An Overview of Glycemic Control in the Coronary Care Unit with Recommendations for Clinical Management

Abstract

The observation that elevated glucose occurs frequently in the setting of acute myocardial infarction was made decades ago. Since then numerous studies have documented that hyperglycemia is a powerful risk factor for increased mortality and in-hospital complications in patients with acute coronary syndromes. While some questions in this field have been answered in prior investigations, many critical gaps in knowledge continue to exist and remain subjects of intense debate. This review summarizes what is known about the relationship between hyperglycemia, glucose control, and outcomes in critically ill patients with acute coronary syndromes, addresses the gaps in knowledge and controversies, and offers general recommendations regarding glucose management in the coronary care unit. J Diabetes Sci Technol 2009;3(6):1342-1351 SYMPOSIUM Relationship between Glucose Levels and Outcomes in Patients with Acute Myocardial InfarctionAmong various cardiovascular disorders, the relationship between glucose levels and outcomes has been studied most extensively among patients with acute myocardial infarction (AMI). Numerous studies have demonstrated that hyperglycemia is common and is associated with a higher risk of mortality and inhospital complications in this patient group. While the definition of hyperglycemia varies across different studies, several large observational investigations have demonstrated that elevated admission glucose (random glucose value >140 mg/dl-the definition of hyperglycemia used by the American Heart Association 27 ) occurs in 51-58% of patients presenting with AMI. 2,28 Although some patients with AMI may experience resolution of hyperglycemia during hospitalization, in most cases, hyperglycemia persists throughout the hospital course. Recent analysis of nearly 17,000 patients hospitalized with AMI showed that 41% of AMI patients have persistent hyperglycemia (mean hospitalization glucose >140 mg/dl) and about 14% have persistent severe hyperglycemia (mean hospitalization glucose >200 mg/dl). 28The relationship between higher glucose levels and increased mortality risk in AMI has been shown across various glucose metrics. Among these, admission glucose has been evaluated the most thoroughly. The largest epidemiologic study that evaluated the relationship between admission glucose levels and mortality in AMI patients was the analysis from the Cooperative Cardiovascular Project.2 In a cohort of 141,680 elderly patients, a clear, linear relationship was demonstrated between admission glucose levels and both 30-day and 1-year mortality (Figure 1). Other studies have confirmed these findings, showing a significant increase in the risk of short-and long-term mortality in hyperglycemic AMI patients, 15, 21 and extended it to the entire range of acute coronary syndromes, including ST elevation myocardial infarction, non-ST elevation myocardial infarction, and unstable angina.5,29 A similar relationship between elevated glucose and increased risk of death has also been demonstrated with othe...

Glucose Control in Acute Myocardial Infarction: A Pilot Randomized Study Controlled by Continuous Glucose Monitoring System Comparing the Use of Insulin Glargine with Standard of Care

“…Persistent hyperglycemia occurring in any time during hospitalization due to AMI is a predictor of mortality. 10 Both time to initiate insulin therapy and goals of control have been the subject of controversy. Targets initially recommended (blood glucose < 110 mg/dL) were based on the results obtained in the surgical ICU and have been challenged by recent studies that failed to demonstrate the benefit of tight glucose control.…”

“…Targets initially recommended (blood glucose < 110 mg/dL) were based on the results obtained in the surgical ICU and have been challenged by recent studies that failed to demonstrate the benefit of tight glucose control. 3,[8][9][10] Protocols recommended intravenous insulin infusion in the first 24-48 h after AMI followed by transition to a scheme using subcutaneous insulin. 11,12,19 The handling of intravenous insulin infusion requires proper equipment, the use of structured algorithms for correction, and well-trained staff.…”

“…3,9 Although the ideal target for glycemic control is not known, data indicate that it should be between 80 mg/dL and 180 mg/dL. 10 The usual protocol consists of continuous insulin intravenous infusion during the first 24-48 h after an AMI event, followed by subcutaneous insulin therapy. 11 However, the task of monitoring the intravenous infusion in order to achieve glycemic targets requires welldesigned protocols and continuous attention by well-trained nursing staff.…”

“…11 However, the task of monitoring the intravenous infusion in order to achieve glycemic targets requires welldesigned protocols and continuous attention by well-trained nursing staff. 12 According to other studies, 10,13 continuous intravenous insulin is not an absolute requirement if glucose levels are adequately controlled by other means. Thus, an alternative strategy may be the use of insulin glargine (iGlar), coupled with subcutaneous regular insulin (iReg) to adjust for postprandial hyperglycemia.…”

Early Improvement in Carotid Plaque Echogenicity by Acarbose in Patients With Acute Coronary Syndromes

“…Acarbose may be useful for glucose management in AMI patients with known type 2 DM, because management of glucose levels within a given range and with minimal risk of hypoglycemia is recommended for the treat-H Carotid Plaque Echogenicity and Acarbose in ACS ment of hyperglycemia in patients with AMI. 24 Acarbose directly targets postprandial hyperglycemia, 23 which has been identified as an important cardiovascular risk factor. 25 Unlike acarbose, other antidiabetic medications, such as sulfonylureas, have a greater effect on fasting hyperglycemia than on postprandial hyperglycemia.…”