Thigh to Ankle Gradient Index (TAGI)

Parameters:

(1) lower thigh systolic blood pressure in mm Hg

(2) ankle systolic blood pressure in mm Hg

TAGI =

= ((lower thigh systolic blood pressure) - (ankle systolic blood pressure)) / (lower thigh systolic blood pressure)

Interpretation:

• Ideally there should be little arterial resistance over the distances involved, and the TAGI should be close to 0.

• McCoy et al found an 88% success rate for profundoplasty if the TAGI was < 0.55. The success rate was 32% if the TAGI was > 0.55.

• Towne and Berhnhard reported a successful outcome if the TAGI was <= 0.39 but a poor outcome if it was 0.79.