Unsp athscl nonaut bio bypass of the extremities, left leg

This code describes the hardening and narrowing of a non-native, biologically derived bypass graft located in the left leg, where the specific type of atherosclerosis is not documented. This graft was surgically implanted to bypass an obstructed artery, and it is now experiencing atherosclerotic changes.

Use this code when documentation indicates atherosclerosis affecting a biological bypass graft in the left leg, and the physician has not specified the type of atherosclerosis (e.g., native vessel, in situ, etc.). This applies to situations where the graft itself, rather than the native vessel, is the site of the atherosclerotic disease.

• Ensure the documentation clearly specifies a biological bypass graft, not a synthetic one.
• Verify the laterality is explicitly stated as "left leg" to avoid miscoding.
• Do not use this code if the type of atherosclerosis is specified; instead, select a more specific code from the I70.5- series.