Cystatin C and NGAL as Biomarkers for Early Detection of Acute Kidney Injury in Geriatrics

Abstract

Acute kidney injury (AKI) is associated with cardiovascular mortality and morbidity especially in high-risk patients undergoing cardiac surgery. It ranges from 7.7% to 28.1% in different studies. The aim of this study was to compare cystatin C and neutrophil gelatinase-associated lipocalin (NGAL) with Creatinine as an early marker for acute kidney injury in geriatrics. From 2013 through 2015, 307 consecutive high-risk elderly patients older than 70 years undergoing emergency coronary artery bypass grafting using extracorporeal circulation were studied. All patients underwent diagnostic coronary angiography and the surgical procedure within 1 week in single hospital stay and were randomized according to timing of interval between coronary angiographyand cardiac procedure as follows: group I, less than 2 days; group II, between 2 and 4 days; and group III, higher than 4 days. Renal function was analyzed by serum cystatin C, NGAL, and creatinine. Blood samples were obtained from each patient at five time points: basal value before operation, in the four hours after operation, and on the first, third, and fifth postoperative days. Glomerular filtration rate (GFR) was calculated by Cockcroft-Gault (CG). A total of 56 patients developed postoperative acute kidney failure according to the risk, injury, and failure; and loss; and end-stage kidney disease classification. Perioperative fluid requirements, urine output, and vasopressor need during and after cardiopulmonary bypass were similar. 30-day mortality in groups was higher in group I