Exposure to contrast media in the perioperative period confers no additional risk of acute kidney injury in surgical patients

Background: Iodinated contrast media used in angiography and computed tomography (CT) scans is an important cause of AKI in hospitalized patients undergoing surgery. Contrast induced nephropathy leads to AKI soon after contrast media administration. The aim of the study was to determine whether the timing of contrast media exposure related to diagnostic imaging during the immediate peri-operative period influences the risk of post-operative AKI.

Methods: All patients aged 18 or over who underwent diagnostic imaging within 7 days of non-cardiac surgery between the1 st of January 2003 and 31st of December 2013 in the Tayside region of Scotland, UK were included in the analysis. The primary outcome of AKI was defined using the KDIGO creatinine based criteria. Multiple logistic regression was performed to identify predictors for AKI.

Results: Of 9,300 patients, 6,224 were exposed to CM in the immediate peri-operative period and 3,076 were not. Post-operative AKI occurred in 678 (10.9%) of the 6,224 patients who were exposed to CM. On multiple logistic regression, independent predictors of post-operative AKI were increasing age, male gender, lower baseline renal function and treatment with ACE inhibitors or ARB. Timing of CM exposure did not affect risk of developing AKI, OR 0.972 (95% CI 0.935 - 1.010), p=0.146.

Conclusions: For patients who have either just had or are soon to undergo general surgical procedures there appears to be no need to limit CT scan quality by avoiding the administration of contrast media. These patients may benefit from the increased diagnostic utility of contrastenhanced CT scans without increasing their risk of peri-operative AKI.