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Overview :
The thigh to ankle gradient index (TAGI) can be used to
evaluate a patient with peripheral artery disease in the lower extremity. It is
particularly useful in patients with atherosclerosis in tibial artery. It can
help identify a patient who may benefit from a profundoplasty.
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 aTAGI 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.
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