Evaluating preload dependence of a novel Doppler application in assessment of left ventricular diastolic function during hemodialysis.

BACKGROUND: Left ventricular (LV) diastolic dysfunction, commonly found in hemodialysis (HD) patients, is a major cause of intradialytic hypotension. Conventional Doppler interrogation of mitral flow velocities typically is load dependent. Tissue Doppler imaging (TDI) recently was proposed as a new and relatively load-independent approach to assess diastolic function. The aim of this study is to determine whether HD-related volume reduction affects mitral annular velocities in a large number of patients.
METHODS: One hundred twenty-eight uremic patients underwent Doppler echocardiography 1 hour before and after HD. Two-dimensional and M-mode echocardiography were used to analyze LV size, volume, mass, systolic function, and the inferior vena cava. Doppler signals were obtained from the mitral inflow and TDI of the mitral annulus to measure variations in hemodynamics and LV diastolic filling parameters.
RESULTS: After HD, LV size, volume, mass, stroke volume, and cardiac output were significantly decreased (all P < 0.001). Peak early (E) and late diastolic velocities (A) and E/A ratio decreased significantly after HD (all P < 0.001). Mitral annulus E' velocity and E'/A' ratio also changed significantly (both P < 0.001), whereas A' did not. Consequently, changes in E and A significantly differed with respect to the varying amount of ultrafiltration (both P < 0.05).
CONCLUSION: Our larger cohort study shows that the proposed technique of TDI is still volume dependent. Therefore, LV diastolic function in HD patients must be assessed carefully in a timely manner, even when the new Doppler application is used.