Diabetes mellitus significantly increases the risk for both small and large blood vessel complications e.g. diabetic eye problems and coronary heart disease. Vital organs such as the eye, kidney, heart and brain represent well− recognized preferential targets in patients with diabetes mellitus. The presence of such end−organ damage powerfully influences cardiovascular risk and the benefits of therapeutic interventions. Unfortunately, by the time symptoms develop or events occur as manifestations of target−organ damage, the disease process is already at an advanced stage. Although not traditionally viewed as an end−organ, it is altered structure and function of arterial small blood vessels that acts as the substrate for accelerated disease development and the increased occurrence of vascular events in patients with diabetes mellitus. The ability to detect and monitor sub−clinical damage, representing the cumulative and integrated influence of all risk factors in impairing arterial wall integrity, holds potential to further refine cardiovascular risk stratification and enable early intervention to prevent or attenuate disease progression.