| Part one:Analysis of Left Atrial Volumes and Function in Heart Transplantation Recipients Using Two-Dimensional Speckle Tracking Echocardiograp-hyBackground Speckle tracking imaging (STI) is a newly developed two-dimensional echocardiographic technology that based on high frame rate gray-scale image without angular dependence. And STI, with high temporal and spatial resolution, is correlated well with magnetic resonance imaging (MRI) and tissue doppler imaging (TDI). It can be used to accurately evaluate the mechanical movement of myocardial tissue. STI can generate volume-time curves and calculate the left ventricular end systolic volume, end-diastolic volume, ejection fraction. Previous studies demonstrated the feasibility of LA volume assessed by two-dimensional speckle tracking echocardiography in healthy volunteers. However, its performance in assessing LA volume in heart transplantation recipients has not yet been evaluated. The aim of this study was to compare left atrial volumes derived from STI and examinations with respect to manual trace method in orthotopic heart transplant recipients operated with bicaval anastomotic techniques.Methods The study subjects consisted of 20 heart transplantation recipients(aged 28-62years,15 men, transplanted between 2005 July and 2010 March). All subjects were transplanted by bicaval technique. STI of the LA was acquired from the apical 4-chamber view (frame rate:90-110/sec, Philips iE33) using prototype speckle tracking software (QLAB, Philips Medical Systems, Andover, MA) in 20 heart transplant recipients. LA wall was tracked on a frame-by-frame basis, and LA volume waveforms were generated. Maximum LA volume (LAVmax) and minimal LA volume (LAVmin), and the LA volume before atrial contraction (LAVpre-a) were measured. Two independent observers used both STI and manually tracing to measure LA volumes in 20 heart transplant recipients. Inter-observer agreement for STI was determined.Results Adequate LA volume waveforms were obtained in all subjects. There was moderate agreement between STI and manual trace method for LA volume(LAVmax:r=0.70,p<0.001,LAVmin:r=0.52,p<0.05,LAVpre-a:r=0.75,p<0.001). There were not significant difference in LAVmin between the two methods (p=0.9714, t=-0.0364). LAVpre-a was mildly larger in manual trace than in STI without significance(p=0.1589, t=-1.466). LAVmax was remarkably larger in manual trace than in STI (p=0.0088, t=-2.92). Intraobserver and Interobserver agreement for STI analysis of LA volume were excellent (P>0.05)Conclusions STI can effectively and easily measure LA volume and has the potential for the noninvasive assessment of LA function in heart transplantation recipients, especially in LAVmin and LAVpre-a.Part two:Assessment of left ventricular systolic synchronicity in heart transplantation recipients by speckle tracking imaging and real-time three-dimensional echocardiographyBackground Orthotopic heart transplantation is a choice of treatment for end-stage heart disease, and cardiac allograft rejection has been the main cause of graft injury, and it contributed to heart transplantation mortality and morbidity Nowadays, the primary method to monitor the effect of immunosuppressive therapy after heart transplantation is regular repeated endomyocardial biopsy. However, the endomyocardial biopsy is an expensive exam with serious complications. Echocardiography is a noninvasive widely used follow-up method in heart transplantation patients. Speckle tracking imaging and real-time three-dimensional echocardiography are the recently developed technologies, and have significant advantages comparing with traditional technology. The prognosis value of STI and RT-3DE in allograft rejection after heart transplantation is still unclear. This study aims to explore the predictive value of left ventricular systolic synchrony index of STI and RT-3DE in evaluation of heart transplantation rejection Methods Sixteen posttransplantation patients were divided into two groups. Group A consisted of eight patients with biopsy specimens showing an ISHLT grade of 0 or 1a, and group B included eight patients with ISHLT grade of higher than la. All patients were studied at apical four-chamber, two-chamber view, apical longitudinal and short-axis images acquired at the mitral valve and the papillary muscle level. We acquired the left ventricular(LV) end-diastolic volume(LVEDV), end-systolic volume(LVESV), LV ejection fraction(LVEF), the standard deviation of time to peak systolic longitudinal strain of the 16,12 and 6 left ventricular segments, the standard deviation of time to peak systolic transversal strain of the 16,12 and 6 left ventricular segments, the standard deviation of time to peak systolic circumferential strain of the 12 and 6 left ventricular segments, the standard deviation of time to peak systolic radial strain of the 12 and 6 left ventricular segments, (LS-SD16/SD12/SD6, TS-SD16/SD12/SD6,CS-SD12/SD6, RS-SD12/SD6) and the standard deviation of time to peak systolic transversal displacement of the 16,12 and 6 left ventricular segments, the standard deviation of time to peak systolic radial displacement of the 12 and 6 left ventricular segments (TD-SD16/SD12/SD6, RD-SD12/SD6). The systolic synchrony parameters derived from RT-3DE included the standard deviation of time to minimum regional volume for 16,12 and 6 left ventricular segments (Tmsv16-SD、Tmsv12-SD and Tmsv6-SD) and the maximum difference of time to minimum regional volume for 16,12 and 6 left ventricular segments (Tmsv16-Dif Tmsv12-Dif and Tmsv6-Dif).Results There were no difference in age, heart rate and LVEDV between the two groups (P> 0.05). LVESV of group B was significantly larger than that of group A(P< 0.05), and LVEF of group B was significantly lower than that of group A (P < 0.05). LS-SD16/SD12/SD6, TD-SD16/SD12/SD6, TD-SD16/SD12/SD6 and RD-SD12/SD6 were not significantly different between the two groups (all P> 0.05), however RS-SD12/SD6.TS-SD16/SD12/SD6 and CS-SD12/SD6 were significantly larger in group B than those in group A(all P< 0.05), especially RS-SD12 and RS-SD6 of group B were remarkably longer than those of group A(P-0.001), Tmsvl6-Dif-> Tmsvl2-Dif and Tmsv6-Dif were not significantly different between the two groups(all P>0.05), however Tmsvl6-SDN Tmsvl2-SD and Tmsv6-SD were significantly larger in group B than those in group A(all P< 0.05)。Conclusions Both RT-3DE and STI can evaluate left ventricular systolic synchrony of heart transplantation recipients, RS-SD12 and RS-SD6 may be potential parameters for assessing acute rejection in heart transplantation recipients.Part three:The Role of Speckle Tracking Imaging in the Noninvasive Detection of Acute Rejection after Heterotopic Cardiac Transplantation in RatsBackground Acute cardiac allograft rejection continues to be the cause of graft loss and contributes to the morbidity and mortality after cardiac transplantation. Repetitive endomyocardial biopsies are necessary to monitor the effects of immunosuppressants after cardiac transplantation. Speckle tracking imaging (STI) is a newly developed two-dimensional echocardiographic technology that based on high frame rate gray-scale image without angular dependence. And STI, with high temporal and spatial resolution, is correlated well with magnetic resonance Imaging (MRI) and tissue Doppler imaging (TDI). It can be used to accurately evaluate the mechanical movement of myocardial tissue. Its prognosis value in allograft rejection after heart transplantation is still unresolved. In this study, we examined whether speckle tracking imaging (STI) could be employed for the assessment of acute cardiac rejection.Methods Hearts from Brown Norway rats or Lewis rats were transplanted into other Brown Norway rats. Isografts and groups of allografts either untreated or treated with cyclosporine A (CsA) at a low dose (3 mg-kg-1-d-1) or high dose (10 mg-kg-1-d-1)from 1 day before transplantation were compared at posttransplantation day 7. Two-dimensional short-axis images acquired at the papillary muscle level data digitally stored for further analysis. Data were analyzed using a speckle-tracking algorithm incorporated into Echopac PC workstation (GE Medical). Peak systolic strain and strain rate were obtained for each segment, and the average was used to compute global radial or circumferential strain and strain rates. At last, the correlation between speckle tracking imaging parameters(strain and strain rate) and rejection grade according to the International Society for Heart and Lung Transplantation (ISHLT) criteria were determined. Results Echocardiography derived left ventricular post wall thickness was increased only in untreated allografts. The left ventricular ejection fraction was significantly lower in the allografts compared with isograft, but allografts treated without or with low-dose CsA showed similar results.The radial velocity and systolic radial strain rate showed a lower value in untreated allografts than other grafts, but there was no significant differences between allograft treated with high-or low-dose CsA and isografts. The circumferential strain and circumferential strain rate was comparable among the 4 groups. However the radial strain exhibited a clear gradient in these groups (2.8+1.3 in untreated allografts,5.2+0.9 in allografts treated with low-dose CsA,6.3+1.8 in allografts treated with high-dose CsA, and 12.7+7.9 in isografts, P<0.001).Conclusions STI offers a promising noninvasive method for detecting transplant allograft rejection. The value of left ventricular radial strain could reflect the level of heart transplantation rejection in rat model. |
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