Improvement of cardiac function after haemodialysis. Quantitative evaluation by colour tissue velocity imaging.
BACKGROUND
Overhydration and accumulation of uraemic toxins may influence the myocardial function in haemodialysis (HD) patients. To evaluate cardiac function and the effects of fluid and solute removal during a single session of HD, colour tissue velocity imaging (TVI) was used. This new technique, which is less load dependent than conventional echocardiography, allows an objective quantitative assessment of myocardial contractility, contraction and relaxation.


METHODS
Conventional echocardiographic and TVI images were recorded before and after a single HD session in 13 clinically stable HD patients (62+/-10 years, six males) and in 13 sex- and age-matched healthy controls. Myocardial tissue velocities (v; cm/s) for isovolumetric contraction (IVC), peak systole (PS), early (E') and late (A') diastolic filling and strain rate (SR) were measured.


RESULTS
Left ventricular hypertrophy (LVH) was present in 12 patients. TVI gave additional information in comparison with conventional echocardiography. Before HD, PS (5.0+/-0.8 vs 6.0+/-1.2 cm/s, P<0.05), E' (5.7+/-1.7 vs 7.3+/-2.0 cm/s, P<0.05) and A' (6.6+/-1.7 vs. 8.3+/-2.9 cm/s, P<0.05) velocities were lower in the patients than in the controls, indicating systolic and diastolic dysfunction. The HD session increased IVCv (4.0+/-1.7 to 5.5+/-1.9 cm/s; P<0.001), PSv (5.0+/-0.8 to 5.7+/-0.8 cm/s; P<0.05) and SR (0.7+/-0.2 to 0.9+/-0.2 1/s; P < 0.05) and decreased E/E' (16.7+/-7.7 to 12.2+/-4.0, P<0.05), indicating improved systolic function and decreased LV filling pressure, respectively. Linear regression analysis demonstrated a dependency of systolic contraction (PSv) and contractility (IVCv) upon plasma levels of phosphate (r(2) = 0.70, P<0.005, r(2) = 0.33, P<0.01).


CONCLUSIONS
Using TVI, HD patients demonstrate myocardial dysfunction, which is found less frequently when using conventional echocardiography. The systolic function seems to be impaired by high plasma levels of phosphate and an increased Ca x P product. One single session of HD improved systolic function as indicated by increases in IVCv, PSv and SR. Further studies are needed to clarify if this effect of HD is due to the acute removal of fluid, the removal of solutes or both.
Hayashi
Shirley Yumi
SY
Division of Baxter Novum, Department of Clinical Science, Karolinska Institutet, Karolinska University Hospital Huddinge, Stockholm, Sweden.
Brodin
Lars-Ake
LA
Alvestrand
Anders
A
Lind
Britta
B
Stenvinkel
Peter
P
Mazza do Nascimento
Marcelo
M
Qureshi
Abdul Rashid
AR
Saha
Samir
S
Lindholm
Bengt
B
Seeberger
Astrid
A
D000368:Aged; D015150:Echocardiography, Doppler / Q000379:methods*; D005260:Female; D006801:Humans; D017379:Hypertrophy, Left Ventricular / Q000000981:diagnostic imaging / Q000209:etiology / Q000503:physiopathology; D008297:Male; D008875:Middle Aged; D009200:Myocardial Contraction / Q000502:physiology; D010710:Phosphates / Q000097:blood; D006435:Renal Dialysis / Q000009:adverse effects*; D018487:Ventricular Dysfunction, Left / Q000000981:diagnostic imaging / Q000209:etiology* / Q000503:physiopathology
D010710:Phosphates