What is ICD-10 code I71.010?

I71.010 is the ICD-10-CM diagnosis code for Dissection of ascending aorta. A tear in the wall of the ascending aorta (the main artery leaving the heart) where the inner and outer layers separate. It belongs to the ICD-10-CM chapter for diseases of the circulatory system (i00-i99). I71.010 is a billable code, meaning it can be reported on a claim as a primary or secondary diagnosis when supported by documentation. I71.010 is part of the FY2026 ICD-10-CM code set published by the CMS National Center for Health Statistics and used on Medicare, Medicaid, and commercial claims in the United States.

Yes. I71.010 is a billable ICD-10-CM code that can be reported on professional and institutional claims as a primary or secondary diagnosis when the provider documentation supports the specific condition described. Billable codes in ICD-10-CM are coded to the highest level of specificity available for the documented diagnosis. I71.010 is current for fiscal year 2026 and remains in the active CMS ICD-10-CM code set published by the National Center for Health Statistics.

Which HCC does I71.010 map to under V28?

I71.010 maps to CMS-HCC V28 HCC 264 (Vascular Disease with Complications). The category numbers, labels, and conditions come from the CMS-HCC V28 model file for payment year 2026.

2026 ICD-10-CM I71.010: Dissection of ascending

I71.010 maps to CMS-HCC V28 264. A source-labeled RAF reference is available. Confirm the documented diagnosis and applicable coding requirements. MEAT criteria · RAF Calculator · free HCC coding tools

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Code lookupI71.010

Effective periodFY2026 Apr Update (Apr 1-Sep 30)

FY 2026 Apr update / Diseases of the circulatory system (I00-I99) / Diseases of arteries, arterioles and capillaries (I70-I79)

I71.010

Billable / SpecificICD-10-CMOfficial ICD-10-CMCodebook guidance

Dissection of ascending aorta

A tear in the wall of the ascending aorta (the main artery leaving the heart) where the inner and outer layers separate.

Buddy Insight

Overview Risk Models Code Book Documentation Audit Notes Edition comparison

CMS-HCC V28

Mapped

HCC 264

Vascular Disease with Complic...

Code-level coefficient reference

CMS-HCC V24

Historical

Not used for standard CY2026 Medicare Advantage payment. Select a historical period to review V24.

Not used for CY2026 payment

ACA/HHS

Mapped

HCC 154

HHS-HCC 154 adult, RAF varies...

Code-level coefficient reference

ESRD/PACE

Mapped

HCC 107

Vascular Disease with Complic...

Code-level coefficient reference

RXHCC

N/A

—

Not risk-adjusted for this model/period.

Not mapped

Code Book Path

Official

I71.0Dissection of aorta I71.01Dissection of thoracic aorta I71.010Dissection of ascending aorta

Inclusion Terms

Official

No inclusion terms are included in this display for I71.010. Check the code and parent instructions in the Code Book.

Excludes 2

Official

certain conditions originating in the perinatal period (P04-P96)Inherited from I00-I99
certain infectious and parasitic diseases (A00-B99)Inherited from I00-I99
complications of pregnancy, childbirth and the puerperium (O00-O9A)Inherited from I00-I99
congenital malformations, deformations, and chromosomal abnormalities (Q00-Q99)Inherited from I00-I99
endocrine, nutritional and metabolic diseases (E00-E88)Inherited from I00-I99
injury, poisoning and certain other consequences of external causes (S00-T88)Inherited from I00-I99
neoplasms (C00-D49)Inherited from I00-I99
symptoms, signs and abnormal clinical and laboratory findings, not elsewhere classified (R00-R94)Inherited from I00-I99
systemic connective tissue disorders (M30-M36)Inherited from I00-I99
transient cerebral ischemic attacks and related syndromes (G45.-)Inherited from I00-I99

Related Codes

Official

I71.011Dissection of aortic arch I71.012Dissection of descending thoracic aorta I71.019Dissection of thoracic aorta, unspecified

Includes

Official

No Includes notes are included in this display for I71.010. Check the code and parent instructions in the Code Book.

Excludes 1

Official

No Excludes 1 notes are included in this display for I71.010. Check the code and parent instructions in the Code Book.

Code First

Official

, if applicable:Inherited from I71
syphilitic aortic aneurysm (A52.01)Inherited from I71
traumatic aortic aneurysm (S25.09, S35.09)Inherited from I71

Use Additional

Official

No Use Additional Code instructions are included in this display for I71.010. Check the code and parent instructions in the Code Book.

Code Also

Official

No Code Also instructions are included in this display for I71.010. Check the code and parent instructions in the Code Book.

Buddy Documentation Tip

HCC Buddy guidance

Aortic dissection explicitly documented at the ascending aorta

Classification type documented when possible (Stanford Type A or B, DeBakey I, II, or III)

Imaging confirmation (CT angiography, MRI, transesophageal echocardiography, or surgical findings)

Acute vs. chronic status clarified — this code may be used for both, but clinical context should be clear

MEAT Support

HCC Buddy guidance

Aortic dissection explicitly documented at the ascending aorta

Classification type documented when possible (Stanford Type A or B, DeBakey I, II, or III)

Imaging confirmation (CT angiography, MRI, transesophageal echocardiography, or surgical findings)

Acute vs. chronic status clarified — this code may be used for both, but clinical context should be clear

Audit Caution

HCC Buddy guidance

Confusing aortic dissection with aortic aneurysm — dissection involves intimal tear with false lumen formation, while aneurysm is dilation of the vessel; they can coexist but are distinct diagnoses

Failing to specify the anatomical site of dissection when documented — ascending, arch, descending thoracic, abdominal, and thoracoabdominal each have distinct codes

Not distinguishing between acute and chronic (healed) dissection in the documentation — both map the same but clinical management differs significantly

Missing associated complications that warrant additional codes (aortic regurgitation, malperfusion, hemopericardium)

Common Mistakes

HCC Buddy guidance

I71.10-I71.13 — Thoracic aortic aneurysm, ruptured (aneurysm rupture is different from dissection — though they can coexist)

I71.20-I71.23 — Thoracic aortic aneurysm, without rupture (aneurysm without dissection)

I71.30-I71.33 — Abdominal aortic aneurysm, ruptured (different condition — rupture vs. dissection)

I77.810-I77.812 — Aortic ectasia (dilation without aneurysm or dissection)

Current with CMS: FY2026 ICD-10-CM Apr 1 update (effective Apr 1 – Sep 30, 2026) · CMS-HCC V28, 100% phased in for payment year 2026. FY2027 code set already staged for October 1, 2026. How HCC Buddy stays current →

Is I71.010 an HCC code?

Yes. I71.010 (Dissection of ascending aorta) maps to HCC 264, Vascular Disease with Complications under the CMS-HCC V28 risk adjustment model, with a source-labeled community non-dual aged reference coefficient of 0.455. Source-labeled code-level coefficients are references, not member totals. Actual contribution depends on complete member context, hierarchy and cleanup rules, interactions, and model year. HCC Buddy's RAF Calculator supports CMS-HCC V28 PY2026 and shows no score unless every required source and calculation check passes. It is billable for payment year 2026.

Coder answer: I71.010 is billable and maps to V28 HCC 264, Vascular Disease with Complications. Open it in the Code Book for the tabular path, RAF, and MEAT checklist.

Code: I71.010
Description: Dissection of ascending aorta
HCC (V28): HCC 264 — Vascular Disease with Complications
RAF reference coefficient: 0.455
Billable: Yes
Payment year: 2026

HCC Category Mapping

V28HCC 264, Vascular Disease with Complications

0.455

ESRDHCC 107, Vascular Disease with Complications

Not separately weighted

These are source-labeled model coefficients, not member totals. A category may still be removed by hierarchy or model cleanup rules. Weights are not directly comparable across models: CMS-HCC V28 and V24 use Community, Non-Dual, Aged; ESRD uses the dialysis continuing-enrollee model; RxHCC is the Part D continuing-enrollee, non-low-income, aged weight (a larger scale than CMS-HCC). ACA/HHS has no single weight — it varies by metal level. Actual per-patient RAF contribution depends on member context, hierarchy and cleanup rules, interactions, and the model year used by the payer. V28 is the CMS-HCC model phased in over payment years 2024–2026; V24 remains available for historical review.

Work I71.010 in the Code Book — tabular path, V28 RAF reference, and MEAT checklist →

MEAT review for I71.010

For I71.010, confirm that the documentation supports the diagnosis and meets the applicable coding, encounter, program and payer requirements. MEAT (Monitor, Evaluate, Assess, or Treat) is a review mnemonic, not a universal CMS coding rule.

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

Coder workflow notes

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What This Code Means

I71.010 is the ICD-10-CM diagnosis code for dissection of ascending aorta. A tear in the wall of the ascending aorta (the main artery leaving the heart) where the inner and outer layers separate. I71.010 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, I71.010 maps to Vascular Disease with Complications (HCC 264) with a source-labeled community, non-dual, aged reference coefficient of 0.455. No V24 mapping is shown for I71.010; use the applicable model and payment year when reviewing the V28 mapping. For CY2026 non-PACE Medicare Advantage, CMS uses 100% of the 2024 CMS-HCC model (V28). PACE uses a separate model blend. Source-labeled code-level coefficients are references, not member totals. Actual contribution depends on complete member context, hierarchy and cleanup rules, interactions, and model year. HCC Buddy's RAF Calculator supports CMS-HCC V28 PY2026 and shows no score unless every required source and calculation check passes.

This is a specific dissection of the ascending aorta; do not use unspecified codes if the location is documented. For I71.010, confirm that the documentation supports the diagnosis and meets the applicable coding, encounter, program and payer requirements. MEAT (Monitor, Evaluate, Assess, or Treat) is a review mnemonic, not a universal CMS coding rule. 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, source-labeled coefficient references, and MEAT documentation criteria for I71.010 sourced directly from the CMS-HCC risk adjustment model files and the CMS ICD-10-CM code set.

Coding Tips

•This is a specific dissection of the ascending aorta; do not use unspecified codes if the location is documented
•Dissections are acute emergencies requiring immediate imaging confirmation and documentation of extent

Clinical Significance

Dissection of the ascending aorta is a life-threatening emergency where a tear in the aortic intima allows blood to enter the vessel wall, creating a false lumen that can propagate and compromise branch vessel perfusion. Aortic dissection carries high mortality without prompt diagnosis and treatment, and survivors require lifelong surveillance for aneurysm development, re-dissection, and end-organ damage. This is a high-acuity diagnosis that significantly impacts risk adjustment, reflecting the intensive acute care and ongoing management these patients require.

Documentation Requirements

✓Aortic dissection explicitly documented at the ascending aorta
✓Classification type documented when possible (Stanford Type A or B, DeBakey I, II, or III)
✓Imaging confirmation (CT angiography, MRI, transesophageal echocardiography, or surgical findings)
✓Acute vs. chronic status clarified — this code may be used for both, but clinical context should be clear
✓Extent of dissection (which segments of aorta are involved)
✓Complications documented (malperfusion syndrome, aortic regurgitation, pericardial effusion, end-organ ischemia)
✓Current management plan (medical, endovascular, or open surgical repair)

Commonly Confused Codes

•I71.10-I71.13: Thoracic aortic aneurysm, ruptured (aneurysm rupture is different from dissection: though they can coexist)
•I71.20-I71.23: Thoracic aortic aneurysm, without rupture (aneurysm without dissection)
•I71.30-I71.33: Abdominal aortic aneurysm, ruptured (different condition: rupture vs. dissection)
•I77.810-I77.812: Aortic ectasia (dilation without aneurysm or dissection)