Objective:To investigate the effect of serum cystatin C level on the occurrence and its long-term prognosis of contrast agent-induced acute kidney injury(CI-AKI)after percutaneous coronary intervention(PCI)in elderly patients.Methods:A total of 848 elderly patients(≥60 years)undergoing PCI in our department between Mar 2015 and Dec 2017 were enrolled in a prospective cohort.The CI-AKI was defined as the increase of serum creatinine ≥44.2 μmol/L within 48-72 h after using iodine contrast agent or more than 25 % higher than base level within 48-72 h after PCI.A receiver operating characteristic curve was used to analyze the optimal cut-off value of Cystatin C for predicting CI-AKI after PCI.Patients were divided into 2 groups based on the optimal cut-off value of Cystatin C: the high Cystatin C group(Cystatin C ≥1.3 mg/L, n=178)and the control group(Cystatin C<1.3 mg/L, n=670). The differences in the incidence of CI-AKI after PCI and major adverse cardiac events(MACE)at 1 year follow-up were compared between the two groups.The Cox regression model was further used to analyze the predictors of the long-term prognosis after PCI.Results:Of 848 patients receiving PCI, the incidence of CI-AKI was 9.4%.The incidence of MACE at 1 year after PCI was higher in the high Cystatin C group than in the control group(15.7% vs.9.3%, χ2=6.524, P=0.011). Cox regression analysis confirmed that the high baseline level of Cystatin C was the most independent predictive factor for MACE at 1 year of follow-up( HR=16.244, P<0.001). Conclusions:The high baseline level of Cystatin C(≥1.3 mg/L)is an independent risk factor for CI-AKI and is also the most important predictor for the occurrence of long-term MACE in elderly patients undergoing PCI.

Objective To explore the impact of Enalapril-folic acid tablet on development of contrast-induced nephropathy (CIN) after percutaneous coronary intervention (PCI) in elderly patients with coronary heart diseases(CHD) complicated with mild renal insufficiency. Methods A total of 935 old patients (≥60 years) undergoing selective PCI at our hospital from January 2013 to June 2016 were enrolled in this retrospective study.Based on treatments during the perioperative phase ,the 935 patients were divided into Enalapril-folic acid tablet intervention group (n= 296 ,31.7％ ) ,and other RAS blocker control group with Angiotensin eonverting-enzyme inhibitor (ACEI) or Angiotensin Ⅱreceptor blocker (ARB) (n=639 ,68.3％ ). The levels of serum creatinine for 72 hours after operation were monitored and evaluated.Baseline data and CIN incidence were compared between two groups.The clinical events within 1 month after contrast media application were recorded.Multivariate Logistic regression analysis was used to analyze independent risk factors for CIN after PCI. Results The incidence of CIN after PCI was lower in the intervention group than in the control group with no statistical significance[7.1％ (21/296) vs.11.1％ (71/639) ,χ2 = 3.679 ,P= 0.059].Multivariate regression analysis showed that age (OR=1.103 ,P=0.001) ,hypertension (OR=3.362 ,P=0.017) , and hyper-homocysteinemia (OR=3.528 ,P=0.003) were independent risk factors ,but the treatment with Enalapril-folic acid tablet might be a protective factor for development of CIN after PCI (OR=0.443 ,P=0.042).During the 1-month follow-up ,the rate of recurrent angina pectoris was lower in the intervention group than in the control group ( P < 0.05 ) ,while there were no statistically significant differences between two groups in the rates of rehospitalization due to worsening renal dysfunction ,dialysis/hemofiltration ,acute heart failure ,and new myocardial infarction (all P>0.05). Conclusions The treatment with enalapril-folic acid tablet may prevent the occurrence of CIN after PCI in elderly patients with coronary heart disease and mild renal insufficiency.