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Published on: January 7, 2013
Utility of cystatin C for assessment of renal function after cardiac surgery
D Heise1, R M Waeschle, J Schlobohm
1Department of Anaesthesiology, Emergency and Intensive Care Medicine, University of Gottingen, Gottingen, Germany. dheise1@gwdg.de
Insights
Serum creatinine and cystatin C (CysC) equally detect reduced kidney function in cardiac surgery patients. However, serum creatinine is more effective for detecting milder kidney function decline, showing no superiority for CysC in GFR assessment.
Area of Science:
- Nephrology
- Cardiovascular Surgery
- Clinical Chemistry
Background:
- Acute kidney injury in cardiac surgery increases mortality.
- Early diagnosis of renal failure is challenging due to delayed lab markers.
- Glomerular filtration rate (GFR) estimation using cystatin C (CysC) shows inconsistent results compared to serum creatinine.
Purpose of the Study:
- Compare the diagnostic effectiveness of serum creatinine and CysC for GFR assessment in cardiac surgery patients.
- Evaluate the sensitivity and specificity of both markers in detecting reduced GFR.
- Assess the correlation between estimated GFR and creatinine clearance.
Main Methods:
- GFR was measured via creatinine clearance in 50 cardiac surgery patients.
- GFR was estimated using serum creatinine and CysC concentrations.
- Sensitivity, specificity, and correlation analyses were performed.
Main Results:
- Both creatinine and CysC equally detected GFR <60 ml/min/1.73 m(2).
- Serum creatinine demonstrated higher accuracy (AUC) for detecting GFR <90 ml/min/1.73 m(2).
- Creatinine-based formulas showed a stronger correlation with creatinine clearance.
Conclusions:
- Serum creatinine is not inferior to CysC for GFR assessment in post-cardiac surgery patients.
- CysC offers no significant advantage over serum creatinine in this patient population.
- Serum creatinine remains a reliable marker for monitoring kidney function after cardiac surgery.
Background:
Though acute renal failure among cardiac surgery patients is associated with increased mortality, diagnosis of renal failure is often delayed due to the late detectability of laboratory markers for kidney failure. Recently, a number of clinical studies have shown that glomerular filtration rate (GFR) can be estimated by measuring the serum concentration of cystatin C (CysC). However, comparisons between the diagnostic effectiveness of CysC and serum creatinine have been inconsistent. The present study compares the diagnostic effectiveness of both serum markers in cardiac surgery patients.
Methods:
In 50 cardiac surgery patients, GFR was quantified by measuring creatinine clearance and estimated from serum concentrations of both creatinine and CysC. The sensitivity and specificity of serum creatinine and CysC for detection of reduced GFR values were compared as well as correlation between estimated GFR values and creatinine clearance.
Results:
GFR values <60 ml/min/1.73 m(2) were detected with equal effectiveness using creatinine or CysC, whereas for the detection of GFR <90 ml/min/1.73 m(2) the area under the curve of serum creatinine was significantly higher. Correlation between estimated GFR values and creatinine clearance was higher when creatinine-based formulae were used.
Conclusion:
In patients after cardiac surgery, CysC is not superior to serum creatinine for assessment of GFR.
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