What are the steps and potential complications of the Thoracic Endovascular Aortic Repair (TEVAR) procedure?

Thoracic Endovascular Aortic Repair (TEVAR) Procedure and Complications

TEVAR is the recommended first-line treatment for descending thoracic aortic aneurysms (TAA) that meet criteria for intervention, with significantly lower perioperative morbidity and mortality compared to open surgical repair. 1

Indications for TEVAR

• Descending thoracic aortic aneurysm ≥5.5 cm in diameter
• Complicated type B aortic dissection (persistent pain, uncontrolled hypertension, early aortic expansion, malperfusion, rupture)
• Rapid aneurysm growth (≥0.5 cm/year)
• Symptomatic aneurysms
• Saccular aneurysms
• Ruptured descending thoracic aortic aneurysms

Pre-Procedure Planning

1. Imaging Assessment:

   • Fine-cut (≤0.25 mm) CTA of the entire aorta, iliac and femoral arteries 2
   • CTA of head and neck to evaluate vertebral artery anatomy
   • 3D centerline reconstruction for accurate planning 2
   • Evaluation of proximal and distal landing zones (minimum 2 cm of healthy aorta)

2. Access Evaluation:

   • Review of preoperative CTA of iliofemoral vessels is mandatory 1
   • Alternative access planning if iliac vessels are small or diseased (occurs in up to 21% of cases) 1
   • Consider percutaneous access for suitable anatomy (technical success 94-99%) 1

TEVAR Procedure Steps

1. Patient Preparation:

   • General anesthesia
   • Arterial line placement for blood pressure monitoring
   • Consider cerebrospinal fluid drainage in high-risk patients

2. Access:

   • Open surgical cutdown or percutaneous access of femoral arteries
   • Alternative access (iliac conduit, direct aortic, or iliac exposure) if femoral access inadequate 1

3. Device Delivery:

   • Advancement of delivery system over stiff guidewire under fluoroscopic guidance
   • Careful positioning relative to anatomical landmarks
   • Controlled hypotension during deployment (systolic BP 80-90 mmHg)

4. Stent Graft Deployment:

   • Precise positioning using angiographic guidance
   • 10-15% oversizing for aneurysms, minimal oversizing for dissections 3
   • Sequential deployment from proximal to distal for multiple devices

5. Left Subclavian Artery Management:

   • Revascularization recommended before TEVAR if coverage is planned 1, 3
   • Reduces risk of spinal cord ischemia and stroke

6. Completion Angiography:

   • Confirm proper device positioning
   • Assess for endoleaks
   • Verify patency of branch vessels

Post-Procedure Management

1. Immediate Care:

   • Blood pressure control
   • Neurological assessment
   • Spinal drainage management if placed

2. Surveillance Imaging:

   • CT at 1 month and 12 months post-TEVAR 1
   • If stable, annual imaging thereafter 1
   • MRI is a reasonable alternative for reducing radiation exposure 1

Complications of TEVAR

1. Endoleaks (up to 20% of cases) 1:

   • Type I: Inadequate seal at proximal or distal attachment sites
   • Type II: Retrograde flow from branch vessels
   • Type III: Graft defect or component separation
   • Type IV: Graft porosity
   • Type V: Endotension (sac enlargement without identifiable leak)

2. Neurological Complications:

   • Stroke (7-10%)
   • Spinal cord ischemia (3.9%) 4
   • Higher risk with extensive coverage, prior aortic repair, left subclavian coverage without revascularization

3. Access-Related Complications:

   • Vessel injury/rupture
   • Limb ischemia
   • Hematoma
   • Pseudoaneurysm

4. Device-Related Complications:

   • Stent graft migration (0.7-4%) 1
   • Stent fracture
   • Stent collapse
   • Retrograde type A aortic dissection

5. Aortic-Related Complications:

   • Aortic rupture
   • Aneurysm expansion
   • Unfavorable aortic remodeling in dissection cases 1

Long-Term Follow-Up

• Reintervention rates range from 7-23% 1
• Freedom from reintervention on treated segment is approximately 85% at 10 years 4
• Aneurysm diameter typically decreases from an average of 61 to 55 mm over 5 years 4

Common Pitfalls to Avoid

1. Inadequate sizing: Excessive oversizing can lead to retrograde dissection or bird-beaking
2. Insufficient landing zones: Less than 2 cm increases risk of type I endoleak
3. Neglecting left subclavian revascularization: Increases risk of stroke and spinal cord ischemia
4. Inadequate access planning: Can lead to iliac rupture or inability to deliver device
5. Insufficient surveillance: Missing late complications that require reintervention

TEVAR has revolutionized the treatment of thoracic aortic disease with lower perioperative morbidity and mortality compared to open repair, but requires meticulous planning, execution, and long-term surveillance to achieve optimal outcomes.