Is cystatin C useful for the detection and the estimation of low glomerular filtration rate in heart transplant patients?

Although previously studied in patients with chronic kidney disease, there is less data for the use of cystatin C and cystatin C-based formulas in heart transplant recipients. The ability of creatinine and cystatin C to detect renal failure (glomerular filtration rate [GFR] below 60 mL/min/1.73 m(2)) in heart transplant patients has been compared. The accuracy and precision of a creatinine-based formula (Modification of Diet in Renal Disease [MDRD]) versus a cystatin C-based formula (Rule's formula) to estimate GFR have also been studied. GFR was measured using the (51)Crethylenediamine tetraacetic acid tracer in 27 patients. There was no significant difference between GFR and the reciprocal of creatinine or cystatin C. Receiver operating characteristic curves for cystatin C and creatinine were similar. Both formulas were well correlated with the GFR. The bias of the cystatin C-based was significantly better than one of the MDRD formula, but the standard deviation appeared better for the MDRD formula (bias of +3.9 mL/min/1.73 m(2) versus +12 mL/min/1.73 m(2) and SD of 8.5 versus 11.6, respectively). Plasma cystatin C has no clear advantage over serum creatinine to detect renal failure in heart transplanted patients.