Effect of chronic sympathetic denervation upon local regulation of blood flow in human subcutaneous tissue.

The effect of chronic sympathetic denervation upon the vasoconstrictor response to an increase of vascular transmural pressure in human subcutaneous adipose tissue was investigated in 6 patients suffering from manual hyperhidrosis. Changes in transmural pressure were obtained either by postural changes of a forearm or by venous stasis of 30 mmHg. Blood flow was measured in the distal part of the forearm or crus by means of the local 133Xenon washout technique. 2 patients were studied before and after sympathectomy. When the area under study was lowered about 40 cm below the jugular notch, blood flow decreased about 50% preoperatively, about 30% 24 h after the operation, but remained constant 4 days after or later. Similar results were obtained during venous stasis. Hence about 4 days after sympathectomy, the vasoconstrictor response to an increase in vascular transmural pressure was abolished. In 3 chronically sympathectomized patients blood flow remained constant in the denervated limb, but decreased significantly in the control limb. In another patient studied 580 days after surgery blood flow remained constant during lowering of the denervated forearm as well as during venous stasis. These findings might indicate that the vasoconstrictor response to an increase in vascular transmural pressure in human subcutaneous adipose tissue is due to a local nervous mechanism involving symphathetic adrenergic nerves, but a myogenic mechanism cannot be definitively excluded.