News & Research

    Emory University School of Medicine, Atlanta, Georgia

Intensive insulin therapy in hyperglycemic patients undergoing coronary artery bypass surgery

General Research Subject: Type 2 Diabetes

Focus: Clinical Therapeutics/New Technology\Insulin Delivery Systems, Complications\ Macrovascular-Atherosclerotic CVD and Human Diabetes, Health Care Delivery/Economics

Type of Grant: Clinical Translational Research

Project Start Date: January 1, 2011

Project End Date: December 31, 2013

Diabetes Type: Type 2 diabetes

Research Description

Funded by The Fineberg Foundation

Many patients develop high blood glucose after cardiac surgery.  It is not clear what the best target blood glucose (BG) level in patients is after cardiac surgery.  This study will determine whether tight glucose control will reduce perioperative complications compared to conventional BG control after bypass surgery.  In both groups, subjects will receive intravenous insulin infusion using a computer-guided device (Glucommander).  The primary outcome in this trial is to determine differences between groups on a composite of hospital mortality, perioperative complications including sternal wound infection, blood infections, respiratory failure, pneumonia, kidney failure and major cardiovascular events.  We will also determine differences on hypoglycemia, hospital length of stay, thirty day mortality, hospital readmissions and emergency room visits following discharge.

Research Profile

What area of diabetes research does your project cover?  What role will this particular project play in preventing, treating and/or curing diabetes?

This study aims to determine the importance of intensive glucose control in patients with hyperglycemia after coronary artery bypass graft (CABG) surgery.  Several studies have shown that intensive glucose control has the potential to reduce hospital complications and mortality in patients with hyperglycemia after CABG surgery.  Recent guidelines; however, recommends high BG targets (140-180 mg/dl) for all ICU patients including surgical patients.  There is concern that higher glucose targets may increase the risk of hospital complications in cardiac surgical patients in whom intensive glucose control has consistently reduced infections, length of hospital stay, resource utilization, and cardiac-related mortality.  Thus, determining the optimal level of BG during the perioperative period in cardiac surgery patients is of most importance in reducing hospital complications and mortality.

The overall objective of this proposal is to conduct a prospective randomized controlled trial to determine the optimal BG target during the perioperative period in hyperglycemic subjects who undergo CABG in the United States.  Subjects will be randomized to undergo intensive insulin therapy adjusted to maintain a BG between 80 mg/dl and 140 mg/dl or to a conventional glucose control with a target BG between 141 mg/dl and 200 mg/dl in the ICU.  The central hypothesis guiding this proposal is that intensive insulin management will reduce perioperative complications compared to a conventional BG control in cardiac surgery patients. 

The primary outcome of this trial is to determine differences between intensive and conventional glucose control on a composite of hospital mortality and perioperative complications including sternal wound infection (deep and superficial), bacteremia, respiratory failure, acute renal failure, and major cardiovascular events (acute myocardial infarction, congestive heart failure, and cardiac arrhythmias). 

If a person with diabetes were to ask you how your project will help them in the future, how would you respond?

Many patients without a history of diabetes and most with a history of diabetes undergoing cardiac surgery develop significant hyperglycemia during the perioperative period.  Strong evidence from observational and randomized prospective clinical trials has reported a high risk of infection, hospital complications and higher hospital mortality in patients with hyperglycemia after surgery.  Clinical trial examining the impact of insulin treatment; however, have provided mixed results.  Some early trials reported that intensified insulin treatment reduced complications and mortality, but several recent trials have failed to show improvement with intensive glycemic control.  Thus it is not clear what is the best blood glucose target during the perioperative period in cardiac surgery patients. Accordingly, we propose a multicenter, open label RCT to determine whether intensive glucose control (target BG 100 - 140 mg/dl) will reduce perioperative complications compared to conventional BG control (target BG 141- 180 mg/dl) in subjects who undergo primary, elective CABG surgery.  A computer-guided device will be used in both groups to facilitate BG control with a single insulin delivery program and to reduce the rate of hypoglycemic events.  After discontinuation of insulin treatment in the ICU, subjects will be transitioned in regular floors to subcutaneous insulin to maintain a BG target ?140 mg//dl before meals. 

The primary outcome in this trial is to determine differences between groups on a composite of hospital mortality,  perioperative complications including sternal wound infection (deep and superficial), bacteremia, respiratory failure, pneumonia, acute renal failure and major cardiovascular events (acute myocardial infarction, congestive heart failure, and cardiac arrhythmias).  Secondary outcomes include differences between groups on hypoglycemia, ICU and hospital length of stay, thirty day mortality, hospital readmissions and emergency room visits following discharge, and incidence of organ failures).  

This proposal aims to answer an important clinical question regarding best glucose target in surgical patients.  In addition, this is the first randomized control insulin trial to be conducted in the United States in cardiac surgery patients.    

Why is it important for you, personally, to become involved in diabetes research?  What role will this award play in your research efforts?

Our research team has conducted several observational and randomized clinical trials in impatient glycemic control during the past decade.  We were among the first groups to report on the high incidence of diabetes in the hospital and the deleterious effect of hyperglycemia in ICU and non-ICU patients.  More recently we have completed several randomized trials comparing the efficacy and safety of different insulin regimens in medical and surgical patients admitted in critical and noncritical care settings.  Despite the long-term clinical use of insulin and recent trials, insulin treatment in the hospital is not supported by evidence base medicine and much research is needed to determine best insulin regimens and glucose targets for the management of patients with hyperglycemia. 

This study will allow us to determine if intensive glycemic control is beneficial during the perioperative period in cardiac surgery patients.   This research is of great clinical importance considering that more than 500,000 cardiac procedures are performed yearly in the United States. If our hypothesis that glucose targets recommended by recent guidelines may be associated with increased risk of complications during the perioperative period is correct, the present investigation has the potential to change to help millions of patients around the world that undergoes cardiac surgery every year.

In what direction do you see the future of diabetes research going?

The current epidemic of diabetes and the anticipate increasing number of cases with diabetes in the United States and around the world, makes diabetes research translational research a priority a health care priority.  Important areas of future research include translational research on the prevention of type 1 and type 2 diabetes (lifestyle and pharmacological interventions), genetics, prevention and treatment of microvascular and macrovascular complications, health disparities, new agents and effective treatments to improve glycemic control and reduction of cardiovascular complications.

In the area of inpatients glycemic control, new areas of research include randomized clinical trials aiming to determine 1) effective and safe insulin regimens for glycemic control in medical and surgical patients, 2) use of continuous insulin delivery and glucose monitoring that will allow the implementation of close loop systems for inpatient and outpatient control, 3) determine safe and effective regimens in diabetes in the children and adolescents as well as elderly patients and in long-tern care facilities, 4) education and dissemination of best practices of glycemic control, and 5) new technology for glucose monitoring and insulin administration in the hospital and long-term care facilities.