Segmental analysis of the ascending aorta: definition of normality and classification of aortic dilatation.

To better define and classify ascending aortic abnormalities, we adapted the left ventricular dynamic segmental analysis concept to the ascending aorta. Ascending aortic diameters were measured from contrast aortography in 18 normal subjects at the aortic valve (level 1), and 2, 4, and 6 cm above the aortic valve (levels 2, 3, and 4). Diameters greater than two standard deviations (SD) above the mean normal values at any levels were considered abnormal. Aortograms of 102 consecutive patients with abnormal aorta were analyzed. Three patterns of aortic dilatation were identified: I (n = 55), the largest aortic diameter was at level 2 (normal pattern); II (n = 39), the aortic diameters increased from levels 1 to 4; III (n = 8), all aortic diameters were greater than 2 SD above the mean normal values and increased from levels 1 to 4. Segmental analysis of the aorta provides an objective comparative basis for definition and classification of aortic dilatation and aneurysm.