Left ventricular mass and heart sympathetic activity after renal transplantation in children and young adults

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.

IGF-1 deletion affects renal sympathetic nerve activity, left ventricular dysfunction, and renal function in DOCA-salt hypertensive mice

To determine the influence of IGF-1 deletion on renal sympathetic nerve activity (RSNA), left ventricular dysfunction, and renal function in deoxycorticosterone acetate (DOCA)-salt hypertensive mice. The DOCA-salt hypertensive mice models were constructed and the experiment was classified into WT (Wild-type mice) +sham, LID (Liver-specific IGF-1 deficient mice) + sham, WT + DOCA, and LID+ DOCA groups. Enzyme-linked immunosorbent assay (ELISA) was used to detect the serum IGF-1 levels in mice. The plasma norepinephrine (NE), urine protein, urea nitrogen and creatinine, as well as RSNA were measured. Echocardiography was performed to assess left ventricular dysfunction, and HE staining to observe the pathological changes in renal tissue of mice. DOCA-salt induction time-dependently increased the systolic blood pressure (SBP) of mice, especially in DOCA-salt LID mice. Besides, the serum IGF-1 levels in WT mice were decreased after DOCA-salt induction. In addition, the plasma NE concentration and NE spillover, urinary protein, urea nitrogen, creatinine and RSNA were remarkably elevated with severe left ventricular dysfunction, but the creatinine clearance was reduced in DOCA-salt mice, and these similar changes were obvious in DOCA-salt mice with IGF-1 deletion. Moreover, the DOCA-salt mice had tubular ectasia, glomerular fibrosis, interstitial cell infiltration, and increased arterial wall thickness, and the DOCA-salt LID mice were more serious in those aspects. Deletion of IGF-1 may lead to enhanced RSNA in DOCA-salt hypertensive mice, thereby further aggravating left ventricular dysfunction and renal damage.

Cardiovascular Autonomic Dysfunction in Chronic Kidney Disease: a Comprehensive Review

Cardiovascular autonomic dysfunction is a major complication of chronic kidney disease (CKD), likely contributing to the high incidence of cardiovascular mortality in this patient population. In addition to adrenergic overdrive in affected individuals, clinical and experimental evidence now strongly indicates the presence of impaired reflex control of both sympathetic and parasympathetic outflow to the heart and vasculature. Although the principal underlying mechanisms are not completely understood, potential involvements of altered baroreceptor, cardiopulmonary, and chemoreceptor reflex function, along with factors including but not limited to increased renin-angiotensin-aldosterone system activity, activation of the renal afferents and cardiovascular structural remodeling have been suggested. This review therefore analyzes potential mechanisms underpinning autonomic imbalance in CKD, covers results accumulated thus far on cardiovascular autonomic function studies in clinical and experimental renal failure, discusses the role of current interventional and therapeutic strategies in ameliorating autonomic deficits associated with chronic renal dysfunction, and identifies gaps in our knowledge of neural mechanisms driving cardiovascular disease in CKD.

Direct conscious telemetry recordings demonstrate increased renal sympathetic nerve activity in rats with chronic kidney disease

Chronic kidney disease (CKD) is associated with sympathetic hyperactivity and impaired blood pressure control reflex responses, yet direct evidence demonstrating these features of autonomic dysfunction in conscious animals is still lacking. Here we measured renal sympathetic nerve activity (RSNA) and mean arterial pressure (MAP) using telemetry-based recordings in a rat model of CKD, the Lewis Polycystic Kidney (LPK) rat, and assessed responses to chemoreflex activation and acute stress. Male LPK and Lewis control animals (total n = 16) were instrumented for telemetric recording of RSNA and MAP. At 12–13 weeks-of-age, resting RSNA and MAP, sympathetic and haemodynamic responses to both peripheral (hypoxia: 10% O₂) and central chemoreflex (hypercapnia: 7% CO₂) activation and acute stress (open-field exposure), were measured. As indicators of renal function, urinary protein (U_Pro) and creatinine (U_Cr) levels were assessed. LPK rats had higher resting RSNA (1.2 ± 0.1 vs. 0.6 ± 0.1 μV, p < 0.05) and MAP (151 ± 8 vs. 97 ± 2 mmHg, p < 0.05) compared to Lewis. MAP was negatively correlated with U_Cr (r = −0.80, p = 0.002) and positively correlated with RSNA (r = 0.66, p = 0.014), with multiple linear regression modeling indicating the strongest correlation was with U_cr. RSNA and MAP responses to activation of the central chemoreflex and open-field stress were reduced in the LPK relative to the Lewis (all p < 0.05). This is the first description of dual conscious telemetry recording of RSNA and MAP in a genetic rodent model of CKD. Elevated RSNA is likely a key contributor to the marked hypertension in this model, while attenuated RSNA and MAP responses to central chemoreflex activation and acute stress in the LPK indicate possible deficits in the neural processing of autonomic outflows evoked by these sympathoexcitatory pathways.

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.

Left ventricular mass in dialysis patients, determinants and relation with outcome. Results from the COnvective TRansport STudy (CONTRAST)

BACKGROUND AND OBJECTIVES

Left ventricular mass (LVM) is known to be related to overall and cardiovascular mortality in end stage kidney disease (ESKD) patients. The aims of the present study are 1) to determine whether LVM is associated with mortality and various cardiovascular events and 2) to identify determinants of LVM including biomarkers of inflammation and fibrosis.

DESIGN SETTING PARTICIPANTS & MEASUREMENTS

Analysis was performed with data of 327 ESKD patients, a subset from the CONvective TRAnsport STudy (CONTRAST). Echocardiography was performed at baseline. Cox regression analysis was used to assess the relation of LVM tertiles with clinical events. Multivariable linear regression models were used to identify factors associated with LVM.

RESULTS

Median age was 65 (IQR: 54-73) years, 203 (61%) were male and median LVM was 227 (IQR: 183-279) grams. The risk of all-cause mortality (hazard ratio (HR) = 1.73, 95% CI: 1.11-2.99), cardiovascular death (HR = 3.66, 95% CI: 1.35-10.05) and sudden death (HR = 13.06; 95% CI: 6.60-107) was increased in the highest tertile (>260 grams) of LVM. In the multivariable analysis positive relations with LVM were found for male gender (B = 38.8±10.3), residual renal function (B = 17.9±8.0), phosphate binder therapy (B = 16.9±8.5), and an inverse relation for a previous kidney transplantation (B = -41.1±7.6) and albumin (B = -2.9±1.1). Interleukin-6 (Il-6), high-sensitivity C-reactive protein (hsCRP), hepcidin-25 and connective tissue growth factor (CTGF) were not related to LVM.

CONCLUSION

We confirm the relation between a high LVM and outcome and expand the evidence for increased risk of sudden death. No relationship was found between LVM and markers of inflammation and fibrosis.

TRIAL REGISTRATION

Controlled-Trials.com ISRCTN38365125.

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.

Cardiac magnetic resonance imaging in children with chronic kidney disease and renal transplantation

CV disease is the major cause of death in patients with CKD. Recently, CMR imaging emerges as a complementary method providing advantages in cardiac assessment; however, data on CMR in pediatric CKD are scarce. We performed CMR in 15 children: two with CKD, six on peritoneal dialysis, seven on hemodialysis, and in 18 children 5.1 (0.4-15.4) yr after kidney Tx. Eight children underwent CMR six months before and after Tx. Results are presented as mean z score ± SD. LV EF was higher and in the normal range in Tx patients compared with CKD (-0.3 ± 1 vs. -2.1 ± 1.6, respectively, p < 0.05), whereas RV EF was similar (-0.9 ± 1.4 vs. -0.9 ± 1.8, p = n.s.). End-diastolic and end-systolic LV volume index (0 ± 1.7 vs. 2.1 ± 3.1; 0.2 ± 1.2 vs. 3.1 ± 3.7, both p < 0.05) and LV mass index (1.4 ± 1.5 vs. 3.4 ± 2.9, p < 0.05) were lower in Tx children. All parameters improved in the eight children after Tx. In conclusion, our CMR analysis suggests marked improvement of cardiac function and morphology in children after kidney Tx. CMR might be an appropriate complementary method for measuring detailed cardiac status in children with CKD.

Cardiovascular disease in CKD in children: update on risk factors, risk assessment, and management

In young adults with onset of chronic kidney disease in childhood, cardiovascular disease is the most common cause of death. The likely reason for increased cardiovascular disease in these patients is a high prevalence of traditional and uremia-related cardiovascular disease risk factors during childhood chronic kidney disease. Early markers of cardiomyopathy, such as left ventricular hypertrophy and left ventricular dysfunction, and early markers of atherosclerosis, such as increased carotid artery intima-media thickness, carotid arterial wall stiffness, and coronary artery calcification, frequently are found in this patient population. The purpose of this review is to provide an update of recent advances in the understanding and management of cardiovascular disease risks in this population.

Cardiac dysfunction after renal transplantation; incomplete resolution in pediatric population

BACKGROUND

Long-term data of cardiac function after renal transplantation (RT) are limited, especially in children. Thus, we evaluated the status of left ventricular hypertrophy and various indices of left ventricular (LV) function in pediatric RT patients.

METHODS

Blood pressure, serum biochemical profiles, electrocardiogram, and echocardiogram of 32 pediatric patients (mean age, 15.5+/-4.4 years) who underwent RT 5.1+/-2.5 years before and 29 body surface area-matched control subjects were studied.

RESULTS

Repolarization abnormalities shown on electrocardiogram of pre-RT patients improved significantly after RT (QTc dispersion 50.8+/-37.3 to 37.4+/-11.9 msec, P=0.009). Left ventricular hypertrophy with increased LV mass index of pre-RT patients regressed remarkably after RT (LV mass index 120.9+/-40.5 to 69.2+/-14.5 g/m2, P<0.001); still, LV mass was significantly higher in RT patients than the controls (54.0+/-9.6 g/m2, P<0.001). Compared with the controls, the RT patients showed diastolic dysfunction (lower E/A ratio and higher isovolumic relaxation time) and lower myocardial performance (higher LV Tei index and weaker strain pattern). Patients who had shorter duration of non-RT renal replacement therapy showed better LV function (lower LV Tei index and stronger strain pattern) in the long-term follow-up.

CONCLUSIONS

Because cardiac dysfunction did not resolve after RT in pediatric population, regular evaluation for cardiovascular function after RT is required. Early RT may also be beneficial to global LV performance after RT.