Characterization of Aortic Flow Patterns by High-Frame-Rate Blood Speckle Tracking Echocardiography in Children

Background Blood speckle tracking echocardiography allows for direct quantification of interventricular and aortic flow profiles, principally in children. Here, we sought to demonstrate the feasibility and reproducibility of blood speckle tracking echocardiography in the aortas of healthy children. Methods and Results One hundred healthy White children evaluated for the screening of congenital heart disease were prospectively enrolled. Echocardiographic examinations were performed using a Vivid E 95 ultrasound system, with blood speckle tracking from a focused and zoomed view of the aortic root and the ascending aorta. Vortex position, height (mm), width (mm), sphericity index, and area (cm²) were measured and indexed by body surface area. Median (interquartile range) age was 8.2 (5.6-11.0) years, median (interquartile range) weight was 28 (19-35) kg, and median (interquartile range) body surface area was 1.01 (0.79-1.16) m². Vortices were visualized in only a single phase of the cardiac cycle in 25 subjects-14 (56.0%) were evident in early diastole and 11 (44.0%) in late systole. Vortices visualized in diastole had a mean area of 0.27±0.1 cm²/m², while those in systole had a mean area of 0.34±0.12 cm²/m². In a subset of 20 patients, inter- and intraobserver coefficient of variation and intraclass correlation coefficients were determined and showed good reproducibility. Conclusions We demonstrate feasibility and reproducibility of blood speckle tracking and identified vortical flow patterns in the aortic root and ascending aorta in healthy children. These data may serve as a baseline for evaluating aortic flow patterns in children with congenital and acquired heart disease.