Strain analysis of wall motion in abdominal aortic aneurysms

In this exploratory study, we used ultrasound speckle-tracking methods, originally used for analyzing cardiac wall motion, to evaluate aortic wall motion.

We compared 19 abdominal aortic aneurysm (AAA) patients with 10 healthy volunteers (diameter, 48 mm vs. 15 mm). Motion pictures of the axial view of the aneurysm using ultrasonography were analyzed. Circumferential strain and strain rate at 6 equally divided segments of the aorta were semiautomatically calculated. We termed 'peak' strain and strain rate as the maximum of strain and strain rate in a cardiac cycle for each segment. We also evaluated the coefficient of variation of peak strain rate for the six segments.

In the aneurysm and control groups, the mean values of peak strain along the 6 segments were 1.5% ± 0.6% vs. 4.7% ± 1.6% (p <0.0001), respectively. The coefficient of variation of the peak strain rate was higher in the AAA group (0.74 ± 0.20) than in the control group (0.56 ± 0.12; p <0.05).

Aortic wall compliance decreased in the more atherosclerotic AAA group. The higher relative dispersion of strain rates in the AAA group is indicative of the inhomogeneous movement of the aortic wall.