4 Generic name Diatrizoate Iothalamate Ioxithalamate Ioxaglate Iohexol Iopamidol Ioversol Iopromide Iobitridol Iomeprol Iodixanol § Not Available. Osmolarity High-osmolar Low-osmolar Table 2: Properties of contrast media. Ionicity Ionic monomer Ionic dimer Nonionic monomer Iso-osmolar Nonionic dimer Cardiology Research and Practice Viscosity (mPa.s at 20 C) n/a§ n/a§ 26.0 15.7 20.4 20.9 18.0 22.0 n/a§ n/a§ 26.6 Table 3: Risk score for prediction of contrast-induced nephropathy by Mehran et al. [35]. IABP, intra-aortic balloon pump; CHF, congestive heart failure; eGFR, estimated glomerular ﬁltration rate. Reprinted from [35]. (a) Risk factors Hypotension IABP CHF Age>75 Anemia Diabetes Contrast volume Serum Cr> 1.5 OR GFR<60 mL/min/1.73 m2 Risk score <5 6–10 11–16 >16 Risk of CIN (b) 7.5% 14% 26.1% 57.3% Score 5 5 5 4 3 3 1/100 cc 4 2 for 40–60 4 for 20–40 6 for <20 Risk of dialysis 0.04% 0.12% 1.09% 12.6% (1), congestive heart failure (1), hypertension (1), peripheral vascular disease (1), and contrast volume >260 mL (1). Incidence of CIN in their study was 2% [51]. Mehran et al., similarly, found eight variables (hypoten- sion, intra-aortic balloon pump, congestive heart failure, chronic kidney disease, diabetes, age >75 years, anemia, and volume of contrast) and assigned a weighted integer to each variable to make up a score cumulatively so as to divide low risk (≥5) and high risk (≥16) scores [35]. The overall occurrence of CIN in the development set was 13.1%. Table 3 shows their algorithm. 7. Prognosis CIN is the leading cause of acute renal failure in hospitalized patients and associated with prolonged in-hospital stay and increased morbidity, mortality, and costs. A considerable fraction of this in-hospital development of ARF has been due to the use of contrast media in radiographic procedures [29, 52]. In their retrospective analysis of the Mayo Clinic PCI registry, Rihal et al. found that 22% of the patients with ARF died during the index hospitalization compared with only 1.4% of patients without ARF (P < .0001). One-year and 5-year estimated mortality rates were also signiﬁcantly higher in patients with ARF [17]. Mortality ramped up not only with ARF but even more if dialysis was needed as shown by McCullough et al. [29]. A retrospective analysis of 16,248 patients exposed to contrast media showed that even apparently small decreases in renal function can lead to excessive mortality rates independent of other risk factors, and given that small rises in serum creatinine levels actually represent a signiﬁcant drop in GFR [53]. Furthermore, renal insuﬃciency has been found to be a strong independent predictor of death and subsequent cardiac events in a dose-dependent fashion during and after PCI [54]. 8. Prevention of Radiocontrast Nephropathy 8.1. Volume Administration. Volume administration remains the key factor for the prevention of CIN, even though no randomized controlled trial has compared a strategy of volume expansion with no volume expansion has been per- formed. Possible mechanisms for prevention of renal insult by ﬂuid administration include plasma volume expansion with concomitant suppression of the rennin-angiotensin- aldosterone system with the increased delivery of Na to distal nephron, downregulation of the tubuloglomerular feedback, dilution of the CM, and thus prevention of renal cortical vasoconstriction—and avoidance of tubular obstruction [55]. It may also be due to reduction in Nitric Oxide production.