Effect of preload reduction by haemodialysis on new indices of diastolic function

Assessment of mitral annular motion diastolic velocities by M-mode or tissue Doppler imaging and the propagation velocity of early diastolic filling (V^p) by colour M-mode have been proposed as preload-independent indices of diastolic function. The aim of the present study was to determine the effects of preload reduction by haemodialysis on these new echocardiographic indices and to assess the relationship between these indices. The study group comprised 17 patients with chronic renal failure in sinus rhythm with normal left ventricular systolic function who underwent echocardiography 30 min prior to and 30 min following haemodialysis. Following dialysis there were significant reductions in weight (P<0.001), left atrial diameter (P=0.001), the peak Doppler velocity of early diastolic transmitral flow (P=0.005) and the ratio of Doppler velocities of early to late diastolic transmitral flow (P=0.02), consistent with a reduction in intravascular volume. There was no change after dialysis in early diastolic mitral annular velocity using M-mode (P=0.19) or tissue Doppler imaging from either the septal or lateral walls (P=0.88 and P=0.15 respectively), but there was a reduction in V^p after dialysis (55 to 49 cm/s; P=0.04). There were only weak correlations between V^p and the early diastolic mitral annular velocities (r<0.6 for all). We conclude that the assessment of diastolic function by the mitral annular early diastolic velocity appears to be preload-independent, that V^p may be affected by preload and that there is only a weak relationship between V^p and the early diastolic mitral annular velocity.