Joseph Papanikitas MBBS, Presenter: Nothing to Disclose

Mark William Little MBBS, MSc, Abstract Co-Author: Nothing to Disclose

Suresh Pillai, Abstract Co-Author: Nothing to Disclose

Steven Alderson, Abstract Co-Author: Nothing to Disclose

Aliki Manoras, Abstract Co-Author: Nothing to Disclose

David A. Lewis, Abstract Co-Author: Nothing to Disclose

Stuart McKechnie, Abstract Co-Author: Nothing to Disclose

Raman Uberoi MBChB, FRCR, Abstract Co-Author: Nothing to Disclose

Acute Kidney Injury (AKI) is commonly seen in patients cared for in intensive care units (ICUs) and is associated with significantly increased morbidity and mortality. Moreover, patients receiving iodinated contrast agents whilst undergoing radiological investigations are at increased risk of developing AKI, which is referred to as Contrast-Induced Nephropathy (CIN). CIN has previously been investigated in patients undergoing coronary angiography. These studies have suggested that risk factors for AKI (including pre-existing renal impairment, diabetes, age, and haemodynamic instability) may also increase the risk of patients developing CIN. Despite such risk factors commonly being observed in ICU patients and these patients frequently undergoing radiological investigations using iodinated contrast, CIN has not previously been investigated in large numbers of ICU patients. We therefore undertook a single-centre retrospective observational study of CIN in ICU patients, seeking to define the incidence, risk factors, and outcomes of CIN within this cohort.

Our analysis included 479 scans, involving 331 patients. Univariate analyses demonstrated that male gender was associated with the development of CIN (p=0.01 for any CIN vs no CIN; χ2 for trend across grades of CIN p=0.02). Lower pre-scan eGFR was associated with the development of higher grades of CIN (trend χ2 p<0.001), but not with the development of any CIN (p=0.33). Finally, shorter time from admission to scan was also associated with the development of higher grades of CIN (trend χ2 p=0.03), but not with the development of any CIN (p=0.19). Multivariate analyses with regression modelling confirmed that male gender and pre-scan oliguria were independently associated with the development of CIN (male gender OR 1.30 [95% CI 1.08-1.56]; pre-scan oliguria OR 1.21 [1.11-1.33]). Univariate analyses similarly demonstrated that male gender, lower pre-scan eGFR and a shorter time from admission to scan were all associated with the development of AKI (p-values for any AKI vs no AKI and for trend χ2 across grades of AKI were all <0.05). Additionally, pre-scan shock and pre-scan oliguria were associated with the development of AKI (p-values for any AKI vs no AKI and for trend χ2 across grades of AKI were all <0.05). Multivariate analyses again noted that independent risk factors for the development of higher grades of AKI were male gender, low pre-scan eGFR, and pre-scan oliguria.

AKI and CIN are common amongst adult ICU patients undergoing radiological procedures or investigations involving iodinated contrast. It is clear that male gender, lower pre-scan eGFR, and pre-scan oliguria are independent risk factors for renal impairment or injury post-scan. The association with male gender is a novel finding and requires confirmation in a separate cohort. Shorter time from admission to scan is also associated with the development of both CIN and AKI, and pre-scan shock is associated with the development of AKI alone. These associations may reflect inadequate patient optimisation prior to contrast administration. It is notable, that over half of the patients within this study were shocked or oliguric, or received nephrotoxic medications, prior to their scans. In addition to this, only 22% of patients received any form of CIN/AKI prophylaxis and no patients received a reduced dose of contrast. Increased efforts to prepare patients adequately, prior to investigations with iodinated contrast may result in a reduction in morbidity and mortality rates resulting from AKI and CIN.

We completed a search of an electronic radiology database in a tertiary centre, seeking to identify radiological investigations or procedures undertaken using iodinated contrast, over a three year period (2009-2011). We manually collected data on patient demographics, ICU admission characteristics, radiological investigation/procedure (‘scan’) characteristics, together with post-scan outcome data on AKI/CIN, use of renal replacement therapy (RRT), ICU length of stay, and ICU mortality. We investigated univariate and multivariate associations with CIN and AKI.

Papanikitas, J, Little, M, Pillai, S, Alderson, S, Manoras, A, Lewis, D, McKechnie, S, Uberoi, R, Contrast-induced Nephropathy in Intensive Care Units: Incidence, Outcomes, Risk Factors, and Implications for Clinical Practice.  Radiological Society of North America 2014 Scientific Assembly and Annual Meeting, - ,Chicago IL. http://archive.rsna.org/2014/14009426.html