Improvement of left ventricular mechanics after hemodialysis in patients with end-stage renal disease: a three-dimensional speckle tracking study

Abstract

Background: Cardiovascular diseases are the leading causes of morbidity and mortality in patients with chronic renal insufficiency. We sought to investigate the chronic renocardiac syndrome and the immediate effects of hemodialysis (HD) on myocardial mechanics using three-dimensional (3D) speckle tracking echocardio-graphy. Methods: Forty-four patients (mean age 48±13 years, 54% men) with end-stage renal disease on three times per week maintenance HD, without diabetes and any significant cardiac disease were investigated just before and immediately after HD, and compared to 46 normal controls (NC; 48±12 years, 48% men). Beyond conventional transthoracic echocardiographic examination, 3D recordings were obtained using multi-beat reconstruction from 6 consecutive cardiac cycles (GE Vivid E9). Ejection fraction (EF) and left ventricular mass indexed to body surface area (LVMi) were measured, and 3D speckle tracking analysis was performed to assess global longitudinal-, circumferential-, area- and radial peak systolic strain values (GE 4D Auto LVQ). For statistical analysis, Wilcoxon signed-rank, MannWhitney U, Spearman correlation tests and multivariate linear regression were used. Data are presented as median (interquartile range). Results: LVMi was remarkably increased in patients compared to NC [136 (46) vs. 71 (8) g/m2, p<0.001]. EF and strain values in all directions improved after HD [pre-vs. post-HD; EF: 63 (9.5) vs. 66 (10), longitudinal: -20 (3) vs. -21 (6), circumferential: -20 (4) vs. -22 (7), area: -33 (5) vs. -35 (10), radial: 50 (12) vs. 53.5 (20) %, all p<0.01]. While there was no difference in longitudinal strain, the patients' pre-HD circumferential, area and radial strains were reduced, and after HD only the circumferential strain increased enough to be similar compared to NC [NC longitudinal: -20.5 (3), circumferential: -21 (3), area -36 (3), radial 61 (8) %, p<0.05]. LVMi correlated inversely with post-HD circumferential strain (ρ=0.34, p<0.05), and even stronger with area (ρ=0.54) and radial strains (ρ=-0.58, both p<0.001). In a multivariate linear regression model, circumferential strain was found to be an independent predictor of EF both before (β=-0.88, p<0.001) and after HD (β=-0.96, p<0.001). Conclusions: In chronic renocardiac syndrome the left ventricle can be characterized by increased mass and reduced 3D strain values measured by speckle tracking echocardiography. The increase of LVMi correlates strongly with the reduction of area and radial strains. HD results in immediate improvement of left ventricular function indicated by EF and 3D strain, as well.