Different effects of diabetic autonomic neuropathy on regional transcutaneous oxygen tension in patients with peripheral arterial disease.

Background: Diabetic autonomic neuropathy (DAN) is thought to reduce skin nutritive perfusion through increase of arteriovenous shunting flow, resulting in foot ulceration. However, the correlation between skin tissue oxygenation and DAN has not been fully elucidated. Transcutaneous oxygen tension (TcPO2) is a reliable indicator of skin nutritional microcirculation. The aim of this study was to evaluate the influence of DAN on skin microcirculation by using TcPO2 measurements.

Methods: The resting TcPO2 (REST-TcPO2) and post-exercise TcPO2 (Ex-TcPO2) of the calf and dorsalis pedis regions were measured simultaneously in 52 patients (104 limbs), including 41 diabetes patients. All patients underwent angiography, and the presence of arterial stenosis was evaluated.

Results: TcPO2 levels were compared among the groups of patients with no neuropathy, sensory neuropathy alone, and DAN. In both the calf and dorsalis pedis regions, Ex-TcPO2 levels in diabetes patients with DAN were significantly lower than those in diabetes patients without any neuropathy. However, there was no difference in REST-TcPO2 levels among these groups. We then performed multiple regression analysis to evaluate the influence of DAN on each TcPO2 after adjustment for multiple clinical factors. DAN was a significant determinant of REST- and Ex-TcPO2 in the calf region, and it was independent of arterial stenosis and sensory neuropathy. In contrast, DAN was not an independent determinant of REST- and Ex-TcPO2 in the dorsalis pedis region.

Conclusions: We, for the first time, showed that DAN has significant effects on skin microcirculation of the calf region but not of the dorsalis pedis region.