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

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&#xa0;&#x3bc;mol/L (<1.6&#xa0;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, T, T, and T). AKI was defined as an increase in serum creatinine &#x2265;26.4&#xa0;&#x3bc;mol/L (&#x2265;0.3&#xa0;mg/dl) above baseline within 48&#xa0;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) 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(adjusted mean&#xa0;&#xb1;&#xa0;standard error: 53&#xa0;&#xb1;&#xa0;5.6) in all dogs, and then gradually decreased. LoguCysB increased at T(2.3&#xa0;&#xb1;&#xa0;0.1) in all dogs and remained high. LogCRP and loguClus increased significantly at T(1.9&#xa0;&#xb1;&#xa0;0.1 and 3.6&#xa0;&#xb1;&#xa0;0.1, respectively) in all dogs and remained increased. There was a significant positive association between serum creatinine and SDMA (P&#xa0;<&#xa0;0.001, estimate&#xa0;&#xb1;&#xa0;standard error: 0.06&#xa0;&#xb1;&#xa0;0.00), between logCRP and loguClus (P&#xa0;<&#xa0;0.001, 0.35&#xa0;&#xb1;&#xa0;0.08), between SDMA and creatinine as well as between SDMA and BAIB (P&#xa0;<&#xa0;0.001, 11.1&#xa0;&#xb1;&#xa0;0.83 and P&#xa0;<&#xa0;0.001, 1.06&#xa0;&#xb1;&#xa0;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.