Incidence of Acute Kidney Injury After Exposure to Intravenous Contrast in Emergency Department Patients Presenting for Stroke.

Background: Chronic kidney disease (CKD) is to be considered an independent risk factor for developing post-computed tomography (CT) acute kidney injury (AKI); however, current data are limited.

Objectives: Examine the incidence of AKI after intravenous contrast exposure among patients with and without CKD.

Methods: A single-center retrospective study examined patients that presented to the Emergency Department and activated the stroke protocol, which involved an immediate CT angiogram. Patients were subdivided into "normal to mild" (glomerular filtration rate [GFR] > 60 mL/min/1.73 m), CKD III (GFR 30-60 mL/min/1.73 m), and CKD IV (GFR < 30 mL/min/1.73 m) groups. The primary outcome was the development of AKI. Patients already on dialysis were excluded.

Results: Among the 794 patients identified, 452 (56.9%) were classified as "normal to mild," 280 (35.3%) were classified as CKD III, and 62 (7.8%) were classified as CKD IV. Patients with normal GFR had a 2.4% incidence of developing AKI, those with CKD III had a 1.4% incidence, and patients with CKD IV had an 8.1% incidence of developing AKI. Overall, 2.5% of patients developed AKI. For CKD III vs. "normal" groups, odds ratio (OR) = 0.58 (95% confidence interval [CI] 0.16-1.72). For CKD IV vs. "normal," OR = 3.52 (95% CI 1.07-10.05). Of those patients with CKD IV who had AKI, all saw improvement in their creatinine prior to discharge and none required renal replacement therapy.

Conclusion: This study builds on the evidence demonstrating that patients with CKD III are likely at the same risk of developing post-CT AKI as those with normal renal function. Furthermore, the risk of developing post-CT AKI in CKD IV patients may be far lower than previously thought, was transient, and did not result in renal replacement therapy.