Cystatin C Reduction Ratio Depends on Normalized Blood Liters Processed and Fluid Removal during Hemodialysis

Abstract

SummaryBackground and objectives A negative correlation between the weekly standard Kt/V (urea) and serum cystatin C level (CysC) in functionally anephric dialysis patients has been previously demonstrated. Our objective was to measure the per dialysis CysC reduction ratio (CCRR) and to compare it with other indices of dialytic functions.Design, setting, participants, & measurements In a pilot cross-sectional study of 15 functionally anephric patients on conventional high-flux high-efficiency hemodialysis three times per week, CysC levels were drawn pre-, mid-, and postdialysis over 1 week. CCRR was compared with single-pool Kt/V (Sp Kt/V) using urea kinetic modeling, urea reduction ratio (URR), creatinine reduction ratio (CRR), normalized liters processed (LP/kg), and ultrafiltration volume (UF). Normally distributed data (Shapiro-Wilks test) were described as mean Ϯ SD, otherwise as median and interquartile range. ResultsThe mean pre-and post-CysC levels were 6.0 Ϯ 1.0 and 4.7 Ϯ 1.1 mg/L. The Sp Kt/V and Std Kt/V were 1.5 Ϯ 0.2 and 2.6. The URR, CRR, and CCRR were 70.2% Ϯ 9.0%, 64.5% Ϯ 8.2%, and 26.1% Ϯ 11.8%, respectively. There was no correlation between the CCRR, and the Sp Kt/V, URR, and CRR, whereas CCRR correlated with LP/kg and UF. Multiple regression analysis with these two parameters provided a model that explained 81% of the variance. ConclusionsOur data suggest that normalized liters processed and ultrafiltration volume explain most of the variance of CCRR. Therefore, CCRR may be an excellent method to monitor dialysis efficiency of low molecular weight proteins.

Removal and Rebound Kinetics of Cystatin C in High-Flux Hemodialysis and Hemodiafiltration

“…Mass removal of cystatin C is greater in the initial phase of dialysis, suggesting that increments in sessional frequency may be a more effective removal strategy than increased duration. We found, as have others, that predialysis cystatin C levels correlate with weekly standard Kt/V but not single pool Kt/V (19,20). This finding probably reflects the contribution of RRF to the former parameter.…”

“…Clearance of these molecules may be an important marker of adequate treatment in both peritoneal dialysis (10,16) and hemodialysis (HD) (11,17). Cystatin C has been proposed as a candidate for such a marker (18)(19)(20), but there are little data describing its removal and rebound kinetics in the maintenance HD population.…”

Assessment of glomerular filtration rate in the neonate

“…However, these findings are in contrast to that of Maruniak-Chidek et al [84] and these authors question the validity of CysC as a marker of AKI in neonates. CysC concentrations may change with intravascular volume contraction [85], which frequently occurs in hypovolemic shock. The limitations of the AKI definition with serum creatinine have been discussed in detail in our commentary in Kidney International [72].…”

Diagnostic Accuracy of Cystatin C–Based eGFR Equations at Different GFR Levels in Children

“…The rationale of combining serum creatinine and plasma cystatin C originated from the fact that the sources of error for either marker differ. Serum creatinine levels are confounded by muscle mass and variable tubular secretion, whereas serum cystatin C has a different volume of distribution and may vary with the volume status (12).…”