Fluorescein angiography and distal arterial pressure in patients with arterial disease of the legs.

Fluorescein angiography (FA) of the foot soles was performed in 119 patients with arterial disease of the legs. Fluorescein was injected rapidly intravenously and sequential photographs were taken of the foot soles. Densitometric measurements were performed on three areas of each foot image: the big toe, the foot pad (just proximal to the little toe) and the heel. The relationships between different FA measurements and systolic arterial pressure in the ankle or the big toe were analysed. The appearance times of fluorescence correlated inversely with ankle pressure (P less than 0.001). The initial slopes of the fluorescence-time curves at all three sites of measurement correlated with ankle pressure (P less than 0.001). The initial slopes of fluorescence-time curves of the big toe and the foot pad correlated with toe pressure (P less than 0.001). In 12 patients effective arterial pressure was lowered by elevation of the feet, and in eight patients external pressure was applied to the foot by enclosing it in a box. The changes in FA evoked by these manoeuvres further strengthened the relationship between arterial pressures and FA measurements. We conclude that FA is a good method for evaluating circulation in the foot when neither ankle nor toe pressure is obtainable. In addition, FA may be useful when vascular disease is suspected in the presence of normal pressures, because the fluorescence distribution pattern was clearly abnormal in 11 of 16 such feet.