The Valuation Of Using Real-time Three-dimensional Transthoracic Echocardiography In Functional Mitral Regurgitation

Objective:This study was conducted to elucidate and compare the geometric differences and function changes of mitral valve in patients with significant functional mitral regurgitation(FMR) which is caused by ischemic cardiomyopathy and dilated cardiomyopathy by use of Real-time three-dimensional transthoracic echocardiography(RT 3D-TTE). More over, it was conducted to evaluate the great feasibility of using RT 3D-TTE in the research of mitral valve and to provide a reference for the clinical treatment of FMR. Methods:70 patients enrolled to our study with at least moderate mitral regurgitation with an effective regurgitant orifice area(EROA) greater than or equal to 0.20cm2, consisting of two groups, 35 mitral regurgitation in dilated cardiomyopathy and 35 mitral regurgitation in ischemic cardiomyopathy, who were 45-75 years, mean(53.8±10.3) years. All patients successfully accepted conventional two-dimensional echocardiography and RT 3D-TTE. Left ventricular end-diastolic diameter(LVEDD) and Left ventricular end-systolic diameter(LVESD) were measured by conventional echocardiography. For all patients, transthoracic volumetric images were obtained with apical view. All volumetric images were digitally stored and transferred into computer for offline analysis. The imaging was analyzed offline with TomTec fourdimensional volume software to measure Left ventricular end-diastolic volume(LVEDV), Left ventricular end-systolic volume(LVESV) and Left ventricular ejection fraction(LVEF). Mitral valve structure and function parameters were measured by TomTec four-dimensional mitral valve assessment software. Compare the mitral valve structure and function parameters in FMR between early systole, mid systole and late systole to detect dynamic changing pattern of mitral valve size and shape during cardiac systole. Compare the conventional echocardiograp hy parameters and mitral valve structure and function parameters between normal control group and at least moderate mitral regurgitation FMR group. Compare the conventional echocardiography parameters and mitral valve structure and function parameters between normal control group, ischemic cardiomyopathy and dilated cardiomyopathy. Results:1. All parameters describing mitral valve geometry and function changed significantly during left ventricular systole. Mitral valve structure parameters, including Anteroposterior(AP) diameter, Anterolaterior-posteromedial(AL-PM) diameter, Sphericity index(SPI), Annular circumference(AC), Commissural diameter(CD), function parameter Maximum annular displacement(ADMax), increased from early systole to late systole(p<0.05). Structure parameters Nonplanar angle(NPA), Two-dimensional annular area(AA2D) and Three-dimensional annular area(AA3D)at late systole were larger than those at early systole(p<0.05). Structure parameter Annular height(AH) and function parameter Maximum annular displacement velocity(ADVMax) reached its maximum at mid systole(p<0.05). Structure parameter Tenting height(TH) was at its maximum value at early systole(p<0.05), decreased progressively to mid systole and remained static at late systole. Structure parameter Tenting volume(TV) showed a biphasic change with bi- modal higher peaks at early systole and late systole and a lower peak at mid systole(p<0.05).2. Compared with normal control group, conventional parameters LVEDD, LVESD, LVEDV, LVESV were outstandingly larger in FMR group(p<0.05). LVEF was smaller in FMR group(p<0.05).3. Compared with normal control group, structure parameters AP, AL-PM, SPI, NPA, AC, TH, CD, AA2 D, AA3 D and TV were outstandingly larger in FMR group(p <0.05).Structure parameter AH and function parameters ADMax, ADVMax were smaller in FMR group(p<0.05).4. Compared with normal control group, conventional parameters LVEDD, LVESD, LVEDV, LVESV were significantly greater, while LVEF was smaller in both ischemic cardiomyopathy group and dilated cardiomyopathy group(p<0.05).To compare with ischemic cardiomyopathy group, conventional parameters LVEDD, LVESD, LVEDV, LVESV were significantly greater, while LVEF was smaller in dilated cardiomyopathy group(p<0.05).5. Compared with normal control group, structure parameters AP, AL-PM, SPI, NPA, AC, TH, CD, AA2 D, AA3 D and TV were significantly greater(p<0.05), while structure parameter AH and function parameters ADMax, ADVMax were smaller in both ischemic cardiomyopathy group and dilated cardiomyopathy group(p<0.05). To compare with ischemic cardiomyopathy group, structure parameters AP, AL-PM, SPI, NPA, AC, TH, CD, AA2 D, AA3 D and TV were significantly greater(p<0.05), while structure parameter AH was smaller in dilated cardiomyopathy group(p<0.05). But there is no statistical difference in function parameters ADMax and ADVMax between ischemic cardiomyopathy group and dilated cardiomyopathy group(p>0.05). Conclusion:We can use the Real-time three-dimensional transthoracic echocardiography to elucidate the geometric differences and function changes of mitral valve in patients with significant functional mitral regurgitation(FMR) caused by ischemic cardiomyopathy and dilated cardiomyopathy. More over, it was valuable in the research of mitral valve and a reference can be provided for the clinical treatment of FMR.