Consensus Report from Oncology Advisory Board Meeting

Strategies for Prevention and Management of CI-AKI and the Role of Contrast in Oncology CT Settings • 21 underwent CECT using IOCM iodixanol and those who underwent non-contrast CT scans [1]. The study patients (n = 5758) had been admitted in the neurosurgery department between January 2003 and December 2014. Propensity score matching was used to maximize the homogeneity between the CECT and non-contrast CT groups. Based on the baseline eGFR, the patients were further stratified into subgroups of stages 1-2 CKD (eGFR ≥60 ml/min/1.73 m 2 ), stage 3 CKD (eGFR < 60 ml/min/1.73 m 2 ), and stage 5 CKD (eGFR <30 ml/ min/1.73 m 2 ), respectively. Remarkably, the rates of AKI, dialysis, and mortality were noted to be similar between the patients who underwent CECT using iodixanol and those who had non- contrast CT scans . It was concluded that use of iodixanol does not increase the risk of AKI, emergent dialysis, or mortality even in patients who are at high risk of developing CI-AKI. “Mayo Clinic guidelines [1] recommend use of the IOCM iodixanol for patients at high risk of developing post- contrast AKI (PC-AKI), including patients with greatly elevated baseline SCr levels, reduced eGFR, and other risk factors, in lieu of the use of our standard low-osmolar contrast material.” Another retrospective observational study assessed the risk of CI-AKI in high-risk cancer patients with underlying renal insufficiency, undergoing diagnostic CT examination at a US cancer institute [2]. The comparison group comprised of cancer patients undergoing diagnostic CT scan, but having normal baseline renal function . For comparative analyses, patients were divided into three groups according to their risk profile:patientswithelevatedbaselineserumCrlevels(receiving iodixanol); patients at high risk of CI-AKI with normal baseline serum Cr levels (receiving iodixanol); and patients at low risk of CI-AKI with normal baseline serum Cr levels (receiving iohexol, LOCM). Renal insufficiency was indicated by serum Cr > 1.2 mg/dL in females and > 1.5 mg/dL in males; and CI-AKI was denoted by an absolute elevation of 0.5 mg/dL or 25% elevation in serum Cr level. The AKI rate (Fig. 2) was highest in patients with raised baseline serum Cr levels who additionally had other risk factors, such as diabetes mellitus (23%) and use of nephrotoxic medications (48%); these patients were also generally older than those in the other two groups and had a higher rate of cardiovascular disease. Nonetheless, the authors concluded Important Physicochemical Characteristics of CT CM and Their Clinical Relevance y y Solubility of CM is high with non-ionic agents with hydrophilic side chains and low with ionic media with lipophilic side chains. The adverse reaction profile is better with non-ionic agents. y y Osmolality of CM increases with ionicity as well as iodine concentration. It is advised to use the CM with osmolality closer to blood. y y Viscosity of CM increases with iodine concentration and molecular size and decreases with temperature. So warming the CM before administration is always recommended. Table 1: Structure and properties of various contrast media used in radiological settings. Name Benzene rings Ionicity Iodine content, mg/ml Viscosity at 37°C, mPa·s Osmolality mOsm/kg H 2 O Diatrizoate Monomer Ionic 140–462 1.4–19.5 550–2,938 Iothalamate Monomer Ionic 141–480 1.5–9.0 600–2,400 Ioxitalamate Monomer Ionic 120–380 1.1–8.5 610–2,160 Ioxaglate Dimer Ionic 160–350 1.7–10.5 295–680 Iohexol Monomer Non-ionic 200–350 2.4–10.6 410–780 Iopamidol Monomer Non-ionic 150–370 1.5–9.5 300–832 Ioversol Monomer Non-ionic 160–350 1.6–9.0 355–790 Iopromide Monomer Non-ionic 150–370 1.2–9.5 340–780 Iobitridol Monomer Non-ionic 250–350 4.0–10.0 585–915 Iomeprol Monomer Non-ionic 150–400 1.4–12.6 301–730 Iodixanol Dimer Non-ionic 270–320 5.7–11.1 290 CM: contrast media Adapted from Davidson C, et al . Am J Cardiol . 2006;98(Suppl): 42K–58K. Fig. 1. Fluid shifts across osmotic gradients. Source: Adapted from Tsai, et al . 2008; Swanson, et al . 1990; Rienmuller, et al . 2001 Fluid shifts across osmotic gradients 13-15 Hyperosmolar CM H 2 O H 2 O H 2 O H 2 O H 2 O Adapted from Tsaiet al.2008;Swansonet al.1990;Rienmulleret al.2001