Does an alteration of dialyzer design and geometry affect biocompatibility parameters?

The aim of the study was to assess the biocompatibility profile of a newly developed high-flux polysulfone dialyzer type (FX-class dialyzer). The new class of dialyzers incorporates a number of novel design features (including a new membrane) that have been developed specifically in order to enhance the removal of small- and middle-size molecules. The new FX dialyzer series was compared with the classical routinely used high-flux polysulfone F series of dialyzers. In an open prospective, randomized, crossover clinical study, concentrations of the C5a complement component, and leukocyte count in blood and various thrombogenicity parameters were evaluated before, and at 15 and 60 min of hemodialysis at both dialyzer inlet and outlet in 9 long-term hemodialysis patients using the FX60S dialyzers and, after crossover, the classical F60S, while in another 9 patients, the evaluation was made with the dialyzers used in reverse order. The comparison of dialyzers based on evaluation of the group including all procedures with the FX60S and the group including procedures with the F60S did not reveal significant differences in platelet count, activated partial thromboplastin times, plasma heparin levels, platelet factor-4, D-dimer, C5a, and leukocyte count at any point of the collecting period. Both dialyzer types showed a significant increase in the plasma levels of the thrombin-antithrombin III complexes; however, the measured levels were only slightly elevated compared with the upper end of the normal range. Biocompatibility parameters reflecting the behavior of platelets, fibrinolysis, complement activation, and leukopenia do not differ during dialysis with either the FX60S or the F60S despite their large differences in design and geometry features. Although coagulation activation, as evaluated by one of the parameters used, was slightly higher with the FX60S, it was still within the range seen with other highly biocompatible dialyzers and therefore is not indicative of any appreciable activation of the coagulation system. Thus, the incorporation of various performance-enhancing design features into the new FX class of dialyzers does not result in a deterioration of their biocompatibility profile, which is comparable to that of the classical F series of dialyzers.

Procalcitonin levels in peritoneal dialysis patients.

OBJECTIVE: To examine whether the levels of procalcitonin (PCT), a new marker of infection and/or inflammation, differ between peritoneal dialysis (PD) patients and healthy volunteers, and whether PCT is detectable in uninfected drained dialysate. DESIGN: Observational cross-sectional study. SETTING: PD unit, department of medicine, in a university hospital. PATIENTS: A total of 28 PD patients, free of systemic infection, and 28 age- and sex-matched healthy volunteers. METHODS: PCT was determined by immunoluminometry; detection range 0.01 - 500 ng/mL, reference range < 0.5 ng/mL. RESULTS: Plasma levels of PCT were significantly higher (Wilcoxon's paired test, p < 0.001) in PD patients (median 0.33 ng/mL) compared with healthy volunteers (0.18 ng/mL). Spearman's test demonstrated a significant positive correlation between PCT and serum C-reactive protein (CRP) (r = 0.59, p < 0.01); correlations between PCT and transferrin, total weekly creatinine clearance (ClCr), and the renal components of ClCr and Kt/V urea were negative. PCT levels in dialysate (PCTd) were 0.07 ng/mL and correlated positively with plasma PCT, serum CRP, and dialysate fibrinogen levels. The dialysate-to-plasma ratio (D/P) of PCT was 0.2. Neither PCTd nor D/P PCT correlated with D/P creatinine at 4-hours of dwell. CONCLUSION: Compared with healthy volunteers, PD patients without overt signs of infection showed increased plasma PCT levels. Given the study design, it is impossible to determine to what extent the increase in plasma PCT is due to reduced elimination and to what extent it reflects the microinflammation of uremia. Based on the D/P PCT gradient, we assume that PCT transport is more likely to occur from the systemic circulation to the peritoneal cavity than vice versa.

Fibrinolysis defect in long-term hemodialysis patients with type 2 diabetes mellitus and its relation to metabolic disorders.

BACKGROUND/AIMS: Patients with chronic renal failure (CRF) secondary to diabetes mellitus show a high incidence of atherosclerosis with its thrombotic complications. Both CRF and type 2 diabetes mellitus (DM2) results in fibrinolysis defects causally related to atherogenesis and thrombogenesis. It is not well known whether or not and, if so, how fibrinolysis is altered in patients with both CRF and DM2. Our study was designed (1) to identify the fibrinolysis defect present in patients with DM2-mediated CRF and treated by long-term hemodialysis (DM2HD), and (2) to establish whether the fibrinolysis defect is related to the metabolic abnormalities observed in CRF or DM2. METHODS: Sixteen DM2HD patients and 23 healthy individuals (HI) had their euglobulin clot lysis time (ECLT), and tissue-type plasminogen activator (tPA) and plasminogen activator inhibitor-1 (PAI-1) activities (act) and concentrations (ag) assessed before and after standard fibrinolytic stimulus (i.v. administration of 0.4 microg/kg BW 1-deamino-8-D-arginine vasopressin, DDAVP) along with metabolic status markers. RESULTS: DDAVP caused a significant shortening of ECLT, rises in tPA act and ag, and a significant decrease in PAI-1 act. PAI-1 ag declined significantly in HI, but not in DM2HD. A comparison of responses to DDAVP revealed the groups differed significantly in the change in PAI-1 ag. Whereas, in HI, PAI-1 ag decreased by 11.8 ng/ml, no decrease was seen in DM2HD (0.0 ng/ml) (p < 0.0001; medians given; unpaired Wilcoxon's test). Stepwise regression analysis showed the change in PAI-1 ag was highly group-specific (DM2HD vs. HI, regression coefficient 21.22; partial correlation 0.58; p < 0.0001) and, also dependent on the serum concentrations of apolipoprotein A-I (-32.41; -0.46; p < 0.01) and homocysteine (0.35; 0.36; p < 0.05). CONCLUSIONS: Patients with type 2 DM and CRF on long-term hemodialysis have a fibrinolysis defect manifesting itself after standard fibrinolytic stimulus by an insufficient decrease in PAI-1 concentrations. The defect is related to decreased serum levels of apolipoprotein A-I and increased serum levels of homocysteine. The defect might be a factor contributing to accelerated atherosclerosis and thrombotic complications in these patients.