Incidence and Risk Factors for Postcontrast Acute Kidney Injury in Survivors of Sudden Cardiac Arrest Bradley J. Petek, BS; Paco E. Bravo, MD; Francis Kim, MD; Ian H. de Boer, MD, MS; Peter J. Kudenchuk, MD; William P. Shuman, MD; Martin L. Gunn, MD; David J. Carlbom, MD; Edward A. Gill, MD; Charles Maynard, PhD; Kelley R. Branch, MD, MSc * *Corresponding Author. E-mail: kbranch@cardiology.washington.edu. Study objective: Survivors of sudden cardiac arrest may be exposed to iodinated contrast from invasive coronary angiography or contrast-enhanced computed tomography, although the effects on incident acute kidney injury are unknown. The study objective was to determine whether contrast administration within the first 24 hours was associated with acute kidney injury in survivors of sudden cardiac arrest. Methods: This cohort study, derived from a prospective clinical trial, included patients with sudden cardiac arrest who survived for 48 hours, had no history of end-stage renal disease, and had at least 2 serum creatinine measurements during hospitalization. The contrast group included patients with exposure to iodinated contrast within 24 hours of sudden cardiac arrest. Incident acute kidney injury and first-time dialysis were compared between contrast and no contrast groups and then controlled for known acute kidney injury risk factors. Results: Of the 199 survivors of sudden cardiac arrest, 94 received iodinated contrast. Mean baseline serum creatinine level was 1.3 mg/dL (95% confidence interval [CI] 1.4 to 1.5 mg/dL) for the contrast group and 1.6 mg/dL (95% CI 1.4 to 1.7 mg/dL) for the no contrast group. Incident acute kidney injury was lower in the contrast group (12.8%) than the no contrast group (17.1%; difference 4.4%; 95% CI –9.2% to 17.5%). Contrast administration was not associated with significant increases in incident acute kidney injury within quartiles of baseline serum creatinine level or after controlling for age, sex, race, congestive heart failure, diabetes, and admission serum creatinine level by regression analysis. Older age was independently associated with acute kidney injury. Conclusion: Despite elevated baseline serum creatinine level in most survivors of sudden cardiac arrest, iodinated contrast administration was not associated with incident acute kidney injury even when other acute kidney injury risk factors were controlled for. Thus, although acute kidney injury is not uncommon among survivors of sudden cardiac arrest, early (<24 hours) contrast administration from imaging procedures did not confer an increased risk for acute kidney injury. [Ann Emerg Med. 2015;-:1-8.] Please see page XX for the Editor’s Capsule Summary of this article. 0196-0644/$-see front matter Copyright © 2015 by the American College of Emergency Physicians. http://dx.doi.org/10.1016/j.annemergmed.2015.07.516 INTRODUCTION Background Use of iodinated contrast media as part of imaging procedures, such as coronary angiography or computed tomography (CT), is generally well tolerated but has been associated with adverse allergic reactions and acute kidney injury in susceptible individuals. Although postcontrast acute kidney injury is typically reversible, causing only transient declines in glomerular filtration rates that stabilize after 3 to 7 days, some postcontrast acute kidney injury events have led to dialysis and poor outcomes. 1,2 The majority of studies to date have identi fied risk factors for contrast-associated acute kidney injury such as age, contrast volume, and baseline serum creatinine level in patients presenting for percutaneous coronary interventions or CT scans. 1-7 Patients with poor renal perfusion because of shock, heart failure, or intravascular fluid depletion are especially prone to the development of postcontrast acute kidney injury. Importance Survivors of a sudden cardiac arrest event often have at least transiently decreased renal perfusion and an elevated serum creatinine level on admission. 8-10 In addition, depressed cardiac output and secondary decreased renal perfusion may also occur after a sudden cardiac arrest event. Because survivors of sudden cardiac arrest commonly undergo invasive coronary angiography or contrast-enhanced CT as a part of clinical care, 11 they may be at risk for contrast- associated acute kidney injury. Other reactions to contrast Volume -, no. - : - 2015 Annals of Emergency Medicine 1 CARDIOLOGY/ORIGINAL RESEARCH