The role of adrenergic mechanisms in the blood pressure regulation of leg-amputees.

An increased occurrence of hypertension has been reported among leg-amputees. In order to investigate whether leg amputation is followed by an elevation of sympathetic tone, possibly enhanced by continuous mechanical irritation of the amputation stump by wearing a prosthesis, blood pressure (BP), pulse-rate (PR) and plasma catecholamines (norepinephrine, NE, and epinephrine, E) were measured in six hypertensive leg-amputees during prosthesis walking as well as during irritation of the amputation stump by vacuum suction in the supine position. Six patients suffering from essential hypertension and six normotensive subjects served as control groups. Basal levels of plasma NE and E did not differ in the three investigated groups. Mechanical stump(limb) irritation as well as walking induced a rise of NE but not of E, accompanied by a rise of BP and PR in amputees as well as in the control subjects. Elevation of NE and BP was most accentuated in hypertensive amputees when walking with prosthesis. Within each investigated group there was a positive correlation between NE and mean arterial blood pressure (MAP), (p less than 0.001 in hypertensive amputees and non-amputees, p less than 0.05 in normotensives). We conclude that mechanical limb irritation induces a rise of BP by sympathetic nervous stimulation. Thus wearing of a vacuum-prosthesis may support a consistent rise in BP.