Noninvasive Assessment of the Diabetic Patient for Coronary Artery Disease

Type 2 diabetes has been referred to as “a cardiovascular disease associated with hyperglycemia” (1). Such inversion of traditional terminology stems, in part, from the extraordinary frequency with which heart disease occurs in this condition. Cardiovascular diseases are indeed responsible for 65% of deaths in diabetic patients, the great majority of whom have type 2 diabetes (2). The Framingham Study (3) long ago demonstrated that diabetic individuals had a two- to fivefold increased risk of developing angina, myocardial infarction, and congestive heart failure. When individuals <45 years of age are examined separately, the risk of cardiovascular disease swells to >11-fold that of the general population (4). We recognize the link between diabetes and ischemic heart disease (IHD) on a daily basis in clinical practice, and it has been repeatedly demonstrated in a number of other epidemiological analyses (5,6,7). Even when the diabetic patient comes under appropriate medical care for vascular disease, outcomes are poorer than those of nondiabetic individuals. Specifically, mortality statistics after myocardial infarction (8) or even after revascularization procedures (9) are increased in the setting of preexisting diabetes. In addition to the obvious human costs, health care expenditures related to premature atherosclerosis are considerable, particularly when the additional costs of disability and lost productivity are calculated (4).

The cause of the macrovasculopathy of diabetes becomes apparent when one considers the deleterious effects of the hyperglycemic milieu, such as protein glycosylation, increased oxidative stress, endothelial dysfunction, and an underlying procoagulant state. In type 2 diabetes, these processes conspire with additional cardiovascular risk factors associated with the metabolic syndrome: obesity, hypertension, dyslipidemia, hyperinsulinemia, decreased fibrinolysis, and further endothelial abnormalities.

Offsetting this otherwise sobering picture are recent advances in cardiovascular risk reduction in patients with diabetes. A broad range of clinical trials, for instance, have unequivocally …