I70.491 ICD-10-CM Code: Other atherosclerosis of autologous vein bypass graft(s) of the extremities, right leg
HCC Buddy Code Card
Digital ICD-10 code-book layout with official code detail, always-visible risk models, Code Trumping, and Buddy coding guidance.
FY 2026 Apr update / Diseases of the circulatory system (I00-I99) / Diseases of arteries, arterioles and capillaries (I70-I79)
I70.491
Billable / SpecificICD-10-CMOfficial ICD-10-CMCodebook guidanceOther atherosclerosis of autologous vein bypass graft(s) of the extremities, right leg
This code describes a buildup of plaque in a vein that was surgically transplanted from the patient's own body to bypass a blocked artery in the right leg. This narrowing can reduce blood flow and cause pain or other circulation problems in the leg.
Buddy Insight
This code captures other specified manifestations of atherosclerosis in a autologous vein bypass graft, covering presentations that do not fit the specific categories of 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
Basket needed
Code Book Path
Inclusion Terms
OfficialICD-10-CM does not list inclusion terms for I70.491 in this effective period.
Excludes 2
OfficialICD-10-CM does not list Excludes 2 notes for I70.491 in this effective period.
Related Child Codes
Includes
OfficialICD-10-CM does not list Includes notes for I70.491 in this effective period.
Excludes 1
OfficialICD-10-CM does not list Excludes 1 notes for I70.491 in this effective period.
Code First
OfficialICD-10-CM does not list Code First sequencing instructions for I70.491 in this effective period.
Use Additional
OfficialICD-10-CM does not list Use Additional Code instructions for I70.491 in this effective period.
Code Also
OfficialICD-10-CM does not list Code Also instructions for I70.491 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 I70.491 an HCC code?
Yes. I70.491 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 I70.491
For I70.491to 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 I70.491 during that encounter, not just copy-forwarded from a problem list.
What This Code Means
I70.491 is the ICD-10-CM diagnosis code for other atherosclerosis of autologous vein bypass graft(s) of the extremities, right leg. This code describes a buildup of plaque in a vein that was surgically transplanted from the patient's own body to bypass a blocked artery in the right leg. This narrowing can reduce blood flow and cause pain or other circulation problems in the leg. I70.491 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, I70.491 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.
Verify documentation specifies the graft is autologous (from patient's own vein) and located in the right leg to ensure accurate laterality coding. Because I70.491 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 I70.491 sourced directly from the CMS-HCC risk adjustment model files and the CMS ICD-10-CM code set.
Coding Tips
- •Verify documentation specifies the graft is autologous (from patient's own vein) and located in the right leg to ensure accurate laterality coding
- •Confirm the atherosclerosis is documented as affecting the bypass graft itself, not the native vessel, and check for any associated symptoms or complications that may require additional codes
Clinical Significance
This code captures other specified manifestations of atherosclerosis in a autologous vein bypass graft, covering presentations that do not fit the specific categories of claudication, rest pain, ulceration, or gangrene. These may include conditions such as atheroembolism from the graft, aneurysmal degeneration, or other vascular complications requiring clinical attention. Proper code selection ensures that the full spectrum of peripheral arterial disease severity is captured for risk adjustment.
Documentation Requirements
- ✓Documentation of the type of bypass graft as autologous vein (must distinguish from autologous vein, nonautologous biological, or synthetic/nonbiological grafts)
- ✓Clinical evidence of atherosclerosis affecting the bypass graft (imaging, angiography, or clinical assessment)
- ✓Specific description of the atherosclerotic manifestation that does not fit claudication, rest pain, ulceration, or gangrene categories
- ✓Vascular assessment supporting the diagnosis
- ✓Clear documentation of laterality specifying the right leg
Commonly Confused Codes
- •I70.5xx: Nonautologous biological bypass graft codes; use when the graft is from a donor or animal tissue, not the patient's own vein
- •I70.6xx: Nonbiological bypass graft codes; use when a synthetic graft material (such as Dacron or polytetrafluoroethylene) is used rather than a vein
- •I70.2xx: Native artery atherosclerosis codes; use when no bypass graft is present and disease is in the patient's own arteries