| Summary: | Chronic Kidney Disease (CKD) is a risk factor for contrast induced nephropathy (CIN), defined as an increase in serum creatinine of >25% from baseline or a delta rise of >26.5% μmol/L within 48 hours. This thesis describes the assessment of novel biomarkers for the earlier prediction of CIN. A prospective observational study of 301 CKD patients was performed. Demographics and a Mehran risk score were recorded. Low-osmolar contrast was used. Samples for plasma and urinary neutrophil gelatinase-associated lipocalin (NGAL), serum liver fatty acid-binding protein (L-FABP), serum kidney injury marker 1 (KIM-1), urinary cystatin C (CysC) and serum interleukin 18 (IL-18) were taken at 0, 1, 2, 4, 6 and 48 hours post contrast. Major adverse clinical events (MACE) were recorded at 1 year which included acute myocardial infarction, heart failure, stroke and death. CIN occurred in 28 (9.3%) patients and was associated with older age, diabetes, higher Mehran score, larger contrast volume and anaemia (p <0.05). NGAL performed best at 6 hours with levels of 1,337 ng/ml in AKI patients compared with 931 ng/ml in non-AKI patients, p=0.002, AUC 0.71, sensitivity 75.0%, specificity 96.1 %, OR 2.86. L-FABP performed best at 4 hours with levels of 10.7 ng/ml in AKI patients compared with 6.2 ng/ml in non-AKI patients, p=0.001, AUC 0.69, sensitivity 42.3%, specificity 90.2%, OR 6.75. Median urinary NGAL was higher only after 48 hours, 487 ng/ml in AKI patients versus 155 ng/ml in non-AKI patients, p=0.008, AUC 0.63. CysC, IL-18 and KIM-1 were not predictive at any time-point (p>0.05). A Mehran score >-10 achieved an AUC of 0.65, p=O.006. MACE occurred in 7 (25%) AKI patients and 17 (6.2%) non-AKI patients (p<O.001) with a higher mortality in AKI patients (3 patients [10.7%]) compared with non-AKI patients (8 patients [3.3%]) respectively, p = 0.037. In conclusion, a higher Mehran risk score, 6 hour NGAL and 4 hour L-FABP performed best at earlier prediction of CIN. AKI patients were significantly more likely to develop MACE or have a higher mortality at one year.
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