The effects of magnesium sulfate pretreatment on reperfusion injury after coronary artery bypass graft surgery

Background Myocardial ischemia/reperfusion (IR) injury is a complex phenomenon that leads to organ dysfunction and failure after coronary artery bypass graft surgery (CABG). Data from numerous animal experiments and clinical trials suggest that magnesium, a physiological calcium blocker, may be efficacious for the reduction in reperfusion injury. We investigated whether an intravenous administration of magnesium before reperfusion can decrease IR injury after CABG with cardiopulmonary bypass. Patients and methods A total of 40 patients undergoing CABG were randomly assigned to a MG group ( n = 20) or an NS group ( n = 20). The patients in the MG group were administered 25 mg/kg of MgSO 4 mixed in 100 ml normal saline intravenously before reperfusion, and patients in the NS group were administered an equal volume of normal saline. The levels of lactate and pH were measured to assess reperfusion injury at three specific times, which were before induction and after declamping by 10 min and 30 min. To evaluate postoperative other organ dysfunction, alanine aminotransferase and creatinine levels were measured at postoperative day 0. Results The blood lactate levels were significantly lower at 10 and 30 min after reperfusion in the MG group compared with the NS group. In addition, postoperative alanine aminotransferase was significantly higher in the NS group than in the MG group. Conclusion Magnesium administration before reperfusion of the heart in CABG with cardiopulmonary bypass significantly reduces blood lactate levels. These findings suggest that magnesium treatment may have protective effects on IR injury.