What are the guidelines for performing Thoracic Endovascular Aortic Repair (TEVAR)?

Guidelines for Thoracic Endovascular Aortic Repair (TEVAR)

In patients with unruptured descending thoracic aortic aneurysm (DTA) without heritable thoracic aortic disease, TEVAR is recommended over open repair when the aortic diameter reaches ≥55 mm and the anatomy is suitable for endovascular intervention. 1

Indications for TEVAR

Anatomical Indications

• Descending Thoracic Aortic Aneurysms:

  • Intervention recommended at diameter ≥55 mm 1
  • Lower threshold may be appropriate for:
    • Women
    • Patients with connective tissue disorders
    • Rapid growth (≥10 mm/year or ≥5 mm/6 months) 1

• Complicated Type B Aortic Dissection:

  • TEVAR is the treatment of choice 1
  • Complications include:
    • Persistent/recurrent pain
    • Uncontrolled hypertension despite full medication
    • Early aortic expansion
    • Malperfusion
    • Signs of rupture (hemothorax, increasing periaortic/mediastinal hematoma) 1

• Aortic Arch Aneurysms:

  • Hybrid or endovascular approach may be considered in high-risk patients who meet criteria for intervention 1

Clinical Indications

• Ruptured DTA:

  • Emergency TEVAR is indicated when anatomy is suitable 2
  • Shows significantly better outcomes than open repair in emergency settings 3, 2

• Symptomatic DTA:

  • Urgent TEVAR recommended for symptomatic patients 2
  • Symptoms include chest/back pain not attributable to other causes

Technical Requirements for TEVAR

Landing Zones

• Proximal and Distal Landing Zones:
  • Minimum of 2 cm of healthy aorta required 4
  • Diameter should be less than 40 mm 4
  • Landing zone quality assessment:
    • Avoid zones with thrombus >50%
    • Avoid calcification >25%
    • Avoid tortuosity index ≥1.1 4

Sizing and Device Selection

• Stent-Graft Sizing:
  • 10-15% oversizing for aneurysms 4
  • Minimal to no oversizing for type B dissections 4
  • Excessive oversizing should be avoided to prevent complications 4

Pre-Procedural Imaging

• Required Imaging:
  • Fine-cut (≤0.25 mm) contrast-enhanced CT of entire aorta 3
  • Include iliac and femoral arteries for access planning 3
  • CT of head and neck to determine vertebral artery anatomy 3
  • 3D centerline reconstruction software for accurate planning 3

Procedural Considerations

Spinal Cord Protection

• Preventive Measures:
  • Consider cerebrospinal fluid drainage in high-risk patients 4
  • Avoid covering vessels supplying major spinal cord in elective settings 4
  • Maintain mean arterial pressure >80-90 mmHg post-procedure

Left Subclavian Artery Management

• Revascularization:
  • Revascularize the left subclavian artery before TEVAR if coverage is planned 1
  • Reduces risk of spinal cord ischemia and stroke 1

Intraoperative Management

• Blood Pressure Control:
  • Invasive blood pressure monitoring essential during stent graft placement 4
  • Controlled hypotension during deployment to prevent stent-graft displacement 4

Post-TEVAR Surveillance

Follow-up Protocol

• Imaging Schedule:
  • CT scan at 1 month and 12 months after TEVAR 3
  • Then yearly for life 3
  • More frequent imaging if endoleak or other abnormality is detected 3

Complications to Monitor

• Common Complications:
  • Endoleaks (particularly types I and III require re-intervention) 1
  • Stroke
  • Spinal cord ischemia
  • Device migration
  • Access site complications 5

Special Considerations

Complex Anatomy

• For arch aneurysms requiring TEVAR:
  • May require hybrid procedures (surgical debranching + TEVAR)
  • Consider wire protection techniques for short necks 6

Infection Risk

• Rare but devastating complication
• Risk factors include perioperative contamination and fistulization with esophagus or bronchial tree 7
• Prevention is key through strict sterile technique 7

Comparative Effectiveness

• TEVAR shows reduced perioperative morbidity and mortality compared to open repair 3
• Benefits include:
  • Shorter hospital stay
  • Lower perioperative mortality
  • Reduced morbidity 3

TEVAR has revolutionized the treatment of thoracic aortic diseases, particularly for descending thoracic aortic aneurysms. When anatomically suitable, it offers significant advantages over open repair in terms of morbidity and mortality. Proper patient selection, meticulous planning with advanced imaging, and adherence to technical guidelines are essential for optimal outcomes.