Glucose tolerance and fractional extraction of glucose and insulin in patients with peripheral arterial insufficiency. Effect of arterial reconstructive surgery

Abstract

Glucose tolerance with plasma insulin was determined in 49 nondiabetic patients with peripheral arterial insufficiency before successful arterial reconstruction and 6 mo after the operation. Based on the level of the arterial stenosis, the patients were allocated into two groups, those with stenosis at the level of abdominal aorta or iliac artery (high stenosis) and those with stenosis below the origin of the arteria profunda femoris (low stenosis). In another group of 11 patients with high stenosis and claudication as the only symptom the fractional uptake of insulin and glucose in the leg was determined. Patients with both high and low stenosis had statistically significant lower sums of insulin values during glucose tolerance test than did controls. Sums of glucose values during the test were significantly lower in patients with high stenosis but were unchanged in patients with low stenosis. No significant change occurred in glucose tolerance after operation in patients with low stenosis. In the patients with high stenosis the sums of insulin as well as of glucose values during the glucose challenge had increased 6 mo after the operation. The fractional uptake of insulin (21%) and glucose (8%) was significantly higher in patients with arterial insufficiency than in controls (7% and 3%, respectively). In these patients the insulin:glucose concentration ratio was significantly lower in venous than in arterial blood, indicating a relative extraction of insulin higher than that of glucose in the leg muscles. The results point out that the ratio of insulin and glucose concentration in venous blood, usually used as an index of insulin sensitivity, must be interpreted with caution. The low ratio found in the present work in patients with peripheral arterial insufficiency does not necessarily mean a high insulin sensitivity. Instead, it may be dependent on the increased insulin uptake in the periphery.