Effect Of Allopurinol On Cardiac Function In Patients Undergoing On-pump Coronary Artery Bypass Grafting:a Systematic Review And Meta-analysis

Background and objective:During on-pump coronary artery bypass grafting(CABG), the heart is subjected to total ischemia and reperfusion, causing serious operative and postoperative complications such as arrhythmias, infarctions that may be partly due to free radical generation, and impair the cardiac function. Studies showed that allopurinol therapy can inhibit the generation of free radical and scavenge the free radical. So we conducted a systematic review and meta-analysis to evaluate the effect of allopurinol on cardiac function in patients undergoing on-pump CABG.Methods:Randomized controlled trials comparing the effects allopurinol with control were included. Medical databases including PubMed、Embase、Cochrane Comtrolled Trials Regiser, CBMdisc、CNKI、WANFANG、VIP were searched. The important related Journals and the references of included trials were also searched by hand for potential trials. Two reviewers independently carried out the Study selection, quality sessment and data extraction. The outcome measure were creatinine Kinase isoenzyme MB levels(CK-MB), cardiac index,left ventricular stroke work index(LVSWI),the incidence of arrhythmias,the incidence of inotropic drugs and/or mechanical support needs, the incidence of postoperative myocardial infarction(MI). Analyses were performed using Stata Version9.2.. We calculated odds ratio(OR) and95％confidence intervals for dichotomous variable outcomes, weighted mean differences(WMD)or standardized mean differences(SMD)and95％confidence intervals for continuous variable outcomes using the fixed-effect model or the random.effect model.Results:Eleven randomized controlled trials involving543patients were identified that explored the effectiveness of allopurinol in patients having on-pump coronary artery bypass grafting with or without allopurinol therapy.Allopurinol therapy was associated with significant reduction in creatinine kinase isoenzyme MB levels(SMD-0.46,95％CI-0.78to-0.14,P for effect=0.005; P for heterogeneity=0.435),highly significant improvement in left ventricular stroke Work index (g.m-1.m-2; WMD3.98,95％CI2.43to5.53,P for effect=0.000；P for heterogeneity=0.968),but did not improve cardiac index(L/min per m2； WMD0.26；95％CI-0.05to0.57,P for effect=0.102),significant reduction in the incidence of arrhythmias(OR=0.26,95％CI0.11to0.64,P for effect0.003；P for heterogeneity=0.341),in the incidence of inotropic drugs and/or mechanical support needs(OR=0.32,95％CI0.20to0.53; P for effect=0.000; P for heterogeneity=0.544), but did not reduce the incidence of postoperative myocardial infarction (OR=0.49,95%CI0.22to1.09; P for effect=0.081; P for heterogeneity=0.210).Conclusions:This systematic review and meta-analysis provides evidence that allopurinol therapy significantly reduce myocardial damage, improve left ventricular stroke work index, reduce the incidence of postoperative arrhythmia, and the need for postoperative inotropic drugs and/or mechanical support, but did not improve cardiac index and reduce the incidence of postoperative myocardial infarction. However, further large RCTs are needed to identify the optimal duration, dosage, side effects and pursue more tracing observation on long-term clinical outcomes, especially in patients with high risk (HR) cardiovascular factors.