| Aortic regurgitation (AR) is a common clinical valvular disease. Normal aortic valve was composed of a complicated structure (include valve leaflets, annulus, aortic sinus, ascending aorta and aortic root flap tissue) which was very flexible and substantial, aortic regurgitation could be caused by organic disease of aortic root or valve leaflet. If the aortic valve was taken bad in diastole, human blood which came from the aorta would flow into the left ventricular, it could result overload of the left ventricular volume. Patients with aortic regurgitation may maintain the condition of no clinical symptoms for a few years, but if the left ventricular volume overload increased, left ventricular would generate new sarcomere in order to achieve balance. The change was different of left ventricular morphology and function because of the degree of aortic regurgitation, left ventricular would getting expansion compensatory and left ventricular morphology was reconstructed with the progress of the disease, as a result, left ventricular systolic function decreased. Chronic congestive heart failure is one of the most common complications of aortic regurgitation. Some patients with chronic aortic regurgitation could get a better left ventricular function after aortic valve replacement surgery because the doctor corrected the overload of left ventricular volume in the early stage of the course of disease, these could make the expansion of the left ventricular to slow down. However, in our country, the majority of patients came to see the doctor because they get clinical symptoms obviously, at this time, the left ventricular was expanded and left ventricular function was insufficient seriously because of the heavy preload in a long-term, in fact, the patients would also hard to improve their heart function even if the doctor take the operation immediately.Generally, the left ventricular ejection fraction (LVEF) has been widely used in echocardiography as the detection of left ventricular function in patients with aortic regurgitation. However, the influence factors of left ventricular function were preload, after-loading and myocardial contractility. According to Frank-Starling mechanism, we keep the cardiac contractility unchanged, if we increased the preload, the initial length of myocardial would also increase, but the function of myocardial contractile is enhanced. When aortic regurgitation occurred, human blood which came from the aorta would flow into the left ventricular, the volume load would be gradually increased, then the myocardial contractile function would be enhanced, but the myocardial contractility could not change. At present, the mechanism is not fully clear, the change of left ventricular systolic function could also be due to changes in myocardial contractility or increased volume load. But LVEF cannot detect this state of the development of myocardial dysfunction accurately. In this study, we used speckle tracking imaging to exanimate patients with aortic regurgitation, this analysis software could assess left ventricular function changes in patients with aortic regurgitation using echocardiography with the improvement of this technology. It is based on two-dimensional gray scale ultrasound images and tracking of myocardial tissue space motion in real-time, it has no angular dependence, also without influence from the swinging and stretching movement of the heart. The images which were obtained were compared by the work station from one frame to another, at last, we can get data of left ventricular, including myocardial strain, rotation and twist in both long axis and short axis view. This article evaluated in order to reflect changes in left ventricular geometry left ventricular systolic function and provide a comprehensive means to help providing greater clinical diagnosis, by using parameters of two-dimensional ultrasound and speckle tracking imaging in mild, moderate and severe aortic regurgitation patients. In addition, the application of mathematical model of SPSS was preparation by screening the index of left ventricular geometry, left ventricular rotation and torsion in heart failure patients with aortic regurgitation; it could assess the diagnostic value for such patients with the best time for their aortic regurgitation operation. The study was divided into three parts as followed:Part 1. Assessment of left ventricular geometry in patients with aortic valve regurgitationThe aim of this part was to diagnosis patients with aortic regurgitation(the patients were divided into three groups:mild, moderate and severe group)by conventional two-dimensional and color Doppler echocardiography to obtain parasternal four-chamber view and short axis view of left ventricular papillary, then measured two-dimensional data in left ventricular. We compared of patients with aortic regurgitation and control group with the changes of left ventricular geometry, and then we took the pairwise comparisons.Result:The gender, age, height, weight, heart rate, blood pressure, body surface area, and other indicators of general physical examination had no significant difference in each group (P>0.05). However, the indicators of ultrasonic testing is different in each group:mild AR groups:the indicators showed no significant when compared with the control group (P> 0.05); moderate and severe AR group: the indicators showed significant difference (P<0.05). The relative distance between the two papillary muscle of left ventricular had no significant difference between normal control group and mild AR group (P>0.05), but showed significant difference among moderate and severe AR groups (P<0.05).Moderate AR group:the values of D1, D2, D3, Ld, Ls, LSd, LSs, APd, APs, SIs, [(D1+D2+D3)/3Ld], (2D1/Ld) showed great differences with the normal control group, mild AR groups and severe AR groups(P<0.05); the values of SId, [(D1+D2+D3)/3Ls], (2D1/Ls), LSs/APs also showed significant differences among the control group, mild and severe AR group(P<0.05); the values of LSd/APd showed no significant differences in each group(P> 0.05). Severe AR group:the values of D1, D2, D3, Ld, Ls, LSd, LSs, APd, APs, SIs, [(D1+D2+D3)/3Ld], (2D1/Ld) were significantly higher than the control group (P<0.05); the values of SId, [(D1+D2+D3)/3Ls], (2D1/Ls), LSs/APs were significantly lower than the normal group (P<0.05). the values of LSd/APd showed no significant group differences with normal control (P>0.05). The relative distance between the two papillary muscle of left ventricular had negative correlation with the values of Sid and SIs, the correlation coefficients were respectively 0.798 and 0.777 (P<0.01), the relative distance between the two papillary muscle of left ventricular had positive correlation with the values of [(D1+D2+D3)/3Ld], [(D1+D2+D3)/3Ls], (2D1/Ld), (2D1/Ls), LSd/APd and LSs/APs, the correlation coefficients were respectively 0.766,0.694,0.597,0.557, 0.891,0.830 (P<0.01).Part 2. Assessment of left ventricular 2D Strain and twist in patients with aortic regurgitationIn this study, we examined patients with simple aortic regurgitation (in accordance with the degree of regurgitation, patients were divided into mild, moderate and severe group) which diagnosis by two-dimensional echocardiography, using conventional two-dimensional color Doppler echocardiography. We received two-dimensional gray scale images of parasternal left ventricular short axis view of mitral valve and left ventricular short axis view of apex, all the images were stored in a disc. Echo PAC workstation with STI imaging analysis software was used. Two-dimensional strain, the movement of change in rotation and twist in left ventricular were compared between aortic regurgitation group and normal control group.Result:①there were no significant difference in age, height, weight, heart rate and body surface area in each group (P>0.05).②Compared with normal control group, left ventricular diameter of end diastolic and end systolic, left ventricular volume of end diastolic and end systolic, left ventricular ejection fraction, E peak and A peak in mitral of diastolic, E/A ratio showed no significant difference in mild AR group (P> 0.05). Compared with normal control group, left ventricular diameter of end diastolic and end systolic, left ventricular volume of end diastolic and end systolic were increased in moderate and severe AR group(P<0.05). Compared with normal control group, left ventricular ejection fraction showed not significantly different in both moderate AR group and severe AR group (P>0.05), but E peak and A peak in mitral of diastolic, E/A ratio showed no significant difference (P>0.05).③Compared with normal control group, the left ventricular long axis longitudinal strain, radial strain and circumferential strain of the short axis showed no difference in mild AR group; these parameters were decreased in moderate AR group,but increased in severe AR group(P<0.05).④Compared with normal control group, the rotation and twist at the level of mitral annulus and apex showed no difference in mild AR group; these parameters were decreased in moderate AR group,but increased in severe AR group(P<0.05).Part 3. Assessment of clinical value in aortic regurgitation patients with heart failure by using mathematical modelIn this study, we applied mathematical model of SPSS to screening for indices of left ventricular geometry index, left ventricular rotation and twist, which were between 24 aortic regurgitation patients with heart failure and 30 healthy volunteers. We used Logistic Stepwise regression analysis and get the regression equation relevant indicators were selected to establish the regression equation; also, we draw ROC curve of each index and obtain the critical value. We screened indices of left ventricular geometry, left ventricular rotation and twist parameters in aortic regurgitation patients with heart failure, in order to assess the diagnostic value for patients and fight for the best operation time.Result:①Comparison of conventional and hemodynamic datum:compared with datum between AR group and normal control group:the indices of gender, age, height, weight, body surface area, heart rate, E peak and A peak in mitral of diastolic, E/A ratio showed no significant difference (P>0.05). LVEF of left ventricular were decreased in AR groups than that in the control group (P<0.05). The diameter of left ventricular in end diastolic and end systolic, the volume of left ventricular in end diastolic and end systolic were increased in AR groups than those in the control group (P<0.05).②Comparison of left ventricular geometry parameters between AR group and control group:the indices of SIa,[(D1+D2+D3)/3Ld],(2D1/L)d,LSd/APd in AR Group were significantly higher than the control group (P<0.05); the indices of SId, [(D1+D2+D3)/3Ls]. (2D1/L)s, LSs/APs were significantly lower than the control group (P<0.05)③Comparison of the parameters of left ventricular rotation and twist between AR group and control group:the rotation of short axis views in mitral valve level and apical level(rotation in MV, rotation in AP), peak twist (PTWtwist), twist at aortic valve closure (AVOtwist) and twist at mitral valve opening (MVOtwist) were decreased than those in the normal group, there were significant differences between this two groups (P<0.05)④In Logistic regression model, independent variables of PTWtwist (peak twist) and AVCtwist (twist at aortic valve closure) were selected into the Logistic regression equation in stages, the expression of equation were 88.89% and 94.44%, respectively. The classification capability of independent variables in PTWtwist was greater than AVCtwist. The logistic regression equation was: ln(P/(1-P))=-23.655-1.597*Rotary MV+1.021*PTWtwist+0.886*AVCtwist. Independent variables of 2 (D1/Ld), SId and [(D1+D2+D3)/3Ld] were selected into the Logistic regression equation in stages, the expression of equation were 81.48%,85.19% and 85.19%, respectively. The classification capability of independent variables were 2D1/Ld> [(D1+D2+D3)/3Ld]> SId in proper order. The logistic regression equation was:ln(P/(1-P))=-63.927+31.763*2D1/Ld+15.495*SId+17.198* [(D1+D2+D3/3Ld].⑤The area of under the ROC curve corresponded to rotation AP, rotating MV, PTWtwist, AVCtwist and MVOtwist were 0.790,0.126,0.946,0.899 and 0.924, respectively(P<0.05). The area of under the ROC curve corresponded to SIs, SId, [(D1+D2+D3)/3Ld], [(D1+D2+D3)/3Ls],2D1/Ld, 2D1/Ls, LSd/Apd, LSs/Aps were 0.507,0.876,0.675,0.503,0.894,0.613,0.689 and 0.580. The sensitivity and specificity in aortic regurgitation patients which rotating AP, rotating MV, PTWtwist, AVCtwist and MVOtwist were valued to diagnosis heart failure as follows:62.50% and 96.67%,20.00% and 16.67%,90.00% and 87.50%,83.33% and 83.33% and 93.33% and 79.17%. The sensitivity and specificity in aortic regurgitation patients which SIs, SId, [(D1+D2+D3)/3Ld], [(D1+D2+D3)/3Ls], 2D1/Ld,2D1/Ls, LSd/Apd, LSs/Aps were valued to diagnosis heart failure as follows:100% and 33.33%, 90.00% and 79.17%,53.33% and 87.50%,46.67% and 70.83%,86.67% and 75.00%,60.00% and 66.67%,76.67% and 62.50% and 90.00% and 37.50%. CONCLUSIONS:In this study, our conclusions are as followed:①The left ventricular geometry in longitudinal direction of aortic regurgitation patients showed as followed:the ellipse shape of left ventricular in end-diastolic tends to round, but in end-systolic tends to flat. Along with the aortic regurgitation degree becoming more serious, the spherize of apex was becoming obvious. In the short axis direction, left ventricular tends to round in end diastolic, but tends to flat in end systolic. The geometry characteristics became the most obvious while in severe AR group, then in moderate AR group, but not obvious in mild AR group.②The relative distance between the left ventricular papillary muscle was increased in AR patients. It showed the most obvious in severe AR group, then in moderate AR group, but the same in mild AR group, comparing with the control group. Correlation analysis showed that the relative distance between left ventricular papillary muscles was significantly related to indices of left ventricular geometry. It was a reliable indicator of left ventricular spherical change.③The left ventricular systolic function in mild AR group showed no significant damage. The left ventricular systolic function in mild AR group showed damage in moderate AR group; the long axis of the longitudinal strain, radial strain and axial strain of the short axis were increased; the rotation and twist were increased. The indexes in severe AR group were significantly lower than the control group. The reason could be the change of left ventricular preload and myocardial contractility.④In logistic regression model, The classification capability of independent variables in PTWtwist was greater than AVCtwist. The classification capability of independent variables were 2D1/Ld>[(D1+D2+D3)/3Ld]> SId in proper order.⑤To evaluate the left ventricular rotation and twist parameters with ROC curve, the value of heart failure judging were PTWtwist, MVOtwist, AVCtwist, rotation AP and rotation MV, successively. The indicator of PTWtwists showed perfect accuracy of all the groups. To evaluate the left ventricular geometry with ROC curve, the value of heart failure judging were 2D1/Ld, SId, LSd/Apd and [(D1+D2+D3)/3Ld], while the indicator of SId showed perfect accuracy of all the groups. ⑥Two-dimensional speckle tracking imaging which could evaluate the left ventricular systolic function and movement accurately was combined with parameters of strain, rotation and twist. It also could be sensitive to show the change of left ventricular geometry and left ventricular systolic function dysfunction in patients with aortic regurgitation. |
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