I70.391 ICD-10-CM Code: Other atherosclerosis of unspecified type of bypass graft(s) of the extremities, right leg
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FY 2026 Apr update / Diseases of the circulatory system (I00-I99) / Diseases of arteries, arterioles and capillaries (I70-I79)
I70.391
Billable / SpecificICD-10-CMOfficial ICD-10-CMCodebook guidanceOther atherosclerosis of unspecified type of bypass graft(s) of the extremities, right leg
Hardening of arteries in a bypass graft of the right leg without gangrene, causing reduced blood flow and other complications.
Buddy Insight
This code captures other specified manifestations of atherosclerosis in unspecified type bypass grafts not classified as claudication, rest pain, ulceration, or gangrene.
CMS-HCC V28
00
RAF 0
CMS-HCC V24
MappedHCC 108
RAF 0.297
ACA/HHS
00
RAF 0
ESRD/PACE
MappedHCC 108
RAF 0.0
RXHCC
00
RAF 0
Code Trumping
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Code Book Path
Inclusion Terms
OfficialICD-10-CM does not list inclusion terms for I70.391 in this effective period.
Excludes 2
OfficialICD-10-CM does not list Excludes 2 notes for I70.391 in this effective period.
Related Child Codes
Includes
OfficialICD-10-CM does not list Includes notes for I70.391 in this effective period.
Excludes 1
OfficialICD-10-CM does not list Excludes 1 notes for I70.391 in this effective period.
Code First
OfficialICD-10-CM does not list Code First sequencing instructions for I70.391 in this effective period.
Use Additional
OfficialICD-10-CM does not list Use Additional Code instructions for I70.391 in this effective period.
Code Also
OfficialICD-10-CM does not list Code Also instructions for I70.391 in this effective period.
Buddy Documentation Tip
MEAT Support
Audit Caution
Common Mistakes
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 I70.391 an HCC code?
Yes. I70.391 maps to Vascular Disease under the V24 model but is not retained in V28.
HCC Category Mapping
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 I70.391
For I70.391to 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 I70.391 during that encounter, not just copy-forwarded from a problem list.
What This Code Means
I70.391 is the ICD-10-CM diagnosis code for other atherosclerosis of unspecified type of bypass graft(s) of the extremities, right leg. Hardening of arteries in a bypass graft of the right leg without gangrene, causing reduced blood flow and other complications. I70.391 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, I70.391 maps to Vascular Disease (HCC 108) with a community, non-dual, aged base RAF weight of 0.297. 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 code is for atherosclerosis without gangrene; if gangrene is present, use I70.36x codes instead. Because I70.391 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 I70.391 sourced directly from the CMS-HCC risk adjustment model files and the CMS ICD-10-CM code set.
Coding Tips
- •This code is for atherosclerosis without gangrene; if gangrene is present, use I70.36x codes instead
- •Document any symptoms such as claudication, pain, or tissue damage to support medical necessity
Clinical Significance
This code captures other specified manifestations of atherosclerosis in unspecified type bypass grafts not classified as claudication, rest pain, ulceration, or gangrene. These may include conditions such as atheroembolism from the graft, aneurysmal degeneration of the graft, or other documented vascular complications. Accurate coding of these specified manifestations ensures complete clinical picture capture for risk adjustment and care management.
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
- ✓Specific manifestation of atherosclerosis clearly described
- ✓Vascular studies or imaging documenting graft status
- ✓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