Author + information
- Tomoaki Murakami, MD, PhD∗ (, )
- Yumi Shiina, MD, PhD and
- Koichiro Niwa, MD, PhD
- ↵∗Department of Cardiology, Chiba Children’s Hospital, 579-1 Heta-cho, Midori-ku, Chiba 266-0007, Japan
We read with great interest the paper by Guzzardi et al. (1), which reported that the regions of increased wall shear stress showed greater medial elastin degradation compared with adjacent areas with normal wall shear stress in the ascending aorta of bicuspid aortic valve patients.
It is reported that the heterogeneity or discontinuity of the physical property of the aortic wall could cause the aortic dilation in the model of aortic aneurysm (2). Moreover, the discontinuity would also cause the “aortopathy” in patients with congenital heart diseases (3). Any discontinuity in elastic properties along the arterial tree in which there is a change (or mismatch) in impedance generates pressure wave reflection, and the enhanced pressure wave reflection damages the vessels and ventricle. Whatever the cause of the heterogeneity of the aortic wall property is, the generated structural heterogeneity would be the final common pathway of the aortic aneurysmal change. Needless to say, genetic abnormalities for extracellular matrix dysregulation bring about aneurysmal change of the aorta. The hemodynamics and surgical intervention, which induce the heterogeneity or discontinuity of the physical property of the aortic wall, should also contribute to form the dilation of the aorta.
Although the article by Guzzardi et al. (1) is important to understand the mechanism of aortic dilation, the areas with elevated regional wall shear stress did not always coincide with the areas with the increased elastin degeneration in their data. It is well known that the more the number of cycle stress and the higher the stress of the aorta, the more the “elastin fracture” occurs (4). The wall shear stress, which Guzzardi et al. (1) measured, could reflect the longitudinal stress of the aorta. However, the hemodynamic stress vertical to the vessel wall is also important. We would like to know it in their study.
Please note: The authors have reported that they have no relationships relevant to the contents of this paper to disclose.
- 2016 American College of Cardiology Foundation
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