What is the approach in the treatment of thoracic aortic arch aneurysm?

Treatment Approach for Thoracic Aortic Arch Aneurysm

Aortic arch aneurysms require referral to high-volume multidisciplinary aortic centers for surgical intervention when diameter reaches ≥5.5 cm in asymptomatic low-risk patients, or immediately if symptomatic, with open surgical replacement remaining the gold standard for low-to-intermediate risk patients. 1

Initial Risk Stratification and Referral

All patients with aortic arch aneurysms meeting intervention criteria must be referred to specialized aortic centers with multidisciplinary teams, as outcomes are significantly improved at high-volume centers with experienced surgeons. 1

Intervention Thresholds

• Symptomatic patients (chest pain, dysphagia, hoarseness from recurrent laryngeal nerve compression, dyspnea from tracheal compression, or superior vena cava syndrome) require immediate surgical evaluation regardless of size. 1

• Asymptomatic patients with isolated arch aneurysm ≥5.5 cm and low operative risk should undergo open surgical replacement. 1

• Lower thresholds apply when arch disease extends from adjacent pathology or in genetic syndromes (Marfan syndrome >5.0 cm, Loeys-Dietz syndrome >4.0-4.2 cm). 1

• Rapid growth >1 cm/year or saccular morphology warrant earlier intervention regardless of absolute diameter. 2

Surgical Approach Selection

Open Surgical Repair (Gold Standard)

Open surgical replacement via median sternotomy with cardiopulmonary bypass is the definitive treatment for low-to-intermediate risk patients. 1, 3

Technical Considerations:

• Hypothermic circulatory arrest with retrograde/anterograde cerebral perfusion is essential for brain protection during arch reconstruction. 1

• Cerebrospinal fluid drainage reduces risk of spinal cord ischemia. 1

• Hemiarch replacement is reasonable when aneurysmal disease from the ascending aorta extends into the proximal arch. 1

• Elephant trunk procedure may be considered when disease extends into the proximal descending thoracic aorta, though newer hybrid techniques have reduced the historical >15% mortality risk. 1

Expected Outcomes:

• Stroke risk: 8% 4
• Paraplegia risk: 5.5% 4
• In-hospital mortality: 8% in contemporary series 4

Hybrid Arch Repair (High-Risk Patients)

For high-risk surgical candidates who cannot tolerate conventional open repair due to advanced age, significant comorbidities, or prohibitive operative risk, hybrid arch repair combining supra-aortic debranching with thoracic endovascular aortic repair (TEVAR) may be reasonable. 1, 5

Two-Stage Hybrid Approach:

Stage 1 (Open Debranching):

• Median sternotomy with arch vessel debranching to create a zone 0 landing zone for the endograft. 1
• Ascending aorta replacement if involved. 6
• Endovascular stent placement into distal arch and descending thoracic aorta. 1

Stage 2 (Endovascular Completion):

• The stent graft in the descending aorta serves as the landing zone for second-stage endovascular repair. 1, 7
• This second stage is medically necessary to complete treatment and prevent rupture, dissection, or ischemic events. 7

Hybrid Repair Outcomes:

• 100% stent graft deployment rate after debranching 4
• No type 1 or 3 endoleaks at follow-up 4
• Comparable outcomes to open surgery in appropriately selected high-risk patients 5
• Reduced perioperative morbidity compared to total arch replacement requiring deep hypothermic circulatory arrest 5

Novel Endovascular Techniques

Personalized aortic arch stent grafts can allow complete endovascular approach without sternotomy in select cases, though this technology continues to evolve. 1

Critical Contraindications

Thoracic endovascular aortic repair (TEVAR) is generally avoided and contraindicated for elective intervention in patients with genetically mediated aortic disorders (Marfan syndrome, Loeys-Dietz syndrome, Ehlers-Danlos syndrome) due to fragile tissue and high failure rates. 1, 2

Common Pitfalls to Avoid

• Do not delay referral to specialized centers once intervention thresholds are met, as arch aneurysms carry the highest surgical complexity and mortality risk among thoracic aortic repairs. 1

• Do not use TEVAR alone for arch aneurysms without adequate proximal and distal landing zones, as coverage of brachiocephalic vessels without debranching causes stroke. 8

• Do not apply standard intervention thresholds to genetic syndromes—these patients require lower diameter thresholds and body surface area indexing. 1

• Recognize that arch aneurysms rarely occur in isolation—most result from adjacent pathology (prior dissection in 71.7% of cases), requiring comprehensive aortic imaging. 1