Electrocardiogram (EKG)

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Management

Lifestyle modifications:

• Smoking cessation
• Diet to control hypertension

Medical management:

Aims at reducing stress in the aorta, which in turn prevents the growth of the aneurysm

• β-blockers (first-line drugs): Reduce stress by decreasing both blood pressure and contractility
• Angiotensin receptor blockers (ARBs) and angiotensin-converting enzyme (ACE) inhibitors: Beneficial for patients with Marfan syndrome as they reduce TGF-B signaling
• Lipid-lowering agents (statins): Reduce oxidative stress, rate of rupture, and dissection

Surgical management:

Aims to prevent dissection or rupture of the aneurysm

• Cutoff for surgery:
  • Ascending aorta: 5.5 cm
  • Descending aorta: 6.5 cm
  • Ascending aneurysm (asymptomatic case with Marfan syndrome): 5 cm