Evaluation Of Ventricular Geometry And Function Using Echocardiography In Postoperative Patients With Heart Transplantation

Advances in immunosuppression and vascular surgical technique have allowed cardiac transplatation to be a viable and the most effective treatment for patients with end-stage heart failure. The vast majority of grafts can restore and maintain the normal ejection fraction after the transplantation. Heart graft has experienced the injury of ischemia-reperfusion, surgical trauma during the process of transplantation. Andrejection, immune injury, high blood pressure induced by long-term application of immunosuppressant may occur after surgery. These factors can lead to myocardial impairment and alterations of the cardiac function. Abnormal graft structure and function are the main predictive factors for the prognosis of patients after heart transplantation. Echocardiography is one of the best means in assessment of cardiac morphology and function, with which anatomical structure of the graft can be clearly observed, and the systolic function can be evaluated.Two-dimension speckle track imaging is based on two-dimensional gray scale ultrasound images and tracking of myocardial tissue space motion in real-time. The images which were obtained were analyzed and compared frame by frame in the work station, and parameters of left ventricular function, such as strain and strain rate in both short axis and long axis view, can be obtained. Two-dimension speckle track imaging has the benefit of no angular dependence, also not influencedby the swinging and stretching movement of the heart.In this study, we detected the structure and function of transplanted heart by usingconventional two-dimensional ultrasound and speckle tracking technique in order to explore the changes in cardiac structure and function of heart transplant patients after surgery.This article aimed to reveal the changes in structure and function ofgraft and to provide fundamental information for the treatment of such patients. The study was divided into three parts as followed:Part 1. Assessment of left ventricular mass in postoperative patients with heart transplantation by echocardiographyThe aim of this part was to observe the changes of LV structure over time in patient after HT, and toinvestigate the correlated factorsin LV remodeling. Conventional two-dimensional echocardiography was applied to scan 34 control healthy subjects and 32 patients with HT after 3months (A group),6 months (B group),>12 months (C group) of operation, and two dimensional parametersof the left ventricular were mearsured,andthe left ventricular mass was calculated.Results:①ompared with the control group, each group of HT had larger size of left atrium (LA), faster heart rate (HR) and older age(P<0.05). Body mass index (BMI), sex, left ventricular ejection fraction (LVEF) were similar in the two groups (P>0.05). Gender, age, BMI, LA, HR and LVEF had no significant differencesbetween each HT group (P>0.05).②ndicators of left ventricular geometry were different in each group:LVEDD had no significant difference between each group (P>0.05). IVST, PWT in each group of HT were larger than in control group, and in group C was larger than in group A and B (all P<0.05). However, there were no significant difference between group A and B (P>0.05). Value of LVM in HT groups were higher than in control group, and LVM was higher in group B and C than in group A (P<0.05). However, there were no statistically significant between group B and C (P>0.05).③Prevalence of LVH in group A, group B, group C was 20%,34.6%,54.2%, respectively, increased with the time after operation. But the univariate analysis indicated that there was no significant correlation between LVM and postoperative time (r=0.28, P>0.05). Instead, LVM was significantly related with the incidence of hypertension. In multivariate analysis, hypertension and acute rejection (AR) events were independent risk factors for the development ofLVH. Moreover, LVM in hypertension group of HT was higher than in non-hypertension group of HT (p<0.05), as well as of HT with AR.Part 2. Assessment of left ventricular global systolic function in long-term survival patients over HT operation by 2-dimensional speckle tracking echocardiographyIn this study,24 patientssurvived more than one year after heart transplantation were examined with two-dimensional echocardiography and Color Doppler Flow Imaging (CDFI). These patients weredivided into two groups:one group with left ventricular hypertrophy (LVH), another with normal left ventricular mass (LVM).The short axis view of the left ventricular on the level of papillary muscle and the apical four-chamber view were acquired and stored in dynamic mode, and then analyzed off-line in Qlab Analysis 7.1. We compared the global left ventricular longitudinal strain (GLS), global circumferential strain (GCS), global radial strain (GRS), GLS rate (GLSR), GCS strain (GCSR) and GRS strain (GRSR) between the two groups. The global left ventricular function is evaluated, and the possible factorsare analyzed.Results:①There were no significant differences between the two groups in age, weight, pulmonary artery pressure, left ventricular ejection fraction, donor cold ischemia time, warm ischemia time, aortic cross-clamping, donor age and weight(P>0.05).②here are no significant differences betweenthe HT groups and thenormal control group in age, height, weight, gender and left ventricularejection (P>0.05). The heart rate of both HT groups is significantly faster thanthe normal control group (P<0.05), but the differences betweenthe two HTgroups are not significant (P>0.05). Compared with the normal controlgroup, theE/A ratios in the two HT groups weresignificantly greater than the normal control group (P<0.05), but thedifferences between the two groups were not significant (P>0.05). Theend-diastolic thickness of the interventricular septum and the left ventricular posterior wall inthe two groups is significantly greater than the normal controlgroup (P<0.05), and those in the LVH group weresignificantly greater than those in the group with normal LVM (P<0.05). The differences in left ventricular end diastolic diameter between thegroup of normal left ventricular mass and the normal control group wasnotsignificant (P<0.05), but it wassignificant between the LVH group and the normal control group (P<0.05).③Compared with the control group, in GCS, GLS,GRS, GCSR, GLSR, GRSR were significant lower in both HT groups (P<0.05). GCS, GLS, GRS, GCSR, GLSR, GRSR in the HT group with LVH was even lower than in the HT group with normal LVM (P<0.05).④There was a linear correlation between the increased LVM and the decreased GCS, GLS, GRS, GCSR, GLSR, GRSR..⑤There were high repeatability and consistency of these parameters:GCS, GLS, GRS, GCSR, GLSR, GRSR.Part 3. Assessment of right ventricular systolic function in hearttransplantation patients with late survival by 2-dimensional speckle tracking echocardiographyThe aim of this part was to assess RV regional and global function in asymptomatic HT patients by STI. 19 asymptomatic HT patients whose postoperative period is more than one year and 19 healthy controls were studied. RV longitudinal peak systolic strains were measured in the basal, mid and apical segmentsof RV free wall and interventricular septum (IVS) by STI from the apical 4-chamber view. RV global longitudinal peak systolic strain (GLS) was also measured. The preoperative factorsinfluencing GLS and the predictive factors of postoperative GLS were explored.Results:①There were no significantly difference in age, sex, height, weight between two groups (P>0.05). However, the heart rate in HT patients was faster than in control subjects (P<0.05).〤ompared with controls, the diameters of RA and RV were increased (P<0.05), Pulmonary artery diameter (PA) and the systolic peak velocity of PA were similar(P>0.05). The E/A value of tricuspid in HT patients were greater than in controls (P<0.05), but the RVFAC, PVVTI, Sm in HT patients were lower than in controls (P<0.05). The differential pressure of tricuspid regurgitation flow in HT patients were slightly higher than in control, without statistically significant (P>0.05).③Segmentalstrain of the HT patients and the controls had a same trend, gradually reduced from the basement to apexin RV free wall, and gradually increased from the basement to apexin interventricularseptum (IVS). The strain of the basal and middle segmentsin RV free wall were higher than in IVS (P<0.05), but the strain of apicalsegment between in RV free wall and in IVS had no significantly difference (P>0.05). Although The strain of basal segment in RV free wall and the strain of middle segment in IVS were lower in HT patients than in controls, it was not statistically significant (P>0.05), and there was no significant difference between the strain of apical segment in RV free wall in HT and in controls (P>0.05).@GLS of RV was correlated positively/inversely with these indicators:PVVTI,RV FAC,RV,Sm(r1=-0.451, P1=0.005; r2=-0.489, P2=0.002; r3=0.382, P3=0.018; r4=-0.693, P4<0.001).⑤reoperative warm ischemia time was the independent riskfactor of RV GLS (β=0.515, P=0.001, R2=0.266). Tricuspid valvular annular systolic peak velocity (Sm) after HT operation was the independent predictor for RV global strain and strain rate (/?=-0.693, P=0.000), withadjust R2=0.48. The conjointadjust R2value ofpreoperative warm ischemia time and postoperative Sm was 0.516 (β1=0.275, P1=0.036;β2=-0.579, P2=0.000).Conclusions:In this study, our conclusions are as follow:①The left ventricle in patients after heart transplantation wasreconstructed, mainly showed as the increase in left ventricular mass, and the changes in ventricular cavity size was not obvious.②Left ventricular mass increased in the early postoperative period after transplantation; the incidence of hypertension and left ventricular hypertrophyincreasedwith postoperation time. Hypertension was one of the main reasons for the development of postoperative left ventricular hypertrophy. Acute rejection was also one of the reasons for postoperative left ventricular remodeling, and the left ventricular mass increase was more obvious in patientswith acute rejection.③Left ventricular systolic function was impaired in heart transplant recipients with long-term survival and it was more serious in patients with leftventricular hypertrophy. Left ventricularhypertrophy can affect the left ventricular function. Therefore, prevention of left ventricular hypertrophy after operation can maintain the cantractilefunction of the transplantated heart.④Local and global right ventricular systolic function were impaired after hearttransplantation in patients with long-term survival. Right ventricular dysfunction was closely correlated with the preoperativewarmischemia time, rather than the early pulmonary hypertension.⑤As a commonly used tool for assessment of cardiac transplantation graft morphology and function, ultrasound technology can offera comprehensive and accurate evaluation on thegeometry and function of transplanted heart.