PULSATILE BLOOD-FLOW ASYMMETRY IN PAIRED HUMAN LEGS

Average leg blood flow has been extensively measured using non-invasiv e methods, but knowledge concerning pulsatile flow at specific leg cro ss-sections in normal or vascularly impaired limbs is quite limited. T he present study used nuclear magnetic resonance flowmetry to address two fundamental questions; (1) to what extent are pulsatile flow diffe rences present between paired-legs? and (2) is paired-leg flow symmetr y affected by the presence of lower extremity arterial disease (LEAD)? Comparisons of left-right leg pulsatile blood flow (ml/min), perfusio n (ml/min/100cc), and arterial status index at multiple leg sites show ed highly significant correlations between legs (P < 0.001) in 57 norm al and 37 patients with LEAD. To evaluate symmetry, the ratio of lower to higher paired-leg flow parameter values at five below-knee sites w ere averaged. Results showed all ratios significantly greater in norma l subjects (P < 0.001). These findings establish the distribution and range of leg flow symmetry in vascularly normal individuals and show s ignificant symmetry reductions accompanying bilateral LEAD. Although t he cause of the asymmetry is presently unknown, non-uniform disease pr ogression between paired legs may be involved. These initial findings provide a basis for subsequent research regarding the possible use of bilateral now asymmetry assessment to further clarify the pathophysiol ogical progression process and the possibility of using symmetry-based parameters to develop early markers of sub-clinical peripheral arteri al disease progression.