Correlation Between Serum Uric Acid And Adverse Cardiovascular Events In Patients With Coronary Artery Bypass Grafting

Background:Hyperuricemia is an independent risk factor for cardiovascular disease,and highly predictive of all-cause mortality and adverse events among patients already living with cardiovascular disease.However,it is unclear whether high serum uric acid(SUA)levels were independent risk factors for postoperative major adverse cardiac and cerebrovascular events(MACCE;i.e.,all-cause mortality,stroke,myocardial infarction[MI],or repeat revascularization)among patients undergoing coronary artery bypass grafting(CABG).We aimed to evaluate the relationship between SUA and MACCE among patients undergoing CABG.Methods:Between September 2011 and October 2013,the trial consecutively enrolled 1922 patients who were scheduled for elective cardiac surgery at Fuwai Hospital(Beijing,China).We limited the population for the present study to the 1614 eligible adult patients aged 20-85 years.All participants underwent isolated CABG,had measurements of postoperative SUA,and had no gout preoperatively or treated with urate lowering therapy.Patients were stratified into statistical quartiles of postoperative SUA(between 6 and 18 hours after cardiac surgery):<203.7,203.7-254.1,254.1-316.6,and≥316.6μmol/L.The association of postoperative SUA with MACCE were assessed.All statistical analyses were performed using SPSS 23.0.Risk factors for MACCE were evaluated in logistic regression models for in-hospital MACCE,and Cox regression models for postoperative one-year,three-year,and six-year MACCE in patients undergoing CABG.Reciever operator characteristic(ROC)and propensity score matching were used.Results:Patients had a mean age of 60.3 ± 8.4 years,and 79.3%were male.Patents were routinely followed up for 5.8±1.8 years.1)Eighty-three(5.1%)patients in-hospital MACCE occurred.In separate multivariable regression models,postoperative SUA level was positively associated with in-hospital MACCE(highest vs.lowest SUA quartile:odds ratio[OR]2.62;95%confidence interval[CI]1.38～4.96;p=0.003)and in-hospital composite endpoint of mortality/MI(OR 3.29;95%CI 1.63～6.64;p=0.001)respectively.The area under the receiver operating characteristic curve for in-hospital MACCE model that included postoperative SUA,Cleveland score,body mass index and history of hypertension was 0.73(95%CI 0.67～0.79,P<0.001).After propensity score matching,relative risk of postoperative hyperuricemia for in-hospital MACCE was(OR:2.85;95%CI:1.06～7.70;P=0.04).2)There were 133(8.2%)MACCE during the first year of follow-up.In separate multivariable regression models,the highest quartile of postoperative SUA was independently associated with increased risk of oneyear MACCE when compared with the lowest quartile(hazard ratio[HR]2.44;95%CI 1.44～4.14;p=0.001),one-year all-cause mortality(HR 10.09;95%CI 1.25～81.68;p=0.03)and mortality/MI(HR 3.12;95%CI 1.63～5.95;p=0.001)respectively.3)At the end of the three-year follow-up period,201(12.5%)MACCE had occurred.The highest quartile of postoperative SUA was independently associated with risk of three-year MACCE(vs.the lowest quartile,HR 1.58;95%CI 1.04～2.38;p=0.03)and three-year mortality/MI(HR 2.15;95%CI 1.15～3.99;p=0.02)respectively.The highest quartile of postoperative SUA was not significantly associated with three-year all-cause mortality.4)At the end of the six-year follow-up period,326(20.2%)MACCE had occurred.The highest quartile of postoperative SUA was independently associated with six-year allcause mortality(vs.the lowest quartile,HR 2.25;95%CI 1.08～4.68;p=0.03)and sixyear mortality/MI(HR 1.92;95%CI 1.00～3.66;p=0.049)respectively.The highest quartile of postoperative SUA was not significantly associated with six-year MACCE.The area under the receiver operating characteristic curve for six-year mortality model that included postoperative SUA,age,preoperative ejection fraction was 0.72(95%CI 0.67～0.78,P<0.001)Conclusions:Elevated postoperative SUA level is significantly associated with in-hospital and threeyear MACCE and mortality/MI.High postoperative SUA level is one of independent risk factors for six-year all-cause mortality.Control of hyperuricemia should be added into the cardiac rehabilitation system after CABG.Aggressive urate-lowering therapy might improve the prognosis of patients after CABG.