Analysis of flow motion by the laser Doppler technique in patients with peripheral arterial occlusive disease

Laser Doppler flux was measured at the forefoot in 12 healthy subjects and in 36 patients with different degrees of ischemia due to peripheral arterial occlusive disease. Two characteristic patterns of flow motion waves were observed: Large waves with a mean amplitude of 0.77 +/- 0.4 arbitrary units and a mean frequency of 3.03 +/- 1.0 c/min (0.051 +/- 0.02 Hz) and small waves with a mean amplitude of 0.21 +/- 0.1 arbitrary units and a mean frequency of 21.7 +/- 4.2 c/min (0.362 +/- 0.07 Hz). The prevalence of large waves tended to decrease with more advanced ischemia, whereas small waves occurred almost exclusively in ischemia and most frequently in severe cases. Large flow motion waves were enhanced during reactive hyperemia after arterial occlusion or appeared after peak flux had been reached. Time to peak flux or to vasomotion were reliable parameters for characterizing skin ischemia. The previously undescribed small flow motion waves might represent a compensatory mechanism involved in pathophysiology of ischemia.