| Background and aims: Aortic valve disease is frequently associated with an aortic annulus which is smaller that normal size. This problem might drive cardiac surgeons to enlarge the annulus or to implant a small prosthesis. The former strategy might complicate an operation while the latter, might lead to unsatisfactory pressure gradients across the prosthesis, with consequence of hemodynamic problems. To solve this problem, initially, manufacturers designed the intra-supra annular aortic valve. To further improve the hemodynamic performance, manufacturers constructed complete supra annular aortic valves. Based on a literature review, this thesis focuses on the hemodynamic comparison of these two kinds of valve.Methods: We analysis retrospectively the publications of this field in English literature, compare the differences between them, and regroup their data when necessary to find out the reason resulting in different conclusions.Results: The comparison of hydrodynamic performances of prostheses from different manufacturers is somehow misleading because the differences in reporting nominal valve size are not uniform and standardized across manufacturers. The hemodynamic comparison between complete supra annular mechanical valve and intra-supra annular mechanical valve should be based on patient's tissue annular diameter. Neither valve demonstrates a clear advantage in hemodynamic performance when the grouping of data is based on the patient's tissue annular diameter.Conclusions: The hemodynamic comparison between complete supra annular mechanical valve and intra-supra annular mechanical valve should be based on patient's tissue annular diameter. The chose of prosthesis should be principled by the patient's tissue annular diameter, while conforming to the anatomy of the aortic root. Future progresses may result from the evolving of the Pulse Duplicator System and the visualization of the artificial flow characteristics.
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