What is ICD-10 code I77.5?

I77.5 is the ICD-10-CM diagnosis code for Necrosis of artery. It belongs to the ICD-10-CM chapter for diseases of the circulatory system (i00-i99). I77.5 is a billable code, meaning it can be reported on a claim as a primary or secondary diagnosis when supported by documentation. I77.5 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. I77.5 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. I77.5 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.

Which HCC does I77.5 map to under V28?

I77.5 does not map to a CMS-HCC V28 payment category. Check the current CMS-HCC V28 model file for payment year 2026 rather than an older V24 tip sheet.

What does I77.5 pay in RAF?

I77.5 has no separately stated V28 community RAF weight. If it is not a V28 payment HCC, it adds nothing to a community RAF score.

What is the V28 vs V24 difference for I77.5?

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. I77.5 was a payment HCC under V24 (Vascular Disease) but the V28 recalibration removed it from the risk adjustment model. Both models can still appear in legacy data and in payer-specific lookback periods.

What documentation supports I77.5?

Specify the location of the arterial necrosis when possible, as there are combination codes available for different anatomical sites (e.g., I77.5 with additional characters for specific arteries) Investigate the underlying cause of the necrosis, such as atherosclerosis, trauma, or vasculitis, and code those conditions separately as they may be the primary diagnosis Because I77.5 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. See the MEAT criteria checklist at /meat-criteria for what Monitor, Evaluate, Assess, or Treat looks like in a note. MEAT is generic documentation evidence, not a payer-specific rule.

2026 ICD-10-CM I77.5: Necrosis of artery

I77.5 is not a CMS-HCC payment code. MEAT criteria · RAF calculator · HCC Buddy coding tools

ICD-10-CM Code View

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Code lookupI77.5Effective 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)

I77.5

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

Necrosis of artery

This code describes the death or breakdown of tissue in an artery, which occurs when blood flow to that artery is severely compromised. This is a serious condition that can lead to loss of function in the affected area.

Buddy Insight

Necrosis of artery indicates death of arterial tissue, representing a severe vascular complication that can lead to hemorrhage, organ damage, or limb loss.

CMS-HCC V28

N/A

—

Not risk-adjusted for this model/period.

Not mapped

CMS-HCC V24

Mapped

HCC 108

Vascular Disease

RAF 0.288

ACA/HHS

N/A

—

Not risk-adjusted for this model/period.

Not mapped

ESRD/PACE

Mapped

HCC 108

Vascular Disease

RAF 0.073

RXHCC

N/A

—

Not risk-adjusted for this model/period.

Not mapped

Code Book Path

Official

I77Other disorders of arteries and arterioles

I77.5Necrosis of artery

Inclusion Terms

Official

ICD-10-CM does not list inclusion terms for I77.5 in this effective period.

Excludes 2

Official

collagen (vascular) diseases (M30-M36)
hypersensitivity angiitis (M31.0)
pulmonary artery (I28.-)

Related Child Codes

Official

I77.0Arteriovenous fistula, acquired

I77.1Stricture of artery

I77.2Rupture of artery

I77.3Arterial fibromuscular dysplasia

I77.4Celiac artery compression syndrome

Includes

Official

ICD-10-CM does not list Includes notes for I77.5 in this effective period.

Excludes 1

Official

ICD-10-CM does not list Excludes 1 notes for I77.5 in this effective period.

Code First

Official

ICD-10-CM does not list Code First sequencing instructions for I77.5 in this effective period.

Use Additional

Official

ICD-10-CM does not list Use Additional Code instructions for I77.5 in this effective period.

Code Also

Official

ICD-10-CM does not list Code Also instructions for I77.5 in this effective period.

Buddy Documentation Tip

HCC Buddy guidance

Specific identification of the affected artery

Documentation of necrotic findings (imaging, surgical, or pathological confirmation)

Underlying etiology such as vasculitis, infection, trauma, or radiation

Current treatment plan including surgical intervention, anticoagulation, or vascular monitoring

MEAT Support

HCC Buddy guidance

Specific identification of the affected artery

Documentation of necrotic findings (imaging, surgical, or pathological confirmation)

Underlying etiology such as vasculitis, infection, trauma, or radiation

Current treatment plan including surgical intervention, anticoagulation, or vascular monitoring

Audit Caution

HCC Buddy guidance

Failing to differentiate arterial necrosis from tissue necrosis caused by arterial insufficiency

Using this code when the necrosis is of surrounding tissue rather than the artery itself

Not querying the provider for the underlying cause of the arterial necrosis

Confusing with gangrene codes which refer to tissue death downstream of vascular compromise

Common Mistakes

HCC Buddy guidance

I77.6 — Arteritis, unspecified: inflammatory condition of artery wall without necrosis

I77.4 — Celiac artery compression syndrome: compression rather than tissue death

I70.x — Atherosclerosis codes: chronic plaque buildup, not acute necrosis

I74.x — Arterial embolism and thrombosis: occlusion without necessarily necrosis of the vessel wall

Current with CMS: FY2026 ICD-10-CM Apr 1 update (effective Apr 1 – Sep 30, 2026) · CMS-HCC V28, 100% phased in for payment year 2026. FY2027 code set already staged for October 1, 2026. How HCC Buddy stays current →

Is I77.5 an HCC code?

Yes. I77.5 maps to Vascular Disease under the V24 model but is not retained in V28.

Code: I77.5
Description: Necrosis of artery
HCC (V28): No CMS-HCC V28 mapping
RAF: —
Billable: Yes
Payment year: 2026

HCC Category Mapping

V24HCC 108, Vascular Disease

0.288

ESRDHCC 108, Vascular Disease

0.073

Each model's RAF is its CMS base weight for that model's standard population, so weights are not directly comparable across models: CMS-HCC V28 and V24 use Community, Non-Dual, Aged; ESRD uses the dialysis continuing-enrollee model; RxHCC is the Part D continuing-enrollee, non-low-income, aged weight (a larger scale than CMS-HCC). ACA/HHS has no single weight — it varies by metal level. 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.

Work I77.5 in the Code Book — tabular path, V28 RAF, and MEAT checklist →

MEAT Criteria for I77.5

For I77.5 to 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 I77.5 during that encounter, not just copy-forwarded from a problem list.

Coder workflow notes

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What This Code Means

I77.5 is the ICD-10-CM diagnosis code for necrosis of artery. This code describes the death or breakdown of tissue in an artery, which occurs when blood flow to that artery is severely compromised. This is a serious condition that can lead to loss of function in the affected area. I77.5 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 older CMS-HCC V24 model, I77.5 maps to Vascular Disease (HCC 108) with a community, non-dual, aged base RAF weight of 0.288. 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.

Specify the location of the arterial necrosis when possible, as there are combination codes available for different anatomical sites (e.g., I77.5 with additional characters for specific arteries). Because I77.5 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 I77.5 sourced directly from the CMS-HCC risk adjustment model files and the CMS ICD-10-CM code set.

Coding Tips

•Specify the location of the arterial necrosis when possible, as there are combination codes available for different anatomical sites (e.g., I77.5 with additional characters for specific arteries)
•Investigate the underlying cause of the necrosis, such as atherosclerosis, trauma, or vasculitis, and code those conditions separately as they may be the primary diagnosis

Clinical Significance

Necrosis of artery indicates death of arterial tissue, representing a severe vascular complication that can lead to hemorrhage, organ damage, or limb loss. This diagnosis reflects significant vascular disease burden and typically requires urgent or emergent intervention. It signals high resource utilization and ongoing monitoring needs for risk adjustment purposes.

Documentation Requirements

✓Specific identification of the affected artery
✓Documentation of necrotic findings (imaging, surgical, or pathological confirmation)
✓Underlying etiology such as vasculitis, infection, trauma, or radiation
✓Current treatment plan including surgical intervention, anticoagulation, or vascular monitoring
✓Impact on end-organ perfusion and any related complications

Commonly Confused Codes

•I77.6: Arteritis, unspecified: inflammatory condition of artery wall without necrosis
•I77.4: Celiac artery compression syndrome: compression rather than tissue death
•I70.x: Atherosclerosis codes: chronic plaque buildup, not acute necrosis
•I74.x: Arterial embolism and thrombosis: occlusion without necessarily necrosis of the vessel wall