Enter the Aortic Root Diameter and Body Surface Area into the calculator to determine the Aortic Root Index. This calculator can also evaluate any of the variables given the others are known.

Aortic Root Index Formula

The following formula is used to calculate the Aortic Root Index (ARI).

ARI = Aortic Root Diameter (cm) / BSA (m^2)


  • ARI is the Aortic Root Index (cm/m^2)
  • Aortic Root Diameter is the diameter of the aortic root (cm)
  • Body Surface Area is the total surface area of the body (m^2)

To calculate the Aortic Root Index, divide the Aortic Root Diameter by the Body Surface Area. The result is the Aortic Root Index, which is a measure of the size of the aortic root relative to the body size. This index is used in medical practice to assess the risk of aortic dissection or rupture.

What is an Aortic Root Index?

The Aortic Root Index is a medical measurement used to assess the size of the aortic root in relation to the patient’s body surface area. This index is particularly useful in detecting conditions such as aortic root dilation, which can lead to serious complications like aortic dissection or rupture. The Aortic Root Index is calculated by dividing the diameter of the aortic root by the patient’s body surface area, and the result is expressed in cm/m².

How to Calculate Aortic Root Index?

The following steps outline how to calculate the Aortic Root Index.

  1. First, determine the Aortic Root Diameter (cm).
  2. Next, determine the Body Surface Area (m^2).
  3. Next, gather the formula from above = ARI = Aortic Root Diameter (cm) / Body Surface Area (m^2).
  4. Finally, calculate the Aortic Root Index.
  5. After inserting the variables and calculating the result, check your answer with the calculator above.

Example Problem : 

Use the following variables as an example problem to test your knowledge.

Aortic Root Diameter (cm) = 4.5

Body Surface Area (m^2) = 1.8