Human femoral artery diameter in relation to knee extensor muscle mass, peak blood flow, and oxygen uptake

It is not known whether the diameter of peripheral conduit arteries may imp ose a limitation on muscle blood flow and oxygen uptake at peak effort in h umans, and it is not clear whether these arteries are dimensioned in relati on to the tissue volume they supply or, rather, to the type and intensity o f muscular activity. In this study, eight humans, with a peak pulmonary oxy gen uptake of 3.90 +/- 0.31 (range 2.29-5.03) l/min during ergometer cycle exercise, performed one-legged dynamic knee extensor exercise up to peak ef fort at 68 +/- 7 W (range 55-100 W). Peak values for knee extensor blood fl ow (thermodilution) and oxygen uptake of 6.06 +/- 0.74 (range 4.75-9.52) l/ min and 874 +/- 124 (range 590-1,521) ml/min, respectively, were achieved. Pulmonary oxygen uptake reached a peak of 1.72 +/- 0.19 (range 1.54-2.33) l /min. Diameters of common and profunda femoral arteries determined by ultra sound Doppler were 10.6 +/- 0.4 (range 8.2-12.7) and 6.0 +/- 0.4 (range 4.5 -8.0) mm, respectively. Thigh and quadriceps muscle volume measured by comp uter tomography were 10.06 +/- 0.66 (range 6.18-10.95) and 2.36 +/- 0.19 (r ange 1.31-3.27) liters, respectively. The common femoral artery diameter, b ut not that of the profunda branch, correlated with the thigh volume and qu adriceps muscle mass. There were no relationships between either of the dia meters and the absolute or muscle mass-related resting and peak values of b lood flow and oxygen uptake, peak pulmonary oxygen uptake, or peak power ou tput during knee extensor exercise. However, common femoral artery diameter correlated to peak pulmonary oxygen uptake during ergometer cycle exercise . In conclusion, common and profunda femoral artery diameters are sufficien t to ensure delivery to the quadriceps muscle. However, the common branch m ay impose a limitation during ergometer cycle exercise.