From the Guidelines
The normal diameter range of the ascending aorta in adults is approximately 31.9 to 34.1 mm, with variations based on age, sex, and body surface area. When evaluating the ascending aorta, it is essential to consider factors such as gender, age, and body surface area, as these can influence aortic diameter 1. For men, the average diameter is around 34.1 ± 3.9 mm, while for women, it is approximately 31.9 ± 3.5 mm 1. Some key points to consider when assessing the ascending aorta include:
- Aortic diameters greater than 2 SD above the mean diameter, but not meeting criteria for aneurysm, may be considered ectatic or dilated 1
- The term aneurysm is reserved for diameters that are 150% of normal, which is approximately 5.0 cm for the ascending aorta 1
- Aortic diameters of 5.5 cm or larger place patients at high risk for rupture and should be considered for intervention 1
- In patients with connective tissue diseases, a diameter of 5 cm prompts consideration of prophylactic aortic root replacement 1
From the Research
Ascending Aorta Diameter Range
The range of ascending aorta diameters can vary based on several factors including age, sex, and body surface area.
- According to a study published in 2021 2, the prevalence of ascending aortic dilations was 10.6% in males and 2.1% in females when using an absolute cut-off point of ≥40 mm.
- The same study found that when using an individual cut-off point of ≥25% than expected normal, the prevalence of dilations was 3.3% in males and 2.6% in females.
- A study published in 2016 3 compared measurements of ascending aortic diameter using different techniques and found that the systolic inner edge-to-inner edge technique yielded larger diameters than the diastolic leading edge-to-leading edge technique.
- Another study published in 2022 4 established normal ranges of aortic dimensions across sexes, races, and a wide range of ages, and found that all aortic root dimensions were larger in men compared to women.
Factors Affecting Ascending Aorta Diameter
Several factors can affect the diameter of the ascending aorta, including:
- Age: Aortic dimensions were found to be larger in older age groups in both sexes 4.
- Sex: All aortic root dimensions were larger in men compared to women 4.
- Body surface area: Aortic dimensions were found to be larger in individuals with larger body surface areas 2, 4.
- Race: Differences in aortic dimensions were observed according to race, with Asians having the smallest non-indexed aortic dimensions at all levels 4.
Clinical Implications
The diameter of the ascending aorta has important clinical implications, particularly in the diagnosis and management of aortic aneurysms and dissections.
- A study published in 2016 5 found that preoperative statin use was associated with lower odds of clinically significant ascending aortic dilatation in patients with bicuspid aortic valve disease.
- Another study published in 2013 6 found that reductions in systolic blood pressure were associated with meaningful reductions in aortic wall stress in patients with hypertension and ascending thoracic aortic aneurysms.