Two-dimensional speckle tracking of the abdominal aorta: a novel approach to evaluate arterial stiffness in patients with Turner syndrome.

Background: Turner syndrome (TS) is an X-chromosomal disease affecting one in 2,500-3,000 female newborns. Girls and women with TS show multiple cardiovascular risk factors that all have an impact on arteriosclerosis and thus arterial stiffness. An accurate and non-invasive screening of arterial stiffness is essential to improve the overall outcome in these patients.

Methods: Thirty-five TS patients and 19 healthy, age-matched controls were prospectively recruited for this study. Arterial stiffness was measured at the abdominal aorta in subxiphoid view using two-dimensional speckle tracking (2DST). Acquisition was performed at a frame rate of 60-90 fps. Mean peak circumferential strain (AAO-S, %) was measured offline for respective layers (inner layer = AAO-SENDO, %; middle layer = AAO-SMESO, %; outer layer = AAO-SEPI, %).

Results: Compared with the control group, patients with TS showed significantly lower peak circumferential strain values in each layer [AAO-SENDO (mean ± SD): 10.98%±4.73% 15.32%±4.78%, P=0.002; AAO-SMESO (mean ± SD): 6.36%±2.22% 9.18%±2.83%, P<0.001; AAO-SEPI (mean ± SD): 4.49%±1.76% 6.31%±2.53%, P=0.003]. Abdominal aortic strain values correlated significantly with left ventricular diastolic function assessed by mitral early (E) and late (A) flow ratio (AAO-SENDO and E/A: r=0.475, P<0.001; AAO-SMESO and E/A: r=0.504, P<0.001; AAO-SEPI and E/A: r=0.393, P=0.003). Heart rate correlated significantly negative with 2DST assessed arterial distensibility (r=-0.366; P=0.007). Relative intra- and interobserver variability ranged between 8.67% and 21.03% for 2DST of the abdominal aorta.

Conclusions: 2DST of the abdominal aorta might provide additional diagnostic value to detect possible functional vascular impairments in patients with TS. Left ventricular diastolic function is coupled with increased arterial stiffness in TS patients. The relatively high intra- and interobserver variability of 2DST of the abdominal aorta requires further improvement of the speckle tracking algorithm.