How should I manage a patient with an aortic arch aneurysm measuring 4.5 × 4.4 cm and a descending thoracic aortic aneurysm measuring 5.3 × 5.8 cm?

Management of Aortic Arch and Descending Thoracic Aortic Aneurysms

Your patient requires urgent surgical evaluation and should be referred immediately to a multidisciplinary aortic surgery center, as the descending thoracic aortic aneurysm at 5.3 × 5.8 cm has already exceeded the 5.5 cm threshold for intervention, and the aortic arch at 4.5 × 4.4 cm is approaching the size where surgical planning becomes critical. 1

Immediate Management Priority: The Descending Thoracic Aorta

The descending thoracic aortic aneurysm measuring 5.3 × 5.8 cm mandates intervention now.

• For degenerative or traumatic aneurysms of the descending thoracic aorta exceeding 5.5 cm, endovascular stent grafting should be strongly considered when anatomically feasible. 1
• The 5.8 cm measurement clearly exceeds the Class I recommendation threshold of 5.5 cm for intervention. 1
• Endovascular repair is preferred over open surgery for descending thoracic aneurysms when anatomy permits, given lower morbidity, absence of thoracotomy, no need for aortic cross-clamping, and shorter hospital stays. 1
• The yearly risk of rupture, dissection, or death for aneurysms at 6.0 cm approaches 14.1%, with rupture risk at 3.6% and dissection risk at 3.7% annually. 2
• Even at 5.5 cm, the estimated 1-year rate of aortic events (dissection/rupture) is approximately 7.2%, rising to 9.3% at 6.0 cm. 3

The Aortic Arch Component: Surgical Planning Considerations

The aortic arch aneurysm at 4.5 × 4.4 cm requires close surveillance with imaging every 6 months, but does not yet meet the standard size threshold for isolated arch intervention.

• For isolated aortic arch aneurysms ≥4.0 cm, reimaging with CT or MRI at 6-month intervals is recommended to detect growth. 4
• The standard surgical threshold for degenerative aortic arch aneurysms in low-risk patients is 5.5 cm. 1, 4
• However, the presence of symptoms (hoarseness from recurrent laryngeal nerve stretch, dysphagia, dyspnea, chest or back pain) would mandate immediate intervention regardless of size. 4, 5
• Growth rate ≥0.5 cm/year constitutes an indication for surgery even below the 5.5 cm threshold. 4, 5

Hybrid Surgical Approach: The Elephant Trunk Strategy

Given the combined pathology involving both the arch and descending aorta, the elephant trunk procedure should be strongly considered as it addresses both segments in a staged fashion.

• The elephant trunk procedure involves replacing the ascending aorta and arch with a Dacron graft, leaving a free end ("elephant trunk") within the descending aneurysm, which then serves as a landing zone for subsequent endovascular stent graft placement. 1
• This hybrid approach may reduce the morbidity and mortality compared to traditional two-stage open repairs, with technical success achieved in all patients in one series and 1-month mortality of 6.4%. 6
• The interval between first-stage arch repair and second-stage endovascular completion typically ranges from 0 to 14 months, with a mean of 3.1 months. 6
• Aortic arch surgery requires cardiopulmonary bypass, hypothermic circulatory arrest, and carries higher operative mortality and stroke risk than isolated ascending or descending aortic procedures. 1, 4

Critical Risk Assessment

Both spinal cord ischemia and stroke are major concerns with this combined pathology.

• There is no conclusive evidence that endovascular approaches reduce the prevalence of spinal cord ischemic injury (paraplegia or paresis) compared to open surgical repair of the descending aorta. 1
• Brain protection during arch surgery is achieved through profound hypothermia alone, direct antegrade perfusion of brachiocephalic arteries, or retrograde perfusion via the superior vena cava. 1
• Paraparesis occurred in 2 of 31 patients (6.5%) in one hybrid series, with no paraplegias or strokes reported. 6

Medical Management While Awaiting Surgery

Aggressive blood pressure control and heart rate reduction are essential to slow aneurysm growth and reduce wall stress.

• Target heart rate <60 bpm with beta-blockers as first-line therapy. 7
• Optimize all cardiovascular risk factors to minimize perioperative risk. 7
• Avoid fluoroquinolone antibiotics unless absolutely necessary, as they may increase dissection risk. 7

Surveillance Protocol Until Intervention

Repeat imaging in 3 months or sooner if any symptoms develop.

• Given the descending aorta already exceeds the intervention threshold, surgical planning should proceed immediately rather than waiting for the next surveillance interval. 1
• Any new symptoms (chest pain, back pain, dyspnea, hoarseness, dysphagia) require emergency evaluation for acute dissection or rupture. 4, 5
• The average growth rate for thoracic aneurysms is 0.10 cm/year for ascending and 0.19 cm/year for descending segments, but individual variation is substantial. 2

Referral and Multidisciplinary Planning

Immediate referral to a high-volume aortic surgery center with expertise in both open arch surgery and endovascular techniques is mandatory.

• All physicians should work collaboratively among specialties during initial decision-making to determine via consensus whether endovascular stent graft or open surgical graft replacement is most appropriate for the descending aneurysm. 1
• The surgical team must have experience with elephant trunk procedures and hybrid approaches given the combined arch and descending pathology. 1, 6
• Patients who are not considered candidates for open surgery but undergo endovascular grafting have substantially poorer long-term outcomes than those who are reasonable candidates for open operation. 1

Common Pitfalls to Avoid

• Do not delay referral while waiting for the arch to reach 5.5 cm—the descending aorta already requires intervention, and combined surgical planning is essential. 1
• Do not treat these as separate lesions—the anatomic continuity requires coordinated surgical strategy, likely involving the elephant trunk approach. 1, 6
• Do not underestimate operative risk—arch surgery carries higher mortality and stroke risk than other aortic segments, requiring specialized expertise. 1, 4
• Do not ignore symptoms—any new chest pain, back pain, dyspnea, hoarseness, or dysphagia mandates emergency evaluation regardless of aneurysm size. 4, 5