Prospective evaluation of novel biomarkers of acute kidney injury in dogs following cardiac surgery under cardiopulmonary bypass.

Abstract

To assess the occurrence of acute kidney injury (AKI) in dogs undergoing cardiac surgery under cardiopulmonary bypass (CPB) and explore associations between traditional and novel serum and urinary biomarkers. Prospective cohort study conducted between July 2018 and April 2019. University teaching hospital. Nineteen dogs undergoing cardiac surgery under CPB with preoperative serum creatinine <140μmol/L (<1.6mg/dl). Blood and urine samples were obtained at 4 time points: preoperatively following general anesthesia induction, immediately postoperatively, and 2 and 4 days postoperatively (T1 , T2 , T3 , and T4 ). AKI was defined as an increase in serum creatinine ≥26.4μmol/L (≥0.3mg/dl) above baseline within 48hours. Serum creatinine, C-reactive protein (CRP), symmetric dimethylarginine (SDMA), inosine, beta-aminoisobutyric acid (BAIB), urinary clusterin (uClus), and urinary cystatin B (uCysB) were measured. Data were log-transformed (log10 ) when appropriate and assessed using linear mixed-effects models. AKI occurred in 3 of 19 dogs (15.8%, 95% confidence interval: 0.047-0.384). Inosine increased at T2 (adjusted mean±standard error: 53±5.6) in all dogs, and then gradually decreased. Log10 uCysB increased at T2 (2.3±0.1) in all dogs and remained high. Log10 CRP and log10 uClus increased significantly at T3 (1.9±0.1 and 3.6±0.1, respectively) in all dogs and remained increased. There was a significant positive association between serum creatinine and SDMA (P<0.001, estimate±standard error: 0.06±0.00), between log10 CRP and log10 uClus (P<0.001, 0.35±0.08), between SDMA and creatinine as well as between SDMA and BAIB (P<0.001, 11.1±0.83 and P<0.001, 1.06±0.22, respectively) for all dogs at all time points. Inosine and uCysB concentrations changed in all dogs immediately following a surgery under CPB and may indicate tubular injury. Further studies are required to ascertain the usefulness of those biomarkers in early detection of AKI.