Correlation of Values for Indocyanine Green Angiography in the Arterographically Normal Lower Extremity

Indocyanine green angiography (ICGA) is an assessment tool used to detect the degree of perfusion of tissue. This technology is being utilized in a variety of applications, including in the lower extremity. Principally, ICGA has been reported as a tool to determine pre-, intra-, or post-operative perfusion. The aim of this study is to determine objective values for ICGA in patients with arterographically normal lower extremities.

Prospectively, 20 patients were identified with no history of peripheral vascular disease who were scheduled to undergo distal subtraction angiography of the lower extremity. Based on the angiogram, 18 patients were deemed anatomically normal-a patent posterior tibial, anterior tibial, and peroneal artery with blood flow past the ankle into the foot. These patients then underwent ICGA on the dorsal and plantar aspects of the foot. The time to blush (seconds) and ingress and egress rates (units/second) were calculated.

The mean time to blush for the dorsal aspect is 26.7s (standard deviation [SD]=22.16) and the median is 14s (range=4-81s) and for the plantar aspect is 9.33s (SD=18.64), and the median is 3.5s (range=1-68s). The region of interest (ROI) ingress rates for the dorsal foot is: mean 3.29 (SD=5.18) and median is 1.60 (range=0.2-21.7). The ROI egress rates for the dorsal foot is: mean 0.55 (SD=0.43) and median is 0.35 (range=0.3-1.40). The ROI ingress rates for the plantar foot is: mean 10.02 (SD=11.91) and median 2.60 (range=0.30-34.20). The ROI egress rates for the plantar foot is: mean 1.57 (SD=1.65) and median is 1.00 (range=0.10-5.70).

This is the first study attempting to establish objective values for ICGA in the vascularly patent lower extremity.