Carotid intima-media thickness in children and young adults with renal transplant: Internal carotid artery vs. common carotid artery

Long-term Effects of Kidney Transplantation Compared With Dialysis on Intima-media Thickness in Children-Results From the 4C-T Study

BACKGROUND

Children requiring kidney replacement therapy experience high burden of cardiovascular (CV) disease leading to increased mortality. Intima-media thickness (IMT) indicating atherosclerosis is a validated surrogate marker for future CV events.

METHODS

We investigated the effect of different treatment modalities (dialysis, preemptive kidney transplantation (KTx), late KTx after dialysis) on IMT by multivariable linear mixed-effect modeling. Patients were enrolled in a prospective cohort study.

RESULTS

A total of 261 analyzed children had a mean follow-up of 3 y. Children after preemptive and late KTx had lower levels of IMT when compared with dialysis. Using an interaction term, a significant progression of IMT over time was seen during dialysis (β = 0.0053 mm/y, P   =  0.004). IMT before the start of therapy was the most influential determinant in all models. Low IMT was associated with maintenance steroid treatment after preemptive KTx. High IMT on dialysis was associated with higher systolic blood pressure, lower body mass index, lower serum albumin, and lower bicarbonate.

CONCLUSIONS

IMT remained rather stable in children several years after KTx. In contrast, children on dialysis had higher IMT values, which increased over time. In these children, blood pressure control, calorie and protein intake, and acid-base homeostasis seem important. Taken together, children might profit from early transplantation to limit accumulation of CV risk.

Relation Between Calcium-Phosphorus Product and Total Coronary Artery Occlusion in a Nonchronic Kidney Disease Population: A Cross-Sectional Study

Excessive calcium-phosphorus product (Ca-P product) in patients with chronic kidney disease (CKD) is associated with coronary artery calcification and coronary artery disease, but the relation between Ca-P product and coronary artery disease in non-CKD populations has rarely been reported. Therefore, we designed a cross-sectional study to investigate the role of Ca-P product in total coronary artery occlusion (TCAO) in a non-CKD population. We reviewed 983 patients who underwent coronary angiography at Guangyuan Central Hospital from February 2018 to January 2020. Ca-P product (mg2/dl2) was calculated as Ca (mmol/L) × 4 × P (mmol/L) × 3.1 and was analyzed as a continuous and tertiary variable. TCAO was defined as complete occlusion of any coronary artery by coronary angiography (thrombolysis in myocardial infarction flow grade 0). Statistical analysis was performed using univariate and multivariate logistic regression models and restricted cubic splines. Univariate logistic regression analysis showed a statistically significant association between Ca-P product and TCAO (odds ratio [OR] 0.97, 95% confidence interval [CI] 0.95 to 0.99, p <0.001). After stepwise adjustment for covariates, the risk of TCAO was reduced by 40% in the high versus low Ca-P group (OR 0.6, 95% CI 0.38 to 0.95, p = 0.031), and the risk of TCAO was predicted to decrease by 4% (OR 0.96, 95% CI 0.94 to 0.99, p = 0.006) for each unit increase in Ca-P product. Restricted cubic splines showed a nonlinear relation between Ca-P product and TCAO, with a significant decrease in the risk of TCAO after reaching 27.46 (nonlinear p = 0.047). In conclusion, in non-CKD populations, a higher Ca-P product (≥27.46 mg2/dl2) may help avoid TCAO.

Cardiovascular involvement after liver transplantation: role of non-alcoholic fatty liver disease and non-alcoholic steatohepatitis

Patients submitted to liver transplantation (LT) are exposed to high risk of cardiovascular (CV) complications which are the main determinants of both short-term and long-term morbidity and mortality in LT. Non-alcoholic fatty liver disease (NAFLD) is a very frequent condition in general population and is associated with a high risk of cardiovascular disease (CVD) which represents the first cause of death of these patients. NAFLD is predicted to become the first indication to LT and nowadays is also frequently detected in patients submitted to LT for other indications. Thus, the risk of CVD in patients submitted to LT is forecasted to increase in the next years. In this review the extent of CV involvement in patients submitted to LT and the role of NAFLD, either recurring after transplantation or as de novo presentation, in increasing CV risk is analysed. The risk of developing metabolic alterations, including diabetes, hypertension, dyslipidemia and weight gain, all manifestations of metabolic syndrome, occurring in the first months after LT, is depicted. The different presentations of cardiac involvement, represented by early atherosclerosis, coronary artery disease, heart failure and arrhythmias in patients with NAFLD submitted to LT is described. In addition, the tools to detect cardiac alterations either before or after LT is reported providing the possibility for an early diagnosis of CVD and an early therapy able to reduce morbidity and mortality for these diseases. The need for long-term concerted multidisciplinary activity with dietary counseling and exercise combined with drug treatment of all manifestations of metabolic syndrome is emphasized.

Evaluation of carotid intima-media thickness and factors associated with cardiovascular disease in children and adolescents with chronic kidney disease

OBJECTIVE

To assess the carotid intima-media thickness and factors associated with cardiovascular disease in children and adolescents with chronic kidney disease.

MATERIAL AND METHODS

Observational, cross-sectional study carried out at the Universidade Federal de São Paulo (chronic kidney disease outpatient clinics) with 55 patients (60% males) with a median age of 11.9 years (I25-I75: 9.2-14.8 years). Of the 55 patients, 43 were on conservative treatment and 12 were on dialysis. Serum laboratory parameters (creatinine, uric acid, C-reactive protein, total cholesterol and fractions, and triglycerides), nutritional status (z-score of body mass index, z-score of height/age), body fat (fat percentage and waist circumference), and blood pressure levels were evaluated. The carotid intima-media thickness measure was evaluated by a single ultrasonographer and compared with percentiles established according to gender and height. Data collection was performed between May 2015 and March 2016.

RESULTS

Of the children and adolescents with chronic kidney disease, 74.5% (95% CI: 61.0; 85.3) showed an increase (>P95) in carotid intima-media thickness. In patients with stages I and II hypertension, 90.9% had increased carotid intima-media thickness. Nutritional status, body fat and laboratory tests were not associated with increased carotid intima-media thickness. After multivariate adjustment, only puberty (PR=1.30, p=0.037) and stages I and II arterial hypertension (PR=1.42, p=0.011) were independently associated with carotid intima-media thickness alterations.

CONCLUSION

The prevalence of increased carotid thickness was high in children and adolescents with chronic kidney disease. Puberty and arterial hypertension were independently associated with increased carotid intima-media thickness.

Increased carotid intima-media thickness in African American pediatric kidney transplant recipients

Early signs of subclinical CV dysfunction can be detected by ultrasound for CIMT. Although A-A are at high risk for CV disease, CIMT of A-A kidney transplant recipients has not been previously investigated. The aim of this prospective, controlled, longitudinal study was to investigate determinants of CIMT in a multiracial pediatric kidney transplant population, with a focus on A-A. Transplant recipients (n = 42) had BMI, waist-to-height ratio, fasting glucose, lipid panel, HbA1c%, and CIMT measured at 1, 18, and 30 months post-transplant. Twenty-four healthy children (14 A-A) served as controls. CIMT of A-A transplant (0.49, 0.49, and 0.48 mm) was higher than non-AA transplant (0.43, 0.44, and 0.44 mm) at 1, 18, and 30 months and higher than A-A controls (0.47 mm). Hyperparathyroidism prior to transplant predicted high CIMT-for-race. A-A race was associated with 10% higher CIMT vs non-A-A transplant. Metabolic syndrome was associated with 0.03 ± 0.01 mm increase in CIMT among A-A transplant recipients only. In conclusion, A-A kidney transplant recipients have increased CIMT. Metabolic syndrome disproportionately affects CIMT of A-A children post-transplant. Identification of subclinical CV damage, detected by CIMT, may provide an opportunity for early detection of CV risk in this vulnerable population.

Cardiovascular effects of metabolic syndrome after transplantation: convergence of obesity and transplant-related factors

Children are at increased risk of developing metabolic syndrome (MS) after kidney transplantation, which contributes to long-term cardiovascular (CV) morbidities and decline in allograft function. While MS in the general population occurs due to excess caloric intake and physical inactivity, additional chronic kidney disease and transplant-related factors contribute to the development of MS in transplant recipients. Despite its significant health consequences, the interplay of the individual components in CV morbidity in pediatric transplant recipients is not well understood. Additionally, the optimal methods to detect early CV dysfunction are not well defined in this unique population. The quest to establish clear guidelines for diagnosis is further complicated by genetic differences among ethnic groups that necessitate the development of race-specific criteria, particularly with regard to individuals of African descent who carry the apolipoprotein L1 variant. In children, since major CV events are rare and traditional echocardiographic measures of systolic function, such as ejection fraction, are typically well preserved, the presence of CV disease often goes undetected in the early stages. Recently, new noninvasive imaging techniques have become available that offer the opportunity for early detection. Carotid intima-media thickness and impaired myocardial strain detected by speckle tracking echocardiography or cardiac magnetic resonance are emerging as early and sensitive markers of subclinical CV dysfunction. These highly sensitive tools may offer the opportunity to elucidate subtle CV effects of MS in children after transplantation. Current knowledge and future directions are explored in this review.

Hypertension in the Pediatric Kidney Transplant Recipient

Hypertension after kidney transplant is a frequent occurrence in pediatric patients. It is a risk factor for graft loss and contributes to the significant burden of cardiovascular disease (CVD) in this population. The etiology of posttransplant hypertension is multifactorial including donor factors, recipient factors, medications, and lifestyle factors similar to those prevalent in the general population. Ambulatory blood pressure monitoring has emerged as the most reliable method for measuring hypertension in pediatric transplant recipients, and many consider it to be essential in the care of these patients. Recent technological advances including measurement of carotid intima-media thickness, pulse wave velocity, and myocardial strain using specked echocardiography and cardiac magnetic resonance imaging have improved our ability to assess CVD burden. Since hypertension remains underrecognized and inadequately treated, an early diagnosis and an appropriate control should be the focus of therapy to help improve patient and graft survival.

Cardiovascular risk after orthotopic liver transplantation, a review of the literature and preliminary results of a prospective study

Improved surgical techniques and greater efficacy of new anti-rejection drugs have significantly improved the survival of patients undergoing orthotopic liver transplantation (OLT). This has led to an increased incidence of metabolic disorders as well as cardiovascular and cerebrovascular diseases as causes of morbidity and mortality in OLT patients. In the last decade, several studies have examined which predisposing factors lead to increased cardiovascular risk (i.e., age, ethnicity, diabetes, NASH, atrial fibrillation, and some echocardiographic parameters) as well as which factors after OLT (i.e., weight gain, metabolic syndrome, immunosuppressive therapy, and renal failure) are linked to increased cardiovascular mortality. However, currently, there are no available data that evaluate the development of atherosclerotic damage after OLT. The awareness of high cardiovascular risk after OLT has not only lead to the definition of new but generally not accepted screening of high risk patients before transplantation, but also to the need for careful patient follow up and treatment to control metabolic and cardiovascular pathologies after transplant. Prospective studies are needed to better define the predisposing factors for recurrence and de novo occurrence of metabolic alterations responsible for cardiovascular damage after OLT. Moreover, such studies will help to identify the timing of disease progression and damage, which in turn may help to prevent morbidity and mortality for cardiovascular diseases. Our preliminary results show early occurrence of atherosclerotic damage, which is already present a few weeks following OLT, suggesting that specific, patient-tailored therapies should be started immediately post OLT.

Subclinical cardiovascular changes in pediatric solid organ transplant recipients: A systematic review and meta-analysis

CV disease is a major cause of morbidity and mortality following solid organ transplantation in adults. While the prevalence of multiple cardiometabolic risk factors is increased in pediatric solid organ transplant recipients, it is not clear whether they have subclinical CV changes. cIMT, central pWV, and CAC are indicative of subclinical CV disease, and, in adults, predict future CV events. The objective of this systematic review and meta-analysis was to investigate the prevalence of subclinical CV changes, as measured by cIMT, pWV, and CAC among pediatric solid organ transplant recipients. We searched MEDLINE(®) and EMBASE and conducted meta-analysis for studies that evaluated cIMT, central pWV, and CAC among pediatric solid organ transplant recipients (kidney, lung, intestine and liver). The search identified nine eligible studies that included a total of 259 patients and 685 healthy controls. Eight studies reported on kidney transplant recipients and one study on a combined cohort of kidney and liver transplant recipients. The mean cIMT of transplant recipients was significantly higher than that of healthy controls (mean difference = 0.05 mm, 95% CI 0.02-0.07; p < 0.0001) with an estimated pooled prevalence of elevated cIMT of 56.0% (95% CI 17.0-95.0). The one study that assessed pWV showed increased vascular stiffness in transplant recipients compared to healthy controls. No studies assessing for CAC were found. There were limited data regarding subclinical CV disease following pediatric solid organ transplantation. In conclusion, kidney transplantation in childhood is associated with a higher prevalence of subclinical CV changes compared to healthy children. Longitudinal studies are needed to determine whether children have increased CV morbidity and mortality after transplantation.

Left ventricular mass and systolic function in children with chronic kidney disease-comparing echocardiography with cardiac magnetic resonance imaging

BACKGROUND

Increased left ventricular mass (LVM) is an important risk marker of uremic cardiovascular disease. Calculation of LVM by echocardiography (Echo) relies on geometric assumptions and in adults on hemodialysis overestimates LVM compared to cardiac magnetic resonance (CMR). We compare both techniques in children with chronic kidney disease (CKD).

METHODS

Concurrent Echo and CMR was performed in 25 children with CKD (14 after kidney transplantation) aged 8-17 years.

RESULTS

Compared to normal children, CMR-LVM was increased (standard deviation score (SDS) 0.39 ± 0.8 (p = 0.03)), stroke volume and cardiac output decreased (SDS -1.76 ± 1.1, p = 0.002 and -1.11 ± 2.0, p = 0.001). CMR-LVM index but not Echo-LVMI correlated to future glomerular filtration rate (GFR) decline (r = -0.52, p = 0.01). Mean Echo-LVM was higher than CMR-LVM (117 ± 40 vs. 89 ± 29 g, p < 0.0001), with wide limits of agreement (-6.2 to 62.8 g). The Echo-CMR LVM difference increased with higher Echo-LVMI (r = 0.77, p < 0.0001). Agreement of classifying left ventricular hypertrophy was poor with Cohen's kappa of 0.08. Mean Echo and CMR-ejection fraction differed by 1.42% with wide limits of agreement (-12.6 to 15.4%).

CONCLUSIONS

Echo overestimates LVM compared to CMR, especially at higher LVM. Despite this, CMR confirms increased LVM in children with CKD. Only CMR-LVMI but not Echo-LVMI correlated to future GFR decline.

The consequences of pediatric renal transplantation on bone metabolism and growth

PURPOSE OF REVIEW

During childhood, growth retardation, decreased final height and renal osteodystrophy are common complications of chronic kidney disease (CKD). These problems remain present in patients undergoing renal transplantation, even though steroid-sparing strategies are more widely used. In this context, achieving normal height and growth in children after transplantation is a crucial issue for both quality of life and self-esteem. The aim of this review is to provide an overview of pathophysiology of CKD-mineral bone disorder (MBD) in children undergoing renal transplantation and to propose keypoints for its daily management.

RECENT FINDINGS

In adults, calcimimetics are effective for posttransplant hyperparathyroidism, but data are missing in the pediatric population. Fibroblast growth factor 23 levels are associated with increased risk of rejection, but the underlying mechanisms remain unclear. A recent meta-analysis also demonstrated the effectiveness of rhGH therapy in short transplanted children.

SUMMARY

In 2013, the daily clinical management of CKD-MBD in transplanted children should still focus on simple objectives: to optimize renal function, to develop and promote steroid-sparing strategies, to provide optimal nutritional support to maximize final height and avoid bone deformations, to equilibrate calcium/phosphate metabolism so as to provide acceptable bone quality and cardiovascular status, to correct all metabolic and clinical abnormalities that can worsen both bone and growth (mainly metabolic acidosis, anemia and malnutrition), promote good lifestyle habits (adequate calcium intake, regular physical activity, no sodas consumption, no tobacco exposure) and eventually to correct native vitamin D deficiency (target of 25-vitamin D >75 nmol/l).

Circulating endothelial cells in pediatric renal transplant recipients

BACKGROUND

An increase in the number of circulating endothelial cells (CEC) indicates endothelial damage and the risk of cardiovascular disease. The aim of our study was to investigate the association of CEC with various clinical parameters in pediatric renal transplant recipients.

METHODS

CEC, defined as CD45(-)CD146(+), were enumerated by flow cytometry from the peripheral blood of 50 pediatric renal transplant recipients and 20 healthy controls. Clinical parameters, including renal function tests, fasting blood glucose, serum cholesterol and triglyceride, cyclosporine A (CsA) (trough and 2nd-hour) and tacrolimus (tac) trough blood levels and their association with CEC numbers were analyzed.

RESULTS

CEC numbers of patients were higher than those of controls (respectively, 128 ± 89 cells/ml (42-468 cells/ml), 82 ± 33 cells/ml (32-137 cells/ml), p = 0.024). There was a statistically significant negative correlation between CEC numbers and glomerular filtration rate (GFR) (r = -0.300, p = 0.012). There was also a statistically positive association between CEC numbers and transplant duration as well as cyclosporine trough level (respectively, r = 0.397, p = 0.004, r = 0.714, p = 0.004). CEC numbers in patients on tac and CsA were similar (p = 0.716).

CONCLUSIONS

Our results demonstrate that renal transplant recipients with high CsA trough blood level, longer transplant duration, and lower GFR, are at greater risk of developing endothelial damage.

High serum adiponectin concentration in children with chronic kidney disease

Adiponectin (ADPN) counteracts the inflammatory response of the endothelium, which plays an important role in the development of atherosclerosis in patients with chronic kidney disease (CKD). Data in children with CKD are scarce. We examined serum ADPN concentration in 90 children with various renal disorders: 28 with CKD on conservative treatment (CKD), 21 on regular dialysis treatment (D), and 41 after kidney transplantation (Tx); 27 age-matched healthy children served as controls (C). Body mass index (BMI), estimated glomerular filtration rate (eGFR), lipids, homocysteine, high sensitivity CRP (hsCRP), and systolic blood pressure (SBP) were also measured. Mean serum ADPN concentration was significantly higher in patients with CKD (27.3 μg/ml ±15.0), on D (34.2 μg/ml ±14.9), and after Tx (23.6 μg/ml ±9.5) compared with ADPN levels in C (13.5 μg/ml ±6.1) (p < 0.0001). Serum ADPN concentration was inversely related to BMI (p = 0.001) and SBP (p = 0.004). In the multiple linear regression analysis, only SBP remained independently associated with ADPN plasma levels. Data show that children with CKD have significantly higher serum ADPN, even after Tx. The protective antiarthrosclerotic effect of ADPN may be mediated by lower SBP, a finding that deserves further study.

Determinants of premature atherosclerosis in children with end-stage renal disease

Cardiovascular disease is a major cause of morbidity and mortality in young adults with end-stage renal disease (ESRD), but its basis is still not well understood. We therefore evaluated the determinants of atherosclerosis in children with ESRD. A total of 37 children with ESRD (with 31 who had undergone transplantation) were examined and compared to a control group comprising 22 healthy children. The common carotid intima-media thickness (CIMT) was measured by ultrasound as a marker of preclinical atherosclerosis. The association of CIMT with anthropometrical data, blood pressure, plasma lipid levels, and other biochemical parameters potentially related to cardiovascular disease was evaluated. Children with ESRD had significantly higher CIMT, blood pressure, and levels of lipoprotein (a), urea, creatinine, ferritin, homocysteine, and serum uric acid as well as significantly lower values of apolipoprotein A. The atherogenic index of plasma (log(triglycerides/HDL cholesterol)) was also higher in patients with ESRD; however, this difference reached only borderline significance. In addition, a negative correlation was found between CIMT and serum albumin and bilirubin in the ESRD group, and this correlation was independent of age and body mass index. In the control group, a significant positive correlation was observed between CIMT and ferritin levels. Factors other than traditional cardiovascular properties, such as the anti-oxidative capacity of circulating blood, may be of importance during the early stages of atherosclerosis in children with end-stage renal disease.

Increased intima-media thickness of the carotid artery in childhood: a systematic review of observational studies

Increased carotid intima-media thickness (cIMT) in adults may be caused by a childhood exposure to cardiovascular risk factors. We systematically reviewed observational studies to determine whether obesity, insulin-dependent diabetes mellitus (IDDM), dyslipidemia (DL), hypertension (HT), and chronic renal failure (CRF) are associated with increased cIMT in children and adolescent patients compared with control subjects. We performed a PubMed literature search from January 1986 to February 2010. Two reviewers separately verified the inclusion criteria of relevant studies for the objective of the review. The data extracted in the patient and control groups were sample size, age, gender, cIMT measurement methods, cIMT values, and statistical analysis results. From 348 citations, 65 cross-sectional studies (2 cited twice) with case-control design met the inclusion criteria: 26 in obesity, 14 in IDDM, 11 in DL, 8 in HT, and 8 in CRF. cIMT measurement protocols varied according to the studies, with measurements being performed on the common carotid artery in 65/67 cases and on the far wall in 57/67 cases. From the 67 studies cited, 22/26 reported a significantly increased cIMT in obese children and adolescents compared with the control group, 8/14 in IDDM patients, 10/11 in DL patients, 7/8 in HT patients, and 8/8 in CRF patients.

CONCLUSION

Despite the heterogeneity of ultrasound measurement methods, cIMT was significantly increased in 55 out of the 67 cited studies, confirming early vascular damages in pediatric populations with an increased future risk for vascular diseases.

Outcomes in pediatric solid-organ transplantation

LaR Pediatric solid-organ transplantation is an increasingly successful treatment for organ failure. Five- and 10-yr patient survival rates have dramatically improved over the last couple of decades, and currently, over 80% of pediatric patients survive into adolescence and young adulthood. Waiting list mortality has been a concern for liver, heart, and intestinal transplantation, illustrating the importance of transplant as a life-saving therapy. Unfortunately, the success of pediatric transplantation comes at the cost of long-term or late complications that arise as a result of allograft rejection or injury, immunosuppression-related morbidity, or both. As transplant recipients enter adolescence treatment, non-adherence becomes a significant issue, and the medical and psychosocial impacts transition to adulthood not only with regard to healthcare but also in terms of functional outcomes, economic potential, and overall QoL. This review addresses the clinical and psychosocial challenges encountered by pediatric transplant recipients in the current era. A better understanding of pediatric transplant outcomes and adult morbidity and mortality requires further ongoing assessment.

CKD-MBD after kidney transplantation

Successful kidney transplantation corrects many of the metabolic abnormalities associated with chronic kidney disease (CKD); however, skeletal and cardiovascular morbidity remain prevalent in pediatric kidney transplant recipients and current recommendations from the Kidney Disease Improving Global Outcomes (KDIGO) working group suggest that bone disease-including turnover, mineralization, volume, linear growth, and strength-as well as cardiovascular disease be evaluated in all patients with CKD. Although few studies have examined bone histology after renal transplantation, current data suggest that bone turnover and mineralization are altered in the majority of patients and that biochemical parameters are poor predictors of bone histology in this population. Dual energy X-ray absorptiometry (DXA) scanning, although widely performed, has significant limitations in the pediatric transplant population and values have not been shown to correlate with fracture risk; thus, DXA is not recommended as a tool for the assessment of bone density. Newer imaging techniques, including computed tomography (quantitative CT (QCT), peripheral QCT (pQCT), high resolution pQCT (HR-pQCT) and magnetic resonance imaging (MRI)), which provide volumetric assessments of bone density and are able to discriminate bone microarchitecture, show promise in the assessment of bone strength; however, future studies are needed to define the value of these techniques in the diagnosis and treatment of renal osteodystrophy in pediatric renal transplant recipients.

Carotid intima-media thickness after pediatric renal or liver transplantation at high-resolution B-mode ultrasonography

In a previous study, we observed a higher incidence of dyslipidemia in pediatric renal recipients compared with liver recipients. In the present study, we measured common carotid artery intima-media thickness (IMT) in 13 pediatric renal recipients, 9 liver recipients, and 26 control individuals with median age of 11.4, 10.8, and 12.0 years, respectively. The patients were studied from 0.2 to 10.8 years after renal transplantation (RTx) or liver transplantation (LTx). An experienced radiologist (T.K.) blinded to the status of the children measured the IMT using a high-resolution B-mode ultrasonography method. In patients who underwent RTx or LTx, serum fasting lipid profile, estimates of renal and liver function, and glucose metabolism were determined. Children undergoing RTx or LTx more often had hypertension compared with the control individuals (P = .004). Before transplantation, dyslipidemia was greater in patients undergoing RTx compared with those undergoing LTx (P < .05). Children who underwent RTx, compared with those who underwent LTx or control individuals, had thicker mean IMT at the 6 sites measured (mean [SD], 0.57 [0.07], 0.51 [0.05], and 0.53 [0.06] mm, respectively; P = .02]. As a result of linear regression in renal recipients, variability of glomerular filtration rate (<60 mL/min/1.73 m(2) vs normal) accounted for 43.3% of variability of the mean of maximal IMT (B = 8.9; SE = 3.1; P = .01). Variability of pre-RTx serum triglyceride concentration (B = 1.6; SE = 0.6; P = .03) and actual triglyceride concentration (B = 10.3; SE = 2.2; P = .002) accounted for 82.2% of variability of maximal IMT. Our findings support previous data on the importance of maintenance of good graft function with sufficient but not overly efficient immunosuppression after transplantation in prevention of future cardiovascular disease.

Subclinical atherosclerosis and related risk factors in renal transplant recipients

Long-term survival after successful renal transplantation is shortened by cardiovascular disease. Cardiovascular disease is a main cause of morbidity and death among children and young adults after renal transplantation. The aim of our study was to measure the carotid intima media thickness (cIMT) and determine its relationship to the risk factors for early arteriopathy in renal transplant recipients. Sixty-six stable renal transplant patients (36 female and 30 male), 7-25 years of age (mean 18.3 +/- 4.5 years) were enrolled in this study. The cIMT was measured by high-resolution B mode ultrasonography in multiple projections. The results were correlated with clinical and paraclinical parameters, including age, gender, body mass index (BMI), blood pressure, glomerular filtration rate (GFR), duration of dialysis, duration of chronic kidney disease (CKD), post-transplantation interval, calcium-phosphate (CaxP) product, cumulative dose of Ca-based P binder and calcitriol, lipid profile, uric acid, and cyclosporine level. The mean post-transplantation follow-up period was 64 +/- 40 months. The mean cIMT standard deviation score (SDS) of the patients and the control group was 0.60 +/- 0.81 mm (range -1.10 mm to 2.75 mm) and -1.25 +/- 0.95 mm (range -3.23 mm to 0.26 mm), respectively. Renal transplant recipients had a significantly greater cIMT than that of the controls (P < 0.001). Among several risk factors, there were positive correlations between cIMT SDS and gender, and cumulative dose of calcitriol (P = 0.02 and P = 0.02, respectively). In conclusion, subclinical atherosclerosis is present in young transplant recipients. Non-invasive monitoring of cIMT in renal transplant patients for the detection of early vascular lesions might be of value in preventing cardiovascular disease. Further studies are needed to see if proper monitoring of vitamin D therapy before and after transplantation could be helpful in the prevention of arteriopathy in renal transplant recipients.

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.

Cardiovascular disease in children with CKD or ESRD

Cardiovascular disease accounts for 40% of all deaths among pediatric patients with end-stage renal disease (ESRD). ESRD has a particularly large influence on the cardiovascular system in children, as indicated by the more than 700-fold increased risk of cardiac death in affected individuals compared with healthy children of the same age. The prevalence of ESRD is low in children, however, and, consequently, few cardiac deaths occur. As a result, prospective follow-up studies of cardiac risk factors in the pediatric setting are lacking. Nevertheless, cross-sectional data on cardiac disease in children with ESRD have started to emerge. Arterial medial calcification is more prominent in children than classic atherosclerotic intimal calcification. Current data suggest that endothelial dysfunction appears early in renal failure in children, and is followed by arterial medial calcification. This calcification causes arterial wall stiffening and subsequently left ventricular hypertrophy. High systolic blood pressure and serum concentrations of intact parathyroid hormone, calcium and phosphate, as well as long-term dialysis, seem to be important risk factors for cardiovascular disease in pediatric patients with ESRD. These features are important targets for preventive intervention. This Review summarizes the currently available data on cardiovascular disease in children with renal failure.

Intima-media thickness measurements in children with cardiovascular risk factors

Measuring intima-media thickness (IMT) is now a standard diagnostic procedure in assessing cardiovascular risk and hypertensive target-organ damage (TOD) in adults. There is also an increasing number of pediatric publications evaluating IMT in children from high-risk groups, such as those with arterial hypertension, diabetes, chronic kidney disease, obesity, dyslipidemia, and homocystinurias. It has been shown that carotid IMT is strongly related with other markers of TOD in children with arterial hypertension and with metabolic cardiovascular risk factors. In children with coarctation of the aorta, carotid IMT correlated both with blood pressure and even with mild residual aortic gradient. On the other hand, studies in children with high cardiovascular risk have shown that normalization of blood pressure and metabolic abnormalities led to regression of arterial changes and decrease of IMT. Although not yet accepted as standard pediatric procedure, IMT measurement is emerging as a promising method of assessing TOD and cardiovascular risk and monitoring treatment efficacy. From a practical point of view, clinical utility of IMT measurements seems to be similar to use of echocardiography in assessing left ventricular mass. However, IMT measurements in children and adolescents should be standardized to avoid bias caused by the use of different measurement methods.

Subclinical impairment of coronary flow velocity reserve assessed by transthoracic echocardiography in young renal transplant recipients

BACKGROUND

In renal transplant recipients (RTR) an increased risk to develop cardiovascular injury is present. Transthoracic Doppler echocardiographic assessment of coronary flow velocity reserve (CFVR), a sensitive and minimally invasive technique, was recently employed to detect both macrovascular and microvascular coronary artery disease (CAD) in different clinical settings. The prevalence of coronary involvement in young adult RTR is still unknown. The aim of the study was to investigate the presence of early cardiovascular damage in asymptomatic young adult RTR.

METHODS

Transthoracic Doppler echocardiographic-derived CFVR and common carotid intima-media thickness (IMT) were assessed in 25 asymptomatic young adult RTR (mean age 25.7+/-7.0 years; range 17.3-43.9) without CAD and 25 healthy controls.

RESULTS

CFVR was lower in young adult RTR compared to controls (2.8+/-0.6 vs. 3.5+/-0.8; P<0.001), meanwhile left ventricular wall motion and common carotid IMT were comparable in both groups. We found a negative correlation between CFVR and age (r=-0.50; P=0.018) and months on dialysis (r=-0.54; P<0.01).

CONCLUSIONS

Young adult RTR showed a reduced CFVR reflecting an impaired coronary microcirculation, which is significantly related to the age and duration of dialysis; coronary microvascular damage is detectable in the absence of changes in common carotid IMT. Non-invasive evaluation of CFVR by transthoracic stress echocardiography could be a reliable method for identification of early coronary microvascular involvement in young adult RTR.

Carotid intima-media thickness as a cardiovascular risk marker in pediatric end-stage renal disease patients on dialysis and in renal transplantation

Cardiovascular diseases are the principal cause of morbidity and mortality among young adults with chronic renal disease. Atherosclerotic structural changes as detected by high-resolution B-mode ultrasonography preceed clinical findings by several decades. The carotid intima-media thickness (cIMT) is being used as a marker of early atherosclerosis. We determined the cIMT of common carotid artery (CCA) in 8 asymptomatic children on dialysis or 12 after renal transplantation for comparison with 30 healthy controls. This prospective study of 40 children showed a mean age of 13.5 years (range, 8 to 18). We evaluated cIMT, hemoglobin, serum creatinine levels, lipid profile, and homeostasis model assessment (HOMA). The statistical analysis for variables with normal distribution was Student's t test. Parameters with a non-normal distribution were evaluated by the Mann-Whitney or Spearman correlation analysis with P < .05 considered statistically significant. The mean measurements of cIMT (mm) of both CCA were dialysis 0.450 +/- 0.042; transplant 0.467 +/- 0.033, and controls 0.380 +/- 0.009 (P < .03). The homa levels of 2.45 +/- 0.98 for dialysis and 1.8 +/- 0.62 for transplant, were both significantly higher than the control group (0.8 +/- 0.09; P < .01). The Ca x P product was higher in dialysis vs transplant group: 63.0 +/- 10.0 versus 46.2 +/- 2.2 (P < .03). The intact parathyroid hormone levels were 666.7 +/- 276.7 versus 44.2 +/- 2.8, respectively (P < .008). The low-density lipoprotein cholesterol was 129.0 +/- 23.1 versus 80.8 +/- 10.6, respectively (P < .04). The cIMT correlated with the duration of dialysis before transplantation. Changes in IMT can be detected by ultrasonography in early childhood in uremic patients. The etiology of atherosclerosis is multifactorial in children with end-stage renal disease. It seems possible to prevent or improve the factors related to cardiovascular risk in these patients.