Table 1.

(A) Original/Composite Femoropopliteal (FP) disease grading in GLASS. (B) Original/Composite Infrapopliteal (IP) disease grading in GLASS.

(A)
Femoro-Popliteal (FP) Grading
0	Mild or no significant (<50%) disease
1	Total length SFA disease <1/3 (<10 cm); may include single focal CTO (<5 cm) as long as not flush occlusion; popliteal artery with mild or no significant disease
2	Total length SFA disease 1/3–2/3 (10–20 cm); may include CTO totaling <1/3 (10 cm) but not flush occlusion; focal popliteal artery stenosis <2 cm, not involving trifurcation
3	Total length SFA disease >2/3 (>20 cm) length; may include any flush occlusion <20 cm or non-flush CTO 10–20 cm long; short popliteal stenosis 2–5 cm, not involving trifurcation
4	Total length SFA occlusion >20 cm; popliteal disease >5 cm or extending into trifurcation; any popliteal CTO
(B)
Infra-Popliteal (IP) Grading
0	Mild or no significant (<50%) disease
1	Focal stenosis <3 cm not including TP trunk
2	Total length of target artery disease <1/3 (<10 cm); single focal CTO (<3 cm not including TP trunk or target artery origin)
3	Total length of target artery disease 1/3–2/3 (10–20 cm); CTO 3–10 cm (may include target artery origin, but not TP trunk)
4	Total length of target artery disease >2/3 length; CTO >1/3 (>10 cm) of length (may include target artery origin); any CTO of TP trunk

A—Involvement of trifurcation means disease includes the origin of either the anterior tibial or tibioperoneal trunk. Severe calcification (e.g., >50% of circumference, diffuse, bulky or “coral reef” plaques) within the TAP increases the within-segment grade by +1. B—IP grading is applied only to the primary selected vessel in the TAP. Severe calcification (e.g., >50% of circumference, diffuse, bulky or “coral reef” plaques) within the TAP increases the within-segment grade by +1. TP trunk disease is only included if the TAP is the posterior tibial or peroneal artery.