| Objective:To investigate the protective effect of levo-carnitine (L-carnitine) in the myocardium of elder patients undergoing off pump coronary artery bypass grafting.Methods:50elder patients scheduled for coronary artery bypass grafting were divided into control group and L-carnitine group. Three days prior to the surgery, the control group patients received routine coronary dilation, anti-coagulant and hypolipidemic treatments, including Isosorbide mononitrate50mg qd, asprin100mg qd, low molecular weight heparin4250u q12h, atorvastatin20mg qn, along with0.9%saline250ml intravenously. L-carnitine group patients received identical treatments as control group patients, with the addition of L-carnitine (3g dissolved in0.9%saline250ml) daily. Serum were collected at multiple time points:TO (After induction of anesthesia operation and before skin incision), T1(Immediately after the surgery), T2(eight hour post surgery), T3(24hour post surgery), the levels of creatine knase (CK), cardiac troponin I (cTnl) and CK-MB were assessed. The total dose of dopamine used post surgery and the incidence of post-surgery arrhymia (ventricular fibrillation and ventricular premature beat) were recorded. The cardiac index (CI) and left ventricular ejection fraction (LVEF) were measured one day prior to surgery, and seven days post surgery. Statistics were performed with SPSS18.0software.Results:The general condition, age, sex ratio, body weight, American society Of anesthesiologists (ASA) classisfication, cardiac function classification and surgery operation duration of the two groups of patients did not statistically differ from each other (P>0.05). In both group, cTnl levels first elevated, then decreased post surgery, which was significantly different from the levels prior to surgery (TO)(P<0.05). Comparing to control group, the cTnl significantly decreased in L-carnitine group at T1, T2and T3time point (P<0.01). Investigation to CK-MB level revealed persistent elevation in control group until24hour (T4)(P<0.01), while the CK-MB levels in L-carnitine group patients peaked at eight hour post surgery (P<0.05), the levels showed a trend of decreasing at24hour post surgery but not ststistically significant comparing to eight hour time point(P>0.05). On the other hand, CK-MB levels of L-carnintine group patients were significantly lower comparing to those of control group patients (P<0.01). In both group, CK levels were persistently elevated and peaked at24hour post surgery (P<0.01relative to TO). However, L-carnitine treatment significantly decreased CK level at Tl, T2and T3time point (P<0.01). The total dose of dopamine used by L-carnitine group patients was332.4±51.6mg, and the incidence of arrhymia was1/25, both were significantly lower than control group (659.8±53.8mg and8/25, respectively, P<0.05). In control group patients, CI and LVEF significantly decreased seven days post surgery comparing to one day prior to surgery (P<0.05), while no such significant differences were observed in that of L-carnitine treated patients (P>0.05). The CI and LVEF seven days post surgery of L-carnitine group patients were significantly higher than those of control group patients (P<0.05).Conclusion:The use of L-carnitine (3g daily,9g in total) could exert protective effect in the myocardium of elder patients undergoing off pump coronary artery bypass grafting, alleaviating the myocardial ischemic damage in perioperative period. |
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