Cardiac dysfunction after renal transplantation; incomplete resolution in pediatric population

Changes in Cardiac Structure and Function of Recipients after Kidney Transplantation

Background: Chronic kidney disease (CKD) elevates the risk of cardiovascular disease (CVD) and mortality. Uremic cardiomyopathy, frequently observed in CKD and end-stage renal disease (ESRD), involves alterations in cardiac structure and function, which may reverse post-kidney transplantation, although data remain controversial. This study examines the relationship between graft function and changes in cardiac parameters pre- and post-transplantation in kidney transplant recipients. Methods: A total of 145 pediatric and adult recipients of living or deceased donor kidney transplants were enrolled at Gazi Yaşargil Training and Research Hospital. This cohort study utilized transthoracic echocardiographic (TTE) imaging pre-transplant and at least two years post-transplant. Echocardiographic parameters were analyzed using standard techniques. Results: The mean age of the participants was 35 years, with 60% male. The average dialysis duration prior to transplantation was 27 months. Most recipients (83.4%) received kidneys from living donors. Left ventricular diastolic dysfunction increased significantly post-transplant (p < 0.05), while other cardiac dimensions and functions, such as ejection fraction and pulmonary artery pressure, showed no significant change (p > 0.05). Notably, diastolic dysfunction worsened in patients with dysfunctional grafts (GFR < 45), correlating with increased pulmonary artery pressure post-transplant. The rate of antihypertensive drug use and the prevalence of diabetes mellitus increased significantly post-transplant (p < 0.05). Conclusions: This study demonstrates that left ventricular diastolic dysfunction present before kidney transplantation continues to persist post-transplantation in patients with end-stage renal disease undergoing chronic kidney disease treatment. Furthermore, it shows an increased rate of pulmonary artery pressure and pericardial effusion in patients with dysfunctional grafts after transplantation. Further research is required to explore strategies to reverse uremic cardiomyopathy and reduce cardiovascular risk in these patients.

Echocardiogram screening in pediatric dialysis and transplantation

Transthoracic echocardiography is commonly used to identify structural and functional cardiac abnormalities that can be prevalent in childhood chronic kidney failure (KF). Left ventricular mass (LVM) increase is most frequently reported and may persist post-kidney transplant especially with hypertension and obesity. While systolic dysfunction is infrequently seen in childhood chronic KF, systolic strain identified by speckle tracking echocardiography has been frequently identified in dialysis and it can also persist post-transplant. Echocardiogram association with long-term outcomes has not been studied in childhood KF but there are many adult studies demonstrating associations between increased LVM, systolic dysfunction, strain, diastolic dysfunction, and cardiovascular events and mortality. There has been limited study of interventions to improve echocardiogram status. In childhood, improved blood pressure has been associated with better LVM, and conversion from hemodialysis to hemodiafiltration has been associated with better diastolic and systolic function. Whether long-term cardiac outcomes are also improved with these interventions is unclear. Echocardiography is a well-established technique, and regular use in childhood chronic KF seems justified. A case can be made to extend screening to include speckle tracking echocardiography and intradialytic studies in high-risk populations. Further longitudinal studies including these newer echocardiogram modalities, interventions, and long-term outcomes would help clarify recommendations for optimal use as a screening tool.

Risk Assessment for Arrhythmia in Pediatric Renal Transplant Recipients

OBJECTIVES

Renal transplant recipients are at risk for ventricular arrhythmia and sudden death. To assess that risk, we compared the ventricular repolarization markers of pediatric renal transplant recipients with those of healthy children.

MATERIALS AND METHODS

We included 30 children and adolescents who were followed for at least 6 months after renal transplant; 30 age- and sex-matched children were included for the control group. Demographic features, medications, and laboratory findings were recorded. Blood pressure measurements, ventricular repolarization indexes including QT dispersion, corrected QT dispersion, T-wave peak-to-end interval dispersion, the T-wave peak-to-end interval∕QT ratio, the T-wave peak-to-end interval∕corrected QT ratio, left ventricular mass index, and relative wall thickness were compared between groups. In addition, the correlations of ventricular repolarization indexes with other variables were evaluated.

RESULTS

Blood pressure standard deviation scores, the mean heart rate, QT dispersion, corrected QT dispersion, the T-wave peak-to-end interval∕QT ratio, the T-wave peak-to-end interval/corrected QT ratio, left ventricular mass index, and relative wall thickness values were significantly higher in renal transplant patients, whereas T-wave peak-to-end interval dispersion, ejection fraction, and fractional shortening were similar between groups. Although ventricular repolarization indexes were similar in patients with and without left ventricular hypertrophy, only corrected QT dispersion was significantly higher in patients with hypertension (P = .006). The only variable that significantly predicted prolonged corrected QT dispersion was the systolic blood pressure standard deviation score (P = .005, β = .403).

CONCLUSIONS

Ventricular repolarization anomalies, hypertension, left ventricular hypertrophy, and cardiac geometry irregularity may be observed after renal transplant in pediatric recipients despite acceptable allograft functions and normal serum electrolyte levels. Control of systolic blood pressure would decrease the risk of ventricular repolarization abnormalities, namely, the corrected QT dispersion. Follow-up of cardiovascular risks with noninvasive methods is recommended in all pediatric renal transplant recipients.

The effect of different treatment strategies on left ventricular myocardial deformation parameters in patients with chronic renal failure

The aim of this study was to compare left ventricular (LV) functions by speckle tracking echocardiography (STE) in chronic kidney disease (CKD) patients in various stages and under different renal replacement treatments in order to evaluate possible differences between them. This prospective study included 150 patients with CKD. Renal transplantation patients with glomerular filtration rate greater than 60 ml/min/1.73 m², patients receiving hemodialysis three times a week, and patients in the predialysis stage with glomerular filtration rate less than 30 ml/dk/1.73 m² were assigned into Group 1 (n = 50), Group 2 (n = 50), and Group 3 (n = 50), respectively. LV longitudinal, circumferential, and radial myocardial deformation parameters (strain, strain rate [SR], rotation, twist) were evaluated by STE. Peak systolic longitudinal strain was higher in the transplantation group than the hemodialysis group (- 19.93 ± 3.50 vs - 17.47 ± 3.28%, p < 0.017). Peak systolic circumferential strain was lower in the hemodialysis group (- 20.97 ± 4.90%) than Groups 1 and 3 (- 25.87 ± 4.20 and - 24.74 ± 4.55%, respectively, p < 0.001). Peak systolic radial SR was higher in the transplantation group than the hemodialysis group (1.84 ± 0.52 vs 1.55 ± 0.52 s^-1, respectively, p < 0.017). Other longitudinal and circumferential deformation parameters together with peak early diastolic radial SR and twist were also significantly different between the groups. Strain, SR, and twist values were mostly lower in the hemodialysis patients, but generally higher in the transplantation patients. LV functions evaluated by STE are better in the renal transplantation patients than the hemodialysis patients and than those in the predialysis stage. This may indicate beneficial effects of renal transplantation on cardiac functions.

Longitudinal assessment of myocardial function in childhood chronic kidney disease, during dialysis, and following kidney transplantation

BACKGROUND

Childhood chronic kidney disease (CKD) and dialysis are associated with increased long-term cardiovascular risk. We examined subclinical alterations in myocardial mechanics longitudinally in children with CKD, during dialysis, and following renal transplantation.

METHODS

Forty-eight children with CKD (stage III or higher) who received kidney transplants from 2008 to 2014 were included in a retrospective study and compared to 192 age- and sex-matched healthy children. Measurements of cardiac systolic and diastolic function were performed, and global longitudinal strain (GLS) and circumferential strain (GCS) were measured by speckle-tracking echocardiography at CKD, during dialysis, and 1 year following kidney transplantation. Mixed-effects modeling examined changes in GLS and GCS over different disease stages.

RESULTS

Children with CKD had a mean age of 10 ± 5 years and 67% were male. Eighteen children received preemptive transplantation. Children with CKD had increased left ventricular mass, lower GLS, and impaired diastolic function (lower E/A ratio and E' velocities) than healthy children. Changes in left ventricular diastolic parameters persisted during dialysis and after renal transplantation. Dialysis was associated with reduced GLS compared to CKD (β = 1.6, 95% confidence interval 0.2-3.0); however, this was not significant after adjustment for systolic blood pressure and CKD duration. Post-transplantation GLS levels were similar to those at CKD assessment. GCS was unchanged during dialysis but significantly improved following transplantation.

CONCLUSIONS

There are differences in diastolic parameters in childhood CKD that persist during dialysis and after transplantation. Systolic parameters are preserved, with significant improvement in systolic myocardial deformation following transplantation. The impact of persistent diastolic changes on long-term outcomes requires further investigation.

Myocardial Performance Index in Childhood Onset Essential Hypertension and White Coat Hypertension

BACKGROUND

As a global measure of ventricular systolic and diastolic function, the myocardial performance index (MPI) can be an early indicator of hypertensive cardiomyopathy in children with essential hypertension (EH).

METHODS

Children with untreated newly diagnosed EH and white coat hypertension (WCH) by a 24-hour ambulatory blood pressure monitoring (ABPM), both groups without any identifiable etiology for the hypertension, were enrolled for the study. Echocardiograms and vascular ultrasounds for carotid artery intimal medial thickness were performed on all children prior to therapy. Diastolic function (peak E and A velocities, E/A ratio, isovolumic relaxation time, and deceleration times) and MPI were evaluated by simultaneous transmitral and transaortic spectral Doppler flow velocities. Systolic function was evaluated by shortening fraction and ejection fraction.

RESULTS

A cohort of 66 children (24 with EH, 42 with WCH, males 61%, median age of 13 years, range 10-17 years) were enrolled in the study. The demographic, anthropometric, laboratory tests, vascular ultrasound, and conventional echocardiographic parameters were similar between the 2 groups. There was a very small difference in MPI between the EH and WCH children (0.28 SD: 0.07 vs. 0.31 SD: 0.08, P = 0.045). However, in EH children, MPI increased by 0.14 units for every 10 unit increase in mean ABPM systolic BP (95% confidence interval: 0.03-0.25).

CONCLUSIONS

We found the increasing MPI was associated with increasing 24-hour mean systolic BP in children with EH. Therefore, MPI may have utility as a single, quick, noninvasive method of detection and tracking of subclinical hypertensive heart disease.

A longitudinal retrospective analysis of left ventricular mass in a cohort of pediatric kidney transplant recipients

Childhood end-stage kidney disease is associated with increased risk for early adulthood cardiovascular (CV) morbidity and mortality. Increased LVM is an early indicator of CV disease. Previous studies have suggested that LVM decreases after kidney transplantation; however, trends have been inconsistent. A single center retrospective longitudinal cohort analysis of LVM, documented annually, starting before kidney transplantation for up to 10 yr after transplantation was performed. BP documented by annual 24-h ambulatory monitoring studies, and BMI values were also reviewed. Twenty-seven children followed for a mean period of 5.3 yr were included. Depending on definition of LVH, its prevalence pretransplant and in the first years post-transplant was up to 33% dropping to 0-25% thereafter. Individual longitudinal LVM z-score trends were highly variable but generally trended toward the mean immediately after transplant and toward negative values in the following years. BP was stable during the follow-up period while mean annual BMI increased in the first-year post-transplant but declined thereafter. In a cohort of pediatric renal transplant recipients, prevalence of LVH decreased after transplant; however, individual longitudinal LVM trends were highly variable among patients. Prospective studies are needed to correlate individual LVM trends with outcomes.

Long-term outcomes of children after solid organ transplantation

Solid organ transplantation has transformed the lives of many children and adults by providing treatment for patients with organ failure who would have otherwise succumbed to their disease. The first successful transplant in 1954 was a kidney transplant between identical twins, which circumvented the problem of rejection from MHC incompatibility. Further progress in solid organ transplantation was enabled by the discovery of immunosuppressive agents such as corticosteroids and azathioprine in the 1950s and ciclosporin in 1970. Today, solid organ transplantation is a conventional treatment with improved patient and allograft survival rates. However, the challenge that lies ahead is to extend allograft survival time while simultaneously reducing the side effects of immunosuppression. This is particularly important for children who have irreversible organ failure and may require multiple transplants. Pediatric transplant teams also need to improve patient quality of life at a time of physical, emotional and psychosocial development. This review will elaborate on the long-term outcomes of children after kidney, liver, heart, lung and intestinal transplantation. As mortality rates after transplantation have declined, there has emerged an increased focus on reducing longer-term morbidity with improved outcomes in optimizing cardiovascular risk, renal impairment, growth and quality of life. Data were obtained from a review of the literature and particularly from national registries and databases such as the North American Pediatric Renal Trials and Collaborative Studies for the kidney, SPLIT for liver, International Society for Heart and Lung Transplantation and UNOS for intestinal transplantation.

Left ventricular function in children and adults after renal transplantation in childhood

BACKGROUND

Renal transplantation improves left ventricular (LV) function, but cardiovascular mortality remains elevated. The aim of this cross-sectional study was to determine whether subclinical abnormalities of LV longitudinal function also persist in patients who underwent renal transplant in childhood.

METHODS

Conventional and speckle tracking echocardiography was performed in 68 renal transplant recipients (34 children and 34 adults, median 9.8 years (range 2.0-28.4 years) after first transplantation and 68 age- and sex-matched healthy controls.

RESULTS

Mean age at first transplantation was 8.8 ± 4.8 years. Forty-three percent had a pre-emptive transplant. Of the remaining, 70% received haemodialysis and 30% peritoneal dialysis on average for 6.9 months. Thirty-one percent of paediatric and 35% of adult patients had hypertension. LV mass index was increased in adult patients (92 ± 24 vs 75 ± 11 g/m(2), P< 0.01). LV diastolic function and exercise capacity were impaired in both paediatric and adult patients. LV longitudinal peak systolic strain and strain rate were comparable in patients and controls. In multivariate analysis, systolic blood pressure and LV diastolic relaxation were the main covariates of LV peak systolic strain and strain rate (all P < 0.01).

CONCLUSIONS

Patients who underwent renal transplantation in childhood have abnormal LV diastolic function and impaired exercise capacity, despite preserved LV longitudinal systolic deformation.

Cardiorespiratory fitness in young adults with a history of renal transplantation in childhood

Limited knowledge exists on cardiorespiratory fitness (CR fitness) in adults having a renal transplant (Rtx) during childhood. Our aim was to assess CR fitness (V0(2peak)) with a maximal treadmill test in former Rtx children reaching adulthood (ped-tx, n = 31), compared to patients Rtx as adults (adult-tx, n = 17) and healthy controls (HC, n = 36). Median age was 26.9 (19-41), 28.6 (23.5-34) and 33.5 (20-42) years, respectively. Median time since first Rtx was 18.1 (7-29) and 3.7 (1.2-12.6) years. Body composition was measured by dual-energy X-ray absorptiometry (DXA). V0(2peak) was median 37.9 (12.5-56.3), 40.8 (26.5-57.5), and 44.4 (29.5-65.6) ml kg (-1)min (-1) in the ped-tx, adult-tx, and HC, respectively. Ped-tx had significantly lower V0(2peak) compared to HC (p = 0.01). Adult-tx had higher exercise capacity (test duration) compared to ped-tx (median 10.5 (7.5-16) and 9 (6-14) min, respectively (p = 0.016). In multiple linear regression analysis, test duration, fat-free mass (FFM, kg) and Hgb (g/dl) were significant predictors of V0(2peak) explaining 86% of its variance. There was no significant difference between ped-tx and adult-tx in V0(2peak.) CR fitness depicts long-term health outcome in Rtx patients both in regard to physical functioning and is a plausible indirect marker of CV health.