Evaluation Of Hemodynamic Changes After Mitral Valve Replacement In Pigs By Echocardiography

Objective(1) The study aimed to measure the subvalvular flow after mitral valve replacement and access its advantages and disadvantages of MVRP and MVRNP by Doppler ultrasound.(2) Using echocardiography we can detect the structure and left heart changes before the MVRP, instantly after the MVRP and in an hour after the MVRP.(3) Adopting PW and HFA to carry out the correlation study on hemodynamic of animal model.MethodsSubjects:Twelve of Diannan Small Ear Pigs (body weight 45-80 kg, age 12-18months) were used for MVR. Both male and female are in healthy status.Inclusion criteria:(1) Following parameters were studied before a week to perform surgery-blood biochemistry, ECG recording, basic vital signs, food consumption and water intake were measured. The abnormal animals were not included in the samples;(2) All selected pigs are weighted 45-80kg, their heart rates were measured 80-140 beats per min, belong to sinus rhythm.(3) All animals were restricted to 12-18 months; (4) Routine Echocardiograhy were performed to exclude valvular Heart diseases in the selected samples.Exclusion criteria:(1) Dianan pigs with valvular heart diseases are not inclued; (2) The animals with cardiac diseases, including myocardiopathy, congenital heart disease, pericardial disease, congestive Heart Failure, severe Hepatic and Kidney insufficiency, Arrhythmia (frequent premature ventricular contractions, supraventricular tachycardia, ventricular tachycardia, atrial fibrillation) or Atrioventricular block, Right bundle branch block,left bundle branch block, pathological valvular regurgitation are not included.Group of Experiments:12 cases of small-Diannan pigs randomly divided into two groups,6 cases were assigned to the preservation of valve apparatus and 4 were not.Instrument:Echocardiography ViViD-S5 made by American based GE Company. Probe frequency of 2.0-2.5MHz.Valve selection:St.Jude bifoliate mechanical valves.Surgical procedures:Twelve 45-80 kg pigs were allocated to undergo either 1 or 2 surgical procedures, (1) preservation of the entire subvalvular apparatus (n= 6). (2) Excision of the entire subvalvular apparatus. (n= 4).ResultsPostoperative artificial heart valve was examined by Echocardiography.1. Echocardiographic index:(1) No significant difference was found between the MVRP and MVRNP groups in terms of LVEDD,LAD instantly and 1 hour after operations (P>0.05)(2) Significant decrease of SV, FS, in all Pigs was observed(p<0.05), and Significant decrease of, EF, CI, CO, E/A in all Pigs was observed(p<0.01), and statistical difference between the MVRP and MVRNP groups was seen.(3) Significant increase E and A in all the Pigs was observed(p<0.05),and statistical difference between the MVRP and MVRNP groups was seen.2. Hot-film anemometry indicator:There were higher correlations between HFA and PW (r=0.792).3. The velocities of the left ventricular outflow tract detected by Echocardiography in both groups are normal.Conclusion(1) Using the HFA and PW methods to measure the animal models in terms of hemodynamics, the results showed that there were higher correlations between HFA and PW. This result was further elaborated that the accuracy of for mitral valve of hemodynamics. (2) No significant difference was found between the MVRP and MVRNP groups in terms of configuration of left ventricule instantly and 1 hour after operations. (3) There is no difference between the flow velocity of downstream of MVRP and that of MVRNP, thus shows that MVRP of this study group had no effect on the mitral valve of hemodynamics, so this operative way was recommend to treat mitral valve diseases.