Background. Cardiovascular disease is the leading cause of death in chronic kidney disease (CKD) patients. Tissue Doppler velocity imaging (TVI) is a new objective method that accurately quantifies myocardial tissue velocities, deformation, time intervals and left ventricular (LV) filling pressure. In this study, TVI was compared with conventional echocardiography for the assessment of left ventricular (LV) function in pre-dialysis patients with different stages of CKD. The results obtained by TVI were used to analyse possible relationships between LV function and clinical factors such as hyperparathyroidism and hypertension that could influence LV function.
Methods. Conventional echocardiography and TVI images were recorded in 40 patients (36 men and 4 women, mean age 60 +/- 14 years, range 28-80 years) and in 27 healthy controls (21 men and 6 women, mean age 58 +/- 17 years, range 28-82 years). Twenty-two patients had mild/moderate CKD (CCr > 29 ml/min; Group 1) and 18 patients had severe CKD (CCr <= 29 ml/min; Group 2). Using TVI, the myocardial tissue velocities (v; cm/s) for isovolumetric contraction (IVCv), peak systole (PSv), early (E') and late (A') diastolic filling velocities as well as strain rate (SR), mitral annulus displacement, isovolumetric relaxation time (IVRT) and LV filling pressure were estimated using TVI. The average of six LV wall measurements was used to evaluate LV global function.
Results. Using TVI, we were able to identify significantly more patients with diastolic dysfunction than using conventional echocardiography (33 vs 26, P < 0.05). There was no difference in the prevalence of diastolic dysfunction between Group 1 and 2. However, using TVI, Group 2 CKD patients had lower E' velocities (6.2 +/- 1.9 vs 8.0 +/- 2.9 cm/s, P < 0.05) and higher IVRT (137.4 +/- 13 vs 88.2 +/- 26 ms, P < 0.001) in comparison with controls, indicating more accentuated diastolic dysfunction. Systolic blood pressure (SBP) was associated with E' velocities (rho = -0.68, P < 0.005) and E'/A' was strongly associated with SBP (rho = -0.60; P < 0.01) and PTH (rho = -0.64, P < 0.005) in Group 2. Using conventional echocardiography, there was no difference in the prevalence of systolic and diastolic dysfunction between patients with and without LVH. However, using TVI, patients with LVH had significantly lower IVCv (2.8 +/- 1.3 vs 3.8 +/- 1.5 and 3.8 +/- 1.5 cm/s, P < 0.05) and PSv (5.5 +/- 1.0 vs 6.3 +/- 1.2 and 6.4 +/- 1.3 cm/s, P < 0.05) compared with patients without LVH and controls, and they also had lower E' velocities (7.1 +/- 2.7 vs 8.0 +/- 2.9 cm/s, P < 0.05) compared with controls, indicating disturbances in systolic and diastolic left ventricular function.
Conclusions. TVI provided additional information on left ventricular function in CKD patients. In patients with advanced renal failure, TVI revealed more accentuated diastolic dysfunction associated with increased systolic blood pressure (SBP) and increased levels of PTH. TVI also demonstrated disturbances in contractility and contraction in patients with LVH, which could not be detected by conventional echocardiography.
2006. Vol. 21, no 1, 125-132 p.
chronic kidney disease; parathyroid hormone; predialysis; tissue Doppler echocardiography