Perioperative Versus Postoperative Glycemia Control in Cardiac Surgery Patients

It is known that acute stress of organism often leads to hyperglycemia even in nondiabetic patients. It is also known that pathophysiological mechanisms: enhanced gluconeogenesis, impaired insulin secretion and decreased insulin sensitivity due to anti-insulin effect of stress hormones and proinflammatory cytokines, or changes of glucose excretion and renal tubular resorption. Many studies proved the negative effects of hyperglycemia to different tissues and organs, e.g. hearth (increasing size of myocardial necrosis, reducing coronary collateral blood flow, exaggerating ischemia-reperfusion injury, impairing ischemic preconditioning), vascular (increased risk of thrombosis, endothelial dysfunction, activation of systemic inflammation with destabilization of atherosclerotic plaques), kidneys and its association with infectious complications. The first Leuven study (published in 2001) demonstrated that hyperglycemia in critical care patients significantly increases risk of organ complication and total mortality. Although the importance of postoperative tight glycemia control is now widely accepted, glycemia stability during cardiac surgery is often neglected. It is known that postoperative hyperglycemia has negative effects, but it is not known what effect has its peroperative elevation. Goal of this study is to demonstrate, whether full perioperative intensive glycemia control can reduce the incidence of postoperative morbidity even more than postoperative glycemia control only.