Serial Changes in Right Ventricular Systolic Function Among Rejection-Free Children and Young Adults After Heart Transplantation

Speckle-Tracking Echocardiography in Right Ventricular Function of Clinically Well Patients with Heart Transplantation

Heart transplantation (HT) is the mainstream therapy for end-stage heart disease. However, the cardiac graft function can be affected by several factors. It is important to monitor HT patients for signs of graft dysfunction. Transthoracic echocardiography is a simple, first-line, and non-invasive method for the assessment of cardiac function. The emerging speckle-tracking echocardiography (STE) could quickly and easily provide additive information over traditional echocardiography. STE longitudinal deformation parameters are markers of early impairment of ventricular function. Although once called the "forgotten ventricle", right ventricular (RV) assessment has gained attention in recent years. This review highlights the potentially favorable role of STE in assessing RV systolic function in clinically well HT patients.

Clinical Outcomes and Echocardiographic Predictors of Reintervention After Interrupted Aortic Arch Repair

Left ventricular outflow tract obstruction (LVOTO) remains a significant complication after primary repair of interrupted aortic arch with ventricular septal defect (IAA-VSD). Clinical and echocardiographic predictors for LVOTO reoperation are controversial and procedures to prophylactically prevent future LVOTO are not reliable. However, it is important to identify the patients at risk for future LVOTO intervention after repair of IAA-VSD. Patients who underwent single-stage IAA-VSD repair at our center 2006-2021 were retrospectively reviewed, excluding patients with associated cardiac lesions. Two-dimensional measurements, LVOT gradients, and 4-chamber (4C) and short-axis (SAXM) strain were obtained from preoperative and predischarge echocardiograms. Univariate risk analysis for LVOTO reoperation was performed using unpaired t-test. Thirty patients were included with 21 (70%) IAA subtype B and mean weight at surgery 3.0 kg. Repair included aortic arch patch augmentation in 20 patients and subaortic obstruction intervention in three patients. Seven (23%) required reoperations for LVOTO. Patient characteristics were similar between patients who required LVOT reoperation and those who did not. Patch augmentation was not associated with LVOTO reintervention. Patients requiring reintervention had significantly smaller LVOT AP diameter preoperatively and at discharge, and higher LVOT velocity, smaller AV annular diameter, and ascending aortic diameter at discharge. There was an association between LVOT-indexed cross-sectional area (CSAcm2/BSAm2) ≤ 0.7 and reintervention. There was no significant difference in 4C or SAXM strain in patients requiring reintervention. LVOTO reoperation was not associated with preoperative clinical or surgical variables but was associated with smaller LVOT on preoperative echo and smaller LVOT, smaller AV annular diameter, and increased LVOT velocity at discharge.

Feasibility Value of Right Ventricular Longitudinal Shortening Fraction and the Prognostic Implications in Patients With Heart Transplantation

BACKGROUND

Right ventricular longitudinal shortening fraction (RVLSF) is a 2-dimensional speckle tracking echocardiography parameter based on tricuspid annular displacement analysis that could be used to assess right ventricular (RV) systolic function. The value of RVLSF in the assessment of RV systolic function in recipients of heart transplantation (HT) and whether RVLSF can replace strain parameters remains unknown.

METHODS AND RESULTS

A total of 153 adult patients who underwent HT were consecutively enrolled in this prospective longitudinal study. All subjects were examined by conventional transthoracic 2-dimensional echocardiography and 2-dimensional speckle tracking echocardiography to evaluate the RV end-diastolic basal diameter, RV end-diastolic area, fractional area change, peak systolic velocity of tricuspid annulus, tricuspid annular plane systolic excursion, RV free wall strain, and RVLSF. Cox proportional hazards regression was used to test if the parameters of interest had independent prognostic value for adverse outcome prediction in patients who underwent HT. A significant positive correlation was found between the measurements of RVLSF and RV free wall strain (r=0.927, P<0.001). Compared with the event-free group, the adverse outcome group displayed reduced RVLSF and RV free wall strain and higher age (P<0.001, <0.001, =0.016, respectively) in patients who underwent HT. RVLSF and RV free wall strain were independently associated with poor prognosis in multivariable analysis (both P<0.001).

CONCLUSIONS

RVLSF assessment provides an effective evaluation of RV longitudinal systolic function in the transplanted hearts and has prognostic value for adverse outcomes in patients undergoing HT.

Echocardiographic assessment of pediatric heart transplantation: A single-center experience in China

BACKGROUND

Pediatric heart transplant (HT) has become the standard of care for end-stage heart failure in children worldwide. Serial echocardiographic evaluations of graft anatomy and function during follow-up are crucial for post-HT management. However, evolution of cardiac structure and function after pediatric HT has not been well described, especially during first year post-HT. This study aimed to characterize the evolution of cardiac structure and function after pediatric HT and investigate the correlation between biventricular function with adverse clinical outcomes.

METHODS

A single-center retrospective study of echocardiographic data obtained among 99 pediatric HT patients was conducted. Comprehensive echocardiographic examination was performed in all patients at 1-, 3-, 6-, 9- and 12-months post-HT. We obtained structural, functional and hemodynamic parameters from both left- and right-side heart, such as left ventricular stroke volume (LVSV), left ventricular ejection fraction (LVEF), right ventricular fractional area change (RVFAC), etc. The cardiac evolution of pediatric HT patients during first post-HT year was described and compared between different time points. We also explored the correlation between cardiac function and major adverse transplant events (MATEs).

RESULTS

1) Evolution of left heart parameters: left atrial length, mitral E velocity, E/A ratio, LVSV and LVEF significantly increased while mitral A velocity significantly decreased over the first year after HT (P < .05). Compared with 1 month after HT, interventricular septum (IVS) and left ventricular posterior wall (LVPW) decreased at 3 months but increased afterwards. (2) Evolution of right heart parameters: right ventricular base diameter and mid-diameter; right ventricular length diameter, tricuspid E velocity, E/A ratio, tricuspid annular velocity e' at free wall, and RVFAC increased, while tricuspid A velocity decreased over the first year after HT (P < .05). (3) Univariate logistic regression model suggests that biventricular function parameters at 1-year post-HT (LVEF, RVFAC, tricuspid annular plane systolic excursion and tricuspid lateral annular systolic velocity) were associated with MATEs.

CONCLUSION

Gradual improvement of LV and RV function was seen in pediatric HT patients within the first year. Biventricular function parameters associated with MATEs. The results of this study pave way for designing larger and longer follow-up of this population, potentially aiming at using multiparameter echocardiographic prediction of adverse events.

Tricuspid Annular Plane Systolic Excursion (TAPSE) correlates with mean pulmonary artery pressure especially 10 years after pediatric heart transplantation

Tricuspid annular plane systolic excursion (TAPSE) is important in the noninvasive echocardiographic assessment of right heart function. This retrospective observational study shows correlations of TAPSE with invasive right heart catheterization parameters after pediatric heart transplantation (HTx). The study included patients after pediatric HTx with cardiac catheterizations in 2018/2019 and measurement of TAPSE (n = 52 patients with 57 examinations; 50.9% adults, 52.6% female, median age: 18.54 years). TAPSE was compared with normal values. Stepwise, linear and multiple regression were used to show influencing variables on TAPSE. Mean TAPSE z-score was -3.48 (SD: 2.25) and 68.4% of HTx-recipients showed abnormally reduced TAPSE (z-score ←2) compared to normal values. Multiple regression (p-value <0.001; corrected R² = 0.338) showed significant correlations of time since HTx (p-value <0.001) and mPAP (p-value: 0.008) with TAPSE z-scores. Divided into subgroups (time since HTx <10 and ≥10 years), TAPSE and mPAP correlated only ≥10 years after HTx (p-value = 0.002). This study provides data of TAPSE even ≥10 years after pediatric HTx. Most patients showed a decreased TAPSE early after HTx, which improved over time. TAPSE z-scores correlated significantly with time since HTx and mPAP, especially ≥10 years post-HTx. Therefore, TAPSE must be used carefully in the early follow-up.

Serial changes of right ventricular function assessed by three-dimensional speckle-tracking echocardiography in clinically well adult heart transplantation patients

PURPOSE

The present study aimed to evaluate serial changes of right ventricular (RV) function in clinically well adult heart transplantation (HT) patients using three-dimensional speckle-tracking echocardiography (3D-STE).

METHODS

We included 58 adult HT patients, who were free from severe valvular insufficiency, severe coronary artery disease, acute rejection, or multiple organ transplantation, and 58 healthy controls. The healthy controls were matched by the distribution of age and sex with HT group. Conventional and three-dimensional (3D) echocardiography was performed in all HT patients at 1-, 3-, 6-, 9- and 12-months post-HT. And all the healthy controls underwent conventional and 3D echocardiography when recruited. Tricuspid annular plane systolic excursion (TAPSE), S' and RV fractional area change (RV FAC) were measured. Two-dimensional RV free wall longitudinal strain (2D-RV FWLS) was derived from two-dimensional speckle-tracking echocardiography (2D-STE). 3D RV free wall longitudinal strain (3D-RV FWLS) and RV ejection fraction (RVEF) were assessed by 3D-STE.

RESULTS

TAPSE, S', RV FAC, 2D-RV FWLS, 3D-RV FWLS, and RVEF increased significantly from 1 to 6 months post-HT (P < 0.05). TAPSE, S', RV FAC and 2D-RV FWLS showed no significant changes from 6 to 12 months post-HT (P > 0.05), while 3D-RV FWLS and RVEF were still significantly increased: 3D-RV FWLS (17.9 ± 1.0% vs. 18.7 ± 1.4%, P < 0.001) and RVEF (45.9 ± 2.2% vs. 46.8 ± 2.0%, P = 0.025). By 12 months post-HT, TAPSE, S', RV FAC, 2D-RV FWLS, 3D-RV FWLS and RVEF were significantly lower than the healthy controls: TAPSE (15.1 ± 2.1 mm vs. 23.5 ± 3.0 mm, P < 0.001), s' (10.3 ± 1.9 cm/s vs. 12.9 ± 2.0 cm/s, P < 0.001), RV FAC (45.3 ± 1.8% vs. 49.2 ± 3.8%, P < 0.001), 2D-RV FWLS (19.9 ± 2.3% vs. 23.5 ± 3.8%, P < 0.001), 3D-RV FWLS (18.7 ± 1.4% vs. 22.4 ± 2.3%, P < 0.001) and RVEF (46.8 ± 2.0% vs. 49.9 ± 5.7%, P < 0.001).

CONCLUSION

RV systolic function improved significantly over time in clinically well adult HT patients even up to 12 months post-HT. By 12 months post-HT, the patient's RV systolic function remained lower than the control. 3D-STE may be more suitable to assess RV systolic function in HT patients.

Prognostic Value of Exercise Stress Echocardiography in Pediatric Cardiac Transplant Recipients

BACKGROUND

Cardiac allograft vasculopathy (CAV) is a leading cause of long-term morbidity and mortality in pediatric heart transplant (HTx) recipients. Exercise stress echocardiography (ESE) has been shown to be useful in the detection of angiographically-confirmed CAD in children. However, the prognostic utility of ESE for prediction of cardiac events in HTx survivors is unknown.

STUDY AIM AND HYPOTHESIS

Therefore, we aim to assess if an abnormal (positive) ESE will be associated with a higher risk of future cardiovascular (CV) outcomes in pediatric HTx recipients.

MATERIAL AND METHODS

We conducted a retrospective review of CV outcomes of a cohort of 95 pediatric HTx recipients who underwent 188 ESE over a 10-year period. A composite endpoint for CV events including myocardial infarction, hospitalization for non-rejection heart failure, coronary revascularization, need for repeat transplantation, and death was used. Based on the interpretation of the ESE results, each ESE study was classified for this study as either positive (abnormal), or negative (normal) for ischemia. Results of the coronary angiograms performed near the time of ESE were also assessed and classified for this study as positive (abnormal) or negative (normal) for CAV according to standard HTx criteria for CAV.

RESULTS

51 (27%) ESE were positive for ischemia. There was a total of 35 CV events in 23 patients. A positive ESE was associated with increased risk of any CV event [Hazard ratio [HR] 3.55, 95% CI 1.52, 8.28, and also an increased risk of CV death (HR 3.19, 95% CI 1.23, 8.28) Freedom from composite CV outcome at 1, 2, and 3 years following a positive ESE was 89.9% (CI = 77.3%, 95.7%), 81.5% (CI = 65.9%, 90.5%), and 63.2% (CI = 41.9%, 78.5%), respectively. Freedom from composite cardiovascular outcome at 1, 2, and 3 years following a negative ESE was 99.3% (94.8, 99.9), 98.4% (93.6, 99.6), and 97.0% (90.6, 99.1) respectively. No patient died within 1 year of a negative ESE.

CONCLUSIONS

In this largest study of ESE in pediatric HTx recipients, a positive or abnormal ESE is associated with increased future cardiovascular morbidity and mortality. Conversely, a negative ESE can help predict CV event-free survival. Even in the setting of a normal ANG, our pilot data show that an abnormal ESE may be still clinically important. Use of ESE in follow-up may improve risk stratification and management of pediatric HTx recipients.

Echocardiographic assessment of radial right ventricular function in heart transplant recipients

Aims

Right ventricular (RV) allograft dysfunction is present in half of all heart transplant (HT) recipients. Non‐invasive assessment of RV function in the setting of rejection is not well described. We outline an echocardiographic technique, short‐axis fractional area change (SAXFAC), to evaluate RV function in the HT population and correlate this with the grade of pathologic rejection.

Methods and results

We retrospectively reviewed the electronic medical records of 110 people who received a HT between 1 January 2015 and 29 February 2020 and had no evidence of rejection. One hundred eighty‐two transthoracic echocardiograms (TTEs) completed up to 1 year from the date of transplantation were analysed for the target acoustic window, the parasternal mid‐ventricular short‐axis view. Sixty‐one TTEs from 23 healthy transplants were deemed appropriate for SAXFAC determination. Thirty‐three organ recipients with at least grade 1R allograft rejection were also identified, and their TTEs screened for SAXFAC analysis. Two expert readers independently calculated SAXFAC as follows: RV end‐diastolic area minus end‐systolic area divided by end‐diastolic area. Using commercially available software (Epsilon, Ann Arbor, Michigan), we quantified RV radial strain, longitudinal strain, and apical fractional area change (FAC). Twenty‐eight transplant recipients with grade 0R or 1R rejection and nine patients with clinically significant rejection completed the study analysis. SAXFAC demonstrated significant variability in the entire population with an inverse relationship to severity of allograft rejection (P ≤ 0.01). Radial strain and FAC were also associated with clinically significant rejection (P ≤ 0.01).

Conclusions

Short‐axis fractional area change is a simple two‐dimensional technique to assess RV function in HT recipients and showed no significant inter‐observer variability. In our small, single‐centre, retrospective case series, lower SAXFAC values were associated with clinically significant allograft rejection. The small sample size and infrequent occurrence of rejection make our observations hypothesis‐generating only. We advocate dedicated RV SAXFAC imaging planes be included when assessing allograft function.

Assessment of biatrial function in clinically well pediatric bicaval heart transplantation patients by three-dimensional echocardiography

Atrial size and function are closely correlated with atrial contributions to cardiovascular performance. Therefore, in this study, we aimed to assess atrial size and function in pediatric heart transplantation (HTx) patients using three-dimensional echocardiography (3DE). We enrolled 33 clinically well pediatric HTx patients and 33 healthy controls with a similar distribution of sex and age to the HTx patients. All patients underwent two-dimensional echocardiography (2DE) and 3DE. 2DE- and 3DE-derived biatrial maximal volume (Vmax), minimal volume (Vmin), ejection volume (EV), ejection fraction (EF), volume before atrial contraciton (VpreA), passive EV, passive EF, active EV and active EF were obtained in all patients. The 3D left atrail (LA) Vmax, Vmin and VpreA increased significantly in HTx patients after being indexed by BSA, while 3D LAEV and passive EV decreased significantly (P < 0.05). Moreover, the 3D LAEF, LA passive EF, and LA active EF all decreased significantly in HTx patients (P < 0.05). The 3D right atrial (RA) Vmax, Vmin, and VpreA increased significantly in HTx patients (P < 0.05), while the 3D RAEF and RA passive EF decreased significantly in HTx patients (P < 0.05). 3DE-derived LAVmax, LAVpreA, LA passive EV, LAEF, and LA passive EF were all lower than the corresponding 2D parameters. 3DE-derived RAVpreA, RA passive EV and RAEF were all lower than the corresponding 2D parameters. Atrial sizes and function assessed by 3DE- and 2DE-derived parameters, yield significantly discordant results in pediatric HTx patients. 3DE confirms significantly enlarged atrial sizes and decreased atrial functions in pediatric HTx patients.

Multi-modal imaging of the pediatric heart transplant recipient

The assessment of pediatric patients after orthotropic heart transplantation (OHT) relies heavily on non-invasive imaging. Because of the potential risks associated with cardiac catheterization, expanding the role of non-invasive imaging is appealing. Echocardiography is fast, widely available, and can provide an accurate assessment of chamber sizes and function. Advanced echocardiographic methods, such as myocardial deformation, have potential to assess for acute rejection or cardiac allograft vasculopathy (CAV). While not currently part of routine care, cardiac magnetic resonance imaging (CMR) and computed tomography may potentially aid in the detection of graft complications following OHT. In particular, CMR tissue characterization holds promise for diagnosing rejection, while quantitative perfusion and myocardial late gadolinium enhancement may have a role in the detection of CAV. This review will evaluate standard and novel methods for non-invasive assessment of pediatric patients after OHT.