From the Guidelines
Intervention is recommended for increasing aortic diameter in aortic dilatation when the diameter is ≥5.5 cm.
Key Considerations
- The risk of aortic-related events, such as rupture or dissection, increases with aortic diameters >6 cm, justifying intervention at a diameter of ≥5.5 cm 1.
- High-risk features of rupture, including rapid aortic growth (≥0.5 cm/y), symptomatic aneurysms, underlying connective tissue disorder or heritable thoracic aortic disease (HTAD), saccular aneurysm morphology, female sex, and infected aneurysm, support repair at a smaller diameter threshold when these criteria are met 1, 2.
- In patients with Marfan syndrome, an aortic root diameter of ≥4.5 cm and features associated with an increased risk of aortic dissection (AoD) may prompt consideration of surgery 3.
- For patients with bicuspid aortic valve (BAV), a diameter of the aortic root or ascending aorta of 5.0 to 5.4 cm and an additional risk factor for AoD may justify surgical intervention 3, 4.
Additional Factors
- Growth rate: an increase of ≥0.5 cm/y may indicate the need for intervention, regardless of absolute diameter 2.
- Symptoms: symptoms consistent with an enlarging thoracoabdominal aortic aneurysm (TAAA) that are not attributable to alternative pathology may prompt consideration of surgery 2.
- Aortic diameter indexation and the use of aortic length and age/sex may also be considered for risk assessment 5.
From the Research
Intervention Recommendations for Aortic Dilatation
Intervention for increasing aortic diameter in aortic dilatation is recommended based on various factors, including:
- Aortic diameter: Intervention is indicated with an aortic diameter of 5.5 cm, although some surgeons may intervene earlier (at 5.0 cm) for patients at low surgical risk or with known connective tissue disorders such as Marfan's syndrome 6
- Nondiameter criteria: Other factors such as pain, aortic length/tortuosity, genetic aberrations, family history, and biomarkers can also be useful in decision-making regarding surgical intervention 7
- Aortic wall thickness: The ratio of aortic diameter to medial wall thickness may be a useful marker of risk for aortic dissection, particularly in patients with mild aortic dilatation 8
Specific Guidelines
- The American College of Cardiology and American Heart Association recommend surgical intervention for patients with bicuspid aortic valves and severe aortic enlargement, although the exact threshold for intervention is not specified 9
- The Society for Vascular Surgery recommends repairing abdominal aortic aneurysms when they reach 5.5 cm in diameter 10
- Studies have shown that maximal aortic diameter affects outcome after endovascular repair of abdominal aortic aneurysms, with larger aneurysms associated with higher mortality, complication, and reintervention rates 10
Key Factors Influencing Intervention
- Aortic diameter: The size of the aortic diameter is a key factor in determining the need for intervention
- Patient risk factors: Patients with known connective tissue disorders, family history of aortic dissection, or other high-risk factors may require earlier intervention
- Nondiameter criteria: Other factors such as pain, aortic length/tortuosity, and biomarkers can also influence the decision to intervene 7