Neurons Over Nephrons

Noninvasive vascular imaging techniques, such as computed tomographic angiography (CTA) and CT perfusion (CTP), are becoming increasingly important in evaluation and triage of patients with acute ischemic stroke (AIS). In fact, recently published American Heart Association and American Stroke Association guidelines strongly recommend using CTA in evaluation of patients with AIS secondary to large vessel occlusion. Evaluation of serum creatinine levels on arrival to the emergency department and before performing CTA/CTP has become an ingrained part of the workup of patients with AIS. Many centers have policies stating that CTA/CTP cannot be performed without a baseline serum creatinine level. However, waiting for these results to come back can cost the patient precious minutes and negatively impact neurological outcomes. Furthermore, it is important to question whether or not it is justifiable to withhold a CTA or CTP, even in a patient with baseline chronic kidney disease (CKD) because of the perceived risk of acute kidney injury (AKI) secondary to contrast-induced nephropathy. Although several studies have been performed to date evaluating the risk of AKI in patients with AIS undergoing CTA/CTP, the overall risks remain unclear, and there remains no change in practice patterns at most institutions. We performed a systematic review and meta-analysis of the literature to (1) determine whether patients with AIS receiving CTA/CTP have higher rates of AKI than patients with AIS undergoing noncontrast computed tomography (NCCT) alone, (2) determine the overall rate of AKI among patients Background and Purpose—Because of the perceived risk of contrast-induced acute kidney injury (AKI), many centers require pre-imaging serum creatinine levels, potentially delaying care. We performed a systematic review and metaanalysis evaluating AKI rates in patients with acute ischemic stroke receiving computed tomographic angiography (CTA) and computed tomographic perfusion (CTP). Methods—We searched MEDLINE, EMBASE, and the Web of Science through December 2016 for studies reporting on AKI in patients with acute ischemic stroke receiving CTA/CTP. Using a random-effects model, estimates were pooled across studies. Outcomes of interest were (1) the odds of AKI in patients receiving CTA/CTP versus noncontrast computed tomography, (2) overall rate of AKI and hemodialysis in patients with acute ischemic stroke undergoing CTA/CTP, and (3) the odds of CTA/CTP-associated AKI among patients with and without chronic kidney disease. Results—Fourteen studies were included (6 case–control studies and 8 single-arm studies) with 5727 CTA/CTP and 981 noncontrast computed tomography patients. In case–control studies, AKI was significantly lower among CTA/CTP patients compared with noncontrast computed tomography patients (odds ratio=0.47; 95% confidence interval=0.33–0.68; P<0.01). Adjusting for baseline creatinine, there was no difference in AKI rates between groups (odds ratio=0.34; 95% confidence interval=0.10–1.21). The overall rate of AKI in CTA/CTP patients was 3% (95% confidence interval=2%–4%). The overall rate of hemodialysis in the CTA/CTP group was 0.07% (3 of 4373). There was no difference in AKI among CTA/CTP patients with and without chronic kidney disease (odds ratio=0.63; 95% confidence interval=0.34–1.12). Conclusions—Nonrandomized evidence suggests that CTA/CTP are not associated with statistically significant increase in risk of AKI in patients with stroke, even those with known chronic kidney disease. (Stroke. 2017;48:1862-1868. DOI: 10.1161/STROKEAHA.117.016771.)