Hemodynamic evaluation of the mechanical valve and bioprosthesis in the mitral position

Abstract

After mitral valve replacement the hemodynamic characteristics of the five commercially available prosthetic mitral valves, 12 cases of Starr-Edwards 6520 valve, 13 cases of Björk-Shiley valve, 12 cases of Hancock porcine xenograft, 7 cases of Carpentier-Edwards valve, 3 cases of Ionescu-Shiley valve were studied and compared by Impedance Cardiography in acute stage and cardiac catheterization in chronic stage. In acute stage, bioprosthesis such as Hancock valve, Carpentier-Edwards valve, Ionescu-Shiley valve is hemodynamically superior to mechanical valve. But one month after operation, there is no significant difference in valve function between mechanical valve and bioprosthesis. Three cases of mitral valve replacement using Ionescu-Shiley pericardial xenograft valve showed the best hemodynamic results at rest but on exercise mean diastolic gradient across the prosthesis increased from 4.5mmHg to 25.5mmHg. All of these three cases were assorated with giant left atrium and small left ventricle. In such cases, low profile valve such as Björk-Shiley valve seems to be superior.