Early diagnosis of contrast-induced renal damage and the protective effect of hydration therapy

Objective To investigate the diagnostic value of urine neutrophil gelatinase apolipoprotein (NGAL) and kidney injury molecule 1 (KIM-1) as markers of CIN, and the effectiveness of hydration therapy in the prevention of CIN. Methods One hundred and twenty patients were randomly divided into control group and treatment group. The patients of treatment group received hydration therapy through intravenous fluid infusion. Urine samples were taken for detecting the value of albumin (mAlb), NGAL, and KIM-1 before surgery (T0), after surgery 12 h (T1), 24 h (T2), 48 h (T3), 72 h (T4) by ELISA assay. The levels of urinary mAlb, Scr, BUN and cystatin C were detected at the same time. Results ⑴ The urine NGAL/Cr and KIM-1/Cr significantly increased and were more than twice the baseline value at the time of 12 h after PCI in 87 of 120 cases of the participants. There are eight cases occurred CIN (6.67%) and one case occurred in hydration treatment group (1.7%), seven cases were in control group (11.7%). The difference was statistically significant. ⑵ There were no significant difference in BUN, Scr, mAlb/Cr, Cys-C and GFR between two groups (P＞0.05). ⑶ NGAL/Cr, KIM-1/Cr were elevated at T1 in both groups (P＜0.01). In hydration treatment group, levels of NGAL/Cr and KIM-1/Cr decreased substantially to the level of T0 at T4(P＜0.01), while in the control group they didn't. ⑷ Area under the ROC curve (AUC) of NGAL/Cr and KIM-1/Cr 12 h after PCI were 0.931 [95% CI (0.889, 0.973)] and 0.811 [95% CI(0.736, 0.886)] respectively (all P＜0.05). Conclusions NGAL and KIM-1 are sensitive and specific indicators for predicting early renal injury induced by contrast medium and can be used for early diagnosis of CIN. Hydration therapy can prevent the contrast agent-induced renal damage.