The venoarteriolar response in diabetics

Resting skin blood flow and the venoarteriolar response (VAR) were studied in 40 patients with diabetic microangiopathy and neuropathy, in 40 diabetics with microangiopathy, and in 30 normal subjects by means of laser-Doppler flowmetry. In patients with microangiopathy and neuropathy, resting flow (RF) was increased and the VAR was impaired to a greater extent than in patients without neuropathy. There was also a significant delay in the VAR in diabetics, particularly in patients with neuropathy. The microangiopathy index (VAR/RF) was on the average 71.3 in normal subjects, significantly lower (p less than 0.05) in diabetics without neuropathy (34.8), and even lower in those with neuropathy (13.6). The VAR was evaluated with different postural changes; The authors observed that in the passage from supine to standing the VAR is more evident. In conclusion these results confirm that the postural control of blood flow in the skin of the foot is impaired in diabetic microangiopathy, particularly in patients with neuropathy. The increased skin blood flow and the impaired VAR are causes of edema and may contribute to the thickening of capillary basement membranes observed in diabetes.