Toe-Brachial Index in the Second Toe: Substitutability to Toe-Brachial Index in the Great Toe and Ankle-Brachial Index.

Objective: Toe-brachial index (TBI) is usually measured in the great toe (TBI-1). However, this is not always possible. To determine the usefulness of TBI measurement in the second toe (TBI-2), we examined the relation between systolic pressure in the second toe (toe pressure [TP-2]) and that in the great toe (TP-1) and evaluated the association between TBI and ankle-brachial index (ABI). Materials and Methods: We retrospectively analyzed patients who underwent a series of measurements of TBI-2, TBI-1, and ABI using an automatic oscillometric device at Kawasaki Medical School Hospital, Japan in 2012. Results: We evaluated 114 feet without severe ischemia symptoms in 57 patients (median age: 73 years). TP-2 was similar to TP-1 (correlation coefficient [r] = 0.769, 95% confidence interval [CI]: 0.681-0.836, p <0.001). ABI showed a mild correlation with TBI-2 (r = 0.463, 95% CI: 0.303-0.598, p <0.001) and a moderate correlation with TBI-1 (r = 0.586, 95% CI: 0.450-0.696, p <0.001). The TBIs of 0.65 and 0.5 corresponded to the ABIs of about 1.0 and 0.9, respectively, in both toes. Conclusion: TBI-2 measurement can be considered as an acceptable substitute to TBI-1 or ABI measurement to assess the patients in whom ABI and TBI-1 cannot be measured.