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

Abstract

Abstract Objective 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. Design Prospective cohort study conducted between July 2018 and April 2019. Setting University teaching hospital. Animals Nineteen dogs undergoing cardiac surgery under CPB with preoperative serum creatinine <140 μmol/L (<1.6 mg/dl). Interventions Blood and urine samples were obtained at 4 time points: preoperatively following general anesthesia induction, immediately postoperatively, and 2 and 4 days postoperatively (T 1 , T 2 , T 3 , and T 4 ). AKI was defined as an increase in serum creatinine ≥26.4 μmol/L (≥0.3 mg/dl) above baseline within 48 hours. 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 (log 10 ) when appropriate and assessed using linear mixed‐effects models. Measurements and Main Results AKI occurred in 3 of 19 dogs (15.8%, 95% confidence interval: 0.047–0.384). Inosine increased at T 2 (adjusted mean ± standard error: 53 ± 5.6) in all dogs, and then gradually decreased. Log 10 uCysB increased at T 2 (2.3 ± 0.1) in all dogs and remained high. Log 10 CRP and log 10 uClus increased significantly at T 3 (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 log 10 CRP and log 10 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. Conclusions 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.