Vascular: Thoracic Aortic Aneurysm (TAA)

Basics

• Aneurysm Definition: 1.5x Dilation of Normal Vessel Diameter
• Normal Diameters:
  • Ascending Aorta: 3.0 cm
  • Aortic Arch: 2.5-3.5 cm
  • Descending Thoracic Aorta: 2.0-3.0 cm
• Causes:
  • Medial Degeneration with Atherosclerosis (80% – Most Common)
  • Dissection (15-20%)
  • Infection
  • Connective Tissue Disorders
  • Trauma

Risk Factors

• Disease Risk Factors:
  • Smoking
  • Male
  • Older Age
  • Hypertension
  • Atherosclerosis
  • Marfan Syndrome
• Rupture Risk Factors:
  • COPD
  • Overall Size
  • Pain
  • Increasing Age

Presentation

• Mostly Asymptomatic & Found Incidentally
• Most Common Symptom: Vague Pain
• Symptoms Develop from Compression
  • Back Pain (Vertebrae)
  • Hoarseness (RLN)
  • Dyspnea (Bronchi)
  • Dysphagia (Esophagus)

Thoracoabdominal Aneurysm (TAAA) Modified Crawford Classification

• Type I: Extends from Left Subclavian to Suprarenal Aorta, Most of the Descending Thoracic Aorta
• Type II: Extends from Subclavian to Aortoiliac Bifurcation
• Type III: Distal Thoracic Aorta to Aortoiliac Bifurcation
• Type IV: Limited to Abdominal Aorta Below Diaphragm
• Type V: Distal Thoracic Aorta to Suprarenal Aorta, Does Not Extend Below the Renal Arteries

Isolated Abdominal Aortic Aneurysm (AAA)

• *See Vascular: Abdominal Aortic Aneurysm (AAA)

Repair Indications

• Rupture
• Symptomatic
• > 5.5 cm
  • High Surgical Risk: > 6.0 cm
• Rapid Expansion > 0.5 cm/year

Treatment

• Nonoperative Management:
  • Strict Blood Pressure Control (Beta-Blockade & ACE-I)
  • Statin Therapy
  • Smoking Cessation
  • Serial Imaging
• Approach to Repair:
  • Ascending TAA: Open Surgery
    • Open Surgical Repair: Median Sternotomy
      • Often Requires Aortic Root Replacement or Coronary Artery Reimplantation
  • Descending TAA: Open Surgery vs TEVAR
    • Open Surgical Repair: Left Thoracotomy
      • Reimplant Intercostal Arteries Below T8 (Avoid Paraplegia)
    • Thoracic Endovascular Aneurysm Repair (TEVAR)