Analysis On The Correlation Between Serum Bilirubin And Unstable Angina Pectoris

Objective:To analyze of the correlation between presence of unstable angina pectoris(UAP),severity of coronary lesions,short-term cardiac function and serum bilirubin(BIL)respectively,contributing to the prevention,diagnosis and treatment of UAP.Methods:A total of 1 094 patients with available and intact clinical data referred to the Department of Cardiology,the Second Hospital of Tianjin Medical University,between January 2005 to August 2008,who underwent selective coronary angiography(CAG),were included in our study.All patients were divided into two groups.All of 641 patients with UAP constitute the UAP group which was further divided into single-,double-and triple-vessel disease groups according to the number of vessels with significant stenosis(luminal narrowing of 50%or more).A total of 453 subjects with coronary lesions less than 50%luminal narrowing or entirely normal coronary tree constitute the control group.Patients with any situations below were not included in our study:(1)hematological disease; (2)hepatobiliary disease;(3)pancreatic disease;(4)connective tissue disease and rheumatic disease;(5)endocrine system disease;(6)chronic wasting disease; (7)congenital cardiovascular disease;(8)pulmonary heart disease;(9)valvular heart disease,heart muscle disease or pericardial disease not caused by coronary atherosclerotic heart disease(CHD).We recorded age,sex,the presence of smoke, hypertension and diabetes,the results of physical examination,electrocardiogram, ultrasonic cardiogram(UCG)and CAG of all subjects.Gensini's score was calculated depending on the degree of luminal narrowing and the geographical importance of location of diseased coronary arteries.Blood samples were obtained immediately after admission to measure fibrinogen and drawn at 6am on the second morning after an 8-hour fasting period to measure the levels of serum BIL,liver-function enzymes, lipid profile,plasma glucose and insulin.The homeostasis model assessment of insulin resistance(HOMA-IR)was calculated as fasting insulin(μU/mL)×fasting plasma glucose(mmol/L)/22.5 and served as an index to assess the state of insulin resistance.We compared the levels of serum BIL,liver-function enzymes and known risk factors of CHD between UAP group and control group and analyzed of the correlation between presence of UAP,severity of coronary lesions,short-term cardiac function and serum BIL respectively.Results:(l)Significantly lower natural logarithm transformation of the serum total bilirubin(TBIL)and indirect bilirubin(IBIL)levels were noted in UAP group((2.05±0.39)and(1.60±0.45),respectively)compared to those in control group ((2.11±0.40)and(1.69±0.46),respectively)(t=2.60,P＜0.01;f=3.11,P＜0.01);The natural logarithm transformation of serum direct bilirubin(DBIL)level was also lower in UAP group than controls;however,the difference did not reach statistical significance(P＞0.05).(2)Spearman rank correlation test showed that the levels of TBIL and IBIL were negatively and statistically correlated with the presence of UAP(r_s=-0.07,P＜0.05;r_s=-0.09,P＜0.01)and severity of coronary lesions.They decreased with the increase of the number of diseased vessels(r_s=-0.08,P＜0.01; r_s-0.09,P＜0.01)and negatively correlated with Gensini's score(r_s=-0.07,P＞0.05), we got the same conclusion in both sexes;the level of serum DBIL was also negatively correlated with the presence of UAP and severity of coronary lesions; however,the correlation had no statistically significance(P＞0.05).(3)Spearman rank correlation test also showed that serum TBIL,DBIL and IBIL concentrations are all higher in male than those in female(r_s=0.09~0.19,P＜0.01),positively and statistically associated with high density lipoprotein cholesterol(HDL-C)(r_s=0.09~0.14,P＜0.01), negatively and statistically related with fibrinogen(Fg)(r_s=-0.13～-0.09,P＜0.05或0.01) and correlated with many other known risk factors of CHD respectively.(4)Multivariate Logistic regression analyses showed serum IBIL was inversely and statistically significantly related to the presence of UAP after adjustment for liver-function enzymes(alanine aminotransferase(ALT),aspartate aminotransferase (AST),alkaline phosphatase(ALP)and gamma-glutamyl transferase(GGT))and known risk factors of CHD(sex,age,smoking,hypertension,diabetes,HOMA-IR, triglycerides(TG),total cholesterol(TC),HDL-C,low density lipoprotein cholesterol(LDL-C)and very low density lipoprotein cholesterol(VLDL-C)and Fg).We got the same conclusion in both sexes.(5)We explored the association between the level of serum BIL and the result of UCG in patients with UAP.The levels of TBIL and DBIL were positively interrelated with left ventricular end-diastolic diameter and left ventricular end-systolic diameter and negatively interrelated with left ventricular ejection fraction significantly(r_s=-0.12～0.15, P=0.001～0.020);The interrelations between left ventricular end-diastolic diameter, left ventricular end-systolic diameter,left ventricular ejection fraction with the level of IBIL were not statistically significant(P＞0.05).Conclusion:(l)Serum TBIL,especially IBIL was negatively related to the presence of UAP and severity of coronary lesions,we got the same conclusion in both sexes.(2)Serum BIL was associated with several known risk factors of CHD.(3) Serum IBIL was inversely and statistically significantly related to the presence of UAP after adjustment for liver-function enzymes(ALT,AST,ALP and GGT)and known risk factors for CHD(sex,age,smoking,hypertension,diabetes,HOMA-IR, TG,TC,HDL-C,LDL-C,VLDL-C and Fg).We got the same conclusion in both sexes.(4)Serum TBIL,especially DBIL was positively related to short-term cardiac function of patients with UAP.(5)The monitoring of serum IBIL concentration is helpful to the prevention,diagnosis and treatment of UAP,which may contribute to decrease the morbidity and mortality of acute coronary syndrome.