AN EVALUATION OF THE PRELOAD INDEPENDENCE OF THE NEW ECHOCARDIOGRAPHIC INDICES OF DIASTOLIC FUNCTION IN PATIENTS UNDERGOING HAEMODIALYSIS

R J Graham, L Donelan, P Mottram, J S Gelman, R E Peverill. Centre for Heart and Chest Research, Department of Medicine, Monash University and Monash Medical Centre, Melbourne, Australia

Assessment of mitral annular motion velocities by tissue Doppler imaging (TDI) and the propagation velocity of early diastolic filling by colour M-mode have been proposed as preload-independent indices of diastolic function. The aim of this study, performed in patients with chronic renal failure and volume overload, was to determine the effects of preload reduction by haemodialysis on these new echocardiographic indices and compare them with standard mitral inflow variables. The study group comprised 16 patients in sinus rhythm, of mean age 57 years (range 29–75 years) without regional wall motion abnormalities or significant pericardial or valvular disease. Subjects underwent echocardiography 30 minutes prior to and 30 minutes following haemodialysis.

Following dialysis there were significant reductions in weight (68.9±18.0 to 67.3±17.6 kg, p<0.001), left ventricular end diastolic diameter (5.0±0.7 to 4.7±0.8 cm, p=0.01), left atrial diameter (4.7±0.6 to 4.5±0.5 cm, p=0.001), peak mitral E velocity (86±19 to 73±24 cm/s, p=0.005) and E/A ratio (1.2±1.0 to 1.1±1.0, p=0.02), consistent with a preload reduction in cardiac volumes and the recognised preload-dependence of mitral inflow indices. By contrast, there was no change after dialysis in mitral annular early or late diastolic velocities by TDI from either lateral or septal walls (p.0.25 for all), although the TDI early diastolic velocity from the lateral annulus was consistently greater than that from the septal annulus (p<0.0001). There was a trend to a decrease in colour M-mode propagation velocity after dialysis (61 to 56 cm/s, p=0.09).

In conclusion, our findings suggest that TDI of mitral annular motion provides an echocardiographic measurement of diastolic function which is independent of preload, but raise the possibility that colour M-mode propagation velocity …