Bioprosthetic Valve Size Selection to Optimize Aortic Valve Replacement Surgical Outcome: A Fluid-Structure Interaction Modeling Study

Aortic valve replacement (AVR) remains a major treatment option for patients with severe aortic valve disease. Clinical outcome of AVR is strongly dependent on implanted prosthetic valve size. Fluid-structure interaction (FSI) aortic root models were constructed to investigate the effect of valve size on hemodynamics of the implanted bioprosthetic valve and optimize the outcome of AVR surgery. FSI models with 4 sizes of bioprosthetic valves (19 (No. 19), 21 (No. 21), 23 (No. 23) and 25 mm (No. 25)) were constructed. Left ventricle outflow track flow data from one patient was collected and used as model flow conditions. Anisotropic Mooney-Rivlin models were used to describe mechanical properties of aortic valve leaflets. Blood flow pressure, velocity, systolic valve orifice pressure gradient (SVOPG), systolic cross-valve pressure difference (SCVPD), geometric orifice area, and flow shear stresses from the four valve models were compared. Our results indicated that larger valves led to lower transvalvular pressure gradient, which is linked to better post AVR outcome. Peak SVOPG, mean SCVPD and maximumvelocity forValveNo. 25 were 48.17%, 49.3%, and 44.60% lower than that fromValveNo. 19, respectively. Geometric orifice area from Valve No. 25 was 52.03% higher than that from Valve No. 19 (1.87 cm(2) vs. 1.23 cm(2)). Implantation of larger valves can significantly reduce mean flow shear stress on valve leaflets. Our initial results suggested that larger valve size may lead to improved hemodynamic performance and valve cardiac function post AVR. More patient studies are needed to validate our findings.