Cardiovascular risk in patients undergoing maintenance hemodialysis with Helixone® membrane: a multicenter randomized study.

INTRODUCTION: The high prevalence and incidence of atherosclerotic vascular complications, such as cardiovascular disease, remain the major cause of morbidity and mortality in patients undergoing dialysis. OBJECTIVES: The aim of the study was to evaluate cardiovascular risk factors in patients dialyzed with a high­flux polysulfone membrane (Helixone®) compared with those dialyzed with a low­flux polysulfone membrane. PATIENTS AND METHODS: This was a crossover randomized study including 90 hemodialysis patients. Group 1 was treated first with high­flux and then with low­flux membranes, while group 2, first with low­flux and then with high­flux membranes for 13 months. Clinical, biochemical, and echocardiographic data were evaluated at baseline and every 3 months during the study. RESULTS: After 6 months of high­flux dialysis, we observed a significant decrease in ß2­microglobulin, lipoprotein(a), C­reactive protein, and parathormone levels and an increase in serum albumin levels. Initially, both groups showed left ventricular hypertrophy. After 6 months of high­flux dialysis, we observed a tendency for an increase in the cardiac index and cardiac output and a decrease in isovolumic relaxation time. CONCLUSIONS: Our study showed that the use of high­flux dialysis with the Helixone® membrane, in comparison with low­flux dialysis with polysulfone membranes, improves middle-molecular clearance. In addition, we showed that a reduction in chronic inflammation during high­flux dialysis may decrease cardiovascular risk. However, further research with longer follow­up is needed to verify our echocardiographic findings.

The clinicopathological determinants of native arteriovenous fistula failure in patients on maintenance hemodialysis.

BACKGROUND: Progressive narrowing of the venous part of dialysis fistulae is caused by hemodynamic and inflammatory factors. OBJECTIVES: The pathogenic and clinical determinants of deterioration of the functioning of arteriovenous fistulae in chronically hemodialyzed patients were evaluated. MATERIAL AND METHODS: The hemodynamic parameters and the activity of inflammatory growth factors in the vessel wall of newly implanted fistulae were assessed and correlated with the clinical course of 34 hemodialyzed patients. Measurements taken at the time of implanting the fistulae included blood flow in the venous part of the anastomosis and its widest diameter by ultrasound Power Doppler, a histopathologic examination of fistula wall samples and measurements of mRNA expression for growth factors PDGFß1 and TGFß in the fistula wall. The results were correlated with clinical data from 36 months' observation: duration of fistula maturation, adequacy of dialysis treatment (eKt/V), the patient's survival, morbidity linked with vascular access problems and general cardiovascular morbidity. RESULTS: The mean duration of fistula maturation was 44.9 days (N = 43, SD = 38.6), whereas the average duration of fistula usage as dialysis access was 795.9 ± 480.6 days. Fistula blood flow at the time of implantation, averaged 1782.2 ± 1735.3 ml/min. The mean number of hospitalization days due to vascular access morbidity was 9.9 ± 15.6 days and it correlated positively with the fistula blood flow (R = 0.596, P = 0.004). There was a negative correlation between the expression of PDGFß1 mRNA and fistula blood flow (R = -0.673, P = 0.011), as well as between TGFß expression and patient survival (R = -0.722, P = 0.002). CONCLUSIONS: Inflammatory activity of the vessel wall growth factors PDGFß1 and TGFß implies impairment of fistula function and the patient's cardiovascular morbidity.