Decrease of macrovascular hyperemic response of blood flow in diabetics with arterial neuropathy.

Doppler sonographic examination of 51 diabetic subjects showed that the macrovascular hyperemic response of the pedal blood flow was negatively correlated to the duration of the disease (p less than 0.01). In comparison with non-diabetic controls (n = 20), the response was increased by more than 210% in newly detected diabetics, but decreased by more than 20% in long-term diabetics. Vascular response was correlated also not only to the duration of the diabetes, but to peripheral neuropathy (p less than 0.001). The hyperemic response was reduced in patients with reduced nerve conduction time, or somatic neuropathy (142 + 152%, p less than 0.005), and in patients with reduced arterial pulsation, or autonomic neuropathy (152 + 88, p less than 0.005), both in comparison with non-diabetic controls (293 +/- 108%). The frequency of decreased macrovascular hyperemic response was in agreement with somatic neuropathy in 69.7% and with autonomic neuropathy in 75.8% of all patients. The results demonstrate that the macrovascular hyperemic response of blood flow in diabetic feet is already reduced at an early stage of peripheral neuropathy without peripheral vascular occlusive disease. The functional reduction of pedal blood flow may be important for the development of diabetic foot gangrene.