What is ICD-10 code I70.342?

I70.342 is the ICD-10-CM diagnosis code for Atherosclerosis of unspecified type of bypass graft(s) of the left leg with ulceration of calf. Hardening of arteries in a bypass graft on the left leg with an open sore on the calf. I70.342 is a billable code, meaning it can be reported on a claim as a primary or secondary diagnosis when supported by documentation. I70.342 is part of the FY2026 ICD-10-CM code set published by the CMS National Center for Health Statistics and used on Medicare, Medicaid, and commercial claims in the United States.

Yes. I70.342 is a billable ICD-10-CM code that can be reported on professional and institutional claims as a primary or secondary diagnosis when the provider documentation supports the specific condition described. Billable codes in ICD-10-CM are coded to the highest level of specificity available for the documented diagnosis. I70.342 is current for fiscal year 2026 and remains in the active CMS ICD-10-CM code set published by the National Center for Health Statistics.

What is the V28 vs V24 difference for I70.342?

I70.342 does not map to a payment HCC under either the CMS-HCC V28 risk adjustment model or the older V24 model. V28 reached 100% phase-in for payment year 2026, replacing V24 which was used during the PY2024–PY2025 transition. Because neither model rewards I70.342 with a risk adjustment factor, it contributes zero to a Medicare Advantage beneficiary's RAF score in either version. Coders should check whether provider documentation supports a more specific child code that does map to a payment HCC.

What should coders know when reporting I70.342?

Document the specific location as calf to differentiate from other lower leg ulcerations. Review medical record to confirm the ulcer is related to the atherosclerotic bypass graft disease.

I70.342 ICD-10 Code: Atherosclerosis

ICD-10-CM Code View

HCC Buddy Code Card

Digital ICD-10 code-book layout with official code detail, always-visible risk models, Code Trumping, and Buddy coding guidance.

Code lookupI70.342Effective periodFY2026 Apr Update (Apr 1-Sep 30)

FY 2026 Apr update / Diseases of the circulatory system (I00-I99) / Diseases of arteries, arterioles and capillaries (I70-I79)

I70.342

Billable / SpecificICD-10-CMOfficial ICD-10-CMCodebook guidance

Atherosclerosis of unspecified type of bypass graft(s) of the left leg with ulceration of calf

Hardening of arteries in a bypass graft on the left leg with an open sore on the calf.

Buddy Insight

This code identifies atherosclerosis in unspecified type bypass grafts with ulceration of calf, indicating significant peripheral arterial insufficiency causing tissue breakdown.

CMS-HCC V28

Not risk-adjusted for this model/period.

RAF 0

CMS-HCC V24

Not risk-adjusted for this model/period.

RAF 0

ACA/HHS

Not risk-adjusted for this model/period.

RAF 0

ESRD/PACE

Not risk-adjusted for this model/period.

RAF 0

RXHCC

Mapped

HCC 311

Diabetic and Chronic Skin Ulcer

RAF 0.0

Code Trumping

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Compare selected patient codes to show trumped or trumps impact.

Code Book Path

Official

I70.3Atherosclerosis of unspecified type of bypass graft(s) of the extremities

I70.34Atherosclerosis of unspecified type of bypass graft(s) of the left leg with ulceration

I70.342Atherosclerosis of unspecified type of bypass graft(s) of the left leg with ulceration of calf

Inclusion Terms

Official

ICD-10-CM does not list inclusion terms for I70.342 in this effective period.

Excludes 2

Official

ICD-10-CM does not list Excludes 2 notes for I70.342 in this effective period.

Related Child Codes

Official

I70.341Atherosclerosis of unspecified type of bypass graft(s) of the left leg with ulceration of thigh

I70.343Atherosclerosis of unspecified type of bypass graft(s) of the left leg with ulceration of ankle

I70.344Atherosclerosis of unspecified type of bypass graft(s) of the left leg with ulceration of heel and midfoot

I70.345Atherosclerosis of unspecified type of bypass graft(s) of the left leg with ulceration of other part of foot

I70.348Atherosclerosis of unspecified type of bypass graft(s) of the left leg with ulceration of other part of lower leg

Includes

Official

any condition classifiable to I70.312 and I70.322
chronic limb-threatening ischemia of unspecified type of bypass graft(s) of the left leg with ulceration
critical limb ischemia of unspecified type of bypass graft(s) of the left leg with ulceration

Excludes 1

Official

ICD-10-CM does not list Excludes 1 notes for I70.342 in this effective period.

Code First

Official

ICD-10-CM does not list Code First sequencing instructions for I70.342 in this effective period.

Use Additional

Official

code to identify severity of ulcer (L97.-)

Code Also

Official

ICD-10-CM does not list Code Also instructions for I70.342 in this effective period.

Buddy Documentation Tip

HCC Buddy guidance

Documentation of peripheral arterial disease or atherosclerosis affecting the bypass graft

Identification of graft type as unspecified type (if autologous vein is confirmed, document the vein source; if type is unknown, document it as unspecified)

Laterality clearly stated as left leg

Ulcer site specifically documented (in this case, calf)

MEAT Support

HCC Buddy guidance

Documentation of peripheral arterial disease or atherosclerosis affecting the bypass graft

Identification of graft type as unspecified type (if autologous vein is confirmed, document the vein source; if type is unknown, document it as unspecified)

Laterality clearly stated as left leg

Ulcer site specifically documented (in this case, calf)

Audit Caution

HCC Buddy guidance

Failing to verify the bypass graft type from operative reports — defaulting to unspecified when the specific type is documented elsewhere in the record

Selecting the wrong laterality — always confirm left leg matches the documentation; bilateral disease requires separate codes for each side

Not coding the ulcer site to the highest specificity available — the 6th and 7th characters specify exact anatomical location of the ulcer

Forgetting to assign an additional code from L97 or L98 to identify the severity of the ulcer when applicable

Common Mistakes

HCC Buddy guidance

I70.4xx (autologous vein bypass graft codes) — Use when the graft is specifically documented as the patient's own vein (saphenous vein, cephalic vein)

I70.5xx (nonautologous biological bypass graft codes) — Use when the graft is documented as biological material from a donor source

I70.6xx (nonbiological bypass graft codes) — Use when the graft is documented as synthetic material such as polytetrafluoroethylene or Dacron

I70.2xx (native artery atherosclerosis codes) — Use for atherosclerosis of native arteries, not bypass grafts; verify whether disease is in the graft or native vessel

Last updated: FY2026 ICD-10-CM Apr update, Apr 1, 2026 through Sep 30, 2026. CMS-HCC V28 is 100% phased in for payment year 2026.

Is I70.342 an HCC code?

No. I70.342 is a billable ICD-10-CM code but does not map to any HCC category in V28, V24, ESRD, or RxHCC.

HCC Category Mapping

RxHCCHCC 311, Diabetic and Chronic Skin Ulcer

0.000

RAF weights shown are the community, non-dual, aged base weights from the CMS risk adjustment model file. Actual per-patient RAF contribution depends on member segment, interactions, and the model year used by the payer. V28 is the CMS-HCC model phased in over payment years 2024–2026; V24 remains in use during the transition and for historical data.

MEAT Criteria for I70.342

For I70.342to count as a valid HCC diagnosis in a given encounter, the provider's documentation must show MEAT: Monitor, Evaluate, Assess, or Treat. A diagnosis from a prior year does not carry forward automatically, it has to be re-documented and supported each calendar year.

MMonitor: signs, symptoms, disease progression, or lab trending documented in the note
EEvaluate: test results, medication response, or physical findings reviewed by the provider
AAssess: explicit mention in the assessment or plan with acknowledgment of status
TTreat: medication, referral, procedure, therapy, or counseling tied to the diagnosis

Only one of M/E/A/T is required to support the code, but the documentation must be specific enough to show that the provider actually addressed I70.342 during that encounter, not just copy-forwarded from a problem list.

What This Code Means

I70.342 is the ICD-10-CM diagnosis code for atherosclerosis of unspecified type of bypass graft(s) of the left leg with ulceration of calf. Hardening of arteries in a bypass graft on the left leg with an open sore on the calf. I70.342 sits in the ICD-10-CM chapter for diseases of the circulatory system (i00-i99), within the section covering diseases of arteries, arterioles and capillaries (i70-i79).

I70.342 is a billable ICD-10-CM code but does not map to a payment HCC under the CMS-HCC V28, V24, ESRD, or RxHCC risk adjustment models. It can be reported on Medicare Advantage encounter data submissions but it does not contribute to a beneficiary's RAF score and therefore does not affect risk-adjusted payments to the plan.

This code does not map to an HCC in the CMS-HCC V28 model. It does not map to an HCC in the CMS-HCC V24 model. In the RxHCC model, it maps to RxHCC 311 (Diabetic Foot Ulcer) with a RAF weight of 0.0. This code only maps in the RxHCC model (used for Medicare Part D payment) and does not affect the CMS-HCC RAF score for Parts A and B. However, capturing it is still relevant for pharmacy risk adjustment and complete clinical documentation.

HCC Buddy maintains structured V28 and V24 mapping, RAF weights, and MEAT documentation criteria for I70.342 sourced directly from the CMS-HCC risk adjustment model files and the CMS ICD-10-CM code set.

Coding Tips

•Document the specific location as calf to differentiate from other lower leg ulcerations.
•Review medical record to confirm the ulcer is related to the atherosclerotic bypass graft disease.

Clinical Significance

This code identifies atherosclerosis in unspecified type bypass grafts with ulceration of calf, indicating significant peripheral arterial insufficiency causing tissue breakdown. Ulceration complicating bypass graft atherosclerosis signals graft stenosis or failure with inadequate distal perfusion, requiring wound care management and potential revascularization. Accurate capture matters for risk adjustment as it reflects the progression from stable peripheral arterial disease to limb-threatening ischemia.

Documentation Requirements

✓Documentation of peripheral arterial disease or atherosclerosis affecting the bypass graft
✓Identification of graft type as unspecified type (if autologous vein is confirmed, document the vein source; if type is unknown, document it as unspecified)
✓Laterality clearly stated as left leg
✓Ulcer site specifically documented (in this case, calf)
✓Ulcer severity, size, and depth documented (consider Wound, Ischemia, and foot Infection classification or similar staging)
✓Causal link between atherosclerotic graft disease and the ulceration must be established in the documentation
✓Current wound care plan and treatment documented
✓History of bypass graft surgery with date and indication when available

Commonly Confused Codes

•I70.4xx (autologous vein bypass graft codes): Use when the graft is specifically documented as the patient's own vein (saphenous vein, cephalic vein)
•I70.5xx (nonautologous biological bypass graft codes): Use when the graft is documented as biological material from a donor source
•I70.6xx (nonbiological bypass graft codes): Use when the graft is documented as synthetic material such as polytetrafluoroethylene or Dacron
•I70.2xx (native artery atherosclerosis codes): Use for atherosclerosis of native arteries, not bypass grafts; verify whether disease is in the graft or native vessel
•L97.xxx (non-pressure chronic ulcer of lower limb): Use L97 as an additional code for ulcer severity/laterality, but the primary etiology code should be the I70 code when atherosclerosis is the underlying cause