What is ICD-10 code I70.361?

I70.361 is the ICD-10-CM diagnosis code for Atherosclerosis of unspecified type of bypass graft(s) of the extremities with gangrene, right leg. Hardening of arteries in a bypass graft on the right leg with tissue death (gangrene) due to severe lack of blood flow. I70.361 is a billable code, meaning it can be reported on a claim as a primary or secondary diagnosis when supported by documentation. I70.361 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. I70.361 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. I70.361 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 I70.361?

CMS phased in the V28 risk adjustment model over payment years 2024 (33%), 2025 (67%), and 2026 (100%), replacing V24. V28 consolidates HCC categories, removes some lower-acuity conditions, and recalibrates RAF weights across the entire model. For I70.361, V28 maps to Atherosclerosis of the Extremities with Ulceration or Gangrene at RAF 0.742 while V24 mapped to Atherosclerosis of the Extremities with Ulceration or Gangrene at RAF 0.860. Both models can still appear in legacy data and in payer-specific lookback periods.

What should coders know when reporting I70.361?

Gangrene is a serious complication indicating tissue necrosis; ensure documentation supports this diagnosis. Verify the gangrene is specifically on the right leg and related to the bypass graft atherosclerosis. Because I70.361 maps to a payment HCC, the documentation must also satisfy MEAT criteria (Monitor, Evaluate, Assess, or Treat) for the encounter to count toward the patient's risk adjustment score.

I70.361 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 lookupI70.361Effective 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)

I70.361

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

Atherosclerosis of unspecified type of bypass graft(s) of the extremities with gangrene, right leg

Hardening of arteries in a bypass graft on the right leg with tissue death (gangrene) due to severe lack of blood flow.

Buddy Insight

This code captures atherosclerotic disease in unspecified type bypass grafts complicated by gangrene, representing the most severe manifestation of peripheral arterial disease with tissue death.

CMS-HCC V28

Mapped

HCC 263

Atherosclerosis of the Extrem...

RAF 0.742

CMS-HCC V24

Mapped

HCC 106

Atherosclerosis of the Extrem...

RAF 0.860

ACA/HHS

Not risk-adjusted for this model/period.

RAF 0

ESRD/PACE

Mapped

HCC 106

Atherosclerosis of the Extrem...

RAF 0.0

RXHCC

Not risk-adjusted for this model/period.

RAF 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

I70.36Atherosclerosis of unspecified type of bypass graft(s) of the extremities with gangrene

I70.361Atherosclerosis of unspecified type of bypass graft(s) of the extremities with gangrene, right leg

Inclusion Terms

Official

ICD-10-CM does not list inclusion terms for I70.361 in this effective period.

Excludes 2

Official

ICD-10-CM does not list Excludes 2 notes for I70.361 in this effective period.

Related Child Codes

Official

I70.362Atherosclerosis of unspecified type of bypass graft(s) of the extremities with gangrene, left leg

I70.363Atherosclerosis of unspecified type of bypass graft(s) of the extremities with gangrene, bilateral legs

I70.368Atherosclerosis of unspecified type of bypass graft(s) of the extremities with gangrene, other extremity

I70.369Atherosclerosis of unspecified type of bypass graft(s) of the extremities with gangrene, unspecified extremity

Includes

Official

any condition classifiable to I70.31-, I70.32-, I70.33-, I70.34-, I70.35
chronic limb-threatening ischemia of unspecified type of bypass graft(s) of the extremities with gangrene
critical limb ischemia of unspecified type of bypass graft(s) of the extremities with gangrene

Excludes 1

Official

ICD-10-CM does not list Excludes 1 notes for I70.361 in this effective period.

Code First

Official

ICD-10-CM does not list Code First sequencing instructions for I70.361 in this effective period.

Use Additional

Official

code to identify the severity of any ulcer (L97.-, L98.49-), if applicable

Code Also

Official

ICD-10-CM does not list Code Also instructions for I70.361 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 right leg

Gangrene explicitly documented with location and extent

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 right leg

Gangrene explicitly documented with location and extent

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 right leg matches the documentation; bilateral disease requires separate codes for each side

Undercoding gangrene as ulceration — when tissue death (necrosis) is documented, gangrene codes should be used, not ulceration codes

Failing to assign additional code(s) for any associated ulceration of the same extremity, as ulceration often coexists with gangrene

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 I70.361 an HCC code?

Yes. I70.361 maps to Atherosclerosis of the Extremities with Ulceration or Gangrene under the CMS-HCC V28 risk adjustment model (and Atherosclerosis of the Extremities with Ulceration or Gangrene under V24).

HCC Category Mapping

V28HCC 263, Atherosclerosis of the Extremities with Ulceration or Gangrene

0.742

V24HCC 106, Atherosclerosis of the Extremities with Ulceration or Gangrene

0.860

ESRDHCC 106, Atherosclerosis of the Extremities with Ulceration or Gangrene

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 I70.361

For I70.361to 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 I70.361 during that encounter, not just copy-forwarded from a problem list.

What This Code Means

I70.361 is the ICD-10-CM diagnosis code for atherosclerosis of unspecified type of bypass graft(s) of the extremities with gangrene, right leg. Hardening of arteries in a bypass graft on the right leg with tissue death (gangrene) due to severe lack of blood flow. I70.361 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).

Under the CMS-HCC V28 risk adjustment model, I70.361 maps to Atherosclerosis of the Extremities with Ulceration or Gangrene (HCC 263) with a community, non-dual, aged base RAF weight of 0.742. Under the older V24 model, I70.361 mapped to the same category but with a base RAF weight of 0.860, V28 recalibrated weights across the entire model. V28 is the CMS-HCC risk adjustment model that reached 100% phase-in for payment year 2026, replacing V24 which was used during the PY2024–PY2025 transition.

Gangrene is a serious complication indicating tissue necrosis; ensure documentation supports this diagnosis. Because I70.361 maps to a payment HCC, the provider's documentation must satisfy MEAT criteria (Monitor, Evaluate, Assess, or Treat) for the encounter to count toward the patient's Medicare Advantage risk adjustment score. When documentation is ambiguous, coders should issue a provider query rather than assume the highest-specificity variant.

HCC Buddy maintains structured V28 and V24 mapping, RAF weights, and MEAT documentation criteria for I70.361 sourced directly from the CMS-HCC risk adjustment model files and the CMS ICD-10-CM code set.

Coding Tips

•Gangrene is a serious complication indicating tissue necrosis; ensure documentation supports this diagnosis.
•Verify the gangrene is specifically on the right leg and related to the bypass graft atherosclerosis.

Clinical Significance

This code captures atherosclerotic disease in unspecified type bypass grafts complicated by gangrene, representing the most severe manifestation of peripheral arterial disease with tissue death. Gangrene in bypass grafts indicates graft failure or progression of disease beyond the graft, carrying high risk for limb amputation and systemic sepsis. This diagnosis demands urgent vascular intervention and reflects extremely high disease burden for risk adjustment purposes.

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 right leg
✓Gangrene explicitly documented with location and extent
✓Type of gangrene specified (dry, wet, or gas gangrene) when possible
✓Causal relationship between graft atherosclerosis and gangrene established
✓Current treatment plan including any planned amputation or revascularization
✓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
•I70.26x/I70.36x (same graft type without gangrene, with ulceration only): Gangrene codes are more specific and carry higher risk adjustment weight; do not downcode to ulceration when gangrene is documented
•R02 (gangrene, not elsewhere classified): Use the I70 combination code rather than a separate gangrene code when atherosclerosis is the underlying etiology