I77.70 ICD-10-CM Code: Dissection of unspecified artery

Coding instructions

Official Tabular Instructional Notes: the inclusion, exclusion and sequencing notes published for I77.70 in the official ICD-10-CM tabular list, quoted as published.

Source: CMS/CDC — ICD-10-CM Tabular ListRelease: FY2027Effective: October 1, 2026

Trace:FY2027 changesChange historyRelease, file and checksum

Notes without a marker are published on I77.70 itself; “inherited from” names the category or block whose note applies here.

Don’t confuse I77.70 with…

MedCoder analysis — pairs from this code’s official notes, distinctions written by MedCoder

The codes most likely to be picked instead of I77.70 — named in its own official notes, or sharing its laterality or encounter family — with what separates them and which documentation moves the case. Each links to the full comparison.

• I71.0— Excludes2 relationship (Informational)

  Distinct conditions — both may be reported.

  A distinct condition — both may be reported when both are documented.

  What moves you there: Documentation of dissection of aorta adds I71.0; it is not part of this code and both may be reported when both are documented.

  Full comparison: I77.70 vs I71.0 →

• I25.42— Excludes2 relationship (Informational)

  Distinct conditions — both may be reported.

  A distinct condition — both may be reported when both are documented.

  What moves you there: Documentation of dissection of coronary artery adds I25.42; it is not part of this code and both may be reported when both are documented.

  Full comparison: I77.70 vs I25.42 →

• M30— Excludes2 relationship (Informational)

  Distinct conditions — both may be reported.

  A distinct condition — both may be reported when both are documented.

  What moves you there: Documentation of collagen (vascular) diseases adds M30; it is not part of this code and both may be reported when both are documented.

  Full comparison: I77.70 vs M30 →

• M36— Excludes2 relationship (Informational)

  Distinct conditions — both may be reported.

  A distinct condition — both may be reported when both are documented.

  What moves you there: Documentation of collagen (vascular) diseases adds M36; it is not part of this code and both may be reported when both are documented.

  Full comparison: I77.70 vs M36 →

• M31.0— Excludes2 relationship (Informational)

  Distinct conditions — both may be reported.

  A distinct condition — both may be reported when both are documented.

  What moves you there: Documentation of hypersensitivity angiitis adds M31.0; it is not part of this code and both may be reported when both are documented.

  Full comparison: I77.70 vs M31.0 →

• I28— Excludes2 relationship (Informational)

  Distinct conditions — both may be reported.

  A distinct condition — both may be reported when both are documented.

  What moves you there: Documentation of pulmonary artery adds I28; it is not part of this code and both may be reported when both are documented.

  Full comparison: I77.70 vs I28 →

Relationships are read from this code's own official notes, its laterality siblings and its encounter family; the wording of each distinction is MedCoder editorial, and the documentation named in each “what moves you there” line is the official note phrase or sibling title itself. Source: CMS ICD-10-CM tabular instructional notes; ICD-10-CM Official Guidelines, Section I.A.12.a.

Indexed Clinical Terms (1)

Official source data — entries quoted as published, in the Index’s own lookup phrasing

Clinical term phrases from the official ICD-10-CM Index to Diseases and Injuries that map to this code. These are alphabetic-index entries shown as the Index writes them — lookup phrasing, not necessarily the wording of a final diagnosis.

• Dissection, artery

Relationships & Classification

MedCoder-derived relationships — computed from published CMS and AHRQ datasets

MS-DRG Grouper Relationships (FY2027)

Potential MS-DRG participation — not a DRG assignment.

FY2027 MS-DRG: MCC — Major Complication or Comorbidity. Reported as a secondary diagnosis, this code raises the stay's MS-DRG severity tier — except when the principal diagnosis is one of 10 clinically related codes on its CMS exclusion list.

Named in the grouper logic of 3 MS-DRGs: DRG 299 (MDC 05), DRG 300 (MDC 05), DRG 301 (MDC 05).

From the CMS MS-DRG Definitions Manual (Appendices B and C). Actual DRG assignment depends on the complete claim.

Clinical classification (AHRQ CCSR):CIR027 — Arterial dissections (default).

Clinical Classifications Software Refined (CCSR) for ICD-10-CM Diagnoses. Healthcare Cost and Utilization Project (HCUP), Agency for Healthcare Research and Quality.

Related Codes

Same clinical process (MS-DRG)

Acts as MCC — raises the severity of other admissions. CMS groups these diagnoses into one MS-DRG principal-diagnosis exclusion process — a CC/MCC on this list never raises severity when the principal diagnosis is also on it.

I77.2 — Rupture of artery, I77.3 — Arterial fibromuscular dysplasia, I77.5 — Necrosis of artery, I77.6 — Arteritis, unspecified, I77.82 — Antineutrophilic cytoplasmic antibody [ANCA] vasculitis, I77.89 — Other specified disorders of arteries and arterioles, I77.9 — Disorder of arteries and arterioles, unspecified, M31.8 — Other specified necrotizing vasculopathies, M31.9 — Necrotizing vasculopathy, unspecified

Same clinical category (CCSR)

AHRQ's Clinical Classifications Software groups these diagnoses under the same clinical category (Arterial dissections).

I25.42 — Coronary artery dissection, I67.0 — Dissection of cerebral arteries, nonruptured, I71.00 — Dissection of unspecified site of aorta, I71.01 — Dissection of thoracic aorta, I71.010 — Dissection of ascending aorta, I71.011 — Dissection of aortic arch, I71.012 — Dissection of descending thoracic aorta, I71.019 — Dissection of thoracic aorta, unspecified, I71.02 — Dissection of abdominal aorta, I71.03 — Dissection of thoracoabdominal aorta, I77.71 — Dissection of carotid artery, I77.72 — Dissection of iliac artery, I77.73 — Dissection of renal artery, I77.74 — Dissection of vertebral artery, I77.75 — Dissection of other precerebral arteries, I77.76 — Dissection of artery of upper extremity, I77.77 — Dissection of artery of lower extremity, I77.79 — Dissection of other specified artery

Same Index main term, other category

The ICD-10-CM Index to Diseases and Injuries files this code under the main term “Dissection”; these codes share that main term but sit in a different category of the Tabular List.

I25.42 — Coronary artery dissection (artery, coronary), I67.0 — Dissection of cerebral arteries, nonruptured (artery, cerebral), I71.00 — Dissection of unspecified site of aorta (aorta), I71.010 — Dissection of ascending aorta (aorta, thoracic, ascending aorta), I71.011 — Dissection of aortic arch (aorta, thoracic, aortic arch), I71.012 — Dissection of descending thoracic aorta (aorta, thoracic, descending thoracic aorta), I71.019 — Dissection of thoracic aorta, unspecified (aorta, thoracic), I71.02 — Dissection of abdominal aorta (aorta, abdominal), I71.03 — Dissection of thoracoabdominal aorta (aorta, thoracoabdominal), I99.8 — Other disorder of circulatory system (vascular), Q28.1 — Other malformations of precerebral vessels (precerebral artery, congenital)

Lab tests where this diagnosis supports Medicare coverage (NCD)

Medicare's National Coverage Determination (NCD) program lists this diagnosis as medical justification for these lab tests.

Lipid Panel

Contextual Map

Every relationship of I77.70 in one view: hierarchy, official tabular instructions in both directions, clinical classification, risk adjustment, MS-DRG participation, index terms and change history — each edge carrying the CMS source it derives from.

Hierarchy

• I00-I99 — Chapter 9: Diseases of the Circulatory System (I00-I99) (I00-I99)[Hierarchy]— CMS ICD-10-CM tabular structure · icd10cm-fy2027
• I70-I79 — Diseases of arteries, arterioles and capillaries[Hierarchy]— CMS ICD-10-CM tabular structure · icd10cm-fy2027

Clinical classification (CCSR)

• CIR027 — Arterial dissections[CCSR]— AHRQ CCSR for ICD-10-CM Diagnoses (HCUP)

MS-DRG Grouper

• MCC — Major Complication or Comorbidity [MS-DRG severity]: “As a secondary diagnosis this code can raise the stay's MS-DRG severity tier (MCC).”— CMS MS-DRG Definitions Manual (Appendix C) · FY2027
• DRG 299 — PERIPHERAL VASCULAR DISORDERS WITH MCC[MS-DRG]: “PERIPHERAL VASCULAR DISORDERS WITH MCC (MDC 05)”— CMS MS-DRG Definitions Manual (Appendix B) · FY2027
• DRG 300 — PERIPHERAL VASCULAR DISORDERS WITH CC[MS-DRG]: “PERIPHERAL VASCULAR DISORDERS WITH CC (MDC 05)”— CMS MS-DRG Definitions Manual (Appendix B) · FY2027
• DRG 301 — PERIPHERAL VASCULAR DISORDERS WITHOUT CC/MCC[MS-DRG]: “PERIPHERAL VASCULAR DISORDERS WITHOUT CC/MCC (MDC 05)”— CMS MS-DRG Definitions Manual (Appendix B) · FY2027

MDC crossing

• MDC 05 — Diseases and Disorders of the Circulatory System[MDC crossing]: “Diseases and Disorders of the Circulatory System — the grouper's crossing between diagnoses and procedures: a principal diagnosis sets the MDC, and same-MDC procedures move the stay to its surgical DRGs. 15,708 same-MDC procedures group here; browse them on the MDC page.”— CMS MS-DRG Definitions Manual · FY2027

Index entries

• Dissection, artery[Index term]— CMS ICD-10-CM Index to Diseases and Injuries · icd10cm-fy2027

Nearest codes (26)

• I77 — Other disorders of arteries and arterioles[Sibling]— CMS ICD-10-CM tabular structure · icd10cm-fy2027
• I77.0 — Arteriovenous fistula, acquired[Sibling]— CMS ICD-10-CM tabular structure · icd10cm-fy2027
• I77.1 — Stricture of artery[Sibling]— CMS ICD-10-CM tabular structure · icd10cm-fy2027
• I77.2 — Rupture of artery[Sibling]— CMS ICD-10-CM tabular structure · icd10cm-fy2027
• I77.3 — Arterial fibromuscular dysplasia[Sibling]— CMS ICD-10-CM tabular structure · icd10cm-fy2027
• I77.4 — Celiac artery compression syndrome[Sibling]— CMS ICD-10-CM tabular structure · icd10cm-fy2027
• I77.5 — Necrosis of artery[Sibling]— CMS ICD-10-CM tabular structure · icd10cm-fy2027
• I77.6 — Arteritis, unspecified[Sibling]— CMS ICD-10-CM tabular structure · icd10cm-fy2027
• and 18 more

Change history

• FY2017 — Added to the code set[Change history]— CMS release files (code change ledger) · icd10cm-fy2017

Sources for this page

Codes, titles, notes, index terms and mappings on this page are transcribed from the datasets below. Relationships MedCoder computed and text MedCoder wrote are labelled where they appear.

Code, title, tabular notes and index terms Official source data

CMS/CDC ICD-10-CM FY2027 tabular list, index and tables, effective October 1, 2026 Release, file and checksum · Publisher’s page

Claim edits Official source data

CMS Definitions of Medicare Code Edits — v44.0 (October 2026) Release, file and checksum · Publisher’s page

Inpatient payment groups Official source data

CMS MS-DRG Definitions Manual (incl. Appendix B diagnosis index, Appendix C CC/MCC list, Appendix E procedure index) and IPPS Final Rule tables — v44 Release, file and checksum · Publisher’s page

Change history and date-of-service validity Official source data

CMS ICD-10-CM release addenda, ingested release by release into the change ledger Release, file and checksum · Publisher’s page

Comparisons, relationships and the contextual map MedCoder-derived relationship

Computed by MedCoder from the tabular notes and tables above; every derived relationship is marked as derived where it appears

Summary and FAQ answers MedCoder editorial explanation

Written by MedCoder to explain the sources above: drafted with AI assistance, checked by a person against the release files, and labelled as MedCoder text where it appears. Not official text.

Current data releases:ICD-10-CM FY2027 · ICD-10-PCS FY2027 · HCPCS October 2026 · MS-DRG v44 · Medicare Code Editor v44.0 · NCCI PTP Q4 2026 · MUE Q4 2026 · NCD code lists 2026-01 · LCD export September 20, 2026 · All releases and sources

Labels on this page: Official source data · MedCoder-derived relationship · MedCoder editorial explanation. How to read the labels · All data sources and release dates · CMS coding rules

Nearest Codes in This Family

Official ICD-10-CM classifications closest to I77.70 in its code family, with their registry titles.

• I77.3 — Arterial fibromuscular dysplasia
• I77.4 — Celiac artery compression syndrome
• I77.5 — Necrosis of artery
• I77.6 — Arteritis, unspecified
• I77.7 — Other arterial dissection
• I77.71 — Dissection of carotid artery
• I77.72 — Dissection of iliac artery
• I77.73 — Dissection of renal artery
• I77.74 — Dissection of vertebral artery
• I77.75 — Dissection of other precerebral arteries

View all codes in the I77 family