Study Of Swine Model By Mitral Valve Replacement With Prosthetic Valve In Different Configurations

Objective:The purpose of this study was discussing the key factors of established animal model by implanted prosthetic mitral valve to swine. And assessed the feasibility and valve of the animal model. Investigating the hemodynamics actions downstream during different configurations of prosthetic valve.Provided methodological basis.for further study of the relationship about hemodynamics downstream between the preservation of subvalvular apparatus and valve configuration.Methods:Seven closed clony diannan min-ear swine performed mitral valve replacement through the left atrial appendage route under the cardio pulmonary bypass (CPB) and General anesthesia. Seven swine were divided into three groups according to the configuration of prosthetic valve:Single leaf mechanical valve group (n=2); Double leaf mechanical valve group (n=3); Biological valve group (n=2).After the experimental models were found,We used color Doppler echocardiography combining with the analysis of image by computer to study hemodynamics indicators and cardiac structure changes. and take a comparison of turbulent shear stress during different type of artificial valves downstream.Result:All animal model established successfully. The mean operation time was 175.0±38.9min,The mean pump time was 103.8±17.7min,The mean clamping time was 51.2±17.8min,The mean auxiliary time was 31.2±5.7min,the mean pre-filling volume was 555.5±46.3ml. The mean temperature of the nose was 28.5±1.40C. Comparison of conventional hemodynamic parameters showed:heart rate before and after operation (HR) was statistically significant difference (P<0.05); mean arterial pressure (MAP) and central venous pressure (CVP) was not statistically significant difference (P>0.05); Comparison of conventional color Doppler indices showed:left ventricular ejection fraction (LVEF), left ventricular fractional shortening (LVFS), left ventricular end diastolic diameter (LVEDD) and left ventricular end systolic diameter (LVESD) before and after surgery was not statistically significant difference (P>0.05). Comparison of blood gas analysis and biochemical indicators showed that: before and after surgery, PH value was not statistically significant difference (P> 0.05); PaO2, BE, Hb, K+ difference was was statistically significant difference (P <0.05); after 2h compared with the preoperative:PH Value, K+, BE was not statistically significant difference (P> 0.05), PaO2,Hb difference was statistically significant difference (P<0.05). Comparative of heart valves fluid dynamics result shown that:the turbulent shear stress (TSS) during different configurations of artificial heart valve, the core sites was not statistically significant difference (P>0.05); the boundary sites was statistically significant difference (P<0.05).Conclusion:The establishment of MVR swine animal model can simulate to the true objective of the human body MVR hemodynamic status, the method is scientific and feasible.The downstream TSS in prosthetic heart valves of preservation of subvalvular apparatus shown that:The bioprosthetic valve hemodynamic performance to better, less was single leaf mechanical valves, bileaflet mechanical valve was between.Considering improvement of hemodynamic condition downstream of prostheses:the pattern and flow orientation of prosthetic valve present should be made better and be consummated to accord to the principle of minimal stress.