Get to the heart of pediatric kidney transplant recipients: Evaluation of left- and right ventricular mechanics by three-dimensional echocardiography.

Background: Kidney transplantation (KTX) markedly improves prognosis in pediatric patients with end-stage kidney failure. Still, these patients have an increased risk of developing cardiovascular disease due to multiple risk factors. Three-dimensional (3D) echocardiography allows detailed assessment of the heart and may unveil distinct functional and morphological changes in this patient population that would be undetectable by conventional methods. Accordingly, our aim was to examine left- (LV) and right ventricular (RV) morphology and mechanics in pediatric KTX patients using 3D echocardiography. Materials and methods: Pediatric KTX recipients (n = 74) with median age 20 (14-26) years at study enrollment (43% female), were compared to 74 age and gender-matched controls. Detailed patient history was obtained. After conventional echocardiographic protocol, 3D loops were acquired and measured using commercially available software and the ReVISION Method. We measured LV and RV end-diastolic volumes indexed to body surface area (EDVi), ejection fraction (EF), and 3D LV and RV global longitudinal (GLS) and circumferential strains (GCS). Results: Both LVEDVi (67 ± 17 vs. 61 ± 9 ml/m2; p < 0.01) and RVEDVi (68 ± 18 vs. 61 ± 11 ml/m2; p < 0.01) were significantly higher in KTX patients. LVEF was comparable between the two groups (60 ± 6 vs. 61 ± 4%; p = NS), however, LVGLS was significantly lower (-20.5 ± 3.0 vs. -22.0 ± 1.7%; p < 0.001), while LVGCS did not differ (-29.7 ± 4.3 vs. -28.6 ± 10.0%; p = NS). RVEF (59 ± 6 vs. 61 ± 4%; p < 0.05) and RVGLS (-22.8 ± 3.7 vs. -24.1 ± 3.3%; p < 0.05) were significantly lower, however, RVGCS was comparable between the two groups (-23.7 ± 4.5 vs. -24.8 ± 4.4%; p = NS). In patients requiring dialysis prior to KTX (n = 64, 86%) RVGCS showed correlation with the length of dialysis (r = 0.32, p < 0.05). Conclusion: Pediatric KTX patients demonstrate changes in both LV and RV morphology and mechanics. Moreover, the length of dialysis correlated with the contraction pattern of the right ventricle.

Captopril-enhanced renal scintigraphy in the diagnosis of pediatric hypertension.

Hypertension in childhood is no longer a rare condition mainly secondary to renal, or renovascular diseases, as a growing proportion of children are obese and hypertensive, with the phenotype of metabolic syndrome. Thus, we need to reconsider our practice in the examination of the hypertensive child and redefine the place of non-invasive methods for screening of renovascular hypertension, and specifically, to evaluate the value of captopril-enhanced renal scintigraphy at the two ends of the palette: the obese child with hypertension and the severely hypertensive prepubertal child. Renal artery stenosis in children is mainly due to fibromuscular dysplasia and stenoses associated with syndromes involving single or multiple smaller branch vessels. This explains the low specificity and sensitivity of the color-Doppler ultrasound method and captopril renal scintigraphy. Even the more sophisticated computed tomography (CT) and magnetic resonance imaging (MRI) angiographic techniques are, at present, not sensitive enough to exclude stenoses of the small branches definitely. Thus, children in whom there is a strong suggestion of renovascular hypertension should undergo angiography with a view to endovascular treatment, as non-invasive imaging has no significant benefit and might lead to a delay in treatment. In the cases when the probability of renovascular disease is moderate a basic assessment of renal function and structure is sufficient. In the neonate, catheter-associated thromboembolic disease is among the most common causes hypertension. It should be controlled medically until the patient is old enough to undergo angiography and angioplasty successfully. Thus, in this age group, there is a place for functional imaging with renal sonography and angiotensin-converting enzyme inhibitor (ACEI) renography to detect hemodynamically significant renovascular disease, with the limitations mentioned above. However, the rapid technical evolution of non-invasive methods requires periodic re-consideration of the actual standpoints.