Infrarenal aortic diameter in the healthy person.

In order to determine the relevance of abdominal aortic dilatation, knowledge of the normal aortic diameter and its relation to age, sex and body size (height, weight, body surface area) is essential. The diameter of the infrarenal aorta was measured in 146 healthy males and females 4-74 years old with ultrasonography and the influence of the aforesaid factors on aortic diameter was analysed by means of a multiple stepwise regression model. The infrarenal aorta was found to increase steadily in diameter throughout life. From about 25 years the diameter was larger in males than in females (p < 0.01) though this difference vanished if corrected for differences in body surface area. Significant correlations were found between aortic diameter and weight (r = 0.84, p < 0.001), height (r = 0.77, p < 0.001) and body surface area (r = 0.83, p < 0.001). Age followed by body surface area were the factors most influencing aortic diameter in both males (r = 0.92, p < 0.001) and females (r = 0.94, p < 0.001). Nomograms predicting aortic diameters in relation to age, sex, and body surface area are presented.