Effects of Normal Variation in the Rotational Position of the Aortic Root on Hemodynamics and Tissue Biomechanics of the Thoracic Aorta
- 41 Downloads
Variation in the rotational position of the aortic root relative to the left ventricle is present in normal trileaflet aortic valves. Its impact on the resulting fluid mechanics of blood flow in the thoracic aorta and structural mechanics in the aortic wall are unknown. We aimed to determine the regional hemodynamic and biomechanical differences in different rotational positions of the normal aortic root (clockwise, central, and counterclockwise positions).
Cardiac magnetic resonance imaging (CMR) data was acquired from a normal pediatric patient. These were used for reconstruction of the aortic valve and thoracic aorta 3D model. Fluid–structure interaction (FSI) simulations were employed to study the influence of the root rotation with a central position as compared to observed extreme variations. Patient-specific phase-encoding CMR data were used to assess the validity of computed blood flow. The 3D FSI model was coupled with Windkessel boundary conditions that were tuned for physiological pressures. A grid velocity function was adopted for the valve motion during the systolic period.
The largest wall shear stress level is detected in the clockwise positioned aortic root at the sinutubular junction. Two counter-rotating vortex cores are formed within the aortic root of both the central and extreme root configurations, however, in the clockwise root the vortex system becomes more symmetric. This also coincides with more entrainment of the valve jet and more turbulence production along the shear layer.
A clockwise rotational position of the aortic root imparts an increased wall shear stress at the sinutubular junction and proximal ascending aorta in comparison to other root rotation positions. This may pose increased risk for dilation of the sinutubular junction and ascending aorta in the patient with a clockwise positioned aortic root compared to other normal positional configurations.
KeywordsAorta Aortic valve Ascending aorta Fluid–structure interaction Magnetic resonance
Conflict of interest
The authors declare that they have no conflict of interest.
- 8.Deng, X., X. Liu, D. Li, F. Pu, S. Li, and Y. Fan. A numerical study on the flow of blood and the transport of LDL in the human aorta: the physiological significance of the helical flow in the aortic arch. Am. J. Physiol. Circ. Physiol. 297:163–170, 2009.Google Scholar
- 13.Kallenbach, K., M. Karck, D. Pak, R. Salcher, N. Khaladj, R. Leyh, et al. Decade of aortic valve sparing reimplantation: are we pushing the limits too far? Circulation 112:1253–1259, 2005.Google Scholar
- 19.MUMPS. MUltifrontal massively parallel solver (MUMPS 5.0.2) users’s guide, 2016.Google Scholar
- 24.Pasta, S., A. Rinaudo, L. Angelo, M. Pilato, C. Scadulla, T. G. Gleason, et al. Difference in hemodynamic and wall stress of ascending thoracic aortic aneurysm with bicuspid and tricuspid aortic valve. J. Biomech. 42:157–162, 2013.Google Scholar