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Updated: Jun 18, 2025
Murine Renal Transplantation Procedure
Published on: July 10, 2009
Kidney function assessment using cystatin C and serum creatinine in heart transplantation recipients: Implications
Alberto Pinsino1, Douglas L Jennings2, Annamaria Ladanyi1
1Division of Cardiology, Department of Medicine, Columbia University Irving Medical Center, New York, New York.
Insights
In heart transplant recipients, cystatin C-based kidney function estimates (eGFRcysC) differ significantly from creatinine-based estimates (eGFRsCr), impacting valganciclovir dosing and reflecting changes in body composition and steroid use.
Area of Science:
- Nephrology
- Transplantation Medicine
- Clinical Chemistry
Background:
- Serum creatinine (sCr)-based estimated glomerular filtration rate (eGFR) accuracy is limited in heart transplant (HT) recipients due to muscle mass fluctuations.
- Cystatin C (cysC) is less affected by muscle mass but can be influenced by obesity and steroid use.
- Understanding eGFR discrepancies is crucial for optimizing patient management post-HT.
Purpose of the Study:
- To longitudinally compare eGFR calculated using cystatin C (eGFRcysC) and sCr (eGFRsCr) in HT recipients.
- To investigate the impact of body mass index (BMI), steroid use, and muscle mass on eGFR discrepancies.
- To explore the clinical implications of using eGFRcysC for valganciclovir (VGC) dosing.
Main Methods:
- Measured cysC and sCr in 294 blood samples from 80 HT recipients.
- Calculated intraindividual differences between eGFRcysC and eGFRsCr (eGFRdiffcysC-sCr).
- Assessed pectoralis muscle measures in a subset of patients (n=21) to evaluate muscle mass and quality.
Main Results:
- Significant differences between eGFRcysC and eGFRsCr were observed, especially early post-HT (median eGFRdiffcysC-sCr -28 ml/min/1.73 m2 at 1 week).
- eGFRcysC remained stable post-transplant, whereas eGFRsCr declined within the first year.
- Lower BMI, higher prednisone dose, and greater muscle mass were associated with eGFR discrepancies; eGFRcysC would have altered VGC dosing in 46% of samples, mostly reducing the dose.
Conclusions:
- eGFRcysC and eGFRsCr show marked differences in HT recipients, impacting VGC dosing.
- These discrepancies are likely influenced by changes in body composition and steroid use.
- eGFRcysC offers a potentially more stable and accurate assessment of kidney function in this population, guiding medication adjustments.
Background:
Among heart transplantation (HT) recipients, the accuracy of serum creatinine (sCr)-based estimated glomerular filtration rate (eGFR) may be limited by fluctuations in muscle mass. Cystatin C (cysC) is less influenced by muscle mass, but its levels may increase with obesity and steroid use. Herein, we (1) longitudinally compared eGFRcysC and eGFRsCr among HT recipients; (2) investigated the association of body mass index (BMI), steroid use, and muscle mass with discrepancies between eGFRs; and (3) explored the implications of eGFRcysC use on valganciclovir (VGC) dosing.
Methods:
cysC and sCr were measured in 294 blood samples obtained from 80 subjects. Intraindividual differences between eGFRs (eGFRdiffcysC-sCr) were calculated with negative values corresponding to eGFRsCr > eGFRcysC and positive values to eGFRcysC > eGFRsCr. In a patient subset (n = 21), pectoralis muscle measures were obtained.
Results:
Marked differences between eGFRcysC and eGFRsCr were observed, particularly early post-HT (1-week post-HT, median eGFRdiffcysC-sCr -28 ml/min/1.73 m2). eGFRcysC demonstrated stability following a transient postoperative decline, while eGFRsCr decreased in the first year post-HT. Lower BMI and higher prednisone dose displayed a modest association with more negative eGFRdiffcysC-sCr values. Pectoralis muscle measures indicative of greater muscle mass and better tissue quality exhibited a stronger association with more positive eGFRdiffcysC-sCr values. The use of eGFRcysC would have led to VGC dose adjustment in 46% of samples, predominantly resulting in dose reduction.
Conclusions:
Among HT recipients, eGFRcysC and eGFRsCr markedly differ with implications for VGC dosing. The observed discrepancies may reflect changes in body composition and steroid use.
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