Serum cystatin C as a marker of renal function in patients with acute renal failure.

Serum creatinine level is the traditionally used tool to detect changes in renal function. Serum cystatin C (CC) has been suggested to be an equally effective marker of renal function. We measured the serum levels of creatinine and CC in 73 patients with acute renal failure (ARF) and 300 age and sex matched healthy controls. The serum CC was measured by particle enhanced nephlometric immunoassay (PENIA). As expected, the serum creatinine and CC levels were significantly higher in ARF patients than the healthy controls and serum CC levels correlated significantly with serum creatinine (r = 0.47, p< 0.0001). This correlation further increased for multiple measurements, (r = 0.51, p< 0.0001. No gender difference was noted. Serum CC also correlated significantly with calculated GFR. Correlation of serum CC with serum creatinine and calculated GFR was much greater in patients with deteriorating renal function, compared to patients with improving renal function (p< 0.0001). Our study further suggests that the serum CC is a good marker of renal function in ARF patients, especially those with worsening renal function. Further larger studies are needed to evaluate its role in detecting early ARF and institute possible intervention.

Coagulation inhibitors and fibrinolytic parameters in patients on peritoneal dialysis and haemodialysis.

Coagulation inhibitors and fibrinolytic parameters were studied in twelve patients on continuous ambulatory peritoneal dialysis (CAPD) and ten patients on haemodialysis (HD). Patients on CAPD exhibited higher levels of ATIII and proteins C and S than those on HD. No significant differences were noted in tPA and PAI levels. Both groups of patients showed higher levels of tPA than controls. Besides, patients on HD had significantly lower levels of ATIII and protein C than controls. PAI levels in both patient groups were similar to those of the controls, but tPA levels were higher in patients than in controls. These results indicate that HD is associated with marked diminution in the circulating levels of coagulation inhibitors. This is in contrast to CAPD patients who showed elevated levels of these inhibitors, despite their significant loss in the dialysate. The finding of enhanced fibrinolysis in both patient groups may be a natural protective mechanism against the development of a thrombotic tendency.

Comparison of the effects of three haemodialysis membranes on vancomycin disposition.

Polysulfone (PSF) and polyacrylonitrile (PAN) were recently introduced haemodialysis (HD) membranes. The effect of each on vancomycin disposition was compared with cuprophan (SCE) in 12 chronic HD patients who received 14 infusions. Vancomycin (1 g) was infused over 1 hour, followed by three 4-hour HD sessions over 5 days, beginning 1 hour after the end of infusion. The intradialytic clearances of vancomycin were 73, 54 and 15 ml/min for PSF, PAN and SCE, respectively. At the end of the third HD session, vancomycin concentration dropped to subtherapeutic level (< 7.5 micrograms/ml) only in patients dialysed with PSF and PAN. The corresponding elimination half-lives (t1/2 beta) were 61, 60 and 86 hours for the three membranes, respectively. According to these findings, vancomycin should be given every three HD sessions for PSF and PAN. The dosage interval should be extended up to every 5 HD sessions for patients on SCE. The peak (mean +/- S.D.) obtained one hour after the end of infusion was 34.2 +/- 11.4 micrograms/ml, which is within the therapeutic range.