Subclinical myocardial disease in patients with primary hyperoxaluria and preserved left ventricular ejection fraction: a two-dimensional speckle-tracking imaging study.

BACKGROUND: Primary hyperoxaluria (PH) is characterized by progressive chronic kidney disease (CKD) and systemic oxalate deposition. Myocardial dysfunction might be present early in the course of the disease. However, this hypothesis has not yet been tested in the PH population. Therefore, we aimed to determine whether strain imaging using two-dimensional speckle tracking echocardiography (2D-STE) might detect subclinical myocardial disease in otherwise asymptomatic PH patients. METHODS: Prospective study of pediatric and adolescent PH patients with preserved LV ejection fraction (LV EF) and without renal replacement therapy. Subjects underwent conventional echocardiography and 2D-STE. Global (GLS) and segmental peak systolic LV longitudinal strain (LS) measurements were obtained. Data were compared with age- and gender-matched controls, and Z-scores were calculated as appropriate. RESULTS: Fifteen PH patients (age 14.1 ± 5.9 years; 13/15 in CKD stages 1-2) were studied. Although LV EF was preserved (63 ± 6%) in patients, GLS was significantly impaired (GLS - 17.1 ± 2.2% vs - 22.4 ± 1.9%, p < 0.001). This was mainly due to decreased LS values in the apical segments (p < 0.05). Echocardiographic indices of ventricular wall thickness were significantly increased in patients compared to controls (all p < 0.03). GLS correlated significantly with Z-scores of diastolic interventricular wall thickness (r = - 0.57, p = 0.025) and moderately with serum creatinine levels (r = 0.53, p = 0.044). No correlation was found between GLS and blood pressure measurements. CONCLUSIONS: Subclinical myocardial disease is already present early in the course of disease in PH patients with preserved LV EF and some degree of renal dysfunction, but without overt systemic oxalosis. Current recommendations to screen only PH patients with advanced CKD for cardiac disease should be revised accordingly.

Inhomogeneous Longitudinal Cardiac Rotation and Impaired Left Ventricular Longitudinal Strain in Children and Young Adults with End-Stage Renal Failure Undergoing Hemodialysis.

BACKGROUND: Cardiac dysfunction frequently complicates the clinical course of patients with end-stage renal failure (ESRF). Recently, we observed abnormal longitudinal cardiac rotation (LR) among patients with ESRF. In this study, we sought to quantify LR mechanics in patients undergoing hemodialysis (HD). METHODS: Twenty-four subjects, 12 ESRF patients (58% male; age 17.5 ± 4.4 years) receiving HD, and 12 aged-matched controls, were prospectively studied. Patients underwent echocardiographic studies before and after HD. LR mechanics were quantified with two-dimensional speckle tracking echocardiography. Peak systolic left ventricular (LV) longitudinal strain and displacement measurements were obtained in all subjects. RESULTS: LR mechanics were successfully quantified in all subjects using 5 key echocardiographic features of LR. We identified two different inhomogeneous LR motion patterns in 41.7% of ESRF patients, characterized by a delayed timing of LR or increased segmental apical rotation. Inhomogeneous LR patterns were not found in controls. Timing of early-systolic counterclockwise LR increased after HD (P = 0.006). In patients, late-systolic clockwise LR occurred earlier (P = 0.043), and showed a significant prolongation after HD (P = 0.003). Longitudinal strain was significantly impaired in patients (P = 0.015), and further decreased after HD (P < 0.0001). Strong correlations were observed between strain and displacement parameters and LR mechanics. CONCLUSIONS: Quantifying LR using speckle tracking echocardiography was feasible, easy, and reproducible. Inhomogeneous LR motion patterns were demonstrated in a large proportion of patients with ESRF. LV dysfunction seems the most important determinant of inhomogeneous LR. Further studies are required to validate these findings.