2008 Clinical Practice Guidelines - Canadian Diabetes Association

Management of Acute Coronary Syndromes
Canadian Diabetes Association Clinical Practice Guidelines Expert Committee
The initial draft of this chapter was prepared by David Fitchett MD FRCPC
KEY MESSAGES
• Diabetes is an independent predictor of increased shortand
long-term mortality, recurrent myocardial infarction
(MI) and the development of heart failure in patients
with acute MI (AMI).
• Patients with an AMI and hyperglycemia should receive
insulin-glucose infusion therapy to maintain blood glucose
between 7.0 and 10.0 mmol/L for at least 24 hours, followed
by multidose subcutaneous insulin for at least 3 months.
• People with diabetes are less likely to receive recommended
treatment such as revascularization, thrombolysis,
beta blockers or acetylsalicylic acid (ASA) than
people without diabetes. Efforts should be directed at
promoting adherence to existing proven therapies in the
high-risk patient with MI and diabetes.
INTRODUCTION
Acute myocardial infarction (AMI) is responsible for about
11% of deaths in Canada each year. This represents about
half of all deaths attributable to coronary artery disease (1).
Approximately 30% of hospital admissions for AMI are in
patients with diabetes (2-6).The hospital admission rates for
AMI, corrected for age and sex differences, are over 3-fold
higher in patients with diabetes (7). Diabetes is an independent
predictor of increased short- and long-term mortality,
recurrent MI and the development of heart failure in
patients with AMI (8-10). Predictors of 1-year mortality in
the person with diabetes and AMI include blood glucose
(BG) level at hospital admission, age, blood pressure (BP),
prior MI, duration of diabetes, insulin therapy and urine
albumin level (11,12).
THERAPEUTIC STRATEGIES IN ACUTE
CORONARY SYNDROMES
Guidelines for the management of patients with acute coronary
syndromes (ACS) have been developed by the American
College of Cardiology/American Heart Association (13-15)
and the European Society of Cardiology (16). In most situations,
there are no clinical trials that specifically address
management of the patient with diabetes and ACS. However,
subgroup analyses in patients with diabetes and ACS show
either a similar or enhanced benefit from treatment compared
to the overall group for a) reperfusion with fibrinoly-
sis (17) or primary angioplasty (18,19) for ST-segment elevation
ACS; and b) high-risk non-ST-segment elevation ACS
with an early invasive strategy (20), the use of dual
antiplatelet therapy with acetylsalicylic acid (ASA) and clopidogrel
(21), and glycoprotein IIb/IIIa inhibitors in patients
with non-ST segment elevation ACS (22).
ISSUES IN THE MANAGEMENT OF THE
PATIENT WITH DIABETES AND ACS
Thrombolysis and ocular hemorrhage
There is concern that the risk of ocular hemorrhage is
increased in the person with diabetes. In the Global
Utilization of Streptokinase and t-PA for Occluded Coronary
Arteries (GUSTO 1) trial, there was no intra-ocular hemorrhage
in the more than 6000 patients with diabetes who
received thrombolytic therapy (23). Intra-ocular hemorrhage
is an extremely rare complication of diabetes; consequently,
diabetic retinopathy should not be considered a contraindication
to fibrinolysis in patients with ST-segment elevation MI
(STEMI) and diabetes (23).
Glycemic control
Hyperglycemia in the early hours after presentation is associated
with increased in-hospital and 6-month mortality, independent
of the presence of diabetes (24-26), and admission
BG is an independent predictor of survival after AMI (25).
The Diabetes Mellitus Insulin Glucose Infusion in Acute
Myocardial Infarction (DIGAMI 1) study (27-32) indicated
that tight glycemic control with the use of intravenous insulin
in the early hours after presentation, followed by multidose
subcutaneous insulin treatment over the subsequent months,
resulted in a 30% reduction in 1-year mortality.The DIGAMI
2 study (33) failed to achieve the study goals, both in the number
of patients recruited and in glycemic control, but despite
these limitations, it did demonstrate that outcomes were
closely related to glycemic control, however achieved. Studies
have shown that glucose-insulin-potassium infusion in patients
with AMI do not improve outcomes. However, these protocols
often resulted in increased BG levels, and therefore cannot
be used as evidence for outcomes associated with
glycemic control. In the Hyperglycemia: Intensive Insulin
Infusion in Infarction (HI-5) study (34) of glucose and insulin
in patients with AMI, patients with BG maintained