Emergent CT angiography and risk of contrast-induced acute kidney injury in acute ischaemic stroke

Objectives: Emergent computed tomography angiography with contrast is commonly performed for acute ischaemic stroke, but potentially delayed pending admission renal function assessment due to purported risk of contrast-induced acute kidney injury. Such clinical dilemma warrants further evaluation. Methods: We retrospectively examined the incidence of contrast-induced acute kidney injury in acute ischaemic stroke patients who underwent a single initial contrasted computed tomography angiography or two serial contrasted computed tomography angiographies, versus acute kidney injury in patients with no contrast exposure. Acute kidney injury and extended renal dysfunction were defined as increase by >50% in serum creatinine from admission, within 5 days and after 30 days respectively. Results: Of 465 patients with acute ischaemic stroke, 372 underwent computed tomography angiography (203 with single initial contrasted computed tomography angiography, 169 with two serial contrasted computed tomography angiographies), and 93 patients had no contrast exposure. 33% of entire cohort had diabetes mellitus and 9.4% had chronic kidney disease, both comparable between subgroups. Acute kidney injury occurred in 2.5%, 2.4%, and 9.7% with single initial contrasted computed tomography angiography, two serial contrasted computed tomography angiographies, and no contrast exposure, respectively (p = 0.004). Corresponding rates of extended renal dysfunction were 1.5%, 0.6%, and 6.5% (p = 0.185). On multivariate analysis, diabetes mellitus and lower baseline estimated glomerular filtration rate were independently associated with acute kidney injury, while lower estimated glomerular filtration rate was associated with extended renal dysfunction (p < 0.05). Contrast-exposed patients did not have higher risk for acute kidney injury (odds ratio, OR = 0.25, 95% CI 0.096-0.647, p = 0.004) or extended renal dysfunction (OR = 0.083, 95% CI 0.008-0.810, p = 0.032) versus non-contrasted patients. Receiving two computed tomography angiographies within 24 hours did not confer added risk for contrast-induced acute kidney injury. Conclusions: Emergent or serial computed tomography angiographies in acute ischaemic stroke were associated with very low risk of acute kidney injury and extended renal dysfunction, and these risks were not significantly higher than in acute ischaemic stroke patients with no early contrast exposure.