| Objective To investigate the association of renal function indexes, including cystatin C(Cys-C), urinary albumin to creatinine ratio(u ACR), and glomerular filtration rate estimated(e GFR) by three formulas, with coronary artery disease(CAD) and Gensini score in hypertensives without chronic kidney disease(CKD) and diabetes mellitus, and also to find the relationship between several clinical parameters and Cys-C.Methods A total of 258 hypertensives undergoing quantitative coronary angiography for suspected CAD were enrolled in the study. We acquired their demographic features, medical histories and listings of antihypertensive drugs they were taking recently. Echocardiography parameters and routine laboratory examinations were also recorded. The concentrations of serum Cys-C were measured using particle-enhanced turbidimetric immunoassay method. Measurements of albumin and creatinine in urine were used for calculating the u ACR and measurements of serum creatinine(SCr) and/or Cys-C were used for estimating GFR. The hypertensives were grouped according to the results of coronary angiography.Results Compared with controls, patients suffering from CAD had significantly higher concentrations of serum Cys-C(0.85±0.21 vs 0.75±0.13, P<0.01), lower levels of e GFRcys(93.41±21.35 vs 103.09±13.87, P<0.01) and e GFRcr-cys(87.44±17.83 vs 95.16±14.69, P<0.01), but there were no differences in blood urea nitrogen(BUN), SCr, serum uric acid, u ACR or e GFRcr between the two groups. A multiple logistic regression analysis demonstrated that Cys-C was independently associated with CAD(OR 1.292, 95%CI 1.017~1.641, P=0.036), even after adjusting for conventional risk factors and renal function. On receiver operating characteristics(ROC) analysis, the cutoff points for predicting CAD of serum Cys-C was 0.77mg/L, the area under the curve was 0.656(95%CI 0.582~0.730, P<0.001), the sensitivity and specificity were 63.2% and 66.7%, respectively.The concentration of serum Cys-C was higher in triple-branch-lesion group than double-branch-lesion group(0.95±0.23 vs 0.82±0.17, P<0.001), single-branch-lesion group(0.95±0.23 vs 0.75±0.13, P<0.001) and control group(0.95±0.23 vs 0.74±0.13, P<0.001) and was higher in double-branch-lesion group than single-branch-lesion group(0.82±0.17 vs 0.75±0.13, P=0.014) and control group(0.82±0.17 vs 0.74±0.13,P=0.037). But there was no difference between the single-branch-lesion group and control group. The levels of e GFRcys and e GFRcr-cys were lower in triple-branch-lesion group than other three groups. There were no significant differences among these four groups in u ACR.The CAD patients were also classified into three groups in accordance with the tertile of Gensini score. The concentration of serum Cys-C was higher in Gensini score ≥ 70 group than Gensini score 25~69 group(0.91±0.22 vs 0.85±0.22, P=0.049), Gensini score ≤ 24 group(0.91±0.22 vs 0.78±0.15, P<0.001) and control group(0.91±0.22 vs 0.74±0.13, P<0.001) and was higher in Gensini score 25~69 group than Gensini score ≤ 24 group(0.85±0.22 vs 0.78±0.15, P=0.049) and control group(0.85±0.22 vs 0.74±0.13, P=0.003). But there were no differences between Gensini score ≤ 24 group and control group. The levels of e GFRcys and e GFRcr-cys were lower in Gensini score ≥ 70 group and Gensini score 25~69 group than control group. The levels of e GFRcys were also lower in Gensini score ≥ 70 group than Gensini score ≤ 24 group. There were still no significant differences among these four groups in u ACR.Cys-C(r=0.339, P<0.001), fibrinogen(FIB)(r=0.140, P=0.047) and left ventricular mass index(LVMI)(r=0.179, P=0.011) were positively correlated with Gensini score, e GFRcys(r=-0.258, P<0.001), e GFRcr-cys(r=-0.210, P<0.001) and high-density lipoprotein cholesterol(HDL-c)(r=-0.166, P=0.019) were negatively correlated with Gensini score in CAD patients.Furthermore, FIB(r=0.200, P<0.001), left atrial diameter(r=0.199, P=0.005) and LVMI(r=0.139, P=0.049) were positively correlated with serum Cys-C, e GFRcys(r=-0.934, P<0.001), e GFRcr-cys(r=-0.836, P<0.001) and left ventricular ejection fraction(r=-0.156, P<0.001) were negatively correlated with serum Cys-C in CAD patients. However, only measurements of renal function were significantly associated with serum Cys-C in control group.Conclusion In hypertensives without CKD and diabetes mellitus, serum Cys-C was independently associated with CAD. Cys-C was not only an early marker of preclinical renal impairment but also a biomarker which was associated with the severity of CAD. Further researches are needed to clarify the role of Cys-C in the initiation and progression of CAD among different population groups. |
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