Abstract: Objective  To investigate the early diagnostic value of urinary neutrophil gelatinaseassociated lipocalin (uNGAL) in contrastinduced nephropathy (CIN) in elderly patients with coronary heart disease (CHD) after percutaneous coronary angiography and intervention.  Methods  A total of 348 CHD patients who underwent selective coronary angiography and percutaneous coronary intervention (PCI) in the First Hospital of Hebei Medical University from June 2017 to January 2019 were selected. The levels of uNGAL and serum creatinine (Scr) of patients were assessed before the surgery,  4 and 24 hours after the surgery. According to whether CIN occurred after the surgery,  the patients were divided into CIN group and nonCIN group,    and they were divided into the elderly group (≥60 years old) and the young and middleaged group (<60 years old). The changes of uNGAL and Scr of  the two groups were calculated. Results   The study included 348 patients,  and 58 had CIN. Compared with patients in nonCIN group,  those in CIN group were older,  had longer diabetes history,  higher Merhan score,  more implanted stents and higher doses of contrast agent. In the elderly patients,  the Scr levels of CIN group and nonCIN group 24 hours after the surgery  showed significant difference (P<0.05). And the levels of uNGAL in two groups 4 hours after the surgery  and  24 hours after the surgery were statistically significant (P<0.05). In the young and middleaged patients,  there was significant difference in uNGAL levels between CIN group and nonCIN group 24 hours after the surgery(P<0.05). The area under the curve of uNGAL in the diagnosis of CIN 4 hours after the surgery was 0.658,  and the cutoff value,  sensitivity and specificity were 47.50(ng/ml),  0.661 and 0.686,  respectively. Conclusion  The increase of uNGAL level in early stage of percutaneous coronary intervention has high sensitivity and specificity for the diagnosis of early CIN in elderly CHD patients,  and it can be used as a reference index for early diagnosis of the disease.

Key words: contrastinduced nephropathy, urinary neutrophil gelatinaseassociated lipocalin, coronary disease, elderly