From the Guidelines
The normal aortic root diameter typically ranges from 3.5 to 4.0 cm in adults, with variations based on age, sex, and body size, as reported in the most recent study 1. An aortic root is considered abnormal or dilated when its diameter exceeds 4.0 cm. Mild dilation is between 4.0-4.5 cm, moderate dilation between 4.5-5.0 cm, and severe dilation when greater than 5.0 cm. These measurements are important because an enlarged aortic root increases the risk of serious complications including aortic dissection or rupture. The diameter should be indexed to body surface area for more accurate assessment, with a value greater than 2.1 cm/m² generally considered abnormal, as suggested by 1. Regular monitoring with echocardiography or CT imaging is recommended for patients with aortic root dilation, with frequency determined by the degree of enlargement. Underlying causes of abnormal dilation include genetic disorders like Marfan syndrome, bicuspid aortic valve, hypertension, and atherosclerosis. Surgical intervention is typically considered when the diameter reaches 5.0-5.5 cm, though this threshold may be lower for patients with genetic disorders or family history of aortic complications, as indicated in the latest guidelines 1.
Some key points to consider:
- The aortic root diameter varies with age, sex, and body size, and should be indexed to body surface area for accurate assessment.
- Aortic dilatation of <50% over normal qualifies as aortic ectasia, whereas thoracic aortic aneurysms (TAAs) are diagnosed when there is at least 50% enlargement of the aortic lumen, as stated in 1.
- Larger aneurysms that reach >5 cm in diameter, and TAAs that increase in size >0.5 cm per year, trigger an evaluation for possible intervention due to their association with increased morbidity and mortality, as reported in 1.
- The true incidence of TAA in the general population is unknown, but review of the published literature reveals the incidence to be approximately 10.7 to 16.3 cases per 100,000 in men and between 7.1 to 9.1 cases per 100,000 in women per year, as indicated in 1.
It is essential to follow the latest guidelines and consider individual patient factors when determining the threshold for surgical intervention, as emphasized in 1.
From the Research
Normal Aortic Root Diameter
- The normal aortic root diameter varies based on age, body size, and gender 2.
- Studies have shown that aortic root diameter is larger in men and increases with body size and age 2.
- The normal range of aortic root diameter is between 2.1 to 4.3 cm 2.
- Aortic root dimensions are affected by age and gender, with females showing larger aortic root dimensions than males after body surface area correction 3.
Abnormal Aortic Root Diameter
- An aortic root diameter of 5.0 cm or greater is considered abnormal and may indicate a higher risk of adverse events such as dissection, rupture, and death 4.
- A diameter of 5.25 cm or greater in the mid-ascending aorta is also considered abnormal 4.
- Abnormal aortic root dilation is more significant in predicting adverse events than mid-ascending aortic dilatation 4.
- Short stature is a serious risk factor for adverse events related to aortic root dilation 4.