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01-10-2013 | What's New in Intensive Care
Critical research on biomarkers: what’s new?
Published in: Intensive Care Medicine | Issue 10/2013
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A biomarker may be defined as “a characteristic that is objectively measured and evaluated as an indicator of normal biological processes, pathogenic processes, or pharmacologic responses to a therapeutic intervention”. When assessing the need for a biomarker in clinical practice, a crucial aspect of its value is whether it might improve patient management. In this regard, biomarkers may provide important information regarding the presence, severity, and prognosis of specific disease processes, and may also provide important information regarding management options; such information may not be clinically obvious without biomarker measurement. As such, biomarkers are increasingly of interest for use in critical care medicine, for the early recognition of organ injury and to better understand the pathological processes leading to organ failure. Because of both the high prevalence and the poor prognosis associated with acute kidney injury (AKI) and with cardiovascular failure in the critically ill, this paper describes new findings in the critical care application of renal and cardiovascular biomarkers (Table 1).
Table 1
Summary of recent findings with respect to renal and cardiac biomarkers in critically ill patients
|
Biomarkers
|
Potential interest
|
Recent findings
|
Limits
|
|---|---|---|---|
|
Renal biomarkers
|
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|
Cystatin C
|
Increase in plasma cystatin C level reflects a decrease of glomerular filtration rate. Detection of urine cystatin C is a biomarker of tubular injury
|
Urine cystatin C increases the day of AKI, modest increase of plasma levels the day before
|
Poorly predictive of AKI in ICU patients
|
|
NGAL
L-FABP
NAG
KIM-1
IL-18
|
Reflect renal tubular injury
|
Wide variations for prediction of AKI with respect to mechanism of AKI.
Increase of many cases of pre-renal AKI
|
Large gray zone, clinical implications unclear with increase serum or urine levels in patients with preserved renal function
|
|
Serum creatinine
|
Marker of glomerular filtration rate (GFR), renal dysfunction
|
Increase serum creatinine associated with mortality
|
Risk of overestimating GFR (hemodilution, decrease production); delay in detecting drop of GFR
|
|
Urine sodium and urea
|
Marker of tubular function
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Not predictive of rapid recovery from AKI
|
Under influence or renal and systemic hemodynamics and neuro-hormonal status
|
|
Cardiac biomarkers
|
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BNP–Nt-pro-BNP
|
Marker of heart failure and cardiac congestion
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Prediction of respiratory failure after extubation. Guide diuretics treatment for weaning procedure
|
Large gray zone, under influence of renal function
|
|
Troponin (Tns),
high-sensitivity cTns
|
Marker of myocardial injury
|
Prediction of mortality in septic patients. Rapid absolute changes suggest coronary origin in acute chest pain
|
Non-specific of coronary origin, clinical implications unclear in ICU patients
|
|
sST-2
|
Marker of cardiac mechanical stress
|
Associated with poor prognosis in cardiovascular failure
|
Non-specific for the etiology, clinical implications unclear
|
|
Chromogranin A
|
Marker of catecholamine release and β-adrenergic stimulation
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Prediction of mortality and circulatory failure, especially in septic patients
|
Non-specific, clinical implication unclear
|