Objective To compare the effects of nicorandil and trimetazidine on endothelial function and inflammatory cytokines in patients with coronary heart disease after percutaneous coronary intervention (PCI),and to analyze the synergistic effect .Methods 160 patients with coronary heart disease underwent elective PCI were enrolled and randomly divided into four groups ,40cases in each group .The nicorandil group was given nicorandil tab-lets 5mg once time,3 times a day at 72h before PCI.The trimeshamazine group was given trimetazidine tablets 20mg once time,3 times a day.The combined group was given the same dose of nicorandil and trimetazidine .The control group was not given nicorandil or trimetazidine .The changes of CK -MB,cTnI,ET-1,NO,hs-CRP,TNF-αand IL-6 were observed and compared before and after PCI .Results The CK-MB and cTnI in the control group were significantly increased after PCI (t=2.500,3.663,all P<0.05;t=4.168,5.783,4.912,all P<0.05),but there were no statistically significant differences in the other three groups (all P>0.05).The level of cTnI in the control group was higher than that in the other three groups after PCI (F=11.960,15.643,16.078,all P<0.05).After PCI,the levels of ET-1,hs-CRP,TNF-αand IL-6 in the four groups were all significantly increased ( control group:t=6.897,5.293,all P<0.05;t=15.934,16.759,all P<0.05;t=8.516,9.209,all P<0.05;t=6.809, 6.757,all P<0.05;nicorandil group:t=2.254,P<0.05;t=8.903,11.280,all P<0.05;t=5.961,5.992,all P<0.05;t=4.235,4.738,all P<0.05;trimetazidine group:t=3.425,P<0.05;t=10.513,11.582,all P<0.05;t=4.117,5.696,all P<0.05;t =4.130,3.868,all P<0.05;combination group:t =3.180,P<0.05;t =9.204, 10.107,all P<0.05;t=4.839,6.214,all P<0.05;t=5.151,5.883,all P<0.05),and NO level was significantly decreased(control group:t=5.707,5.066,all P<0.05;nicorandil group:t=2.701,2.393,all P<0.05;trimetazi-dine group:t=3.662,3.163,all P<0.05;combination group:t=2.632,2.427,all P<0.05).The levels of ET-1, hs-CRP,TNF-αand IL-6 in the control group were significantly higher than those in the other three groups after PCI(F=9.709,7.794,P<0.05;F=43.772,47.321,P<0.05;F=15.252,10.565,P<0.05;F=5.632,4.372, P<0.05),and NO level in the control group was lower than that in the other three groups (F=14.138,8.374,all P<0.05).The level of NO in the nicorandil group was higher than that in the trimetazidine group (t=2.249,2.305, all P<0.05).There was no synergistic effect between nicorandil and trimetazidine in improving ET -1,NO,hs-CRP,TNF-αor IL-6(P>0.05).Conclusion Both nicorandil and trimetazidine may help to relieve PCI -related myocardial injury , improve endothelial function , inhibit inflammatory factors after PCI , but there is no synergistic effect.Nicorandil may be more effective in improving endothelial function .