Iodinated Contrast Administration for Computed Tomography in Stroke Does Not Cause Acute Kidney Injury: A Retrospective Single-Centre Review of 340 Patients

Background and Rationale: The significance of contrastinduced nephropathy following computed tomography (CT) is questionable (McDonald et al., 2013), making stroke treatment delays introduced in determining renal function prior to CT angiography (CTA) unwarranted. This study aimed to analyse the incidence of acute kidney injury (AKI) amongst patients undergoing acute stroke evaluation, to guide local practice. Methods: We conducted a retrospective analysis of patients from our stroke registry between April 2014 and January 2016. All patients underwent non-contrast CT brain, followed by CTA archto-vertex unless contraindicated. Baseline renal function, based on blood results at or prior to presentation, was compared to renal function after 48 hours of hospital admission; with AKI defined using KDIGO criteria. Results: Data was available for 340 patients, of whom 248 (72.9%) underwent CTA. Mean patient age (68.6 vs. 75.0 years; p < 0.001) and presence of chronic kidney disease (CKD) stage 35 (22.6% vs. 35.9%; p = 0.02) were significantly greater in the non-contrast group. Mean serum creatinine significantly improved over the first 48 hours of admission in both CTA (82.3 vs. 76.2 mmol/l; p < 0.001) and non-contrast groups (95.4 vs. 90.0 mmol/l; p = 0.03). The overall incidence of AKI was 2.65% (9 patients), with no significant difference between the CTA and non-contrast groups (1.61% vs. 5.43%; OR 0.29, 95% CI 0.0751.09; p = 0.078). No patient required dialysis. Amongst patients who underwent CTA, neither age >80 years (0% vs. 2.3%; p = 0.263) nor baseline CKD 35 (1.9% vs. 1.5%; p = 0.793) significantly increased the risk of developing AKI. Conclusion: The incidence of AKI post-CTA is low and consistent with that reported in another recent Australian study (Ang et al., 2015). Contrast administration in acute stroke imaging does not appear to increase the risk of AKI, affirming our practice of not routinely awaiting renal function prior to CTA in the setting of acute stroke.