Athscl nonaut bio bypass of the extrm w gangrene, oth extrm

This code describes the hardening and narrowing of a non-native biological bypass graft in an extremity, specifically when this atherosclerosis has progressed to cause tissue death (gangrene). This graft was surgically implanted to bypass an obstructed artery in a limb, and the gangrene indicates severe ischemia distal to the compromised graft.

Use this code when documentation clearly states atherosclerosis affecting a biological bypass graft (e.g., saphenous vein graft from another patient or animal) in an extremity, and gangrene is present in that same limb. This typically occurs in patients with advanced peripheral artery disease who have undergone prior revascularization.

• Ensure the documentation specifies a nonautologous biological graft; differentiate from autologous grafts (I70.561-I70.563).
• Confirm the presence of gangrene as a direct complication of the graft atherosclerosis.
• Specify the affected extremity (e.g., right, left, bilateral, other) using the appropriate 7th character.