Comparison of Hydrodynamic Performance of the Ozaki Procedure with the Native Aortic Valve and Prosthetic Valves

Objectives: Options for treatment of aortic stenosis (AS) have continuously grown in recent years. However, there are currently no ideal prosthetic valves for younger patients with AS. In this study, we investigated hydrodynamic performance and cusp motion characteristics in the Ozaki procedure in comparison with the native valve and prosthetic valves.

Methods: The native aortic valve of a fresh swine heart was replaced by different aortic valve substitutes, and their hydrodynamic performances (effective orifice area [EOA] and mean pressure gradient [mPG]) were evaluated in a mock circulation loop at different pump flow conditions. We compared the native aortic valve (n = 18), the Ozaki procedure (n = 10), Perimount Magna Ease [PME] (n = 10), trifecta [TRI] (n = 10), and St. Jude Medical Masters HP [SJM] (n = 5). During perfusion, we recorded valve motion with high-speed video camera to analyze the geometric orifice area (GOA) throughout the cardiac cycle.

Result: Hydrodynamic parameters showed a larger EOA in the Ozaki procedure compared with the prosthetic valves (Ozaki: 1.69 ± 0.29 cm², PME: 1.41 ± 0.17 cm² [p < 0.05], TRI: 1.41 ± 0.17 cm² [p < 0.05], SJM: 1.46 ± 0.12 cm² [p = 0.05]) and there was no significant difference between the Ozaki procedure and the native aortic valve in EOA (native aortic valve: 1.78 ± 0.37 cm² [p = 0.54]). All types of valves showed an increase of mPG with increasing forward flow. The native aortic valve and the Ozaki procedure showed a similar increase in mPG which was significantly flatter than prosthetic valves. Regarding EOA, the native valve and Ozaki valve showed a steeper increase of EOA with increasing forward flow than prosthetic valves. Cusp motion characteristics in the Ozaki procedure showed similarities with the native aortic valve while it differed in many aspects from prosthetic valves.

Conclusion: The Ozaki procedure showed excellent hydrodynamic performance compared with the prosthetic valves and showed similar valve motion characteristics to the native aortic valve. Our results suggest that the Ozaki valve behaves physiologically in many aspects. These aspects may contribute to good long-term durability and this procedure may become a more beneficial choice for the patients with AS than prosthetic valves, especially in younger patients.

Publication History

Article published online:
19 February 2021