Low frequency oscillations of skin blood flux in peripheral arterial occlusive disease

Using the laser Doppler technique patterns of spontaneous oscillations of skin blood flux within the low frequency band (< 10 min-1; LF waves) were analysed in 12 healthy controls and 24 patients with different degrees of peripheral arterial occlusive disease (PAOD). Measurements were performed at 5 different sites at the dorsum of the foot in healthy controls and patients with severe claudication or rest pain and/or gangrene due to PAOD. Patterns were classified as "periodic", "aperiodic" or "no flux motion". The aperiodic pattern was characteristic for skin blood flux of controls. In severe claudication prevalence of periodic LF oscillations significantly increased (p < 0.05) whereas it decreased again in patients with severe ischemia. In the latter group, LF waves often were completely absent. Periodic LF waves mainly occurred between an ankle/arm pressure ratio of 0.4 to 0.8. We suggest that periodic LF waves most likely ar the result of a synchronized vasomotor activity of different arterioles within the sample volume, whereas the aperiodic pattern may resemble the net effect of simultaneous activities of different control mechanisms on skin blood flow. Based on animal experiments it is hypothesized that decreased postocclusive driving pressure and flow in patients with advanced PAOD may be the stimulus for synchronized arteriolar vasomotion.