I70.643 Atherosclerosis of nonbiological bypass graft(s) of the left leg with ulceration of ankle

Billable ICD-10-CM code, FY2026. Acts as a Complication or Comorbidity (CC) as a secondary diagnosis.

Applies from I70 Atherosclerosis

Includes

• arteriolosclerosis
• arterial degeneration
• arteriosclerosis
• arteriosclerotic vascular disease
• arteriovascular degeneration
• atheroma
• endarteritis deformans or obliterans
• senile arteritis
• senile endarteritis
• vascular degeneration

Excludes2 (not included here)

• arteriosclerotic cardiovascular disease (I25.1-)
• arteriosclerotic heart disease (I25.1-)
• atheroembolism (I75.-)
• cerebral atherosclerosis (I67.2)
• coronary atherosclerosis (I25.1-)
• mesenteric atherosclerosis (K55.1)
• precerebral atherosclerosis (I67.2)
• primary pulmonary atherosclerosis (I27.0)

Use additional code

• code to identify:
• exposure to environmental tobacco smoke (Z77.22)
• history of tobacco dependence (Z87.891)
• occupational exposure to environmental tobacco smoke (Z57.31)
• tobacco dependence (F17.-)
• tobacco use (Z72.0)

Applies from I70.6 Atherosclerosis of nonbiological bypass graft(s) of the extremities

Use additional code

• code, if applicable, to identify chronic total occlusion of artery of extremity (I70.92)

Applies from I70.64 Atherosclerosis of nonbiological bypass graft(s) of the left leg with ulceration

Includes

• any condition classifiable to I70.612 and I70.622
• chronic limb-threatening ischemia of nonbiological bypass graft(s) of the left leg with ulceration
• critical limb ischemia of nonbiological bypass graft(s) of the left leg with ulceration

Use additional code

• code to identify severity of ulcer (L97.-)

Risk adjustment (HCC)

• CMS-HCC V28: HCC 383 — Chronic Ulcer of Skin, Except Pressure, Not Specified as Through to Bone or Muscle
• CMS-HCC V22: HCC 161 — Chronic Ulcer of Skin, Except Pressure
• ESRD V24: HCC 161

MS-DRG index

Defines the logic of DRG(s) 299-301 in MDC 05.

Approximate ICD-9-CM (GEMs)

• 440.30 Atherosclerosis of unspecified bypass graft of the extremities (approximate)
• 707.13 Ulcer of ankle (approximate)

Medicare Code Edits (MCE v43.1 (April 2026))

• Adult diagnoses (age 15 through 124): Age conflict edit. These diagnoses are clinically expected only in patients age 15 through 124.

Code annotations containing back-references to I70.643

Back-references to I70.64

• Code First: L97 Non-pressure chronic ulcer of lower limb, not elsewhere classified ("atherosclerosis of the lower extremities (I70.23-, I70.24-, I70.33-, I70.34-, I70.43-, I70.44-, I70.53-, I70.54-, I70.63-, I70.64-, I70.73-, I70.74-)")

Back-references to I70.6

• Code First: I70.92 Chronic total occlusion of artery of the extremities ("atherosclerosis of arteries of the extremities (I70.2-, I70.3-, I70.4-, I70.5-, I70.6-, I70.7-)")

Back-references to I70

• Type 1 Excludes: I77.6 Arteritis, unspecified ("deformans (I70.-)")
• Type 1 Excludes: I77.6 Arteritis, unspecified ("obliterans (I70.-)")
• Type 1 Excludes: I77.6 Arteritis, unspecified ("senile (I70.-)")

Diagnosis Index entries for I70.643

• Arteriosclerosis, arteriosclerotic (diffuse) (obliterans) (of) (senile) (with calcification) › with › critical limb ischemia › bypass graft › nonbiological graft › leg › left › with › ulceration (and intermittent claudication and rest pain) › ankle
• Arteriosclerosis, arteriosclerotic (diffuse) (obliterans) (of) (senile) (with calcification) › extremities (native arteries) › bypass graft › nonbiological graft › leg › left › with › ulceration (and intermittent claudication and rest pain) › ankle

Nearby codes

• I70.638 Atherosclerosis of nonbiological bypass graft(s) of the right leg with ulceration of other part of lower leg
• I70.639 Atherosclerosis of nonbiological bypass graft(s) of the right leg with ulceration of unspecified site
• I70.64 Atherosclerosis of nonbiological bypass graft(s) of the left leg with ulceration
• I70.641 Atherosclerosis of nonbiological bypass graft(s) of the left leg with ulceration of thigh
• I70.642 Atherosclerosis of nonbiological bypass graft(s) of the left leg with ulceration of calf
• I70.643 Atherosclerosis of nonbiological bypass graft(s) of the left leg with ulceration of ankle (this code)
• I70.644 Atherosclerosis of nonbiological bypass graft(s) of the left leg with ulceration of heel and midfoot
• I70.645 Atherosclerosis of nonbiological bypass graft(s) of the left leg with ulceration of other part of foot
• I70.648 Atherosclerosis of nonbiological bypass graft(s) of the left leg with ulceration of other part of lower leg
• I70.649 Atherosclerosis of nonbiological bypass graft(s) of the left leg with ulceration of unspecified site
• I70.65 Atherosclerosis of nonbiological bypass graft(s) of other extremity with ulceration