Restoring the Aortic Sinus Shape May Rebuild Healthy Blood Flow After Aneurysm Repair

A study published in Annals of Biomedical Engineering used patient-specific computational modeling to evaluate a novel Hegar dilator-based procedure for restoring a normal sino-tubular junction profile, and found that the reconstructed geometry may bring back swirling blood flow patterns that are normally absent in aneurysmal anatomy.

The team, led by Hannah Zhai, Yurui Chen, Yuichiro Kitada, Hiroo Takayama and Vijay Vedula, retrospectively selected a single patient with an ascending thoracic aortic aneurysm who had undergone both preoperative and postoperative gated computed tomography angiography. From those images they developed a new workflow to segment not only the blood-carrying lumen but also the thick-walled aorta and the aortic valve leaflets, creating a three-dimensional model suitable for blood flow simulation.

Using that model, the researchers ran two complementary types of simulation. Computational fluid dynamics assumed a rigid vessel wall, while fluid-structure interaction modeling allowed the aortic wall and valve leaflets to move in response to the flowing blood. They quantified the morphology and hemodynamics of the aortic root and compared the patient’s pre- and postoperative anatomy against those of a control subject with a healthy aorta.

The central finding concerned sinus vortices, the recirculating flow structures that form within the aortic sinuses during peak systole. In the control subject, these vortices were present. Before surgery, in the aneurysmal aorta, they were absent.

Comparing the two simulation approaches also revealed important differences. When the aortic valve leaflets were included in the fluid-structure interaction studies, the spatial patterning of the high-velocity jet and of wall shear stress along the vessel wall was similar to what the rigid-wall computational fluid dynamics predicted. However, the coupled simulations produced substantially elevated velocities, higher time-averaged wall shear stress, and greater energy dissipation. The researchers attribute this to the dynamically changing valve orifice area and to differing profiles of the left ventricular outflow tract, the channel through which blood exits the heart.

Because no single simulation setup can capture every biological detail, the team carried out extensive sensitivity analyses. They systematically varied the mechanical properties of the surgical graft, the material parameters and heterogeneity of the valve leaflets, the compliance of the aortic wall, the presence of external tissue support, and the boundary conditions applied to the annular region of the solid domain. These analyses map out which modeling assumptions matter most for the predicted flow fields.

The study’s conclusion is deliberately measured. The authors write that restoring a normal sinus shape and sino-tubular junction profile during ascending aortic repair may have potential hemodynamic benefits, a statement grounded in simulation rather than in measured clinical outcomes. The work is a retrospective, single-patient computational investigation, so its findings describe what the models predict for this reconstructed anatomy, not demonstrated improvements in surgical results or patient health.

Equally important, the study highlights the model’s sensitivities, particularly the shape of the left ventricular outflow tract and the morphology and mobility of the valve leaflets. The authors suggest that the workflow may assist in planning sino-tubular junction reconstruction before intervention, helping surgeons choose a target geometry that yields optimal hemodynamics.

Subject of Research: Computational fluid dynamics modeling of hemodynamics after sino-tubular junction reconstruction in ascending aortic aneurysm repair

Article Title: Hemodynamic Analysis of a Repaired Ascending Aorta with Preserved Aortic Root

Article References: Zhai, H., Chen, Y., Kitada, Y., Takayama, H., & Vedula, V. (2026). Hemodynamic Analysis of a Repaired Ascending Aorta with Preserved Aortic Root. Annals of Biomedical Engineering. https://doi.org/10.1007/s10439-026-04375-4

Image Credits: AI Generated

DOI: 10.1007/s10439-026-04375-4

Keywords: aortic aneurysm, sino-tubular junction, computational fluid dynamics, fluid-structure interaction, wall shear stress, aortic valve, CTA imaging, hemodynamics, aortic root, surgical planning, Hemodynamic, Analysis