Effect of glycaemic control on complications following cardiac surgery: literature review

Introduction: No uniform consensus in the UK or Europe exists, for glycaemic management of patients with Diabetes or pre-diabetes undergoing cardiac surgery. Objective: [i] Determine the relationship between glycaemic control and cardiac surgical outcomes; [ii] Compare current vs gold standard management of patients with Diabetes or pre-diabetes undergoing cardiac surgery. Methods: Searches of MEDLINE, NHS Evidence and Web of Science databases were completed. Articles were limited to those in English, German and French. No date limit was enforced. 13,232 articles were identified on initial literature review, and 50 relevant papers included in this review. Results: No national standards for glycaemic control prior to cardiac surgery were identified. Upto 30% of cardiac surgical patients have undiagnosed Diabetes. Cardiac surgical patients without Diabetes with pre-operative hyperglycaemia have a 1 year mortality double that of patients with normoglyacemia, and equivalent to patients already diagnosed with Diabetes. Pre-and peri-operative hyperglycaemia is associated with worse outcomes. Evidence regarding tight glycaemic control vs moderate glycaemic control is conflicting. Tight control may be more effective in patients without Diabetes with pre-/peri-operative hyperglycaemia, and moderate control appears more effective in patients with pre-existing Diabetes. Patients with well controlled Diabetes may achieve comparable outcomes to patients without Diabetes with similar glycaemic control. Conclusions: Pre / peri-operative hyperglycaemia is associated with worse outcomes in both patients with, and without Diabetes undergoing CABG. This review supports the pre-operative screening, and optimisation of glycaemic control in patients undergoing cardiac surgery. Optimal glycaemic management remains unclear and clear guidelines are needed.