Peripheral vascular and nerve function associated with lower limb amputation in people with and without diabetes

Multiple factors, including peripheral vascular disease and neuropathy, con tribute to the development and perpetuation of complications of the lower e xtremities in diabetes. The main aim of the present study was to assess the peripheral vascular and nerve status of diabetic and non-diabetic subjects that had undergone lower limb amputation. Various non-invasive tests of pe ripheral vascular and nerve function were carried out on subjects who had u ndergone unilateral lower limb amputation and were now attending a Rehabili tation Centre. The control group (n = 23), the diabetic amputee group (n = 64) and the non-diabetic amputee group (n = 32) were age-matched. Only the diabetic amputee group had evidence of medial arterial calcification. Trans cutaneous oxygen levels were significantly lower in the diabetic amputee gr oup (median 43 mmHg; interquartile range 33-49 mmHg) than in the control (5 9; 56-74 mmHg) and non-diabetic amputee (57; 43-65 mmHg) groups (control co mpared with diabetic amputee group, P < 0.001; diabetic amputee compared wi th non-diabetic amputee group, P < 0.01). The same trend was found for carb on dioxide levels in the skin [mmHg: diabetic amputees, 25 (21-37); control s, 38 (32-42); non-diabetic amputee, 34 (31-39)] (control compared with dia betic amputee, P < 0.01; diabetic amputee compared with non-diabetic ampute e, P < 0.05). Vibration and pressure perception measurements (which assess A beta nerve fibre function) showed that both the diabetic amputee and non- diabetic amputee subjects had significantly greater impairment than the con trols. However, measures of A alpha and C nerve fibre function were abnorma l only in the diabetic amputee group. Thus the peripheral vascular and nerv e functions of age-matched diabetic and non-diabetic subjects having underg one lower limb amputation show specific differences, with non-diabetic ampu tees exhibiting signs of neuropathy. This indicates that factors characteri stic of diabetes (such as hyperglycaemia and non-enzymic glycation) are ass ociated with calcification, lower oxygen and carbon dioxide levels in the s kin, and abnormal A alpha and C nerve fibre function.