| 1.Methodological study for measuring downstream fluid turbulence shear stres of mitral valveObjective:Turbulent shear stress (TSS) plays an important role in fluid dynamics research about the heart valve. This study aimed to perform a quantitative research on TSS downstream of porcine artificial mitral valves in order to verify the correlation of hot-film anemometry (HFA) and echocardiography combined with image analysis system for the detection of TSS downstream of the mitral valve.Methods:A porcine model of mitral valve replacement was established. HFA and Doppler ultrasound techniques were used to directly and indirectly measure TSS-relevant parameters of the artificial mitral valve following different mitral valve replacements (different approaches were used to reserve the subvalvular apparatus of the mitral valve). Then, a correlation analysis was carried out.Result:There was a significant correlation between the HFA and Doppler ultrasound combined with computer-aided image analysis of the TSS at the same time and same site. No significant difference was found in the TSS measured by the two methods.Conclusion:Compared with HFA, Doppler echocardiography combined with imagination analysis is a safe, non-invasive, and real-time method that enables accurate and quantitative detection of TSS downstream in vivo, reflecting the flow field downstream of the artificial mitral valve objectively. Otherwise, Doppler ultrasound combined with computer-aided image analysis can be employed for quantitatively evaluating the downstream hemodynamic performance of the mitral valve.2.Clinical studies to illustrate the effects of different types of mitral valve plasty techniques and their combined use on downstream valvular hemodynamics and cardiac functionObjective:To compare the effect of different mitral valve plasty techniques and their combined use on downstream valvular hemodynamics, cardiac function index, and its effect on the left ventricular functionMethods:selected patients, according to Carpentier classification for mitral valve disease, were divided into annuloplasty group, valve repair (edge-to-edge repair, ETER) and combined techniques group. And then the data differences, conventional doppler ultrasound, left heart function, the flow field uniformity, the application of doppler ultrasound combined with computer-assisted image through computational fluid mechanics, TSS and ventricular wall stress analysis and statistical analysis were compared between the above groupsResults:There was no significant difference in postoperative cardiac function indices, EF, mitral valve movement speed, Teil, SR and other indicators (P>0.05) between annuloplasty group, ETER group and combined techniques group. There was WSS statistical differences (P<0.05) in postoperative mitral valve of ETER group combined techniques group and valve repair group,Conclusion:1. left heart function improves after surgery in annuloplasty group, ETER group and combined techniques group.2. the natural physiological dimensions single flow channel, downstream flow field uniformity, hemodynamics and wss are better preserved/maintained by simple annuloplasty group compared to ETER group and combined techniques group. 3. A comparative study of subvavular single-channel flow field changes in TSS and cardiac function after mitral valve replacement and plastyObjective:Comparative analysis between different subvavular structure postoperative of mitral valve replacement (MVR) and application of mitral valvaloplasty(MVP),downstream flow field uniformity, turbulent shear stress, such as early postoperative hemodynamics and cardiac functionMethods:According to surgery patients were divided into mitral valve replacement group of26patients (Not retaining subvavular structure group of8patients; Keeping subvavular structure the group of18patients) and MVP group of21patients. Comparing quantitative differences in evaluation of cardiac function and flow field uniformity between the two groups using doppler ultrasound combined with computer aided image,through computational fluid dynamics analysis of mitral valve downstream TSS, Statistical analysis, after three months.Results:1. There was no significant short term post-op difference (P>0.05) between the MVR group (with preserved subvavular structures) and MVP group in patients with left ventricular ejection fraction (LVEF), but quantitative cardiac function indices (such as the velocity of mitral valve motion, TeiI, SR, WS) difference was statistically significant.2. Post-MVR the downstream valvular flow disturbances are increased and the flow field uniformity is changed. MVR group had higher TSS and Irel than the MVP group (P<0.05).Conclusion:1. The cardiac function recovery postoperatively in both mitral valve biological (porcine or bovine) MVR and the central port MVP is very close. But the central port MVP technique maintains the integrity of subvavular and most of the physiological space configuration of the mitral valve.The quantitative evaluation of the postoperative cardiac function recovery is better in biological disc MVR.2. The central flow MVP in maintaining physiological central port operation and valve structure, less effect on the downstream of the valve in patients with hemodynamic, But after the replacement of artificial valve stenosis of the existence of effect, to a certain extent, still disturbs the valve downstream flow field uniformity, Resulting in TSS and Irel. 4.Comparative study of cardiac function and change in TSS in mitral valve replacement and MVP with subvavular dual channel flow.Objective:to compare, analyze and, differentiate the subvavular hemodynamic parameters of downstream valvular flow field uniformity, the turbulent shear stress and changes in the cardiac function (early post-op) after mitral valve double leaf mechanical valve replacement and MVP dominated leaflet repair.Methods:on the basis of different surgical methods45patients can be divided into mechanical valve replacement of mitral valve double leaf group of26patients (Not retaining subvavular structure the group of8cases; Keeping subvavular structure the group of10cases)and MVP group of21patients (Simple leaflet plasty11cases, joint leaflet annuloplasty8cases). And comparing the quantitative evaluations of cardiac function and flow field uniformity of the above, using doppler ultrasound combined with computer aided image at the same time, through computational fluid dynamics analysis of mitral valve downstream TSS, Statistical analysis, after three months.Results:1. There was no significant short term post-op difference (P>0.05) between the MVR group (with preserved subvavular structures) and MVP group in patients with left ventricular ejection fraction (LVEF), but quantitative cardiac function indices (such as the velocity of mitral valve motion, Teil, SR, WS) difference was statistically significant.2. Post-MVR the downstream valvular flow disturbances are increased and the flow field uniformity is changed. MVR group had higher TSS and Irel than the MVP group (P<0.05).Conclusion:1. The biological(bovine/porcine) MVR and the valve central port MVP both have very close cardiac function recovery post-operatively. But the central port MVP technique maintains the integrity of subvavular structures and most physiological space configuration of the mitral valve. The quantitative evaluation of the postoperative cardiac function recovery is better in biological disc MVR.2. The central flow MVP in maintaining physiological central port operation and valve structure, less effect on the downstream of the valve in patients with hemodynamic, But after the replacement of artificial valve stenosis of the existence of effect, to a certain extent, still disturbs the valve downstream flow field uniformity, Resulting in TSS. 5.Study of the correlation between the left ventricular function and TSS in the downstream of the mitral valve after the mitral valve replacement and repairObjective:To analyse relationship between mitral valve downstream of the flow field TSS and left ventricular function.Methods:Analyzed the clinical data of mitral insufficiency patients undergoing mitral valve replacement during the period of2010-01to2013-12in Cardiovascular Surgery Department of the First Affiliated Hospital of Kunming Medical University, through conventional doppler echocardiography and doppler tissue imaging, and combined with computer aided image, through computational fluid mechanics, the quantitative evaluation of postoperative cardiac function and fluid indexs in mitral valve downstream flow field. correlation analysis between left ventricular function after surgery for mitral valve, valve downstream flow field for flow field uniformity index and left ventricular area site of the turbulent shear stress in downstream of mitral valve (TSS) and ventricular wall stress (WS).Results:1. The boundary locus TSS in mitral valve downstream flow field is correlation with mitral valve ring motion velocity.2. WS after mitral valve surgery is correlation with the heart function LVEF and Tei index. Conclusion:TSS in the downstream flow field after mitral valve surgery is correlation with regional left ventricular function, WS and the overall left heart function,have a certain influence to left heart function. |
PDF Full Text Request