Effects of hemodialysis on the cardiovascular system: quantitative analysis using wave intensity wall analysis and tissue velocity imaging

Cardiovascular disease is the leading cause of death in patients with end-stage renal disease (ESRD). The aim of this study was to investigate the changes in cardiovascular function induced by a single session of hemodialysis (HD) by the analysis of cardiovascular dynamics using wave intensity wall analysis (WIWA) and of systolic and diastolic myocardial function using tissue velocity imaging (TVI). Gray-scale cine loops of the left common carotid artery, conventional echocardiography, and TVI images of the left ventricle were acquired before and after HD in 45 patients (17 women, mean age 54 years) with ESRD. The WIWA indexes, W₁ and preload-adjusted W₁, W₂ and preload-adjusted W₂, and the TVI variables, isovolumic contraction velocity (IVCV), isovolumic contraction time (IVCT), peak systolic velocity (PSV), displacement, isovolumic relaxation velocity (IVRV), isovolumic relaxation time (IVRT), peak early diastolic velocity (E′), and peak late diastolic velocity (A′), were compared before and after HD. The WIWA measurements showed significant increases in W₁ (P < 0.05) and preload-adjusted W₁ (P < 0.01) after HD. W₂ was significantly decreased (P < 0.05) after HD, whereas the change in preload-adjusted W₂ was not significant. Systolic velocities, IVCV (P < 0.001) and PSV (P < 0.01), were increased after HD, whereas the AV-plane displacement was decreased (P < 0.01). For the measured diastolic variables, E′ was significantly decreased (P < 0.01) and IVRT was significantly prolonged (P < 0.05), after HD. A few correlations were found between WIWA and TVI variables. The WIWA and TVI measurements indicate that a single session of HD improves systolic function. The load dependency of the diastolic variables seems to be more pronounced than for the systolic variables. Preload-adjusted wave intensity indexes may contribute in the assessment of true LV contractility and relaxation.