Diagnostic Accuracy of Plasma Cystatin C and Renal Resistive Index for Acute Kidney Injury in Critically Ill Patients: A Prospective Observational Study.

Background: Acute kidney injury (AKI) is a quite common problem in critically ill patients. Serum cystatin C has emerged as a marker of AKI. This study was aimed to evaluate the diagnostic ability of serum Cystatin-C and Renal Resistive Index in prediction of AKI among critically ill patients. Methodology: This prospective observational study was carried out in the department of Medicine, over a period of one year. After informed consent and ethical clearance total 120 critically ill patients suffering from sepsis were enrolled, out of which 70 patients developed AKI while 50 did not develop AKI during treatment in Intensive care unit (ICU). Serum cystatin C was measured on day 1 by particle-enhanced immune nephelometric assay, Renal resistive index (RRI) calculated by ratio of the velocities of arterial perfusion throughout the cardiac phase and glomerular filtration rate was measured on days 1, 3, and 7 respectively. Results: S. cystatin C value was significantly higher(>3times) in AKI patients (14.07±4.8 mcg/ml) as compared to those who did not develop AKI (4.28±3.27 mcg/ml) (p<0.001). After ROC analysis it was found that day1, S. cystatin C, at cut off value of ≥9.29 mcg/ml had diagnostic accuracy 90% with sensitivity 91%, specificity89% and PPV 95.5%. While RRI value on day 7, at cut-off value of ≥0.72, had diagnostic accuracy 98%, sensitivity (98.6%) and specificity (96.7%) for AKI with 98.6% PPV, 96.7% NPV. Conclusion: Serum cystatin C appears to be a promising bio- markers for early diagnosis of AKI in critically ill patients. Whereas, RRI although non-invasive had good diagnostic accuracy but it diagnosed AKI after few days thus diagnosis of kidney injury delayed.

Correlation of serum neutrophil gelatinase-associated lipocalin with acute kidney injury in hypertensive disorders of pregnancy.

Hypertensive disorders of pregnancy (HDP) remain one of the largest single causes of maternal and fetal morbidity and mortality, accounting for 16.1% of maternal deaths in developed countries. The aim of the study was to evaluate acute kidney injury (AKI) in hypertensive disorders of pregnancy and to examine the correlation of serum neutrophil gelatinase-associated lipocalin (NGAL) with acute kidney injury. This prospective case control study was carried out over a period of 1 year. After written, informed consent and ethical clearance, 149 cases of hypertensive disorders of pregnancy were screened, and seven were lost to follow-up. Acute kidney injury was detected in 88 cases and acute renal failure in 30 cases of HDP. Thirty-one healthy pregnant nonhypertensive women were enrolled as controls. Quantitative measurement of serum NGAL levels was done by enzyme linked immunosorbent assay technique using a sandwich enzyme-linked immunosorbent assay kit. As per the Kidney Diseases Improving Global Outcomes International guidelines acute kidney injury network (AKIN), 50 cases (42.37%) of AKI stage I, 38 (32.2%) cases of AKI stage II, and 30 (25.42%) cases of renal failure were detected. Serum NGAL had a positive association with increasing proteinuria. It also had a positive correlation with systolic blood pressure (r∼0.36), diastolic blood pressure (r∼0.37), and serum creatinine (r∼0.4). NGAL was found to be significantly correlated with creatinine in the cases with the value of the correlation coefficient being 0.4. This direct correlation might be a consequence of endothelial dysfunction on which hypertension and proteinuria probably depends.