The efficacy of biomarkers in the diagnosis of acute kidney injury secondary to liver cirrhosis

Seeing and Sensing the Hepatorenal Syndrome (HRS): The Growing Role of Ultrasound-Based Techniques as Non-Invasive Tools for the Diagnosis of HRS

More than half of patients hospitalized with liver cirrhosis are dealing with an episode of acute kidney injury; the most severe pattern is hepatorenal syndrome due to its negative prognosis. The main physiopathology mechanisms involve renal vasoconstriction and systemic inflammation. During the last decade, the definition of hepatorenal syndrome changed, but the validated criteria of diagnosis are still based on the serum creatinine level, which is a biomarker with multiple limitations. This is the reason why novel serum and urinary biomarkers have been intensively studied in recent years. Meanwhile, the imaging studies that use shear wave elastography are using renal stiffness as a surrogate for an early diagnosis. In this article, we focus on the physiopathology definition and highlight the novel tools used in the diagnosis of hepatorenal syndrome.

Acute Kidney Injury and Hepatorenal Syndrome in Patients with Cirrhosis

Acute kidney injury (AKI) is common in hospitalized patients with cirrhosis. Hepatorenal syndrome (HRS) is a type of AKI known as HRS-AKI. It is a severe complication of cirrhosis with high morbidity and mortality. While certain vasoconstrictor medications have been shown to improve HRS-AKI, no clear transplant-free survival benefit has been reported with medical therapies. Patients with HRS-AKI should be considered for urgent liver transplantation evaluation. In this review, we discuss the most recent updates on the definition, diagnosis, and management of AKI in cirrhosis, with special a emphasis on HRS.

Value of urine/serum Neutrophil gelatinase-associated lipocalin ratio in distinguishing acute kidney injury from chronic kidney disease

OBJECTIVE

This study was performed to test the hypothesis that neutrophil gelatinase-associated lipocalin (NGAL) as a biomarker would be helpful for differentiation acute kidney injury (AKI) from chronic kidney disease (CKD) in kidney malfunction patients from the nephrology department.

METHODS

This retrospective study included 355 patients admitted from the nephrology department with modification of diet in renal disease estimated glomerular filtration rate (MDRD eGFR) < 60 ml/min/1.73 m². The subjects were categorized into AKI group (n = 204) and CKD group (n = 151). A propensity-matched analysis, incorporating 17 variables, was performed to control potential selection bias.

RESULTS

Urinary NGAL (uNGAL) level in the AKI group was higher than in the CKD group (372.10 (170.10-690.63) vs 88.10 (52.00-238.80), P < 0.001), but there was no significant difference in serum NGAL (sNGAL). Both sNGAL and uNGAL had a correlation with MDRD eGFR in total patients, AKI patients, and CKD patients. The propensity-matched analysis enrolled 75 patients in each group. In matched AKI group, sNGAL was lower (401.20 (239.10-616.00) vs 468.50 (305.00-709.40), P = 0.049) and uNGAL was elevated (284.00 (136.90-690.90) vs 203.70 (69.20-596.00), P = 0.032), compared with the matched CKD group. In all patients (n = 355), the ratio of uNGAL and sNGAL (u/s NGAL), fractional excretion of NGAL (Fe NGAL) discriminated AKI from CKD (area under the curve, 0.803 and 0.790, respectively). After stratified kidney function, the sub-analyses found that u/s NGAL and Fe NGAL were shown to differ substantially between the AKI group and CKD group (all P < 0.01). The u/s NGAL ratio always had the highest AUC area in the sub-analyses.

CONCLUSIONS

u/s NGAL might be helpful to discriminate AKI from CKD in kidney malfunction patients admitted to the nephrology department. Further confirmatory studies might be warranted.