Myocardial ischaemia during coronary artery bypass graft surgery: a review of the pathophysiology (Part 1)

Myocardial mortality and morbidity during cardiac surgery is a devastating emotional phenomenon for both the medical team and the patient's family, often leading to dire financial consequences. Multiorgan dysfunction as a result of the effects of the neurohumoral system, triggered by surgery, anaesthesia, cardiopulmonary bypass, hypothermia and blood transfusion, can lead to prolonged intensive care unit and hospital stay. In this article, a literature review was embarked upon, to understand the pathophysiology and to find ways for early detection, of perioperative cardiac surgery-specific myocardial damage. It is important to appropriately understand and interpret the pattern of enzyme leakage as a marker of myocardial injury during cardiac surgery. Supplemented by clinical findings and echocardiographic evidence of possible causes of low cardiac output, earlier diagnosis may mean more prompt and goal-directed intervention, with a better outcome. A multidisciplinary approach to improve outcomes in this patient population is an absolute necessity. This can lead to modifications in surgical, anaesthetic, perfusion, and postoperative care strategies targeted at attenuating the effects of the neurohumoral insult. Often, the side-effect profile of pharmacological agents limits their use in this patient population, due to their labile haemodynamic profiles. More research is necessary to continue to interrogate the available information, and to produce new information, both in understanding the pathophysiology, and with regard to intervention strategies.