2027 ICD-10-CM Diagnosis Code I70.55Atherosclerosis of nonautologous biological bypass graft(s) of other extremity with ulceration

ICD-10-CM Codes›I00–I99›I70-I79›I70

ICD-10-CM I70.55
CMSSource: CMS FY 2027 ICD-10-CM dataset · Effective Oct 1, 2026 – Sep 30, 2027

I70.55 is a billable ICD-10-CM diagnosis code for atherosclerosis of nonautologous biological bypass graft(s) of other extremity with ulceration. It is valid on HIPAA claims for fiscal year 2027 (October 1, 2026 through September 30, 2027) and groups to MS-DRG 299 through 301. The code is restricted by the Medicare Code Editor to adult patients (age 15 through 124). In AHRQ's Clinical Classifications Software (CCSR), this diagnosis falls under Peripheral and visceral vascular disease.

For Medicare Advantage risk adjustment, I70.55 maps to CMS-HCC Category 263 (Atherosclerosis of Arteries of the Extremities with Ulceration or Gangrene) under the V28 model, adding a risk factor of about 1.118 for a community, non-dual, aged beneficiary in payment year 2027.

Code Identity

ICD-10-CM Code
I70.55
Billable Status
Yes — Valid for Submission
Code Describes
Atherosclerosis of nonautologous biological bypass graft(s) of other extremity with ulceration
Short Description
Athscl nonautologous bio bypass of extremity w ulceration
Parent Code
I70.5
Atherosclerosis of nonautologous biological bypass graft(s) of the extremities

Code Classification

ChapterI00–I99Diseases of the circulatory system
SectionI70-I79Diseases of arteries, arterioles and capillaries
CategoryI70Atherosclerosis
This CodeI70.55Atherosclerosis of nonautologous biological bypass graft(s) of other extremity with ulceration

Code EditsBilling

Medicare Code Editor checks that affect claim validity for I70.55.

Adult diagnoses
The Medicare Code Editor detects inconsistencies in adult cases by checking a patient's age and any diagnosis on the patient's record. The adult code edits apply to patients age range is 15–124 years inclusive (e.g., senile delirium, mature cataract).

Medicare Risk Adjustment (HCC)Billing

I70.55 maps to a payment category in the CMS-HCC model used to risk-adjust Medicare Advantage payments. Weights are the published community factors for payment year 2027.

CMS-HCC V28 Category (Payment Model)
HCC 263— Atherosclerosis of Arteries of the Extremities with Ulceration or Gangrene
Payment HCC · PY 2027 one of 127 ICD-10-CM codes in this category
Risk Adjustment Factor (RAF) Weight
+1.118
community, non-dual, aged · ranges 0.696–1.432 across segments
Hierarchy
Supersedes HCC 264, HCC 383, and HCC 409
less severe related categories are not paid alongside HCC 263
Prior Model (CMS-HCC V24)
HCC 106
V24 retired V28 pays 100% of MA risk scores since PY 2026
Other CMS Models
PACE (CMS-HCC V22): HCC 106 · PACE (CMS-HCC V22): HCC 161 · ESRD (V21): HCC 106 · ESRD (V21): HCC 161 · ESRD (V24): HCC 106 · ESRD (V24): HCC 161
ESRD V21 weights: 0.321 dialysis, 0.754–1.385 functioning graft · ESRD V21 weights: 0.119 dialysis, 0.225–0.503 functioning graft · ESRD V24 weights: 0.358 dialysis, 0.873–1.740 functioning graft · ESRD V24 weights: 0.127 dialysis, 0.243–0.782 functioning graft
Part D (RxHCC)
RxHCC 311 — Chronic Ulcer of Skin, Except Pressure
also risk-adjusts in the Part D prescription drug model (V08)

Source: CMS Payment Year 2027 risk adjustment mappings and model software. Weights are relative factors, not dollar amounts; a beneficiary's total RAF also includes demographics and interactions. Browse all CMS-HCC categories.

Instructional NotesGuidance

Instructions from the official ICD-10-CM Tabular List that apply to I70.55: its own notes plus those printed at I70.5, I70, and Chapter 9. A note printed at a category, block or chapter applies to every code under it.

Includes

Further defines, or gives examples of, the content of the category.

On I70.55 itself
From I70 Atherosclerosis applies to 246 codes
  • arteriolosclerosis
  • arterial degeneration
  • arteriosclerosis
  • arteriosclerotic vascular disease
  • arteriovascular degeneration
  • atheroma
  • endarteritis deformans or obliterans
  • senile arteritis
  • senile endarteritis
  • vascular degeneration

Excludes2

Not included here: the excluded condition is not part of this code, but a patient may have both, so both codes may be reported.

From I70 Atherosclerosis applies to 246 codes
  • arteriosclerotic cardiovascular disease (I25.1-)
  • arteriosclerotic heart disease (I25.1-)
  • atheroembolism (I75.-)
  • cerebral atherosclerosis (I67.2)
  • coronary atherosclerosis (I25.1-)
  • mesenteric atherosclerosis (K55.1)
  • precerebral atherosclerosis (I67.2)
  • primary pulmonary atherosclerosis (I27.0)
From Chapter 9 (I00-I99) Diseases of the circulatory system applies to 1,433 codes
  • certain conditions originating in the perinatal period (P04-P96)
  • certain infectious and parasitic diseases (A00-B99)
  • complications of pregnancy, childbirth and the puerperium (O00-O9A)
  • congenital malformations, deformations, and chromosomal abnormalities (Q00-Q99)
  • endocrine, nutritional and metabolic diseases (E00-E88)
  • injury, poisoning and certain other consequences of external causes (S00-T88)
  • neoplasms (C00-D49)
  • symptoms, signs and abnormal clinical and laboratory findings, not elsewhere classified (R00-R94)
  • systemic connective tissue disorders (M30-M36)
  • transient cerebral ischemic attacks and related syndromes (G45.-)

Use Additional Code

Add a second code, after this one, to fully describe the condition.

On I70.55 itself
  • code to identify severity of ulcer (L98.49)
From I70.5 Atherosclerosis of nonautologous biological bypass graft(s) of the extremities applies to 40 codes
  • code, if applicable, to identify chronic total occlusion of artery of extremity (I70.92)
From I70 Atherosclerosis applies to 246 codes
  • code to identify:
  • exposure to environmental tobacco smoke (Z77.22)
  • history of tobacco dependence (Z87.891)
  • occupational exposure to environmental tobacco smoke (Z57.31)
  • tobacco dependence (F17.-)
  • tobacco use (Z72.0)

Source: CMS ICD-10-CM Tabular List. How to read instructional notes.

Referenced in Other NotesGuidance

Instructional notes printed at other codes that name I70.55, its category, or a range that includes it.

Includes 1

These notes mention I70.55.

  • I70.56 Atherosclerosis of nonautologous biological bypass graft(s) of the extremities with gangrene
    any condition classifiable to I70.51-, I70.52-, and I70.53-, I70.54-, I70.55

Excludes1 3

These codes carry an Excludes1 note naming I70.55: they are not reported together with it, unless the two conditions are unrelated.

  • I77.6 Arteritis, unspecified
    deformans (I70.-) names I70.-, which includes this code
  • I77.6 Arteritis, unspecified
    obliterans (I70.-) names I70.-, which includes this code
  • I77.6 Arteritis, unspecified
    senile (I70.-) names I70.-, which includes this code

Code First 1

These codes say to code first a condition named in the note, and I70.55 is one of the conditions named.

  • I70.92 Chronic total occlusion of artery of the extremities
    atherosclerosis of arteries of the extremities (I70.2-, I70.3-, I70.4-, I70.5-, I70.6-, I70.7-) names I70.5-, which includes this code

Index to Diseases and InjuriesGuidance

Alphabetical index entries that point to this code.

Clinical ClassificationClinical

AHRQ’s CCSR groups this code into broader clinical categories.

CCSR CIR026
Peripheral and visceral vascular disease
Default principal diagnosis: inpatient Yes · outpatient Yes

Clinical InformationClinical

  • Atherosclerosis

    a thickening and loss of elasticity of the walls of arteries that occurs with formation of atherosclerotic plaques within the arterial intima.

Patient EducationClinical

Atherosclerosis

Atherosclerosis is a condition in which plaque builds up inside your arteries. Plaque is a sticky substance made up of cholesterol, fat, blood cells, calcium, and other substances found in the blood. Over time, plaque hardens and causes your arteries to narrow. That limits the flow of oxygen-rich blood to your body.

The full article covers:

  • What is atherosclerosis?
  • What causes atherosclerosis?
  • Who is more likely to develop atherosclerosis?
  • What are the symptoms of atherosclerosis?
  • What other problems can atherosclerosis cause?
  • How is atherosclerosis diagnosed?
  • What are the treatments for atherosclerosis?
  • Can atherosclerosis be prevented?

Read the full article at MedlinePlus

Courtesy of MedlinePlus, a service of the U.S. National Library of Medicine.

Convert I70.55 to ICD-9-CMHistory

The closest ICD-9-CM equivalents under the General Equivalence Mappings.

ICD-9-CM
440.32 Ath ext nonautlg bps gft
ApproximateCombination The match is approximate, and more than one code can be needed to describe the source diagnosis. Confirm with contextual judgment.
ICD-9-CM
707.8 Chronic skin ulcer NEC
ApproximateCombination The match is approximate, and more than one code can be needed to describe the source diagnosis. Confirm with contextual judgment.

Code HistoryHistory

FY 2016AddedAdded to the ICD-10-CM code setEffective October 1, 2015, the first year of ICD-10-CM.
FY 2017–2026No changes
FY 2027CurrentCurrent code set, no changesEffective October 1, 2026 through September 30, 2027.

Questions About I70.55Overview

Is I70.55 a billable code?

Yes. This is a billable ICD-10-CM code, specific enough to report atherosclerosis of nonautologous biological bypass graft(s) of other extremity with ulceration on HIPAA-covered claims from October 1, 2026 through September 30, 2027.

What MS-DRG does I70.55 group to?

When atherosclerosis of nonautologous biological bypass graft(s) of other extremity with ulceration is the principal diagnosis on an inpatient stay, it groups to MS-DRG 301, 300, 299, with relative weights from 0.7132 to 1.5840 depending on complications. Higher weights mean higher Medicare reimbursement.

Who can I70.55 be reported for?

The Medicare Code Editor checks atherosclerosis of nonautologous biological bypass graft(s) of other extremity with ulceration against patient demographics: this code is intended for adult patients (age 15 through 124). Claims outside these limits are flagged as inconsistent.

Does I70.55 need an additional code?

When the condition applies, yes. The Use Additional Code note reads: code to identify severity of ulcer (L98.49). The additional code is reported after I70.55.

What is the ICD-9 equivalent of I70.55?

Under the General Equivalence Mappings, atherosclerosis of nonautologous biological bypass graft(s) of other extremity with ulceration converts to ICD-9-CM 440.32 (ath ext nonautlg bps gft) and 707.8 (chronic skin ulcer NEC). The mapping is approximate, so confirm the match fits the documentation.

What HCC is I70.55?

I70.55 (atherosclerosis of nonautologous biological bypass graft(s) of other extremity with ulceration) maps to CMS-HCC Category 263 (Atherosclerosis of Arteries of the Extremities with Ulceration or Gangrene), commonly written as HCC 263, in the CMS-HCC V28 model used for Medicare Advantage risk adjustment in payment year 2027. It mapped to HCC 106 under the retired V24 model. It also maps in the PACE (CMS-HCC V22), ESRD (V21), and ESRD (V24) models. In the Part D prescription drug model it maps to RxHCC 311.

Does I70.55 risk-adjust for Medicare Advantage payment?

Yes. When documented and reported on a Medicare Advantage encounter, I70.55 adds a risk adjustment factor of about 1.118 to the beneficiary's RAF score for a community, non-dual, aged enrollee (published V28 weights range from 0.696 to 1.432 depending on the payment segment). HCC 263 sits at the top of its hierarchy, so no other condition category supersedes it. See the full factor table on the HCC 263 category page.