|Kurian GA, Paddikkala J|
Effect of Intra-Operative Magnesium Supplementation in Plasma Antioxidant Levels, Trace Elements and Electrolyte Balance in Serum of Coronary Artery Bypass Graft Patients
Journal of Clinical and Basic Cardiology 2007; 10 (1-4): 11-15
Keywords: CABG, Eisen, Kardiologie, Kupfer, magnesium, Myokardium, Zink, cardiology, copper, iron, magnesium, myocardial ischaemia reperfusion, zinc
Objective: Calcium overload and oxidative stress have been identified as pathogenic factors in myocardial ischaemic reperfusion. Experimental studies have demonstrated that intravenous magnesium (Mg) can protect the ischaemic myocardium. It has a free radical scavenging effect and can act as a calcium channel blocker. Although the role of copper, iron, and other metal elements in ischaemic heart injury has been well established, clinical studies are very limited. The link between these serum metal element concentrations and oxidative stress is unclear in humans although, in experimental animal studies, severe Mg deficiency has been shown to lead to increased oxidative stress. Methods: Ninety-two South Indian patients with acute myocardial ischaemia undergoing CABG were randomized to a study and a control group. Magnesium was administered (2 g/kg body weight) to the study group. Control patients received the same protocol without magnesium. Serum levels of copper, zinc, iron, ceruloplasmin, sodium, and potassium were measured in addition to the plasma levels of antioxidant enzyme activities and cardiac marker enzymes such as troponin I, CPK MB, and LDH. Results: There was no mortality in the study group. Serum metal elements like iron and copper were observed to be higher in concentration at the ischaemic stage while during reperfusion higher concentrations of copper, iron, and zinc were observed in both the study and the control groups. Plasma TBARS concentration in magnesium-treated and -untreated patients increased progressively during surgery and peaked during revascularization. However, plasma antioxidant enzyme activities were found to be decreased at the ischaemic stage in both groups. Cardiac marker enzymes also elevated during revascularization, however, the extent of increase (p < 0.05) was higher in the control group. Conclusions: Our study suggests that the use of magnesium for protection of the acutely ischaemic myocardium appears to be a safe technique. Magnesium supplementation stabilizes the plasma membrane and is thereby able to withstand the oxidative stress mediated by ischaemic reperfusion.