Myocardial Protection during Open heart surgery

Abstract

The induction of elective ischemia during cardiac surgery on myocardium that is either diseased or has been -subjected to .previous -periods of ischemia (for variable periods of time) is likely .to cause •significantly deleterious effects on this myocardium. The underlying mechanism for most types ofmyocardial injury during CPB .is ischemia, ischemia develops when oxygen demand outstrips its supply in the hea!i, This process involves a complex cascade uf events that compromise•high energy phosphate and calcium homeostasis. Factors associated with myocardial injury •during {:PB are many, among them the most important are; aortic cross-clamping and re.perfusion injury, reperfusion injury involves metabolic, functional and •structural changes on restoring coronary flow and it can be reversible or irreversible depending on length of the ischemic insuh, reperfusion injury is•suggested to be due to several mechanisms including oxygen par-adox , and neutrophil - complement activation. Opt•imizing myocardial energy supply and demand should •begin early in the patient's care prior to initiation of CPB during CPB. There are many factors that may adverse1y affect the myocatdial 02 •supply- •demand ratio and lead to myocardial energy depletion and ischemia and must be prevented as much as possible.