I74.9
BillableEmbolism and thrombosis of unspecified artery
Last updated: FY2026 ICD-10-CM (Oct 1, 2025 – Sep 30, 2026) | CMS-HCC V28 (100% phase-in, PY2026)
Is I74.9 an HCC code?
Yes. I74.9 maps to Vascular Disease with Complications under the CMS-HCC V28 risk adjustment model (and Vascular Disease with Complications under V24).
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 I74.9
For I74.9to 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 I74.9 during that encounter — not just copy-forwarded from a problem list.
What This Code Means
I74.9 is the ICD-10-CM diagnosis code for embolism and thrombosis of unspecified artery. A blood clot has formed in an artery somewhere in the body, but the specific artery location is not documented. This condition blocks blood flow and can be life-threatening depending on which artery is affected. I74.9 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, I74.9 maps to Vascular Disease with Complications (HCC 264) with a community, non-dual, aged base RAF weight of 0.356. Under the older V24 model, I74.9 mapped to the same category but with a base RAF weight of 0.450 — 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.
Avoid using this unspecified code when possible; query the provider to identify the specific artery involved (e.g., I74.0 for aorta, I74.1 for iliac artery) for more accurate coding. Because I74.9 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 I74.9 sourced directly from the CMS-HCC risk adjustment model files and the CMS ICD-10-CM code set.
Coding Tips
- •Avoid using this unspecified code when possible; query the provider to identify the specific artery involved (e.g., I74.0 for aorta, I74.1 for iliac artery) for more accurate coding
- •This code should only be used when documentation truly does not specify the artery location; check all clinical notes, imaging reports, and provider documentation before defaulting to the unspecified code
Clinical Significance
Embolism and thrombosis of unspecified artery indicates an acute arterial occlusive event where the specific artery has not been documented. While this still captures the vascular complication for risk adjustment, the lack of specificity should prompt a thorough review of all available documentation to identify the affected vessel. Acute arterial occlusion is always a significant clinical event.
Documentation Requirements
- ✓Documentation of arterial embolism or thrombosis
- ✓Attempt to determine the specific artery from imaging, operative, or clinical notes
- ✓Clinical presentation of acute arterial occlusion
- ✓Query provider for vessel specification
- ✓Treatment documentation
- ✓Source evaluation when applicable
Commonly Confused Codes
- •I74.2 — Embolism and thrombosis of arteries of the upper extremities: use when upper extremity artery is specified
- •I74.3 — Embolism and thrombosis of arteries of the lower extremities: use when lower extremity artery is specified
- •I74.8 — Embolism and thrombosis of other arteries: use when artery is named but not elsewhere classified
- •I82.90 — Acute embolism and thrombosis of unspecified vein: venous, not arterial