[Diabetes mellitus and coronary artery disease--a high risk combination]

Abstract

Patients with diabetes mellitus are often not recognized in clinical routine, but also not well characterized in clinical trials. As a diagnostic approach it is recommended to test fasting glucose and glycosylated hemoglobin (HbA1c) in every patient with coronary artery disease (CAD). HbA1c, in addition, provides important prognostic information. Patients with diabetes mellitus do have an enhanced cardiovascular risk in all stages and during all kind of interventions of CAD. However, diabetes is not equal to diabetes; risk modifying factors such as HbA1c, concomitant diseases and medication have to be considered. Absolute benefit of pharmacological therapies is also enhanced in patients with diabetes compared to non-diabetics. However, statins or anti-hypertensive treatment seem to be even more effective in reducing cardiovascular events than pure control of glucose levels alone. During percutaneous interventions (PCI) glycoprotein IIb/IIIa-inhibitors reduce mortality in diabetics, an effect which may be partially also achieved by Clopidogrel. Glitazones reduce restenosis rates; however, clinical end point studies are still ongoing. After PCI, restenosis may be a predictor of mortality in patients with diabetes. Whether drug eluting stents, besides effectively reducing restenosis, may also reduce hard clinical events in patients with diabetes remains to be demonstrated. Current available studies comparing PCI with bypass are limited due to not considered factors (stenosis morphology), randomization bias, and faster progress of technology compared to study termination. During an acute coronary syndrome/myocardial infarction, hyperglycemia is an adverse prognostic marker. However, so far studies using glucose-insulin-potassium (GIK) infusion have not been convincingly demonstrate to be beneficial.