The Research On Serum Bilirubin Concentration In Middle-Aged Chd Patients

Background As a common and epidemic disease, coronary heart disease (CHD) has many causes (about 30 percent)still be ambiguous except some existed risk factors, such as smoking, obesity, hypertension and diabetes. Existing researches consensus that CHD is a disease caused by many factors .It is very important to find the risk factors which effected the CHD before early therapy. As an important endogenesis physiological antioxidant, serum bilirubin may provide important protection against atherosclerosis in some degree because it can protect lower density lipoprotein cholesterol (LDL-C)against peroxidation, and it can also alleviate the toxicity of oxidate-LDL.AS a new possible risk factor to CHD, serum bilirubin is being recognized step by step.Objective To study the association of the serum bilirubinconcentration with severity of coronary artery disease in middle-aged CHD patients ;to find out the relationship of serum bilirubin and the other risk factors of CHD such as smoking, gender and blood lipid; to explore the new idea for prevention and therapy of coronary heart disease.Material and Methods 116 patients who underwent selective angiography were included in the study and divided into two groups according to results of coronary artery angiography.70 middle-aged patients(who was younger than 45 years old,50 men and 20 women ) were included in the CHD group(study group),the mean age was 38.05years anddeviation of 3.57 years. Another 46 persons (31 men and 15 women)who were excluded coronary artery diseases were taken as non-CHD group(control group) ,the mean age was 49.01 years and deviation of 11.73 years. Those with higher liver enzyme; with liver and gallbladder diseases; or with hemolysis anemia and severe heart failure were all excluded. All the patients should e noted age, gender, smoking history and so on. The next morning after hospitaled serum total bilirubin(TBIL),direct bilirubin(DBIL)and indirect bilirubin(IBIL), also total cholestrol(TC), triglycerinate(TG),low density lipoprotein(LDL-C),high density lipoprotein(HDL-C) and lipoprotein a(LP(a)) were all tested in non-acute myocardial fraction patients, and acute myocardial fraction patients were determined in 2 weeks after the onset of acute myocardial fraction. All cases were noted coronary severity scores(CSS) according to coronary angiography. Statistical analysis comparison of serum bilirubin among CHD and non-CHD group were analyzed by t-test for indepent samples. The association of bilirubin and CSS was analyzed by Spearman correlation and multiple linear stepwise regression. The assocation of bilirubin and other risk factors of CHD was analyzed by spearman correlation and multiple linear stepwise regression.Results The two-sample test for independent samples showed that the levels of TBIL,DBIL and IBIL in middle-aged CHD patients are statistically significant lower than those in the controls(p<0.01); the concentration of bilirubin in CHD patients with smoking history are significantly lower than those without; the concentration of the bilirubin in MI patients are lower than those of non-MI patients, but not significantly(p> 0.05);TBIL and IBIL in males are significantly higher than those in females. Spearman correlation reveal that only DBIL have significantly negative correlation with CSS, r = -0.347, p < 0.05, and TBIL has significantly negative correlation with TG and TC, r= -0.344, -0.639 ,jp<0.05; DBIL has significantly negative correlation with TC and LDL r= -0.674,-0.604,/?< 0.05,but positive correlation with HDL r= 0.344, p<0.05; IBIL has significantly negative correlation with LDL r= -0.515, p<0.05. Multiple linear stepwise regression analysis showed that DBIL,TC,GENDER and SQRTSMOKING all enter the following multiple linear stepwise regression equation: CSS=1.831-0.262DBIL+0.915TC+0.719SQRTSMOKING+0.42GENDER,R = -0.614,R2 =0.441. And DBIL is related with LDL,HDL and smoking. The regression equation is DBIL= 1.005-1.164SMOKING-0.243CH+1.504HDL, R= 0.523, R2 =0.274.IBIL is related to both LDL and smoking ,the equation is: IBIL=5.59-2.416SQRTSMOKING-1.45LDL,R=0.569,R2 =0.324.Conculsion In middle-aged CHD patients, serum bilirubin issignificantly lower than that of non-CHD patients. Direct serum bilirubin is inversely associated with coronary serverity. low serum bilirubin concentration may be an indepent risk factor of CHD. There is also relationship between serum bilirubin and blood lipid. serum bilirubin may affect the lipid metabolization by inhibting lipid oxidation and inflammatory precesses. Lower serum bilirubin and other known risk factors affected mutually, they all related to atherosclerosis. By analyzing bilirubin concentration and other risk factors of CHD, it may be helpful to estimate the severity of coronary artery disease and make more reasonable therapy plans. Based on the protective role of bilirubin against atherosclerosis, we may establish theory base and pioneer a new way for precaution and therapy of CHD in the future. Serum bilirubin maybe a new focus for therapy and prevention of CHD.