Impact of cardiac catheterization timing and contrast media dose on acute kidney injury after cardiac surgery

Background: The association between pre-operative cardiac catheterization and cardiac surgery associated acute kidney injury (CSA-AKI) has been reported inconsistently. The purpose of this study is to evaluate the effect of the catheterization timing and contrast media dose on the incidence of postoperative acute kidney injury. Methods: Patients who underwent cardiac catheterization and cardiac surgery successively from January 2015 to December 2015 were prospectively enrolled in this study. The primary outcome was CSA-AKI which was defined as the Kidney Disease: Improving Global Outcomes Definition and Staging (KDIGO) criteria. Univariate analysis and multivariate regression were performed to identify the predictors for CSA-AKI. Baseline characteristics were balanced with propensity score method for better adjustment. Results: A total of 1069 consecutive eligible patients were enrolled into this study. The incidence of CSA-AKI and AKI requiring renal replacement therapy (AKI-RRT) were 38.5% (412/1069) and 1.9% (20/1069) respectively. Preoperative estimated glomerular filtration rate less than 60 mL/min/1.73m(2) (OR = 2.843 95% CI 1374-5.882), the time interval between catheterization and surgery <= 7 days (OR = 2.546, 95% CI 1.548-4.189) and the dose of contrast media (CM) > 240 mg/kg (OR = 2.490, 95%Cl 1.392-4.457) were identified as predictors for CSA-AKI. In the patients with the dose of CM > 240 mg/kg, the incidence of CSA-AKI was higher in patients who underwent cardiac catheterization <7 days before cardiac surgery than in those of <= 7 days before cardiac surgery (39.4% vs. 28.8%, p = 0.025). The longer interval of more than 7 days was revealed to be inversely associated with CSA-AKI through logistic regression (OR = 0.579, 95% CI 0.337-0.994). Conclusion: Catheterization within 7 days of cardiac surgery and a dose of CM > 240 mg/kg were associated with the onset of CSA-AKI. For patients who received a dose of CM > 240 mg/kg, postponing the cardiac surgery is potentially beneficial to reduce the risk of CSA-AKI.