Study of post-contrast acute kidney injury on high-risk patients in the emergency department settings

Introduction: Contrast enhanced computed tomography is one of the most ordered imaging modalities nowadays in emergency departments. Especially for vascular diagnoses, contrast media is essential to use. Due to the concern of contrast induced nephropathy, patients have decreased renal functions occasionally and selectively not been exposed to CECT. Additionally waiting for patient's renal function test results before obtaining CECT imaging leads to longer ED length of stay and slowdown ED operations in general. In our study, we analyzed post-contrast acute kidney injury and its outcomes on high-risk patients in the emergency department settings. Materials and Method: This study conducted in a tertiary care university teaching hospital, patients with a baseline GFR of ≤45 mL/min/1.73 m2 who underwent pulmonary CT angiography (CTA) and thoracic CT imaging over a 6-year period were retrospectively evaluated. 77 patients who underwent pulmonary CTA, 439 patients who underwent thorax CT imaging and in total 516 patients were included in study. The groups were matched 1:1 according to the study variables with the propensity score matching method. Analyzes examining the relationship between potential risk factors (age, gender, baseline renal function tests, triage scale, vital signs, HT, DM) and outcomes (requirement for renal replacement therapy (RRT), development of AKI, 30-day mortality) were analyzed in all patients, then repeated in pre-matched and post-matched groups. Statistical analyzes were performed using the R data terminal and SPSS 20.0. Results: When the pre-matched groups were compared, there was no difference between the groups in terms of mortality (p: 0.210) and RRT requirement (p: 0.803), while AKI (p<0.001) was found to be higher in the pulmonary CT angiography group. There was no difference between the groups in terms of mortality (p: 0.362), RRT (p: 0.681), and AKI (p: 0.150) after 1:1 matching with the propensity score matching method. Conclusion: In our study, in the high-risk patient population which eGFR ≤45 mL/min/1.73 m2, no cause-effect relationship was found between exposure to intravenous contrast media and mortality, the need for renal replacement therapy, and the development of acute kidney injury. Key Words: Post Contrast Acute Kidney Injury, Contrast Induced Nephropathy, High-Risk Patient, Propensity Score Matching