M.F. Meyer and H. Schatz. University Hospital Bergmannsheil, Department of

Internal Medicine, Bh rkle-de-la-Camp-Platz 1, D-44789 Bochum

Postocclusive reactive hyperaemia is reduced and delayed in type 1 and type 2 diabetes as shown by videophotometric capillaroscopy and laser Doppler fluxmetry. The aim of this study was to examine by means of the new technique of laser Doppler anemometry whether type 1 and type 2 diabetic patients differ in the relation of impaired skin microcirculation to metabolic control and duration of diabetes. 16 patients with type I diabetes and 19 patients with type 2 diabetes were investigated and subdivided in patients with ,,good" (HbAlc<7.5%) and ,,bad" (HbAlc>7.5%) metabolic control and in patients with a duration of diabetes of more than 10 or less than 10 years. Two age- and sex-matched control groups comprising 16 and 19 non-diabetic subjects served as controls. The capillary blood cell velocity (CBV) was measured in the dorsal middle phalangeal area of the fourth finger of the left hand by laser Doppler anemometry. CBV in single capillaries was studied during rest and after 3-min arterial occlusion. Resting CBV was similar in diabetic patients and control subjects. Peak CBV was reduced in type I diabetic patients (0.69" 0.08mm/s vs. 0.96" 0.07mm/s, p<0.05) independent of diabetes duration and metabolic control, whereas peak CBV in type 2 diabetes was decreased only in patients with bad metabolic control (0.54" 0.04mm/s vs. 0.70" 0.04mm/s, p<0.05). Time to peak CBV was markedly prolonged both in type I (33.8+" 4.8s vs. 13.6" 1.9s, p<0.001) and type 2 diabetic patients (46.8" 8.5s vs. 16.4" 2.2s, p<0.001). With regard to metabolic control time to peak CBV was prolonged in type 2 diabetes only in the group of patients with HbA1c>7.5 % (56.6" 14.8s vs. 13.7" 2.7s, p<0.01). Disease duration had no significant influence on time to peak in type 1 and 2 diabetes. The results indicate that in type 2 diabetes actual metabolic control is of a greater importance for the microvascular dysfunction than in type I diabetes and that there is no evident relation to the duration of disease.