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Table 2. Lower Extremity Threatened Limb (SVS WIfI)
Classification System
I. Wound
II. Ischemia
III. foot Infection
= W I f I score
W: Wound/clinical category
SVS Grade Ulcer Clinical description Gangrene
0 No ulcer Ischemic rest pain (requires
typical symptoms + ischemia
grade 3); no wound.
No gangrene
1 - mild Small, shallow
ulcer(s) on distal
leg or foot; no
exposed bone,
unless limited to
distal phalanx
Minor tissue loss salvageable
with simple digital amputation
(1 or 2 digits) or skin coverage
No gangrene
2 - moderate Deeper ulcer with
exposed bone,
joint or tendon
generally not
involving the heel;
shallow heel ulcer,
without calcaneal
involvement
Major tissue loss salvageable
with multiple (≥3) digital
amputations or standard
TMA 6 skin coverage.
Gangrenous
changes limited
to digits
3 - severe Extensive, deep
ulcer involving
forefoot and/or
midfoot; deep,
full thickness heel
ulcer ± calcaneal
involvement
Extensive tissue loss salvageable
only with a complex
foot reconstruction or
nontraditional transmetatarsal
amputation (Chopart or
Lisfranc); flap coverage or
complex wound management
needed for large so tissue
defect
Extensive
gangrene
involving
forefoot and/or
midfoot; full
thickness
heel necrosis
± calcaneal
involvement
I: Ischemia
SVS Grade ABI Ankle systolic pressure
TP, TcPO
2
a
0 ≥0.80 >100 mm Hg ≥60 mm Hg
1 - mild 0.6-0.79 70-100 mm Hg 40-59 mm Hg
2 - moderate 0.4-0.59 50-70 mm Hg 30-39 mm Hg
3 – severe
b
≤0.39 <50 mm Hg <30 mm Hg
a
Patients with diabetes should have TP measurements. If arterial calcification precludes reliable ABI
(ABI >1.3) or TP measurements, ischemia should be documented by TcPO2, SPP, or PVR. If TP and
ABI measurements result in different grades, TP will be the primary determinant of ischemia grade.
b
Flat or minimally pulsatile forefoot PVR = grade 3.
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