226 Contrast-Induced Nephropathy in Patients Rapidly Evaluated for Acute Cerebral Infarction Using Contrast-Enhanced Computed Tomography

Abstract

The primary objective of this study is to determine the prevalence of contrast-induced nephropathy (CIN) in patients rapidly evaluated in the emergency department (ED) for acute cerebral infarction who undergo contrast-enhanced computed tomography (CECT) of the head. We conducted an observational, retrospective cohort study of patients who presented to the ED with signs and symptoms of acute ischemic cerebral infarction that were potentially eligible for intravenous (IV) thrombolysis. All patients being considered for IV thrombolysis seen within a single academic tertiary care hospital system that is a Joint Commission Primary Stroke Center with an annual ED visit >160,000 from May 2008 thru February 2011 were evaluated for inclusion in this study. In this institution, patients eligible for IV thrombolysis undergo a rapid imaging protocol (non-contrast head CT, CT angiogram of the head, and CT perfusion study) prior to laboratory results of baseline creatinine. Patients were excluded if they did not receive CECT, they did not have creatinine measurements at 48 to 72 hours, or if they were already receiving dialysis. Data collected included baseline comorbidities, sex, age, serum creatinine level on presentation, and serum creatinine levels daily for the next 5 days after presentation. CIN was defined as either an absolute increase in serum creatinine of 0.5 mg/dl or a relative increase of 25% within 48-72 hours of contrast administration. Prevalence and 95% confidence intervals (CI) were computed using the Agresti-Coull Modified Wald Binomial Method. 403 patients were evaluated utilizing the rapid assessment protocol for acute ischemic stroke. Only 168 of these patients were able to be included for analysis of CIN; 164 patients did not have adequate follow-up creatinine measurements, 69 patients did not receive contrast dye, and 2 patients were receiving dialysis. 3% (5/168, 95% CI 1.1-7%) of patients developed CIN within 48 hours of receiving contrast, and this increased to a total of 5.4% (9/168, 95% CI 2.7-10%) within 72 hours. However, only 1.2% (95% CI 0-4.5%) and 2.4% (95% CI 0.7-6.2%) of the patients with normal baseline creatinine levels developed CIN at 48 and 72 hours, respectively. The prevalence of CIN in our cohort of patients was 5.4% within 72 hours of contrast administration. This low prevalence should encourage physicians to not delay CECT to measure serum creatinine levels when evaluating patients in the ED for acute stroke as “time is brain.”