Myocardial Protection Effect Of L-arginine During Coronary Artery Bypass Graft Surgery

Objects:To observe the myocardial protective effect of L-arginine during Coronary Artery Bypass Graft surgery.Methods:Twenty patients with unstable angina undergoing coronary artery bypass graft were divided randomly into treatment group(L-arginine) and control group from January 2008 to January 2010. C-group (n=10):patients received cold cardioplegic blood solution without L-arginine. L-group (n=10):L-arginine was added to cardioplegia solution (7.5g/L). Oxygen intake rate and lactate content of myocardium were monitored from radial artery and coronary sinus at different time (T2:before CPB, T3, T4:5 and 20 min after aortic declamping). The level of tumor necrosis factor-a (TNF-a), interleukin-6(IL-6), interleukin-8 (IL-8) and cTn I were tested at T1, T5, T6, T7, T8. (Ti:before operation, T5, T6, T7, T8: after operation 6h,12h,24h,48h). At the same time we observed some other items:the time of cardiopulmonary bypass, aortic blocking, ventilator auxiliary and staying in ICU and the clinical prognostic of patients, etc.Results:There were no mortality and serious complications in all patients. And there were no significant difference between two groups at T2,T3 in lactate content(t=-0.87, p=0.40; t=1.99,p=0.06). But the lactate content in L-group was obviously lower than that in C-group at T4 (t=2.50, p=0.02). Myocardial O2 intake in L-group was better than that in C-group at T3,T4 (t=-2.16, p=0.04; t=-2.48, p=0.03).While there were no significant difference of the myocardial O2 intake rate between two groups at T2 (t=-0.54, p=0.60).There were no significant difference of TNF-a, IL-6, IL-8 and cTn I at Ti(p>0.05),but significantly higher at T5, T6, T7 and T8 than that at 1.These factors in L-group were obviously lower than that in C-group at T5, T6, T7 and T8(p<0.05). There were no significant difference between two groups in the time of cardiopulmonary bypass, aortic blocking, ventilator auxiliary and staying in ICU (p>0.05). There were no significant difference in the number of grafting between two groups (p>0.05). The dose of positive inotropic medicine used after operation in L-group was less than that in C-group (p<0.05). Delirium occurred twice in C-group and none in L-group, but there were no significant difference between two groups statistically (p=0.24).Conclusion: 1. L-arginine supplementation could increase NO content to attenuated inflammatory factor, which could reduce systemic inflammatory reaction.2. L-arginine supplementation could improve the myocardial O2 intake rate and reduce lactate extractions, which could mediate myocardial injury.3. Controlled reperfusion with L-arginine enriched cold cardioplegic blood could be a safe method to diminish ischemia/reperfusion injury.