Exercise hyperemia for the study of peripheral circulation.

Blood flow in the calf was measured during postexercise hyperemia in normal subjects and in PAD patients by means of a foot ergometer that gives direct reading of the work performed. In normals, first and peak flow increased with the rise of work load up to 100 KGM. The duration of hyperemia increased with a work load of 30 to 200 KGM. In PAD patients, first flow did not coincide with peak flow. Peak flow was lower and delayed, and the duration of hyperemia was more prolonged than in normal subjects. In patients with intermittent claudication, first flow, peak flow, and work load were higher than in patients with rest pain or impending gangrene. Exercise hyperemia appears as a useful test for screening normal limbs from those with arterial obstruction. Since in PAD patients exercise is interrupted when muscular pain appears, it is evident that the earlier the arrest of work and the appearance of pain, the greater is the involvement in the arterial tree of the leg. Therefore the exercise hyperemia test can be used also as a means of evaluating the different stages of PAD.