Abstract P259: Imaging-based Biomarker: Characterisation of the Ascending Aorta in Children with History of Kawasaki Disease and in a Healthy Control Sample
Background: Few studies have documented alterations in the biophysical properties of the aorta in patients with Kawasaki disease (KD). Our group very recently introduced a novel and innovative method allowing estimation of mechanical properties of the aortic wall using B-mode ultrasound data (ImBioMark), a method derived from the optical flow equations. Our aim was to obtain Z scores for both systolic and diastolic strain in patients with history of KD and in a sample of healthy control subjects.
Methods: We obtained B-mode cine-loop ultrasound data from 20 healthy control (ages 0-13 years) and 11 subjects with history of KD (ages 0-18 years) and estimated elastograms of the wall of the ascending aorta in parasternal views using ImBioMark. Systolic and diastolic strain estimates were calculated and averaged over three to five cardiac cycles. Several regression models of strain were tested with body-surface area (BSA) and height. Z scores were then calculated and tested for normal distribution using the Anderson-Darling test. Comparisons between Z score distributions of normal and subjects with history of KD were made.
Results: Z scores obtained with all models yielded normal distributions. Ergo, linear regressions with respect to height could predict expected ascending aorta strain in normal subjects (mean=-0.001, variance=1.053 for systolic strain; mean=-0.0005, variance=1.0526 for diastolic strain) and yielded curves with slopes approaching zero. Similar results were obtained for regressions with respect to BSA, except that these models tended to be less stable. Globally, calculated Z scores in patients with history of KD did not differ significantly from those in normal subjects, except for those with coronary aneurysms who presented elevated Z scores.
Conclusion: Our preliminary results indicate that height-normalized strain estimation using ImBiomark is stable throughout childhood. Anomalies were detected in subjects with severe vasculitis. This non-invasive operator-independent method could be applied to various childhood vascular illnesses.
- © 2013 by American Heart Association, Inc.