The Heart Valve Society

Back to 2017 Program


Valve Sparing Aortic Root Surgery: Preserved Cusp Durability In Reimplantation vs Remodelling Techniques: A Finite Element Analysis
Yaghoub Dabiri, PhD, Janet Ronsky, PhD, Imtiaz Ali, MD, Kishan Narine, MD PhD.
University of Calgary, Calgary, AB, Canada.

OBJECTIVE: Valve sparing aortic root surgery preserves the native valve, and avoids using artificial valves which have many limitations. Remodeling and reimplantation procedures refer to two different methods of the valve sparing aortic root surgery. The surrounding root and graft have different material properties in each method. The goal of this study was to investigate the effects of graft-aortic wall material properties mismatch on the outcomes of remodeling and reimplantation procedures.
METHODS: Finite Element Method was used to simulate remodeling and reimplantation methods. A three-dimensional model of the valve and surrounding wall was created in SolidWorks SolidWorks (SolidWorks Corp, Waltham, MA, USA). The geometries were exported to ABAQUS (Simulia Inc., Providence, USA) for numerical calculations. Linear elastic materials were used for leaflets, aortic wall and the Dacron graft. A diastolic pressure was applied on the leaflets. To simulate the reimplantation method, the mechanical properties of Dacron graft were used for the surrounding wall. For the remodeling method, the upstream surrounding wall was assigned the properties of the aortic root, and the downstream surrounding wall was assigned properties of the Dacron graft. RESULTS: The radial displacement at the leaflet tip was much higher in the remodeling method (0.232 vs. 0.095mm) whereas the vertical displacement at the leaflet tip was higher in the reimplantation method (0.354 vs. 0.294mm). Within surrounding wall, the von Mises (1.069 vs. 0.295), maximum tensile (0.584 vs. 0.292) and compressive (0.847 vs. 0.357) stresses were much higher in the remodeling compared to the reimplantation method. Within the leaflets, noticeable difference was not observed between remodeling and reimplantation methods in terms of von Mises (1.285 vs. 1.117), maximum tensile (0.903 vs. 0.901) and compressive (0.858 vs. 0.877) stresses. CONCLUSIONS: This study clarified the importance of mismatch in material properties between aortic root and Dacron graft in the outcomes of the remodeling and the reimplantation methods. Cusp height and durability are better preserved in reimplantation compared to the remodelling technique.


Back to 2017 Program