Validity of the Xenon ¹³³ Method for Measurement of Muscle Blood Flow Evaluated by Simultaneous Venous Occlusion Plethysmography

Calf blood flow has been measured simultaneosuly by the Xe 133 clearance method in m. tibialis anterior and m. gastrocnemius and by venous occlusion plethysmography in normal man and in patients with intermittent claudication. At rest Xe 133 muscle blood flow ( MBF xe ) averaged 1.6 ml/100 g/min while plethysmographic total calf blood flow (calf BF) was higher in each instance and averaged 3.0 ml/100 g/min. There was no difference between normal legs and legs with occlusive vascular disease in this respect. Following one to five minutes of arterial occlusion, reactive hyperemia was seen with both methods, the rapid changes being most readily observed with the plethysmographic method. After exhaustive muscular exercise during ischemia in normal man maximal MBF xe averaged 40 ml/100 g/min (48 ml/100 g/min over m. tibialis anterior and 32 ml/100 g/min over m. gastrocnemius). The maximal calf BF averaged 42 ml/100 g/min. The rate of return of blood flow to the resting level was also quite similar with both methods. In the patients with claudication both methods showed a subnormal and delayed hyperemic reaction following ischemic work, but the MBF xe was consistently lower. The results obtained indicate that the Xe 133 modification of Kety's local clearance method for measurement of muscular blood flow in man is essentially valid.