Home
Back
Aortic Size Index Formula:
| From: | To: |
The Aortic Size Index (ASI) is a measurement that normalizes aortic diameter to body surface area. Developed at Yale, it provides a more accurate assessment of aortic size relative to patient body size, helping to identify pathological aortic dilation.
The calculator uses the ASI formula:
Where:
Explanation: The index accounts for variations in patient size, providing a normalized measure of aortic dimensions.
Details: ASI is particularly important in assessing aortic aneurysm risk, monitoring aortic growth over time, and determining the need for surgical intervention. It's especially valuable in Marfan syndrome and other connective tissue disorders.
Tips: Enter aortic diameter in centimeters and BSA in square meters. Both values must be positive numbers. BSA can be calculated using various formulas (Mosteller, DuBois, etc.) before using this calculator.
Q1: What is a normal ASI value?
A: Normal ASI values typically range from 1.5-2.1 cm/m², but this can vary by aortic segment and patient population.
Q2: Why use ASI instead of absolute aortic diameter?
A: ASI accounts for body size differences, making it more accurate for comparing aortic dimensions across patients of different sizes.
Q3: How is BSA calculated?
A: BSA is typically calculated using formulas like Mosteller (√[height(cm)×weight(kg)/3600]) or DuBois (0.007184×height(cm)^0.725×weight(kg)^0.425).
Q4: Which aortic segments should be measured?
A: ASI can be calculated for any aortic segment (root, ascending, arch, descending), but aortic root ASI is most commonly used in clinical practice.
Q5: What ASI values indicate need for intervention?
A: Intervention thresholds vary, but ASI > 2.5-3.0 cm/m² often warrants consideration for surgical repair, depending on the clinical context.