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I73.1 ICD-10-CM Code: Thromboangiitis obliterans [Buerger's disease]

ICD-10-CM Code View

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

I73.1

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

Thromboangiitis obliterans [Buerger's disease]

Buerger's disease is a rare inflammatory condition that causes blood clots in small and medium-sized arteries and veins, typically affecting the legs and feet of young smokers.

Buddy the Bee presenting code insight

Buddy Insight

Thromboangiitis obliterans (Buerger's disease) is an inflammatory vasculitis affecting small and medium arteries and veins, almost exclusively in young smokers.

CMS-HCC V28

N/A

—

Not mapped

CMS-HCC V24

HCC 108

RAF 0.288

ACA/HHS

N/A

—

Not mapped

ESRD/PACE

HCC 108

RAF 0.073

RXHCC

N/A

—

Not mapped

Code Book Path

Official
I73Other peripheral vascular diseases
I73.1Thromboangiitis obliterans [Buerger's disease]

Inclusion Terms

Official

ICD-10-CM does not list inclusion terms for I73.1 in this effective period.

Excludes 2

Official
  • chilblains (T69.1)
  • frostbite (T33-T34)
  • immersion hand or foot (T69.0-)
  • spasm of cerebral artery (G45.9)

Related Child Codes

Official
I73.0Raynaud's syndrome
I73.8Other specified peripheral vascular diseases
I73.9Peripheral vascular disease, unspecified

Includes

Official

ICD-10-CM does not list Includes notes for I73.1 in this effective period.

Excludes 1

Official

ICD-10-CM does not list Excludes 1 notes for I73.1 in this effective period.

Code First

Official

ICD-10-CM does not list Code First sequencing instructions for I73.1 in this effective period.

Use Additional

Official

ICD-10-CM does not list Use Additional Code instructions for I73.1 in this effective period.

Code Also

Official

ICD-10-CM does not list Code Also instructions for I73.1 in this effective period.

Buddy Documentation Tip

HCC Buddy guidance
Documentation of thromboangiitis obliterans or Buerger's disease diagnosis
Clinical findings: claudication, rest pain, digital ulceration, or gangrene
Smoking history documentation (strongly associated)
Angiographic or other imaging findings showing segmental occlusion

MEAT Support

HCC Buddy guidance
Documentation of thromboangiitis obliterans or Buerger's disease diagnosis
Clinical findings: claudication, rest pain, digital ulceration, or gangrene
Smoking history documentation (strongly associated)
Angiographic or other imaging findings showing segmental occlusion

Audit Caution

HCC Buddy guidance
Coding as peripheral arterial disease/atherosclerosis when documentation specifically states Buerger's disease
Not recognizing that Buerger's disease can affect upper and lower extremities — it is not limited to lower extremities
Failing to separately code gangrenous complications when present in addition to the underlying disease
Using unspecified peripheral vascular disease code when the provider has documented the specific diagnosis

Common Mistakes

HCC Buddy guidance
I73.9 — Peripheral vascular disease, unspecified: less specific and does not capture the inflammatory nature
I70.2xx — Atherosclerosis of native arteries of extremities: different pathophysiology — atherosclerotic vs inflammatory
I73.01 — Raynaud's syndrome with gangrene: vasospastic rather than inflammatory thrombotic
M31.x — Other necrotizing vasculopathies: systemic vasculitis conditions have different codes

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 I73.1 an HCC code?

Yes. I73.1 maps to Vascular Disease under the V24 model but is not retained in V28.

Code
I73.1
Description
Thromboangiitis obliterans [Buerger's disease]
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 I73.1 in the Code Book — tabular path, V28 RAF, and MEAT checklist →

MEAT Criteria for I73.1

For I73.1 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 I73.1 during that encounter, not just copy-forwarded from a problem list.

Coder workflow notes

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What This Code Means

I73.1 is the ICD-10-CM diagnosis code for thromboangiitis obliterans [buerger's disease]. Buerger's disease is a rare inflammatory condition that causes blood clots in small and medium-sized arteries and veins, typically affecting the legs and feet of young smokers. I73.1 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, I73.1 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.

This condition is strongly associated with tobacco use; document smoking status in the medical record. Because I73.1 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 I73.1 sourced directly from the CMS-HCC risk adjustment model files and the CMS ICD-10-CM code set.

Coding Tips

  • •This condition is strongly associated with tobacco use; document smoking status in the medical record
  • •Often requires additional codes for complications such as gangrene or ulceration of affected extremities

Clinical Significance

Thromboangiitis obliterans (Buerger's disease) is an inflammatory vasculitis affecting small and medium arteries and veins, almost exclusively in young smokers. It causes segmental thrombotic occlusion leading to digital ischemia, claudication, and potentially gangrene. This relatively rare condition requires accurate coding to reflect the ongoing vascular disease burden and ensure appropriate risk adjustment.

Documentation Requirements

  • ✓Documentation of thromboangiitis obliterans or Buerger's disease diagnosis
  • ✓Clinical findings: claudication, rest pain, digital ulceration, or gangrene
  • ✓Smoking history documentation (strongly associated)
  • ✓Angiographic or other imaging findings showing segmental occlusion
  • ✓Exclusion of other vascular etiologies (atherosclerosis, autoimmune vasculitis)
  • ✓Treatment plan including smoking cessation, vasodilators, wound care

Commonly Confused Codes

  • •I73.9: Peripheral vascular disease, unspecified: less specific and does not capture the inflammatory nature
  • •I70.2xx: Atherosclerosis of native arteries of extremities: different pathophysiology: atherosclerotic vs inflammatory
  • •I73.01: Raynaud's syndrome with gangrene: vasospastic rather than inflammatory thrombotic
  • •M31.x: Other necrotizing vasculopathies: systemic vasculitis conditions have different codes

Child Codes

I73.0Raynaud's syndrome
I73.1Thromboangiitis obliterans [Buerger's disease]
I73.8Other specified peripheral vascular diseases
I73.9Peripheral vascular disease, unspecified

Code Hierarchy

└I73Other peripheral vascular diseases└I73.1Thromboangiitis obliterans [Buerger's disease]
└I73.1Thromboangiitis obliterans [Buerger's disease]

Because I73.1 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.

More on I73.1

Related condition guides

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