Association between the cardiac troponin I level and the risk of contrast-induced nephropathy in patients with acute myocardial infarction undergoing percutaneous coronary intervention

Objective To analyze the association between the cardiac troponin I (cTnI) level and the risk of contrast-induced nephropathy (CIN) in patients with acute myocardial infarction (AMI) undergoing percutaneous coronary intervention (PCI). Methods Clinical data of 235 elderly patients with AMI who underwent PCI from January 2011 to June 2013 in our hospital were analyzed retrospectively. Patients were divided into two groups based on preprocedural cTnI levels: the moderate cTnI level group (0.4 μg/L)<cTnI<4 μg/L, n=133) and the high cTnI level group (cTnI≥4 μgL, n=102). The following data were recorded: the baseline measurements, blood urea nitrogen (BUN), serum creatinine (Scr), (2-microglobulin (β2-MG ) levels before PCI and 1 d, 3 d, and 7 d after PCI, estimated glomerular filtration rate (eGFR), the contrast volume and coronary pathological features after PCI, and occurrence of clinical events within 1 year. Risk factors for CIN were determined by multivariate logistic regression analysis. Results The incidence of CIN was significantly higher in the high cTnI level group than in the moderate cTnI level group〔22.55% (23/102) vs. 10.53% (14/133), χ2=21.56, P<0.01〕. eGFR declined and the β2-MG level increased more significantly in the high cTnI level group than in the moderate cTnI level group (P<0.05), and went back to baseline levels 7 days after PCI. Patients with three-vessel lesions were more likely to be in the high cTnI level group than in the moderate cTnI level group (χ2=16.60, P<0.01), and the number of stents was lower in the high cTnI level group than in the moderate cTnI level group (χ2=6.41, P<0.05). The rates of angina pectoris, acute heart failure and mortality were higher in the high cTnI level group than in the moderate cTnI level group (P<0.05). Multivariate logistic regressive analysis showed that high levels of preprocedural cTnI (OR=2.160), diabetes (OR=3.056), renal insufficiency (OR=1.632), contrast volume (OR=3.665), and old age (OR=3.521) were risk factors for the incidence of CIN. Conclusions The preprocedural cTnI level is associated with the incidence of CIN in patients with AMI undergoing PCI, and high preprocedural cTnI levels are a clinical risk factor for CIN. Key words: Troponin; Nephrosis; Contrast media; Angioplasty, transluminal, percutaneous coronary