Table 1.

TASC-II classification

	Aorto-iliac lesions	Femoropopliteal lesions
TASC A	Single stenosis (<3 cm in length) in the CIA or EIA (unilateral/bilateral)	Single stenosis (<3 cm in length) in the superficial femoral artery or popliteal artery
TASC B	1. Single stenosis (3–10 cm in length) not extending into the CFA 2. A total of 2 stenoses (<5 cm in length) in the CIA and/or EIA and not extending into the CFA 3. Unilateral CIA occlusion	1. Single stenosis (3–10 cm in length) not involving the distal popliteal artery 2. Heavily calcified stenosis up to 3 cm in length 3. Multiple lesions, each <3 cm in length (stenoses or occlusions) 4. Single or multiple lesions in the absence of continuous tibial runoff to improve inflow for distal surgical bypass
TASC C	1. Bilateral stenosis (5–10 cm in length) in the CIA and/or EIA, not extending into the CFA 2. Unilateral EIA occlusion not extending into the CFA 3. Unilateral EIA stenosis extending into the CFA 4. Bilateral CIA occlusion	1. Single stenosis or occlusion >5 cm in length 2. Multiple stenoses or occlusions (each 3–5 cm in length) with or without heavy calcification
TASC D	1. Diffuse, multiple unilateral stenosis involving the CIA, EIA, and CFA (usually >10 cm in length) 2. Unilateral occlusion involving both the CIA and EIA 3. Bilateral EIA occlusions 4. Diffuse disease involving the aorta and both iliac arteries 5. Iliac stenosis in a patient with abdominal aortic aneurysm or other lesions requiring aortic or iliac surgery	Complete CFA or superficial femoral artery occlusion or complete popliteal and proximal trifurcation occlusions

CIA - common iliac artery; CFA - common femoral artery; EIA - external iliac artery; TASC - Trans Atlantic Inter-Society Consensus-II