Vital capillary microscopy for assessment of skin viability and microangiopathy in patients with diabetes mellitus.

Vital capillaroscopy is useful in clinical practice to study the nutritional skin capillaries and for evaluating the risk for skin necrosis in patients with peripheral ischemia. This method is especially valuable in the investigation of patients with diabetes mellitus (DM) in whom the arterial inflow to the foot can be almost normal despite the development of skin necrosis due to impaired nutritional circulation. When the capillary morphology in the feet of asymptomatic diabetic patients was investigated, significantly more areas with widely dilated capillaries were present both in insulin and tablet treated patients compared to controls. By using dynamic capillaroscopy the flow velocity in skin capillaries can be determined under physiological conditions. Fourteen diabetic patients were compared with matched non-diabetic controls. The capillary blood flow during resting conditions was equal in the two groups but a delay in the postocclusive reactive hyperemia response was seen in the diabetic patients. The reason for this may be a vasomotor dysfunction in the precapillary arterioles or an increased blood viscosity. Further studies using dynamic vital capillaroscopy may improve our knowledge of the complex mechanisms responsible for diabetic microangiopathy.