Heart in Diabetes: AMicrovascular Disease

D iabetes currently affects about 5%of world’s populations, and itsprevalence is rapidly increasing particularly in elderly subjects. Because over 80 % of all diabetic subjects have type 2 diabetes, the increase in the num-ber of individuals with diabetes implies an epidemic of type 2 diabetes. Diabetes is associated with hyperglycemia-specific microvascular complications. Further-more, macrovascular complications, es-pecially coronary artery disease (CAD) but also stroke and peripheral vascular disease, are increased by two- to fourfold in type 2 diabetes. Cardiovascular disease (CVD) is the most important long-term complication and by far the greatest cause of death in people with diabetes. In fact, over 50 % of all patients with type 2 di-abetes die of CAD (1). Although much of the excess risk of CAD among patients with diabetes is accounted for by the presence of diabetes-associated CVD risk factors such as LDL cholesterol, elevated blood pressure, and smoking, a substantial proportion remains unexplained. A deleterious effect of the diabetic state on vascular and endothelial function is likely to be impor-tant via its ability to increase the potential for vasoconstriction and thrombosis. In population-based studies, the relationship of hyperglycemia to CAD is evident but the association is less strong than that of LDL cholesterol and elevated blood pres-sure. There is also evidence that the role of hyperglycemia with respect to the risk of CVD is larger among patients with type 1 diabetes than in patients with type 2 diabetes. In our study, an increment of 1 unit (%) of glycated hemoglobin in-creased CVD mortality by 52.5 % (95 % CI 28.4–81.3) in patients with type 1 diabe-tes and by 7.5 % (4.3–10.8) in patients with type 2 diabetes (2). CAD also includes a microvascular component. Diabetic cardiomyopathy, a relatively rare condition, associates with the presence of microvascular complica-tions in diabetes. Therefore, changes in small arteries and capillaries are not only responsible for microvascular long-term complications, but also for other mani-festations of heart disease in diabetes