Left ventricular diastolic dysfunction by tissue Doppler echocardiography in pediatric chronic kidney disease.

BACKGROUND: Myocardial dysfunction is common in chronic kidney disease (CKD) and related to poor outcomes. New non-invasive methods to assess cardiac function have been introduced, but comparative studies evaluating their clinical usefulness in pediatric CKD are lacking. We studied left ventricular (LV) function in pediatric CKD and renal transplant patients, comparing conventional pulse-wave Doppler echocardiography (cPWD) with newer tissue Doppler imaging (TDI) and relating the results to known cardiovascular risk factors. METHODS: The study included 34 children/adolescents with CKD stages 2-5, 44 renal transplant patients and 19 patients with a normal renal function. The mean age was 11.4 (range 0.8-18.8) years. RESULTS: Both patient groups had significantly lower LV diastolic function than those with a normal renal function. The most sensitive determinants were TDI E'/A' and cPWD E/TDI E' ratios. In a stepwise linear regression analysis, high blood pressure, young age and the presence of albuminuria all independently predicted LV diastolic function. CONCLUSIONS: Our study confirms the high prevalence of LV diastolic dysfunction in pediatric CKD patients and following renal transplantation, where TDI appears to be more sensitive than cPWD in assessing early myocardial dysfunction. Our results also underline the importance of preventive measures, such as rigorous blood pressure control, in pediatric CKD.

Use of annual ABPM, and repeated carotid scan and echocardiography to monitor cardiovascular health over nine yr in pediatric and young adult renal transplant recipients.

In adult hypertensive patients, increased cIMT and LVH are independent risk factors for cardiovascular events. We have previously observed that in pediatric RTRs with tight control of BP, cIMT did not progress over time. This investigation is an extension of the aforementioned study aimed at re-examining cIMT and also reporting serial echocardiography results. Twenty-two RTRs aged 9.4 ± 3.3 yr at their baseline carotid scan underwent two additional vascular ultrasounds during a follow-up of 9.1 ± 0.9 yr. Carotid scan and echocardiography examinations were carried out simultaneously with ABPM. Antihypertensive therapy was determined according to the recipient's ABPM results, which were performed at yearly intervals. Baseline cIMT was significantly greater in RTRs than in healthy controls. There was no statistical evidence of systematic changes in cIMT over time. At the last examination, 14 of 17 RTRs with treated hypertension had controlled hypertension (prevalence 82%; 95% CI, 56.5-96.2), and the overall prevalence of LVH was 4.5% (95% CI, -0.01 to 23.5). The lack of progression of cIMT over time and the low prevalence of LVH might reflect the effect of long-standing BP control.

Wave intensity wall analysis: a novel noninvasive method to measure wave intensity.

Wave intensity analysis is a concept providing information about the interaction of the heart and the vascular system. Originally, the technique was invasive. Since then new noninvasive methods have been developed. A recently developed ultrasound technique to estimate tissue motion and deformation is speckle-tracking echocardiography. Speckle tracking-based techniques allow for accurate measurement of movement and deformation variables in the arterial wall in both the radial and the longitudinal direction. The aim of this study was to test if speckle tracking-derived deformation data could be used as input for wave intensity calculations. The new concept was to approximate changes of flow and pressure by deformation changes of the arterial wall in longitudinal and radial directions. Flow changes (dU/dt) were approximated by strain rate (sr, 1/s) of the arterial wall in the longitudinal direction, whereas pressure changes (dP/dt) were approximated by sign reversed strain rate (1/s) in the arterial wall in the radial direction. To validate the new concept, a comparison between the newly developed Wave Intensity Wall Analysis (WIWA) algorithm and a commonly used and validated wave intensity system (SSD-5500, Aloka, Tokyo, Japan) was performed. The studied population consisted of ten healthy individuals (three women, seven men) and ten patients (all men) with coronary artery disease. The present validation study indicates that the mechanical properties of the arterial wall, as measured by a speckle tracking-based technique are a possible input for wave intensity calculations. The study demonstrates good visual agreement between the two systems and the time interval between the two positive peaks (W1-W2) measured by the Aloka system and the WIWA system correlated for the total group (r = 0.595, P < 0.001). The correlation for the diseased subgroup was r = 0.797, P < 0.001 and for the healthy subgroup no significant correlation was found (P > 0.05). The results of the study indicate that the mechanical properties of the arterial wall could be used as input for wave intensity calculations. The WIWA concept is a promising new method that potentially provides several advantages over earlier wave intensity methods, but it still has limitations and needs further refinement and larger studies to find the optimal clinical use.

Prospective analysis of carotid arterial wall structure in pediatric renal transplants with ambulatory normotension and in treated hypertensive recipients.

Increased carotid IMT was found to be associated with cardiovascular risk factors. As pediatric renal transplants are at high risk for cardiovascular disease, we examined whether there is a relationship between BP and IMT in normotensive and in treated hypertensive recipients after transplantation. Thirty-one recipients aged 10 +/- 3.5 yr (16 M, 15 F) underwent repeated carotid ultrasound examinations 5.4 +/- 3.2 yr after transplantation with a 4.1 +/- 1 yr interval and were followed with annual ambulatory BP monitoring. Baseline IMT was significantly higher in transplants compared with controls. When recipients were again investigated, follow-up IMT measurements were similar compared with measurements obtained at baseline. The analysis of variance showed that baseline IMT both in recipients with strict normotension, i.e., ambulatory normotension without antihypertensive therapy at baseline and throughout the study period (n = 9), and in recipients with treated hypertension or newly diagnosed hypertension (n = 22) was significantly higher than in healthy controls (n = 21). Baseline IMT did not differ between these subgroups of recipients. Similarly, pairwise comparisons showed that baseline and follow-up IMT within each subgroup of recipients were not significantly different. Overall and regardless of time-point, no significant associations were found between systolic and diastolic 24-h BP, daytime BP, night-time BP, ambulatory BP standard deviation scores, BP loads and IMT. Our results suggest that increased IMT in pediatric renal transplants does not seem to be related to BP but more likely to other factor(s) not investigated in this study.