[Doppler tissue imaging contribution in the study of diastolic dysfunction in hemodialysis patients]

ABSTRACT

Doppler echocardiography is currently the main tool permitting the diagnosis and the characterization of the stages of diastolic dysfunction. The purpose of this study is to precise the contribution of Doppler tissue imaging in the study of diastolic function and to identify the parameters having the most discriminating power of diastolic dysfunction in hemodialysis patients. Conventional Doppler echocardiography study implies left ventricular diastolic function from - Doppler transmitral flow [E/A, isovolumic relaxation time [TRIV], deceleration of mitral E-wave time [TDE], duration of A wave], color M-mode flow propagation velocity [Vp], - the study of pulmonary venous flow [S/D, Systolic fraction [FS] and duration of pulmonary venous A wave], - the annulus Doppler Tissue Imaging [Ea/Aa, E and A waves durations, VTI of E and A] - and finally combined indexes [ratio of peak E-wave velocity to Vp [E/Vp], difference in duration between pulmonary venous and mitral flow A wave [Ap-Am] and ratio of peak mitral and annulus E-wave velocities [E/Ea]. Left ventricular diastolic dysfunction is found in 88% of the 50 haemodialysis patients abnormal relaxation pattern 56%, pseudo-normal pattern 28% and restrictive pattern 4%. The parameter Vp discriminates normal patterns. The parameters TRIV, S/D and FS characterise abnormal relaxation. Ea/Aa ratio characterises pseudo-normal pattern and E/A ratio restrictive pattern. Discriminating analysis allows a correct classification of 100% of pseudo-normal pattern patients with 3 variables Ea/Aa, FS and Vp or E/Vp. Doppler parameters which discriminating power is significant [p<0.0001] are, in decreasing order E/A, Ea/Aa, TRIV, Vp, FS, S/D, E/Vp and TDE. DTI contributes mainly in the characterization of stage II diastolic dysfunction patients and allows in association with pulmonary venous flow parameters [Ap-Am] and combined indexes [E/Vp et E/Ea] an accurate appreciation of left ventricular filling pressures