Indications for ascending and arch aortic aneurysm repair

Aneurysm type/associated condition	Aneurysm diameter
Sporadic (not associated with disease below)
Ascending	≥5.5 cm
Isolated arch aneurysm	≥5.5 cm
Marfan syndrome (MFS), familial thoracic aortic aneurysm/dissection (FTAAD), others*
Without risk factors^¶^Δ	≥5.0 cm
With risk factors^¶^Δ	≥4.5 cm
Loeys-Dietz syndrome (LDS)
Without risk factors^¶^Δ	≥4.5 cm
With risk factors^¶^Δ	≥4.0 cm
Bicuspid aortic valve (BAV)
Without risk factors^¶^Δ	≥5.5 cm
With risk factors^¶^Δ	≥5.0 cm
Concomitant aortic valve procedure	≥4.5 cm

The aortic diameter values provided in the table are those suggested by expert consensus. Determining the optimal timing for elective TAA repair can be challenging and requires clinical judgment taking into account the patient's age, comorbidities, the rate of aortic expansion, other indications for surgery (eg, aortic valve pathology), and body habitus, among others. In addition, not every syndrome has been identified or characterized genetically, so there may be young individuals who do not obviously have degenerative TAA and will require an individualized approach. Refer to the discussion in the topics discussing TAA.

TAA: thoracic aortic aneurysm; EDS: Ehlers-Danlos syndrome; TGFBR2: transforming growth factor beta receptor 2.
* Others include Turner syndrome and other non-BAV congenital conditions. It is unclear when to intervene for EDS; some suggest surgery for acute events only.
¶ Risk factors for aortic complications include family history of dissection, progressive aortic regurgitation, rapid expansion (increase by 0.5 cm or more per year). For LDS, additional risk factors include female sex and TGFBR2 mutations.
Δ For those with rapid expansion (increase by 0.5 cm or more per year), a lower diameter may be warranted (eg, 5.0 cm for sporadic TAA).

References:

Hiratzka LF, Bakris GL, Beckman JA, et al. 2010 ACCF/AHA/AATS/ACR/ASA/SCA/SCAI/SIR/STS/SVM guidelines for the diagnosis and management of patients with Thoracic Aortic Disease: A report of the American College of Cardiology Foundation/American Heart Association Task Force on Practice Guidelines, American Association for Thoracic Surgery, American College of Radiology, American Stroke Association, Society of Cardiovascular Anesthesiologists, Society for Cardiovascular Angiography and Interventions, Society of Interventional Radiology, Society of Thoracic Surgeons, and Society for Vascular Medicine. Circulation 2010; 121:e266.
Hiratzka LF, Creager MA, Isselbacher EM, et al. Surgery for aortic dilatation in patients with bicuspid aortic valves: A statement of clarification from the American College of Cardiology/American Heart Association Task Force on Clinical Practice Guidelines. J Am Coll Cardiol 2016; 67:724.
Erbel R, Aboyans V, Boileau C, et al. 2014 ESC Guidelines on the diagnosis and treatment of aortic diseases: Document covering acute and chronic aortic diseases of the thoracic and abdominal aorta of the adult. The Task Force for the Diagnosis and Treatment of Aortic Diseases of the European Society of Cardiology (ESC). Eur Heart J 2014; 35:2873.

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